AutoCad Mechanical 2000 Tutorial

AUTOCAD Mechanical 2000



Tutorials

17320-010000-5080

June 28, 1999

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Content Introduction...................................................................................................... 1 Prerequisites...........................................................................................................2 How the Tutorials Are Organized..........................................................................2 Methods for Accessing AutoCAD Mechanical Commands ..................................2 Styles for Different Input Actions .........................................................................3 Chapter 1: Working with Templates ............................................................... 5 Key Terms ..............................................................................................................6 Working with Templates .......................................................................................7 Getting Started ...................................................................................................7 Setting Up the Starting Layer.............................................................................8 Setting the Mechanical Options ........................................................................9 Specifying the Drawing Limits.........................................................................10 Saving a Template ............................................................................................10 Using a Template .............................................................................................11 Chapter 2: Extending the Design of a Lever ................................................. 13 Key Terms ............................................................................................................14 Extending the Design ..........................................................................................15 Getting Started .................................................................................................15 Preliminary Settings: Snap Configuration .......................................................16 Creating Construction Lines (C-Lines) ............................................................17 Creating additional C-Lines.............................................................................19 Creating a Contour and Applying a Fillet .......................................................22 Creating a Contour and Trimming Projecting Edges ......................................24 Cross-Hatching the Lever.................................................................................26 Dimensioning the Lever ..................................................................................27 Creating a Detail and Additional Dimensions ................................................29 Chapter 3: Dimensioning and Annotations.................................................. 33 Key Terms ............................................................................................................34 Dimensioning ......................................................................................................36 Automatic Dimensioning ................................................................................36 Editing Dimensions with Power Commands ..................................................39 Inserting Annotations ......................................................................................43 Inserting a Drawing Border..............................................................................46

Contents

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Chapter 4: Working with Layers and Layer Groups..................................... 49 Key Terms ............................................................................................................50 Working with Layers and Layer Groups .............................................................51 Understanding Layer Management .................................................................51 Getting Started .................................................................................................51 Changing a Layer By Selecting Objects ...........................................................52 Creating Layer Groups .....................................................................................53 Using a Layer Group to Copy Objects .............................................................58 Chapter 5: Working with a Bill of Material and a Parts List ....................... 61 Key Terms ............................................................................................................62 Inserting a Part Reference ................................................................................63 Placing Balloons ...............................................................................................66 Creating a Parts List .........................................................................................71 Merging and Splitting Items in a Parts List .....................................................75 Collecting Balloons ..........................................................................................77 Sorting and Renumbering Items on a Parts List ..............................................79 Using Filters......................................................................................................81 Chapter 6: Working with Model Space and Layouts.................................... 85 Key Terms ............................................................................................................86 Working with Model Space and Layouts ............................................................87 Getting Started .................................................................................................87 Creating a Scale Area........................................................................................88 Creating a Detail ..............................................................................................90 Generating a New Viewport.............................................................................91 Inserting an User Through Hole ......................................................................93 Creating a Subassembly in a New Layout........................................................97 Chapter 7: Designing a Cam ........................................................................ 103 Key Terms ..........................................................................................................104 Cam Design .......................................................................................................105 Getting Started ...............................................................................................105 Configuring the Cam Plate Calculations.......................................................106 Creating Movement Sections.........................................................................108 Creating Velocity and Acceleration Curves...................................................110 Creating Cam Geometry from the Graph .....................................................111 Creating NC Data...........................................................................................112

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Contents

Chapter 8: Calculating Moment of Inertia and Deflection Line ............... 115 Key Terms ..........................................................................................................116 Calculating Moment of Inertia and Deflection Line ..........................................117 Getting Started ...............................................................................................117 Calculating the Moment of Inertia................................................................118 Calculating the Deflection Line.....................................................................119 Chapter 9: Creating a Shaft With Standard Parts....................................... 125 Key Terms ..........................................................................................................126 Creating a Shaft with Standard Parts ................................................................127 Configuring the Snap Options ......................................................................127 Starting and Configuring the Shaft Generator ..............................................127 Creating Cylindrical Shaft Sections and Gears..............................................129 Inserting a Spline Profile................................................................................130 Inserting a Chamfer and a Fillet ....................................................................131 Inserting a Shaft Break ...................................................................................132 Creating a Side View of the Shaft ..................................................................133 Inserting a Thread ..........................................................................................134 Editing and Inserting a Shaft Section ............................................................134 Replacing a Shaft Section ...............................................................................136 Inserting a Bearing .........................................................................................137 Chapter 10: Performing a Shaft Calculation............................................... 139 Key Terms ..........................................................................................................140 Performing a Shaft Calculation .........................................................................141 Getting Started ...............................................................................................141 Creating the Contour of a Shaft ....................................................................142 Specifying the Material ..................................................................................143 Placing the Supports ......................................................................................143 Specifying the Loads ......................................................................................144 Calculating the Shaft and Inserting the Results ............................................147 Chapter 11: Working with Standard Parts.................................................. 149 Key Terms ..........................................................................................................150 Working with Standard Parts ............................................................................151 Getting Started ...............................................................................................151 Inserting a Screw Connection........................................................................152 Copying a Screw Connection with Power Copy ...........................................157 Using Power Recall and Performing a Screw Calculation .............................158 Editing a Screw Connection with Power Edit................................................164 Working with Power View .............................................................................166 Deleting with Power Erase .............................................................................168

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Inserting a Hole..............................................................................................169 Inserting a Pin ................................................................................................171 Hiding C-Lines ...............................................................................................172 Simplifying the Representation of Standard Parts.........................................173 Chapter 12: Chain Calculation .................................................................... 175 Key Terms ..........................................................................................................176 Chain Calculation .............................................................................................177 Getting Started ...............................................................................................177 Performing a Length Calculation ..................................................................178 Optimizing the Chain Length .......................................................................180 Inserting Sprockets.........................................................................................181 Inserting a Chain ...........................................................................................184 Chapter 13: Calculating a Spring ................................................................ 187 Key Terms ..........................................................................................................188 Calculating a Spring ..........................................................................................189 Getting Started ...............................................................................................189 Starting the Spring Calculation .....................................................................190 Specifying the Spring Layout .........................................................................192 Calculating and Selecting the Spring.............................................................196 Inserting the Spring .......................................................................................196 Copying the Spring with Power Copy ...........................................................197 Editing the Spring with Power Edit ...............................................................198 Chapter 14: Using FEA to Calculate Stress .................................................. 201 Key Terms ..........................................................................................................202 2D FEA ...............................................................................................................203 Getting Started ...............................................................................................203 Calculating the Stress in a Lever ....................................................................203 Defining Loads and Supports.........................................................................205 Calculating the Results ..................................................................................207 Evaluating and Refining the Mesh ................................................................208 Improving the Design ....................................................................................210 Recalculating the Stress..................................................................................211

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Contents

Introduction

In This Chapter

Learning how to use AutoCAD Mechanical

„

Prerequisites

2000 for all your mechanical design needs is

„

How the tutorials are organized

„

Methods for accessing AutoCAD Mechanical 2000 commands

„

Styles for different input actions

exciting. This book contains a series of tutorials to teach you how to use AutoCAD Mechanical 2000. The tutorials provide a comprehensive overview of the mechanical design process as well. Drawing files have been included with the program specifically for the tutorials. These drawing files provide the initial state for starting the tutorial exercises.

1

Prerequisites Installing AutoCAD Mechanical 2000 with typical or full installation, the tutorial drawings will automatically be installed. Selecting the compact installation, the tutorial drawings will not be installed. If you select the custom installation, be sure that you have selected the online help files to install the tutorial drawings as well. Because of the fact that the tutorial is completely based on ISO standard, please be sure to have the ISO standards selected during installation. If you have already installed AutoCAD Mechanical 2000 without the ISO standard part standard, please install the ISO standard part standard now.

How the Tutorials Are Organized The tutorials are organized so that each of the tutorial exercises deals with a special function or group of function in AutoCAD Mechanical 2000. The tutorial exercises 9 to 14 deal with AutoCAD Mechanical 2000 Power Pack functions and can only be worked through if you have installed the Power Pack. At the beginning of each tutorial, there is a list of Key Terms. These terms contain pertinent mechanical design terminology and definitions. Understanding the terms before you begin the lessons will help you in the tutorials.

Methods for Accessing AutoCAD Mechanical Commands AutoCAD Mechanical 2000 provides several methods for accessing the commands. You can choose the method you prefer. In the tutorial, all the methods are included in the step-by-step procedures. You decide which method to use. Here is an example of a step that includes the command access options:

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Introduction

1 Open the file tut_ex01 in the acadm\tutorial folder. Toolbutton

Open

Menu

File > Open

Command

OPEN

Styles for Different Input Actions The tutorials contain different styles for different user input actions for more clarity. These styles are: User Actions:

This style is represented in italics. It is used for all actions the user has to make, for example selections.

KEYSTROKES:

This style is represented in All Caps. It is used for keystrokes the user has to make, for example confirmations.

User Entries:

This style is represented bold. It is used for entries the user has to make using the keyboard, for example length or diameter specifications.

Here is an example that contains the different input styles: 2 Choose the Edit icon and respond to the prompts as follows: Select object: Select the first cylindrical section, P1 Specify length : Press ENTER Specify diameter : Enter 18

Getting Started

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3

4

Working with Templates

In This Chapter

In this tutorial, you learn about the AutoCAD Mechanical predefined templates and how to create your own user-defined templates.

1

„

Setting up the starting layer

„

Setting the mechanical options

„

Specifying the drawing limits

„

Saving a template

„

Using a template

5

Key Terms Term

Definition

base layer

A layer made up of working layers and standard parts layers. Base layers are repeated in every layer group.

layer group

A group of associated or related items in a drawing. A major advantage of working with layer groups is that you can deactivate a specific layer group and a complete component. The drawing and its overview are enhanced with a reduction in regeneration time.

part layers

A layer where the standard parts are put. All standard parts layers have the suffix AM_*N.

template

A file with predefined settings to use for new drawings; however, any drawing can be used as a template.

working layer

The layer where you are currently working.

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Chapter 1 Working with Templates

Working with Templates Getting Started In AutoCAD Mechanical, you can use templates (*.dwt files) to create drawings. You can use the predefined templates, which contain settings for various drawings, such as acad.dwt or acadiso.dwt, and are supplied with AutoCAD Mechanical or you can create your own templates. Any drawing can serve as a template. When you use a drawing as a template, the settings in that drawing are used in the new drawing. Although you can save any drawing as a template, you should prepare templates to include settings and drawing elements that are consistent with your office or project standards such as the following • unit type and precision • drawing limits • snap, grid, and ortho settings • layer organization • title blocks, borders, and logos • dimension and text styles • linetypes and lineweights If you start a drawing from scratch, AutoCAD Mechanical reads the system defaults, which have a predefined standard, from the registry. If you create a new drawing, based on an existing template, and make changes to the drawing, those changes do not affect the template. To begin working with templates immediately, you can use the predefined template files stored in the acadm\template folder. However, for this tutorial you will create your own template.

Getting Started

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7

Setting Up the Starting Layer Each time you start AutoCAD Mechanical, layer 0 is active. Since layer 0 does not belong to the Mechanical layers, it is not displayed in the Layer Control dialog box of AutoCAD Mechanical, if you select Mechanical Layer in the Show field. Therefore, you need to specify the mechanical layer AM_0 as the default starting layer. 1 Start the Layer Control command. Toolbutton Layer Control Menu

Assist > Layer / Layer Group > Layer / Layer Group Control

Command

AMLAY

2 In the Layer Control dialog box, choose the Layer Control tab, and specify: Name: AM_0 3 Choose Current.

4 Choose OK. The toolbar shows that the active layer is AM_0.

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Chapter 1 Working with Templates

Setting the Mechanical Options In the Mechanical Options dialog box, you can specify general settings for AutoCAD Mechanical. 1 Start the Mechanical Options command. Menu Assist > Mechanical Options Command

AMCONFIG

2 In the Mechanical Options dialog box, choose the General tab, and specify: Standard: ISO Measurement: Metric Scale: 1:1

3 Choose OK. NOTE When you change the settings in the Standard field, all standard-related settings are changed (Dimensioning, BOM, Symbols, …) and saved in the template file.

Setting the Mechanical Options

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9

Specifying the Drawing Limits Now, specify the drawing limits according to size A0 (841 x 1189 mm). This limits your drawing space to the specified size. 1 Start the Drawing Limits command. Menu Assist > Format > Drawing Limits Command

LIMITS

2 Respond to the prompts as follows: Specify lower left corner or [ON/OFF] : Press ENTER Specify upper right corner : Enter 840,1188 Now, the limits are expanded to A0 format.

Saving a Template Now, save the previously changed drawing as a template. 1 Start the Save As command. Menu File > Save As Command

SAVEAS

2 In the Save Drawing As dialog box, specify: File name: my_own_template Save as type: AutoCAD Drawing Template File (*.dwt)

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Chapter 1 Working with Templates

3 In the Template Description dialog box, specify: Description: Tutorial Template Measurement: Metric

4 Choose OK.

Using a Template Next, you start a new drawing and select a starting template. 1 Start the New command. Toolbutton New Menu

File > New

Command

NEW

2 In the Create New Drawing dialog box, select the Use a Template icon, and specify: Select a Template: My_own_template

3 Choose OK. Now, you start the new drawing, using the settings in the previously saved template. In the next step, you specify your template as the default template. 4 Start the Mechanical Options command.

Using a Template

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11

Menu

Assist > Mechanical Options

Command

AMCONFIG

5 In the Mechanical Options dialog box, choose the General tab, choose Browse, and select my_own_template.

6 Choose OK Now, the my_own_template file will be used when you start AutoCAD Mechanical.

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Chapter 1 Working with Templates

Extending the Design of a Lever

In This Chapter

In this tutorial, you extend the design of an existing lever using various possibilities. You also create a drawing detail and some dimensioning options.

2

„

Using the library to insert a part

„

Preliminary settings: snap configuration

„

Creating construction lines

„

Creating additional construction lines

„

Creating a contour and applying a fillet

„

Creating a contour and trimming projecting edges

„

Cross-hatching the lever

„

Dimensioning the lever

„

Creating a detail and additional dimensions

13

Key Terms Term

Definition

(C-lines) construction lines

Lines, which are infinite in both directions or rays, which are infinite starting at a point that can be inserted into the drawing area. You use C-lines to transfer important points (for example, center points of bores) into other views or drawing areas.

construction geometry

A line or an arc created with construction lines. Using construction geometry in 2D drawings helps define the shape of a contour.

detail

A portion of a design drawing that cannot be clearly displayed or dimensioned in the overall representation (surface texture symbols) but can be enlarged to show the details.

distance snap

To give the dimensions in a drawing a uniform appearance, Power Dimensioning and Automatic Dimensioning enable automatic insertion of the dimension line at a defined distance from the object being dimensioned. While dragging the dimension line dynamically, you will find that it remains "fixed" and is highlighted in red as soon as the required distance to the object being dimensioned is reached.

Library

A feature that makes it possible to store parts such as blocks and drawings in a library. For every inserted part, an icon can be created. The icon is put in the display section on the right side of the dialog box along with an assigned name.

Power Command

A collective term for the Power Copy, Power Recall, Power Edit, Power Dimensioning, Power Erase, and Power View commands.

Power Dimensioning

Power Dimensioning is a very useful tool for generating linear, radial and diameter dimensions, which minimizes the number of the individual actions required while generating a dimension. Power Dimensioning selects the type of linear dimension (horizontal, vertical, or aligned), based on the selected point, and the dimensions of the drawing can have a uniform style using the distance snap.

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Chapter 2 Extending the Design of a Lever

Extending the Design Getting Started First, you load the initial drawing. Here, you use the Library to do this. 1 Start the Library. Toolbutton Library Menu

Insert > Library

Command

AMLIBRARY

2 Double-click the tut_ex02 file in the Library, or select Insert from the context menu.

3 Respond to the prompt as follows: Insertion point: Specify any point in the drawing 4 Start the Zoom Window command. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

Getting Started

| 15

5 Zoom in to the part of the drawing shown in the following figure.

Preliminary Settings: Snap Configuration In addition to the AutoCAD snap, Mechanical snap options, like arc radial, arc tangent, and so forth are available. You also have four different snap settings, which can be configured separately for a quick switch to a different snap setting. For example, you can use different snap settings for detailing or general design. Before starting the design, you should define the object snaps, which you will use in later operations. 1 Start the Power Snap settings. Toolbutton Power Snap Settings 1 - 4 Menu

Assist > Draft Settings > Power Snap Settings 1 - 4

Command

AMPOWERSNAP

2 In the Power Snap Settings dialog box, specify: Setting 1: Endpoint, Intersection Setting 2: Endpoint, Center, Quadrant, Intersection, Parallel Setting 3: Perpendicular

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Chapter 2 Extending the Design of a Lever

3 After configuring the settings, activate Setting 1, and choose OK. TIP The object snap functions are also accessible: hold down the SHIFT key, and click the right mouse button.

Creating Construction Lines (C-Lines) Construction lines are very useful when you start your design process. With their help, you draw some kind of a design grid with your defined values for distance and angles. After generating the design grid, you simply trace your contour with the contour layer. Now insert the construction lines, which will help with the drawing of contour lines. 1 Start the Draw C-Lines command. Toolbutton Cross Menu

Design > Construction Lines > Draw C-Lines

Command

AMCONSTLINES

2 In the Construction Lines dialog box, choose the Cross icon.

Creating Construction Lines (C-Lines)

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3 Respond to the prompt as follows: Insertion point: Specify the intersection of line b and line c

Next, draw two lines parallel to the vertical and horizontal lines of the construction line cross. 4 Start the Draw C-Lines command. Toolbutton Parallel with Full Distance Menu

Design > Construction Lines > Draw C-Lines

Command

AMCONSTLINES

5 In the Construction Lines dialog box, choose the Parallel with Full Distance icon.

6 Respond to the prompts as follows: Select XLINE, RAY or LINE: Select line c Distance(xx|xx|xx..) or Insertion point: Enter 3|9 Side to offset: Specify a point to the left of line c

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Chapter 2 Extending the Design of a Lever

7 Insert the second set of parallel lines, and respond to the prompts as follows: Select XLINE, RAY or LINE: Select line b. Distance(xx|xx|xx..) or Insertion point: Enter 4.5|9.5 Side to offset: Specify a point below line b 8 Press ENTER.

Creating additional C-Lines AutoCAD Mechanical offers a choice of C-line options. 1 Activate snap setting 2. Toolbutton Power Snap Settings 2 Menu

Assist > Draft Settings > Power Snap Settings 2

Command

AMPSNAP2

2 Start the Draw C-Lines command. Toolbutton Two Points or Angle Menu

Design > Construction Lines > Draw C-Lines

Command

AMCONSTLINES

3 In the Construction Lines dialog box, choose the Two Points or Angle icon.

Creating additional C-Lines

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4 Respond to the prompts as follows: First point: Select intersection at point 3 Second point or Angle (xx|xx|xx..): Move the cursor over line a and then back to the rectangle. When the Parallel symbol appears, click.

5 Press ENTER to finish the command. Now, you draw tangential circles between the diagonal C-line and the right vertical line and lower horizontal line of the rectangle. 6 Start the Draw C-Lines command. Toolbutton Circle Tangent to 2 Lines Menu

Design > Construction Lines > Draw C-Lines

Command

AMCONSTLINES

7 In the Construction Lines dialog box, choose the Circle Tangent to 2 Lines icon.

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Chapter 2 Extending the Design of a Lever

8 Draw the two circles by responding to the prompts as follows: Select point for tangent: Select point for tangent: Diameter: Enter 2 Select point for tangent: Select point for tangent: Diameter: Enter 2

Select point P1 Select point P2 Select point P3 Select point P1

9 Press ENTER to end the command.

All construction lines have been inserted, and the contour can be generated.

Creating additional C-Lines

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Creating a Contour and Applying a Fillet Now, you connect the two tangential circles with the right part of the rectangle, to build a filleted triangle. 1 Start the Polyline command. Toolbutton Polyline Menu

Design > Polyline

Command

PLINE

2 Create the contour by responding to the prompts as follows: Specify start point: Specify the intersection at P1 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Specify P2 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Enter A Specify endpoint of arc or [Angle/CEnter/CLose/Direction/Halfwidth/Line/ Radius/Second pt/Undo/Width]: Specify P3 Specify endpoint of arc or [Angle/CEnter/CLose/Direction/Halfwidth/Line/ Radius/Second pt/Undo/Width]: Enter L Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Specify P4 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Enter A Specify endpoint of arc or [Angle/CEnter/CLose/Direction/Halfwidth/Line/ Radius/Second pt/Undo/Width]: Specify P5 Specify endpoint of arc or [Angle/CEnter/CLose/Direction/Halfwidth/Line/ Radius/Second pt/Undo/Width]: Enter CL

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Chapter 2 Extending the Design of a Lever

Now, erase the C-Lines. You can erase all C-lines by calling one command. 3 Erase C-Lines. Toolbutton Erase All C-Lines Menu

Modify > Erase > Erase All C-Lines

Command

AMERASEALLCL

TIP You can switch C-lines on and off temporarily by choosing Assist > Layer/Layergroup > C-Line On/Off. 4 Apply a fillet to the corner of the triangle. Toolbutton

Fillet

Menu

Modify > Fillet

Command

AMFILLET2D

5 Respond to the prompts as follows: (Dimension mode:OFF)(Trim mode) Current fillet radius = 2.5 Select first object or [Polyline/Setup/Dimension]: Press ENTER 6 In the Fillet radius dialog box, specify: Input: 1 Trim Mode: On

7 Choose OK. 8 Respond to the prompts as follows: (Dimension mode:OFF)(Trim mode) Current fillet radius = 1 Select first object or [Polyline/Setup/Dimension]: Enter P Poly Select 2D polyline: Select a point on the polyline near the corner 9 Press ESC to cancel the command. The triangular contour is complete.

Creating a Contour and Applying a Fillet

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Creating a Contour and Trimming Projecting Edges Now, you create another part of the contour and trim projecting edges. 1 Activate Power Snap Setting 3 command. Toolbutton Power Snap Settings 3 Menu

Assist > Draft Settings > Power Snap Settings 3

Command

AMPSNAP3

Next, insert the next contour. 2 Start the Line command. Toolbutton Line Menu

Design > Line

Command

LINE

3 Respond to the prompts as follows: Specify first point: Hold down the SHIFT key, right-click, and choose Intersection _int of: Select line a, P1 and: Select intersection on line b, P2 Specify next point: : Hold down the SHIFT key, right-click, and choose Perpendicular. Then trace over line e, and click the perpendic. point, P3 Specify next point: Drag the cursor to the right, crossing over line c, and select the Extended Intersection point, P4 Specify next point: Press ENTER

Now, trim the projecting edges at the upper edge of the lever. 24

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Chapter 2 Extending the Design of a Lever

4 Start the Trim command. Toolbutton Trim Menu

Modify > Trim

Command

TRIM

5 Respond to the prompts as follows: Projection = UCS, Edge = None Select cutting edges: Select Objects: Select line 1 Select Objects: Select line 2 Select Objects: Press ENTER /Project/Edge/Undo: Select line 3 /Project/Edge/Undo: Select line 4 /Project/Edge/Undo: Press ENTER

6 Zoom to the extents of the lever. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

The contour is complete and looks like this:

Creating a Contour and Trimming Projecting Edges

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Cross-Hatching the Lever Cross-hatching is easy with AutoCAD Mechanical. Just choose one of the predefined cross-hatching styles, and click a point within the contour to be hatched. 1 Start the Hatch command, using an angle of 45 degrees and 2.5 mm / 0.1 inch spacing. Toolbutton Hatch 45 deg.,2.5mm/0.1 inch Menu

Design > Hatch > Hatch 45 deg.,2.5mm/0.1 inch

Command

AMHATCH_45_2

2 Respond to the prompt as follows: Select additional boundary or point in area to be hatched or [Select objects]: Click a point inside the contour (outside the cutouts) The lever is hatched. It looks like this:

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Chapter 2 Extending the Design of a Lever

Dimensioning the Lever Now, dimension the lever, using the Power Dimensioning command. 1 Start the Power Snap Setting 1 command. Toolbutton Power Snap Settings 1 Menu

Assist > Draft Settings > Power Snap Settings 1

Command

AMPSNAP1

2 Start the Power Dimensioning command. Toolbutton Power Dimensioning Menu

Annotate > Power Dimensioning

Command

AMPOWERDIM

3 Respond to the prompts as follows: (SINGLE) First extension line origin or [Angular/Options/Baseline/Chain/ Update] : Select the first corner point of the lever opening, P1 Second extension line origin: Select the second corner point, P2 Place dimension line [Options/Pickobj] : Drag the dimension line to the left until it is highlighted, and click at P3

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4 In the Power Dimensioning dialog box, specify: Upper deviation: +0.1

5 Choose OK. 6 Press ESC to cancel the command. The lever looks like this:

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Chapter 2 Extending the Design of a Lever

Creating a Detail and Additional Dimensions Now, define a detail of the upper part of the lever. 1 Start the Detail command. Toolbutton Detail Menu

Design > Detail

Command

AMDETAIL

2 Respond to the prompts as follows: Center of circle or [Rectangle/Object]: Click a point in the center of the area to be detailed Specify radius or [Diameter]: Drag the radius to the appropriate size

3 Choose OK.

4 Respond to the prompts as follows: Move the title ( for current position): Press ENTER to select the default position Place the detail view: Select a location to the right of the lever Select next point of connection line\ for none: Press ENTER for no connection line

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NOTE Some entities such as dimensions and symbols are automatically filtered out in the detail function.

Now, add a dimension to the detail. 5 Start the Power Dimensioning command. Toolbutton Power Dimensioning Menu

Annotate > Power Dimensioning

Command

AMPOWERDIM

6 Respond to the prompts as follows: (SINGLE) First extension line origin or [Angular/Options/Baseline/Chain/ Update] : Press ENTER [Picking arc/circle yields radius/diameter dimension or pick dimension to edit]: Select the radius, as indicated by the arrow in the following drawing

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7 In the Power Dimensioning dialog box, under Radius Dimensions, select the fourth icon from the left. Choose OK.

8 Select an appropriate position for the dimension. 9 Deactivate the tolerances or fits in the Power Dimension dialog box, if necessary, and choose OK.

10 Press ESC. Now, the lever looks like this:

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NOTE The Power Dimensioning command recognizes the different scale area. If you dimensioned the radius in the original drawing, the dimension value would be the same. The text height is also the same, as related to the standard.

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Dimensioning and Annotations

In This Chapter

In this tutorial, you learn how to add dimensions to your drawing with automatic dimensioning. Then you change the dimensions with Power Commands. You also learn how to add annotations to your drawing and insert a drawing border.

3

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Automatic dimensioning

„

Editing dimensions with Power Commands

„

Inserting annotations

„

Inserting a drawing border

33

Key Terms Term

Definition

annotation

An object, such as text or geometry, that is attached to a drawing to describe a design. Examples are surface finish symbols, callout balloons, and BOMs (bills of materials).

baseline dimension

A dimension that is aligned to extension lines and read from the bottom or right side of the drawing.

centerline

Line in the center of a symmetrical object. When you create centerlines, you specify the start and end points.

datum identifier

A symbol consisting of a frame with a reference letter.

drawing border

A standardized frame that is used for technical drawings.

drawing title

The drawing title is drawn in the lower right corner of the drawing and provides information about your drawing. Some title attributes are pre-assigned. You can modify or add attributes.

feature control frame symbol

Symbol that gives an accurate and concise meaning to specifying geometric characteristics and tolerances. Notes can supplement symbols where appropriate.

feature identifier symbol

Specifies individual features for tolerancing.

fit

Range of tightness or looseness in mating parts (for example shafts or holes). Tolerances in these dimensions are expressed in standard form.

fit name

Name of the selected fit (for example H7).

geometric tolerance

The general term applied to the category of tolerances used to control form, profile, orientation, location, and run out.

multi edit

An option where you determine a selection set of dimensions and edit them together.

Power Dimensioning

A command useful for generating linear, radial, and diameter dimensions while minimizing the number of the individual actions for generating a dimension. Power Dimensioning automatically selects the type of the linear dimension (horizontal, vertical, aligned) based on the selected point.

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Power Erase

Command for deleting. Use Power Erase when you delete part reference numbers or dimensions that were created with Power Dimensioning.

surface texture symbol

Symbol that specifies surface texture finish. The symbols conform, in terms of their geometry and annotations (which includes text and other symbols), to international drafting standards.

title block

A title block contains a series of attributes some already have values. The preassigned values can be modified, and the vacant attributes can be completed with new values.

tolerance

The total amount by which a given dimension (nominal size) may vary (for example, 20 ± 0.1).

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Dimensioning AutoCAD Mechanical offers various dimensioning tools. Here you will learn to use automatic dimensioning to add dimensions to a bush. You also learn how to change these dimensions 1 Open the file tut_ex03 in the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

The file contains a drawing of a bushing.

Automatic Dimensioning First you dimension the shaft of the bushing using automatic dimensioning. 1 Start Automatic Dimensioning. Toolbutton Automatic Dimensioning Menu

Annotate > Automatic Dimensioning

Command

AMAUTODIM

2 In the Automatic Dimensioning dialog box, choose the Parallel tab and specify: Type: Baseline

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3 Choose OK. 4 Respond to the prompts as follows: Select objects: Select the complete shaft Select objects: Press ENTER First extension line origin: Select the lower leftmost corner of the shaft, P1 Place dimension line [Options/Pickobj] : Drag the dimensioning downwards until it snaps in (highlighted), and click Starting point for next extension line: Press ENTER to end the command

In the next step, you generate the shaft dimensioning.

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5 Start Automatic Dimensioning. Toolbutton Automatic Dimensioning Menu

Annotate > Automatic Dimensioning

Command

AMAUTODIM

6 In the Automatic Dimensioning dialog box, choose the Shaft / Symmetric tab, and specify: Type: Full Shaft

7 Choose OK. 8 Respond to the prompts as follows: Select objects: Select the complete shaft Select objects: Press ENTER Select Centerline or new starting point: Select the shaft centerline Place dimension line [Options/Pickobj] : Drag the dimensioning to the right until it snaps in (highlighted), and click Starting point for next extension line: Press ENTER to end the command

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Editing Dimensions with Power Commands Some dimensions in the drawing are not necessary. In the next step, you delete the dimensions that you don’t need. 1 Start Power Erase. Toolbutton Power Erase Menu

Modify > Power Commands > Power Erase

Command

AMPOWERERASE

2 Respond to the prompt as follows: Select objects: Select the baseline dimensions 2 and 61 and the shaft dimensions 12, 14 and 36, and press ENTER The dimensions are deleted, and the other dimensions are rearranged. Your drawing should now look like this:

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Now, add a single dimension with a fit using Power Dimensioning. 3 Start Power Dimensioning. Toolbutton Power Dimensioning Menu

Annotate > Power Dimensioning

Command

AMPOWERDIM

4 Respond to the prompts as follows: (SINGLE) First extension line origin or [Angular/Options/Baseline/Chain/ Update] : Select point P1 as shown in the following figure Second extension line origin: Select point P2 Place dimension line [Options/Pickobj] : Drag the dimensioning to the left until it is highlighted, and click

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5 In the Power Dimensioning dialog box, check the Enable field, choose the Fits tab, and specify: Fit symbol: H7

6 Choose OK. Now continue to apply an angular dimensioning. 7 Respond to the prompts as follows: (SINGLE) First extension line origin or [Angular/Options/Baseline/Chain/ Update] : Enter A Select arc, circle, line or RETURN: Select the line at point P1 Second line: Select the line at point P2 Dimension arc line location (Angle): Drag the dimension to a suitable position, and click Dimension text (Click=Options) : Press ENTER

8 Press ENTER to end the command. Next, you add a fit to the shaft dimensions using Multi Edit.

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9 Start Multi Edit. Toolbutton

Multi Edit

Menu

Modify > Modify Dimension > Multi Edit

Command

AMDIMMEDIT

10 Respond to the prompts as follows: Select objects: Select the dimensions 18 and 30 Select objects: Press ENTER 11 In the Power Dimensioning dialog box, check the Enable field, chose the Fits tab, and specify: Fit symbol: h7

12 Choose OK. The fit description h7 is added to the dimensions.

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Inserting Annotations Annotations are objects used to describe the design, like surface or weld symbols. In this exercise, you will insert a surface texture symbol, a datum identifier, and a feature control frame. First, you add a surface texture symbol. A surface texture symbol is a symbol that describes the roughness of a face. It can also provide information about the finishing method. 1 Start the Surface Texture command. Toolbutton Surface Texture Menu

Annotate > Symbols > Surface Texture

Command

AMSURFSYM

2 To locate the symbol respond to the prompts as follows: Start Point: Specify the leader line start point at P1 Next Point : Specify the second leader line point at P2 Next Point : Press ENTER

3 In the Surface Texture dialog box, choose the Symbol tab, and specify: Surface Type: Select the middle icon A ’: 6.3

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4 Choose OK. Next, you add a datum identifier and a feature control frame. The datum identifier marks a reference face for a geometric tolerance, and the feature control frame provides information about the toleranced face, allowed deviation, and the type of tolerance. 5 Start the Datum Identifier command. Toolbutton Datum Identifier Menu

Annotate > Symbols > Datum Identifier

Command

AMDATUMID

6 Respond to the prompts as follows: Start Point: Specify the leader line start point at P1 Next Point : Specify the second leader line point at P2 Next Point : Press ENTER

7 In the Datum Identifier dialog box, enter A, and choose OK.

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8 Start the Feature Control Frame command. Toolbutton Feature Control Frame Menu

Annotate > Symbols > Feature Control Frame

Command

AMFCFRAME

9 To locate the symbol, respond to the prompts as follows: Start Point: Specify the leader line start point at P1 Next Point : Specify the second leader line point at P2 Next Point : Specify the second leader line point at P3 Next Point : Press ENTER

10 In the Feature Control Frame dialog box, choose the Frame tab, and specify: Sym: Select the symbol for the geometric tolerance circular run-out Tolerance: 0.01 Datum 1: A

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11 Choose OK. Now, your complete bushing looks like this:

Inserting a Drawing Border Finally, you insert a drawing border. 1 Start the Drawing Title/Borders command. Toolbutton Drawing Title/Borders

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Menu

Annotate > Drawing Title/Revisions > Drawing Title/Borders

Command

AMTITLE

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2 In the Drawing Borders with Title Block dialog box, specify: Paper Format: AM_A4

3 Choose OK. 4 Respond to the prompt as follows: Insertion point: Specify an insertion point in the lower left corner 5 In the Change Title Block Entry dialog box, specify: Description, max. 20: Bushing

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6 Choose OK. 7 Respond to the prompts as follows: Select Objects: Select the complete shaft Select Objects: Press ENTER New location for objects: Place the bush in the middle of the drawing border Finally, your drawing looks like this:

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Working with Layers and Layer Groups

In This Chapter

In this tutorial, you learn more about the various commands used for working with layers and layer groups.

4

„

Changing a layer by selecting objects

„

Creating layer groups

„

Using a layer group to copy objects

49

Key Terms Term

Definition

base layer

A layer made up of working layers and standard parts layers. Base layers are repeated in every layer group.

layer group

A group of associated or related items in a drawing. A major advantage of working with layer groups is that you can deactivate a specific layer group and a complete component. The drawing and its overview is enhanced with a reduction in regeneration time.

part layers

The layer where the standard parts are put. All standard parts layers have the suffix AM_*N.

working layer

The layer where you are working.

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Working with Layers and Layer Groups Understanding Layer Management Layers can be customized and renamed according to your needs using: „

Mechanical Options dialog box > Layer / Object Settings…

„

Layer 0 is a default layer and not a mechanical layer, because this layer has special properties (by block). If you want to have this special property available, just rename e.g. layer AM_0 to 0 in the Mechanical Options.

„

Because AutoCAD 2000 always starts with Layer 0, we recommend using template files, where layer AM_0 is always the starting layer.

„

If you move elements on layer 0 to other layer groups, you are asked if you always want to move the elements on layer group layergroupname-AM_0.

Getting Started Open the initial drawing. 1 Open the file tut_ex04 in the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

2 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

3 Zoom in to the area marked with W1 and W2. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

Understanding Layer Management

|

51

4 Respond to the prompts as follows: Specify first corner: Specify W1 Specify opposite corner: Specify W2

Changing a Layer By Selecting Objects First, you move the layer (and layer group) containing two objects to another layer (and layer group) by selecting an object in the aforementioned layer (and layer group). 1 Start the Move to Another Layer command. Toolbutton Move to Another Layer Menu

Modify > Properties > Move to Another Layer

Command

AMLAYMOVE

2 Respond to the prompts as follows: Select objects: Specify the centerlines of the differential gear, P1 and P2 Select objects: Press ENTER Specify new layer using object, layer field or keyboard (RETURN for dialog): Specify the engine centerline, P3

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The centerlines of the differential gear are moved to the layer and layer group of the engine centerline.

Creating Layer Groups Layer groups provide an easy and intelligent way to structure assembly drawings. Using layer groups enable you to highlight single parts and lock and freeze whole parts. This gives you a better overview of your assembly drawing. First, you move a block to a layer group. 1 Start the Move to Another Group command. Toolbutton Move to Another Group Menu

Modify > Properties > Move to Another Layer Group

Command

AMLGMOVE

2 Respond to the prompts as follows: Select objects: Specify the gear, P1 Select objects: Press ENTER

Creating Layer Groups

|

53

3 In the Layer Control dialog box, choose the Create button, and create a new layer group called Gear. Choose OK.

4 In the Named Block dialog box, choose Yes All.

The complete block is moved to the layer group Gear. NOTE You can also perform the task with single elements. Using the Named Block dialog box, you can specify whether to move only the block or to move the block and all parts and lines to the new layer group.

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Now, you create two new layer groups and move the parts (blocks) to those groups. 5 Start the Layer Group Control command. Toolbutton

Layer Group Control

Menu

Assist > Layer / Layer Group > Layer / Layer Group Control

Command

AMLG

6 In the Layer Control dialog box, choose the Layer Group Control tab, and choose Create. Enter Coverplate for the layer group name. 7 Choose Create again, and create a layer group called Bushing. Choose OK.

8 Start the Move to Another Group command. Toolbutton Move to Another Group Menu

Modify > Properties > Move to Another Layer Group

Command

AMLGMOVE

9 Respond to the prompts as follows: Select objects: Specify the coverplate, P1 Select objects: Press ENTER

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55

10 In the Layer Control dialog box, select the layer group Coverplate, and choose OK.

11 In the Named Block dialog box, choose Yes All.

Now, move the bushing to the new Bushing layer group. 12 Start the Move to Another Group command.

56

Toolbutton

Move to Another Group

Menu

Modify > Properties > Move to Another Layer Group

Command

AMLGMOVE

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13 Respond to the prompts as follows: Select objects: Specify the bushing, P1 Select objects: Press ENTER

14 In the Layer Control dialog box, select the layer group Bushing, and choose OK.

15 In the Named Block dialog box, choose Yes All.

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57

The coverplate and the bushing have now been moved to their respective layer groups.

Using a Layer Group to Copy Objects Now, copy the objects of the layer group Shaft to a new drawing border. 1 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

2 Start the Visibility Enhancement command. Toolbutton Visibility Enhancement Menu

Assist > Layer / Layer Group > Visibility Enhancement

Command

AMLAYVISENH

3 In the Visibility Enhancement dialog box, specify: Focus Enhancer: Special coloring for non-current Layer Groups

4 Choose OK.

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5 Start the Layer Group Control command. Toolbutton Layer Group Control Menu

Assist > Layer / Layer Group > Layer / Layer Group Control

Command

AMLG

6 In the Layer Control dialog box, choose the Layer Group Control tab, and select the layer group Shaft. Choose the Current button, and then choose OK.

In the following drawing, you can see which elements belong to the current layer.

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59

7 Start the Copy command. Toolbutton Copy Menu

Modify > Copy > Copy

Command

COPY

8 Respond to the prompt as follows: Select objects: Select Layer Group Control Toolbutton Layer Group Control Menu

Assist > Layer / Layer Group > Layer / Layer Group Control

9 In the Layer Control dialog box, choose the Layer Group Control tab, and select the layer group Shaft. Choose the Selection Set button. In the AutoCAD dialog box, choose OK. 10 Respond to the prompts as follows: Select objects: Press ENTER Specify base point or displacement, or [Multiple]: Specify a point on the shaft Specify second point of displacement or : Specify another point in the drawing border on the right

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Working with a Bill of Material and a Parts List

In This Chapter

In this tutorial, you learn how to create and modify part references and balloons, insert and edit a parts list, and work with the bill of material (BOM) database.

5

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Creating part references

„

Inserting and modifying balloons

„

Inserting and modifying parts lists

61

Key Terms Term

Definition

balloon

Circular annotation tag that identifies a bill of material item in a drawing. The number in the balloon corresponds with the number of the part in the bill of material.

bill of material

A dynamic database containing a list of all the parts in an assembly. Used to generate parts lists that contain associated attributes such as part number, manufacturer, and quantity.

BOM attribute

An entity that contains attributes by default (the attribute is invisible) that can add information to and describe details of a part in the drawing. The values of these attributes are transformed into the parts list attributes when converting BOM attributes and creating a parts list.

part reference

Part information for a bill of material, which is attached to the part in the drawing.

parts list

A dynamic list of parts and associated attributes generated from a bill of material database. The parts list automatically reflects additions and subtractions of parts from an assembly.

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Inserting a Part Reference The part reference the part information required for the bill of material. The information of the part reference is available in the parts database for creating a parts list. Here, you use the part reference command to enter part information for your part. First, load the initial drawing. 1 Open the file tut_ex05 from the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

2 Zoom in to the area of interest, marked with W1 and W2. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

3 Respond to the prompts as follows: Specify first corner: Specify W1 Specify opposite corner: Specify W2

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4 Start the Part Reference command. Toolbutton Place Reference Menu

Annotate > Parts List > Create BOM Attribute

Command

AMPARTREF

5 Respond to the prompt as follows: Select point or [Block/Copy/Reference]: Specify P1

6 In the Part Ref Attributes dialog box, enter the settings shown below.

7 Choose OK. The Part Reference is inserted into the drawing. 8 Start the Part Reference command again. Toolbutton Place Reference

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Menu

Annotate > Parts List > Create BOM Attribute

Command

AMPARTREF

Chapter 5 Working with a Bill of Material and a Parts List

9 Right click to display the context menu and select Reference, or enter R at the Command prompt.

10 Select the first part reference (P1) in the drawing to create a reference. This means that the same part shows a quantity of 2 in the BOM database. NOTE You can use the option Copy to create a new part with similar text information. 11 Select the insertion point (P2).

The Part Ref Attribute dialog box is displayed. 12 Choose OK. 13 Start the Edit Part Reference command. Toolbutton Edit Part Ref Data Menu

Annotate > Parts List > Edit BOM Attribute

Command

AMPARTREFEDIT

14 Pick the part reference at P3.

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The Part Ref Attributes dialog box is displayed. 15 For Reference Quantity, enter 3, and choose OK.

NOTE For the related nut and the screw connection on the right side the reference quantity is already changed in the drawing. 16 Zoom extents to display the entire drawing.

Placing Balloons 1 Start the Balloon command. Toolbutton Place Balloon Menu

Assist > Parts List > Place Balloon

Command

AMBALLOON

2 Respond to the prompt as follows: Select part/assembly or [Auto/Collect/Manual/One/Renumber]: Enter A

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The command line options include: Auto – Creates balloons for selected part references and aligns them horizontally or vertically. Collect – Creates a multiple balloon or attaches new balloons to an existing balloon. Manual – Creates a new part reference with a balloon. One – Creates a single balloon. Renumber – Renumbers selected balloons in the drawing and changes item numbers in the BOM. TIP If you use one of the commands AMBALLOON or AMPARTLIST the BOM-database will be created automatically. This means all part references will be added to the database and item numbers will be created inside the database. To create and edit a database manually, you can also use the AMBOM command . 3 Use a window to select all objects from W3 to W4.

TIP Use right-click to switch between the horizontal or vertical orientation of the balloons. 4 Place the balloons horizontally, above the assembly.

Because the balloons are numbered automatically, depending on where you have located the part references, the appearance of your drawing can be different.

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5 Start the Balloon command again. Toolbutton Place Balloon Menu

Annotate > Parts List > Place Balloon

Command

AMBALLOON

6 On the command line, enter Renumber. 7 Respond to the prompt as follows: Enter starting item number: : Press ENTER

Enter increment: : Press ENTER

Select balloon: Select the balloons from 1 to 7, in the order shown above and press ENTER Your drawing needs to look like the following in order for you to to continue:

NOTE Since balloon 7 has a reference, you do not have to select balloon 8. It will get the number 7 automatically. 8 Use a window to select the 6 balloons on the right. This turns on the grips.

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9 Right-click to activate the context menu. Choose Reorganize. 10 Move the cursor through the center of balloon 1 to get the horizontal tracking line. NOTE Make sure that the OTRACK function is active. 11 Move the cursor to the right, along the line, and select a insertion point.

The result needs to look like the following:

TIP You can reorganize one balloon by selecting and using grip point editing. Create a part reference and a balloon in one step with the manual option. 12 Start the AMBALLOON command again, and choose Manual. 13 Click a point inside the shaft.

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TIP Instead of selecting a point to create a part reference, you can use Copy or Reference from the Manual option, to get the information from an existing balloon or part reference. 14 In the Part Ref Attribute dialog box, enter the following settings, and choose OK.

15 Press ENTER to start the leader line of the balloon in the center of the part reference. 16 Move the cursor through the center of balloon 1 to get the tracking line, and enter the insertion point. TIP Instead of entering the insertion point, you can select another point to create an extended leader line.

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17 Press ENTER.

Creating a Parts List 1 Start the Parts List command. Toolbutton

Place Parts List

Menu

Annotate > Parts List > Parts List

Command

AMPARTSLIST

2 Respond to the prompt as follows: Select border: Move the cursor over the border until the tooltip AM_A2 is displayed, and pick the border 3 Respond to the prompts as follows: Parts List name . Press ENTER Select type of Parts List: [All/Parts/Range] : Press ENTER The parts list appears dynamically on the cursor. 4 Move the cursor to the top of the title block. Click to insert the parts list. The parts list should look like the following:

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TIP If you are working with more than one drawing border, you can create border-specific parts lists. In this case, a BOM database is created for each border automatically when the AMBALLOON or AMPARTLIST commands are used. You can use the AMBOM command to create or edit a BOM manually. An example of a BOM database that contains more than one border is shown below. Selecting BORDER1 or BORDER2 displays the contents for each BOM database.

5 Start the Edit Part List/Balloon command. Toolbutton Edit Part List/Balloon Command

AMEDIT

6 Select balloon 2.

The Balloon dialog box is displayed.

7 Enter 8.8 in the Material column, as shown above.

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8 Choose OK. Notice the changes in your parts list.

TIP Choose Apply to see the results in the drawing immediately without leaving the dialog box. All changes made in the dialog box are associative and change the data in the drawing immediately. 9 Double-click the parts list. The Parts List dialog box is displayed.

You can edit your data in this dialog box. Some examples are shown next. 10 Select 8.8 in the Material column, and move the cursor down three cells to copy the data into these rows.

11 Select the Set Value displayed.

button. The Set Value dialog box is

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12 Choose OK. The result should look like the following.

13 For the two nuts (ISO 4034 M6), from 8.8 to 8, change the material by double-clicking the field. The result should look like the following:

TIP Using the context menu inside a field provides additional functions such as cut, copy, and paste.

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Merging and Splitting Items in a Parts List 1 In the Parts List dialog box, select the field to the left of row 1, hold down CTRL, and select row 6, as shown below.

2 Select the active Merge button together.

to merge these two items

Item 1 now has a quantity of 2, and Item 6 is missing.

Selecting several rows allows you to merge or split items. The selected rows need to have the same entries. 3 Choose Apply to display the changes in the drawing.

Balloon 1 is displayed twice.

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TIP Select the gray field to the left of row 1, and the active split icon is displayed.

In this case, if you choose split, you can select one of the two part references in the drawing to split them. Selecting the gray field in the upper left corner near Item allows you to select all rows at once, as shown in the following.

In this case, the merge and split icons are active. Selecting one of the icons allows you to merge or split all items at once. All data will be compared, and if it is the same, they are merged together. Otherwise, if they are merged items they are split at once. Now that you have merged the bearing, you can delete one of the balloons and add an additional leader. 4 Use Power Erase, and select the left balloon with the item number 1.

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5 Press ENTER to delete the balloon. NOTE Deleting a balloon in the drawing, doesn’t delete any data. Data is only lost if you delete a part reference. You can add more than one balloon to a part reference, for example, to create a balloon with the same item number, for the same part in another view. 6 Select the remaining balloon 1. 7 Right-click to display the context menu. Select Add Leader. 8 Select the start point in the center of the bearing, and move the cursor near the number 1 in the balloon. 9 Select that point. Your drawing should look like the following:

Collecting Balloons Collecting balloons enables you to place balloons of related parts to one leader line. For example, you can place the balloons of a screw and a nut to one common leader line. 1 Use a window to zoom in the top view of the drawing. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

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2 Start the AMBALLOON command. Toolbutton Place Balloon Menu

Annotate > Parts List > Place Balloon

Command

AMBALLOON

3 Respond to the prompt as follows: Select part/assembly or [Auto/Collect/Manual/One/Renumber]: Enter C 4 Select the part reference of the left nut, and press ENTER.

5 Select balloon 2. The collected balloon is displayed. 6 Move the cursor to switch between the horizontal or vertical orientation of the balloons. Select the point for vertical orientation.

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7 Repeat the collect balloon command for the screw and nut on the right side. 8 Use Power Erase to delete balloons 4 and 5. The result should look like this:

Sorting and Renumbering Items on a Parts List You can sort a parts list for manufacturing and sort standard parts with updated item numbers. 1 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

2 Double-click the parts list to display the Parts List dialog box.

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3 Select the Sort button

to display the Sort dialog box.

TIP You can sort within a selection set, otherwise you are sorting all items. 4 Enter the settings in the dialog box, as shown below.

5 Choose OK to see the following results.

6 Click the Item cell to select the Item column.

7 In the Set Value dialog box, select the Set Value icon change the Start value

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, and

8 Choose OK to return to the Parts List dialog box. Choose Apply to see the results in the drawing (also the balloons). The result should look like the following.

9 Choose OK to return to the drawing.

Using Filters You can create and use one or more filters for every parts list you have inserted in the drawing. 1 Double-click the parts list to display the Parts List dialog box. 2 Move the cursor over the white Filters field, and right-click.

3 Select Add Filter to display the List of Filters dialog box.

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4 Select Custom and choose OK. The details for this filter are displayed.

5 Set the following values to define the filter.

6 Activate the filter with the Custom check box.

7 Choose Apply in the Parts List dialog box. The Standards that contain ISO are displayed.

8 Choose OK. The filtered parts list is displayed in the drawing. The defined filters are saved with the parts list and can be used again later. If you only want to print the filtered list, choose the Print icon .

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9 Choose Cancel to close the dialog box. The filter will not be used in this drawing again.

The result looks like the following:

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84

Working with Model Space and Layouts

In This Chapter

6

In this tutorial, you learn to create scale areas and

„

Creating a scale area

viewports as well as detail views in model space

„

Creating a detail

and in the layout.

„

Generating a new viewport

„

Inserting an user through hole

„

Creating a subassembly in a new layout

85

Key Terms Term

Definition

base layer

A layer made up of working layers and standard parts layers. Base layers are repeated in every layer group.

detail

A portion of the design drawing that cannot be clearly displayed or dimensioned. The overall representation (surface texture symbols) can be enlarged.

drawing

A layout of drawing views in model space or layout.

drawing mode

Establishes the settings for paper space so that you can create a drawing of your model. When Drawing mode is off, you are in model space.

layer group

A group of associated or related items in a drawing. A major advantage of working with layer groups is that you can deactivate a specific layer group and a complete component. The drawing and its overview are enhanced by reduction in regeneration time.

layout

The tabbed environment in which you create and design paper space floating viewports to be plotted. Multiple layouts can be created for each drawing.

Power Dimensioning

A command useful for generating linear, radial, and diameter dimensions, which minimizes the number of the individual actions while generating a dimension. Power Dimensioning automatically selects the type of the linear dimension (horizontal, vertical, aligned), based on the selected point.

scale area

Displays a particular scale area (corresponds to zoom viewport). The respective scales can be viewed before zooming.

scale monitor

A function where you can control the scale for each viewport.

viewport

In Drawing mode, a bounded area that displays a drawing view.

view scale

The scale of a base drawing relative to the model scale. Also, the scale of dependent views relative to the base view.

working layer

The layer where you are currently working.

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Working with Model Space and Layouts Using model space and layouts, you can create different views with different scales from the same model. The main advantage to working with layouts is that you always have associated views; that is, if you make changes in one viewport, those changes are made in all other viewports as well, since each viewport is just another view of the same model.

Getting Started In this tutorial, you work with viewports. You generate an associative detail and create a subassembly drawing. 1 Open the file tut_ex06 in the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

The drawing contains parts of a four-stroke engine.

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Creating a Scale Area To generate correct views with correct zoom factors in a layout, you must define a scale area in model space. First, create the scale area. 1 Start the Viewport/Scale Area command. Toolbutton Viewport/Scale Area Menu

View > Viewports > Viewport/Scale Area

Command

AMSCAREA

2 Respond to the prompts as follows: Define the border ... First point or [Circle/Object]: Select the drawing point 1 Second point: Select the drawing point 2

3 In the Scale Area dialog box, specify: Scale: 1:1

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4 Choose OK. In the next step, you use Viewport Auto Create to create a viewport automatically. Here, the viewport will be created, because of the defined scale area. 5 Start the Viewport Auto Create command. Toolbutton Viewport Auto Create Menu

View > Viewports > Viewport Auto Create

Command

AMVPORTAUTO

6 Respond to the prompts as follows: Enter layout name ( for "Layout1"): Press ENTER Select target position ( for current position): Zoom to the extents of the drawing Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

7 Respond to the prompt as follows: Select target position ( for current position): Place the viewport on

the left, inside the drawing border

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Creating a Detail There are two types of details, associative and non-associative. In this exercise, you create an associative detail, because you use a viewport. Create an associative detail of the valve. 1 Start the Detail command. Toolbutton Detail Menu

Design > Detail

Command

AMDETAIL

The viewport is activated automatically. You will recognize it by its thick (highlighted) frame. 5 Respond to the prompts as follows: Define the enlargement area for the detail ... Center of circle or [Rectangle/Object]: Select drawing point 3 Specify radius or [Diameter]: Drag the radius to drawing point 4 3 In the Detail dialog box, specify the settings shown in the following figure..

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4 Choose OK. 5 Respond to the prompt as follows: Move the title ( for current position): Press ENTER Select target position ( for current position): Place the detail to the right of the current viewport

Generating a New Viewport Now, you create a viewport inside a layout. 1 Start the Viewport/Scale Area command. Toolbutton

Viewport/Scale Area

Menu

View > Viewports > Viewport/Scale Area

Command

AMVPORT

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2 Respond to the prompts as follows: Define the border ... First point or [Circle/Object]: Select drawing point 5 Second point: Select drawing point 6 3 In the View dialog box, specify: Scale: 5:1

4 Choose Midpoint Holes > Through Holes

Command

AMTHOLE

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3 In the Browser, choose User Through Holes – Front View. 4 Respond to the prompts as follows: Specify insertion point: Hold down the shift key and press the right mouse button. Choose Midpoint from the context menu. Specify insertion point:_mid of Select the midpoint of the housing, P1 Specify the hole length: Select the perpendicular point, P2

5 In the User Through Holes – Nominal Diameter dialog box, specify: Nominal Diameter: 8

6 Choose Finish. The user through hole is inserted into your drawing. Now, the drawing looks like this:

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Because of the associativity, the through hole created in the detail view appears in the original view. In the next step, you dimension the through hole diameter in the detail view. Since the dimension is to appear only in the detail view, you generate the dimension directly in the layout without having a viewport active. 7 Change to the layout. Toolbutton Paper/Model Space Menu Command

PSPACE

8 Start the Power Dimensioning command Toolbutton Power Dimensioning Menu

Annotate > Power Dimensioning

Command

AMPOWERDIM

9 Respond to the prompts as follows: (SINGLE) First extension line origin or [Angular/Options/Baseline/Chain/ Update] : Select the first edge of the hole Second extension line origin: Select the second edge of the hole Place dimension line [Options/Pickobj]: Drag the dimension line to the right until it is highlighted, and click (SINGLE) First extension line origin or [Angular/Options/Baseline/Chain/ Update] : Press ENTER

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10 In the Power Dimensioning dialog box, choose OK.

Now, the viewport looks like this:

NOTE You can also dimension the hole in model space and turn off the layer of one specific viewport. But the dimension text will only be correct in the 1:1 viewport and not in the detail view. Therefore, you can dimension directly on the layout.

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Creating a Subassembly in a New Layout If you use layer groups in your assembly drawing, you can easily create detail and subassembly drawings in layouts. You can switch off selected layer groups in the viewports, so that only the detail or subassembly is visible. Now, create an associative view of a subassembly in layout 2. 1 Change to layout 2, by selecting the Layout 2 tab on the bottom of your drawing area, as shown below.

2 Start the Viewport/Scale Area command. Toolbutton Viewport/Scale Area Menu

View > Viewports > Viewport/Scale Area

Command

AMVPORT

3 Respond to the prompts as follows: Define the border ... First point or [Circle/Object]: Select drawing point 7 Second point: Select drawing point 8 4 In the View dialog box, specify: Scale: 5:1

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5 Choose Midpoint Layer / Layergroup > Layer/Layer Group Control

Command

AMLG

9 In the Layer Control dialog box, choose the Layer Group Control tab, mark SUBASSEMBLY1, and choose Current. 10 Move the cursor to the icon in the column Viewport Control, and right-click. 11 In the context menu, choose Select Viewport.

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12 Respond to the prompts as follows: Select viewports: Select the viewport frame Select viewports: Press ENTER The Layer Control dialog box is displayed. 13 In the Layer Control dialog box, move the cursor to the icon in the Freeze column and the Base Layer Group row, and click.

14 Choose OK. AutoCAD Mechanical freezes the Base Layer Group, and the subassembly remains visible. Your drawing looks like this:

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Now, you can finish your detail drawing with text, remarks, annotations, and so on. NOTE When you plot the drawing, the red viewport frame is turned off automatically. If you have a plotter or printer driver installed, use the plot command, and preview the drawing.

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102

Designing a Cam

In This Chapter

In this exercise, you perform a cam calculation. The cam contour is calculated based on existing boundary conditions. Data for NC production is also created.

7

„

Configuring the cam plate calculation

„

Creating movement sections

„

Creating velocity and acceleration curves

„

Creating a cam geometry from the graph

„

Creating NC data

103

Key Terms Term

Definition

acceleration

Graph of acceleration of the straight driven element of the rotation angle acceleration of a rocker and the cam plate angle of rotation.

cam

Types of gears for obtaining unusual and irregular motions that would be difficult to produce otherwise.

curve path

Geometric shape of the cam.

movement diagram

The representation of the cam as a graph of the lift and the angle of rotation of the cam plate (straight driven element). If the driven element is a rocker, the lift corresponds to an angle of rotation of the rocker.

movement section

Part of the movement diagram. Some sections are defined by design. For example, the maximum lift of 15 mm is reached at an angle of 90°.

NC

Numerical Control. Used in the manufacturing industry to represent the control on machine tool movement through numeric data for 2 to 5 axis machining.

resolution

Controls the precision of curves. A low value increases computing time. Use a higher value for initial design.

step width

Specifies the distance between the points used for the NC records

velocity

Graph of the speed of the straight driven element, or the rotation angle of a rocker and the cam plate angle of rotation.

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Cam Design With cam plates, you can implement all movements required in the scope of process control with a minimum number of gear elements. The basis for systematic design procedures is offered using standardized laws of movement in the development of new cam gears. With AutoCAD Mechanical create cams (cam plates and cylindrical cams) based on sections drawn in a movement diagram. You can also calculate velocity and acceleration of an existing section of the movement diagram. The cam curve path can be determined via the calculated cam sections. An existing curve path can be scanned and transferred in the movement diagram. A driven element can be coupled to the cam. NC data can be created via the curve path.

Getting Started With cam design, you can generate a flat or cylindrical cam. In this example, you create a flat cam from a diagram. Insert the initial drawing. 1 Open the file tut_ex07 in the acadm\tutorial folder. Toolbutton Open Menu

File -> Open

Command

OPEN

2 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View -> Zoom -> Extents

Command

ZOOM

3 Zoom in to the area marked with W1 and W2. Toolbutton Zoom Window Menu

View -> Zoom -> Window

Command

ZOOM

4 Respond to the prompts as follows: Specify first corner: Specify W1 Specify opposite corner: Specify W2

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Now you can start designing the cam plate.

Configuring the Cam Plate Calculations The first task is to specify the settings for the cam plate calculations. Here you define the resolution, the base diameter, the revolution of the cam, and the scale for velocity and acceleration. 1 Start the cam configuration. Toolbutton Cam Configuration Menu

Content -> Cam Plates and Cylinders -> Cam Configuration

Command

AMCAMCONF

2 In the Configuration dialog box, specify: Resolution: 2 Base Diameter for CAM: 0 Revolutions of cam: 1000 Scale for velocity v: 0.01 Scale for acceleration a: 0.0001

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3 Choose OK. Two icons in the Configuration dialog box show the two cam calculating options: flat cams and cylindrical cams (in case of parallel lift). Note that in our example, the velocity is inscribed in color 1 (red), and the acceleration in color 3 (green). Next you specify the baseline and cam position. NOTE The base cam diameter with stroke 0 can have the value 0 or a positive value. The following figure explains the meaning of the base diameter. The cam radius with stroke 0 is composed of the half base diameter and the distance (X), calculated from the diagram. In case, the base diameter is 0, only the distance calculated from the diagram will be effective.

4 Respond to the prompts as follows: Specify 0° point on baseline: Select the left end of line a at point 1 Specify 360° point on baseline: Select the right end of line a at point 2 Specify center of cam: Select the centerline cross midpoint at point 3 Specify 0° direction of cam : Press ENTER Select baseline for diagram to store the configuration: Select line a

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Next you create the movement sections.

Creating Movement Sections In this section, you create two movement sections. The gap between the defined movements in the diagram (b, c, d) needs to be connected by a polynom of 5 degrees. In 80 percent of all cases, you need a polynom of 5 degrees to get a smooth transition between two movements (for example, between b and c). The program only supports a polynom of 5 degrees. The movement sections are created by the transition command using the start point and the end point of the section, as well as the first and second derivations at these points.

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1 Start the Transition command. Toolbutton Transition Menu

Content -> Cam Plates and Cylinders -> Transition

Command

AMCAMTRANS

2 Respond to the prompts as follows: Specify start point: Select the right end of line b Specify ending point: Select the left end of line c Specify slope at start point or velocity[mm/s] or [Read from vdiagram]: Select a point on line b Specify slope at the end point or velocity[mm/s] or [Read from vdiagram]: Select a point on line c Enter acceleration at start point a[mm/s^2] or [Read from a-diagram] : Press ENTER Enter acceleration at end point a[mm/s^2] or [Read from a-diagram] : Press ENTER The movement section is automatically drawn. 3 Repeat steps 1 and 2 to define the second movement section between lines c and d. The resulting movement sections should look like the following:

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Creating Velocity and Acceleration Curves The Calculate Vel/Acc command determines the velocity and acceleration of an existing section of the movement diagram. The calculation uses the graphical commands and is based on the gradient of the movement diagram. Consequently, the beginning and the end of these curves may not coincide precisely with the ends of the movement section. For this purpose, you simply select the existing movement sections. In order to complete the velocity and acceleration curves, you need to generate the velocity and acceleration curves for sections b, c, and d. The previous section only resulted in the respective curves for sections b – c and c – d. 1 Start the velocity and acceleration calculation. Toolbutton CalculateVel/Acc Graphs Menu

Content -> Cam Plates and Cylinders -> CalculateVel/Acc Graphs

Command

AMCAMGRAPH

2 Respond to the prompts as follows: Select movement diagram for cam: Select objects: Select lines b, c and d Select objects: Press ENTER

NOTE In this case, the movement sections b, c, and d appear horizontal in the movement graph. Thus, velocity and acceleration are equal to 0 (the lines overlap on line a).

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Creating Cam Geometry from the Graph In this section, you generate the cam geometry from the previously created movement graph. Creating the curve path is easy; you select the sections in the movement diagram. The colors of the sections correspond to the colors of the curve path sections. The curve path is developed in counter-clockwise direction. 1 Start the command Create Cam from Graph. Toolbutton Create Cam from Graph Menu

Content -> Cam Plates and Cylinders -> Create Cam from Graph

Command

AMCAMCRCAM

2 Respond to the prompts as follows: Select movement diagram for cam: Select objects: Select the lines b, c, d and the previously created movement (sections b – c and c – d) Select objects: Press ENTER Select movement diagram for cam: Select objects: Press ENTER

AutoCAD draws the cam geometry from the movement diagram as represented in the following figure:

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111

Creating NC Data Now, you generate the NC data for a milling machine to produce the part. 1 Start the NC Data calculation. Toolbutton Calculate NC Data Menu

Content -> Cam Plates and Cylinders -> Calculate NC Data

Command

AMCAMNC

2 In the Create NC-Data dialog box, specify: New Origin for Milling Machine: On Enter the step width: 0.5

3 Choose OK. 4 In the Enter filename dialog box, enter Cam.nc as the filename, and choose Save. 5 Respond to the prompts as follows: Select cam polyline (offset may be needed for cylinder cam): Select the 5 path sections around point 3 Select objects: Press ENTER

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6 Continue to respond to the prompts as follows: Specify coordinate origin for milling machine: Select the intersection at point 4 Reverse direction due to milling tool [Y/N] : Press ENTER

The NC data is created from the geometry and stored in the specified file. Next, you need to define the run-out and run-in points of the milling cutter. 7 Continue to respond to the prompts as follows: Specify run-out from end point: Select the intersection at point 5 Specify run-in to starting point: Select the intersection at point 5

The generation of the NC data is completed. The NC data can be displayed with any text editor as represented in the following figure:

Creating NC Data

|

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Calculating Moment of Inertia and Deflection Line

In This Chapter

In this tutorial, you calculate the moment of inertia for a profile section, and calculate the deflection line on a beam, based on the profile

8

„

Calculating the moment of inertia

„

Calculating the deflection line

calculation.

115

Key Terms Term

Definition

deflection line

Deflection lines are calculated based on the predefined force direction (F) or to radial direction (s).

deflection moment

Deflection moment is calculated based on the predefined force direction (F) or to radial direction (s).

distributed force

A force that is spread over a certain area.

fixed support

A support that is fixed to the part and cannot be moved.

load

Forces and moments, which act on a part.

moment of inertia

An important property of areas and solid bodies. Standard formulas are derived by multiplying elementary particles of area and mass by the squares of their distances from reference axes. Moments of inertia, therefore, depend on the location of reference axes.

movable support

Support that is not fixed.

point force

A force that is concentrated on a point.

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Calculating Moment of Inertia and Deflection Line 4

4

The measurement unit for the moment of inertia is mm or inches . These are geometrical values, which appear at deflection, torsion, and buckling calculation. AutoCAD Mechanical uses the result of the moment of inertia calculation for the deflection line calculation. Moment of inertia calculations are performed on cross sections of beams or on other objects that can be represented as closed contours. Calculations can be performed on a cross section of any shape, as long as the geometry of the cross section forms a closed contour. AutoCAD Mechanical determines the center of gravity for a cross section, draws the main axes, and calculates the moment of inertia for each of those axes. You can also select a load direction for a cross section; AutoCAD Mechanical calculates the moment of inertia and angle of deflection for that load. NOTE The ISO standard part standard has to be installed for this tutorial exercise.

Getting Started First, you load the drawing. 1 Open the file tut_ex08 in the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

The drawing contains this profile:

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Calculating the Moment of Inertia Before you can perform any calculations on a profile, you need to know its moment of inertia. 1 Start the calculation for the moment of inertia. Toolbutton Moment of Inertia Menu

Content > Calculations > Moment of Inertia

Command

AMINERTIA

2 Respond to the prompts as follows: Select objects: Select the entire profile section Select objects: Press ENTER Is the area filled correctly? (Y/N)? : Press ENTER The coordinates of the centroid and the moment of inertia along the principle axes are displayed on the command line, as follows: Coordinates of centroid (in user coordinates): X coordinate: 228.071933 Y coordinate: 150.027674 Moments of inertia along principal axes: I1: 2.359e+004 I2: 1.4095e+004 Axis angle for major moment (I1): 5.3 Now, define the direction of the loads: they must be in one plane. 3 Respond to the prompt as follows: Specify direction of load forces (must all lie in one plane): Enter 270 The data for this load direction is displayed on the command line, as follows: Effective moment of inertia for this load direction: 2.341e+004 Angle of deflection: 266.5 Maximum distances neutral line - border: Extension side: 16.690 Compression side: 14.444 Now, you have to enter a description for the calculated profile and locate the block with the calculation data in the drawing. 4 Respond to the prompts as follows: Enter description: Enter Frame Profile Insertion point: Place the calculation block next to the profile

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Your drawing looks like this:

NOTE The main axes, 1 and 2, are the axes with the most and least deflection. The F arrow displays the direction of the force, the s arrow displays the resultant deflection. The moment of inertia block shows the moments related to the main axis, the maximum distances from the edges, and the calculated area. For more detailed information, see the online help. A side view of the profile has been created for the deflection line. 5 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

Calculating the Deflection Line The calculation of the deflection line requires the calculation result from the moment of inertia calculation. Now, you calculate the deflection line under a specific load situation.

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119

1 Start the deflection line calculation. Toolbutton Deflection line Menu

Content > Calculations > Deflection Line

Command

AMDEFLINE

2 Respond to the prompts as follows: Select Moment of Inertia block: Select the previously generated calculation block, P1 Specify start point or [Existing beam]: Select the left end of the beam, P2 Specify end point: Select the right end of the beam, P3

3 In the Beam Calculation dialog box, choose Table.

4 In the Material dialog box, select ANSI standard and the material Al. bronze cast. NOTE If ANSI standard is not installed at your system, selecting a different standard according to your preference is also possible, but the results will differ from the results in this tutorial exercise (if you select DIN for example, you can select a similar material like AlMgSi0.5F22 to achieve similar results).

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Next, you define the supports and the loads. 5 Choose the Fixed Support icon, and respond to the prompt as follows: Insertion point: Select the left edge of the beam 6 Choose the Movable Support icon, and respond to the prompt as follows: Insertion point: Select the right edge of the beam 7 Choose the Uniform Load icon, and respond to the prompts as follows: Insertion point: Select the left edge of the beam Endpoint: Select the midpoint of the beam using the midpoint snap Uniform Load [N/mm] : Enter 10 8 Choose the Moment icon, and respond to the prompts as follows: Insertion point: Select a point approximately in the middle of the uniform load Bending Moment (Nm) : Enter 3 9 In the Beam Calculation dialog box, choose Moments and Deflection. 10 In the Select Graph dialog box, select the options as shown in the figure below, and choose OK.

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11 Respond to the prompts as follows: Enter scale for bending moment line (drawing unit:[Nm] : Press ENTER Enter scale for deflection line (drawing unit:mm) : Press ENTER Insertion point: Select an appropriate position in the drawing The result looks like this:

The calculation result block displays all important data on your calculation:

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124

Creating a Shaft With Standard Parts

In This Chapter

In this tutorial, you learn how to use the shaft generator. You create and edit shaft sections. You also insert a bearing and perform a bearing calculation.

9

„

Configuring the snap options

„

Starting and configuring the shaft generator

„

Creating shaft sections

„

Inserting a profile

„

Inserting a chamfer and a fillet

„

Inserting a shaft break

„

Creating a side view

„

Inserting a thread

„

Editing and inserting a shaft section

„

Replacing a shaft section

„

Inserting a bearing

125

Key Terms Term

Definition

bearing calculation

Calculates limiting value, dynamic and static load rating, dynamic and static equivalent load, and fatigue life in revolutions and hours.

chamfer

A beveled surface between two faces or surfaces.

dynamic calculation

Calculation required for a revolving bearing. The result is the Adjusted Rating Life. This is the life associated with 90% reliability with contemporary, commonly used material, and under conventional operating conditions. With the number of revolutions you get the life in working hours.

dynamic dragging

The act of determining the size of a standard part with the cursor while inserting it into a side view. The standard part is displayed dynamically on the screen and can be dragged to the next possible size and length. The values (sizes) are taken from the Standard parts database.

fillet

A curved transition from one part face or surface to another. The transition cuts off the outside edge or fills in the inside edge.

gear

Any several arrangements, especially of toothed wheels in a machine, which allow power to be passed from one part to another to control the power, speed, or direction of movement.

radius reflection line

Thin line that represents the radius in the side or top view.

shaft break

Interruption of a shaft. A shaft can be interrupted at a point, and the shaft break symbols are inserted in a suitable size.

shaft generator

Tool to draw rotationally symmetric parts. A shaft is usually created from left to right using different sections. These sections are positioned automatically one after the other. Additionally, any shaft section can be inserted, deleted, or edited.

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Creating a Shaft with Standard Parts In this section you generate a shaft with standard parts with the shaft generator. You also perform a bearing calculation. NOTE The ISO standard part standard has to be installed for this tutorial exercise.

Configuring the Snap Options First, you configure the snap options. 1 Start the Power Snap Settings. Toolbutton Power Snap Settings 1-4 Menu

Assist > Draft Settings > Power Snap Settings 1-4

Command

AMPOWERSNAP

2 In the Power Snap Settings dialog box, activate the tab Setting 4 and configure the snap settings as shown in the following:

3 Choose OK.

Starting and Configuring the Shaft Generator In the next steps, you start and configure the shaft generator. 1 Start the Shaft Generator command. Toolbutton Shaft Generator Menu

Content > Shaft Generator

Command

AMSHAFT2D

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127

2 Respond to the prompts as follows: Specify start point or select centerline [New shaft]: Enter 150,150 Centerline ending point: Enter 240,150 NOTE The start and end points of the centerline are only important in determining the direction. The length of the centerline is automatically adapted to the length of the shaft. 3 In the Shaft Generator dialog box, press the appropriate button, and enter the values as indicated in the following:

4 Choose the Config button to start the Shaft Generator Configuration, and configure the shaft generator as shown in the following figure:

5 Choose OK. You return to the Shaft Generator dialog box.

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Creating Cylindrical Shaft Sections and Gears The shaft generator is configured. Now you want to generate the first shaft segments. 1 Choose the lower cylinder button to define a cylinder section, and respond to the prompts as follows: Specify length : Enter 12 Specify diameter : Enter 20 2 Choose the gear button, and enter the values for module, number of teeth, and length as shown in the following figure:

NOTE Here, the DIN standard requires that you give the module. The ANSI standard requires the reciprocal 1/module. You can switch between these two representations using the DIN and ANSI toggle. 3 Choose the lower cylinder button to define a further cylinder section, and respond to the prompts as follows: Specify length : Enter 5 Specify diameter : Enter 20 4 Choose the gear button, and enter the values for module, number of teeth, and length as shown in the following figure:

Creating Cylindrical Shaft Sections and Gears

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5 Choose the lower cylinder button to define another cylinder section, and respond to the prompts as follows: Specify length : Enter 4 Specify diameter : Enter 24 6 Choose the lower cylinder button to define another cylinder section, and respond to the prompts as follows: Specify length : Enter 33 Specify diameter : Enter 20 Now, you have created the first five sections of the shaft as represented in the following figure:

Inserting a Spline Profile Now, you add a spline profile to the shaft. 1 Choose the Profile button. 2 Choose ISO 14 in the database browser. 3 In the Splined Shaft ISO 14 dialog box, select the nominal size 6 x 13 x 16 and define a length of 26. Choose OK.

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Now, you have created another section of the shaft as represented in the following figure:

Inserting a Chamfer and a Fillet In this step, you apply a chamfer and a fillet to the shaft. 1 Choose the Chamfer icon to apply a chamfer to a shaft section, and respond to the prompts as follows: Select object: Select the leftmost cylinder section as shown in the following figure, P1 Specify length (max. 12) : Enter 2 Specify angle (0–79) : Enter 45

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2 Choose the Fillet icon to apply a fillet to a shaft section, and respond to the prompts as follows: Select object: Select the cylinder section between the two gears as shown in the following figure, P1 Enter radius (max. 5.00) : Enter 2

After applying the chamfer and the fillet, the shaft looks like the following figure:

Inserting a Shaft Break Here, you insert a shaft break in the drawing. 1 Choose the Break icon to insert shaft break, and respond to the prompts as follows: Specify point: Select the midpoint of the cylindrical section as shown in the following figure Specify length : Enter 10

The shaft break is inserted.

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Creating a Side View of the Shaft Next, you insert a side view of the shaft. 1 Choose the Side view icon. 2 In the Side view from dialog box, select right. Choose OK.

3 Respond to the prompt as follows: Specify insertion point: Press ENTER The right side view is inserted at the proposed position as shown in the following figure:

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Inserting a Thread Now, you add a thread to the shaft. 1 Choose the Thread button to insert a thread, and select ISO 261 – M in the browser. 2 In the Thread ISO 261 – M dialog box, select M10 and enter a length of 20. Choose OK.

The thread is added to the shaft, which looks like this now:

Editing and Inserting a Shaft Section In this section, you edit an existing shaft section and insert a new section. 1 Choose the Edit button, and respond to the prompts as follows: Select object: Select the first cylindrical section, P1 Specify length : Press ENTER Specify diameter : Enter 18

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The diameter is changed to 18 while the length remains 12. 2 Choose the Insert button, and respond to the prompt as follows: Specify point: Select a point after the second gear, P1

3 Choose the Slope icon, and respond to the prompts as follows: Specify length or [Dialog] : Enter 4 Specify diameter at start point : Enter 28 Specify diameter at end point or [Slope/Angle] : Enter 22 A slope is inserted at the specified point.

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Replacing a Shaft Section The previously inserted slope needs to be deleted again. 1 Choose the Undo button. The previous slope insertion is undone. Now, replace an existing shaft section. To do this, you change the settings in the configuration. 2 Choose the Config button to start the shaft generator configuration, and change the setting For Segment inserted to Overdraw. Choose OK.

3 Choose the Slope icon, and respond to the prompt as follows: Specify length or [Dialog] : Enter D 4 In the Shaft Generator – Cone dialog box, make the following settings and choose OK.

The slope replaces the cylindrical shaft section.

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Inserting a Bearing Here, you insert a bearing and perform a bearing calculation. 1 Choose the Standard Parts button, and select a radial bearing ISO 355 in the browser. Respond to the prompts as follows: Specify insertion point on shaft contour: Specify point P1 Direction to Left/Right: Select a point to the right

2 In the ISO 355 dialog box, choose Next >.

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3 In the ISO 355 dialog box, specify the loads as shown, and choose Next >.

4 In the ISO 355 dialog box, select the bearing 2BD – 20 x 37 x 12, and choose Finish.

The bearing is inserted, and you can select the available sizes by dragging. 5 Choose 2BD – 20 x 37 x 12 and press ENTER. The bearing is inserted.

6 Choose Close to leave the Shaft Generator.

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Performing a Shaft Calculation

In This Chapter

In this tutorial, you perform a calculation on an existing shaft. You apply various loads to a supported shaft, perform the calculation, and insert results into a drawing.

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Creating the contour of a shaft

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Specifying the material

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Defining the supports

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Specifying the loads

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Calculating and inserting the results

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Key Terms Term

Definition

deflection line

Deflection line calculations are based on the predefined force direction (F) or the radial direction (s).

deflection moment

Deflection moment calculations are based on the predefined force direction (F) or the radial direction (s).

fixed support

A support that is fixed to a part and cannot be moved.

load

The forces and moments that act on a part.

gear

Any several arrangements, especially of toothed wheels in a machine which allows power to be passed from one part to another so as to control the power speed or the direction of movement.

movable support

A support that is not fixed.

point force

A force that is concentrated on a point.

stress

Force or pressure on a part. Stress is the force per area.

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Performing a Shaft Calculation With AutoCAD Mechanical, you can perform a shaft calculation using a contour created with the Shaft Generator or any other symmetric shaft contour. The function provides a static calculation, which is important for the design of the shaft and the bearing load. NOTE The ISO standard part standard has to be installed for this tutorial exercise.

Getting Started In this tutorial, you calculate a gear box shaft. The general way to calculate an existing shaft is to define the contour and insert forces and supports. The routine calculates all necessary values and draws the respective graphs for moment and deflection. First, you insert the initial drawing. 1 Open the file tut_ex10 in the acadm\tutorial folder. Toolbutton Open Menu

File -> Open

Command

OPEN

2 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View -> Zoom -> Extents

Command

ZOOM

3 Zoom in to the shaft using Zoom Window. Toolbutton Zoom Window Menu

View -> Zoom -> Window

Command

ZOOM

4 Respond to the prompts as follows: Specify first corner: Specify point P1 Specify opposite corner: Specify point P2

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Creating the Contour of a Shaft First, you create the contour of the shaft. 1 Start the Shaft Calculation. Toolbutton Shaft Calculator Menu

Content -> Calculations -> Shaft Calculation

Command

AMSHAFTCALC

2 Respond to the prompts as follows: Select contour or [Create contour] : Enter C Select objects for outer contour Select objects: Select the complete shaft Select objects: Press ENTER Select shaft centerline: Select the centerline of the shaft After you have created the contour of the shaft, the Shaft Calculation dialog box is displayed so that you can select the boundary conditions, the material, and the representation of the calculation results.

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Specifying the Material You specify the material by entering its characteristics in the respective fields or by selecting it from a table containing the most commonly used materials. 1 Choose Table, select the ANSI standard, and select the material SAE 1045 from the table. NOTE If the ANSI standard is not installed on your system, you can select a different standard, but the results may differ from the results in this tutorial (if you select DIN for example, you can select a similar material like, E335, to achieve similar results).

Placing the Supports Now, you specify the positions where the shaft is to be supported. 1 In the Shaft Calculation dialog box, select the Fixed Support icon, and respond to the prompt as follows: Fixed Support Insertion point: Select the midpoint of the leftmost shaft section 2 Select the Fixed Support icon again, and respond to the prompt as follows: Fixed Support Insertion point: Select the midpoint of the third cylindrical shaft section, as shown in the following drawing

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Specifying the Loads After specifying the positions of the supports, you specify the effective loads. 1 In the Shaft Calculation dialog box, select the Gear icon and respond to the prompt as follows: Gear Insertion point: Select the midpoint of the second gear, as shown in the following figure

2 In the Gear dialog box, specify: Torsion Moment: 15 Pitch Diameter d1: 38

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3 Choose OK. 4 Select the Point Load icon, and respond to the prompts as follows: Point Load Insertion point: Select the midpoint of the profile section, as shown in the following figure Specify an rotation angle: Press ENTER

5 In the Point Load dialog box, specify: Point Load: 2500

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6 Choose OK. 7 Select the Torque icon, and respond to the prompt as follows: Torsion Moment Insertion point: Select the midpoint of the profile section as shown in the following figure

8 In the dialog box, specify: Torsion Moment: 15

9 Choose OK. You have finished specifying the boundary conditions, and you are returned to the Shaft Calculation dialog box.

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Calculating the Shaft and Inserting the Results Now, you calculate the shaft and insert the results in your drawing in three graphs. 1 Choose Moments and Deformations to start the calculation. 2 In the Select Graph dialog box, select options as shown in the following figures and choose OK.

3 Respond to the prompts as follows: Specify first corner point: Press ENTER Enter scale for deflection line dy (drawing unit : mm) : Press ENTER

Enter scale for deflection line dz (drawing unit : mm) : Press ENTER Enter scale for torsion moment line (drawing unit : Nm) : Press ENTER

Insertion Point: Select an appropriate point to the right of the shaft The deflection and torsion moment lines are inserted automatically. Your drawing looks like this:

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The result table gives you the most important information for your calculated shaft such as safety factor, maximum deflection, maximum stress, etc.

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Working with Standard Parts

In This Chapter

In this tutorial, you learn to work with standard parts. You insert a screw connection, a hole,

„

Inserting a screw connection

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Copying a screw connection with Power Copy

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Inserting a screw connection with Power Recall and performing a screw calculation

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Editing a screw connection with Power Edit

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Working with Power View

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Deleting with Power Erase

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Inserting a hole

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Inserting a pin

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Hiding C-lines

„

Simplifying the representation of standard parts

and a pin. You also edit the standard parts with Power Commands.

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Key Terms Term

Definition

background

A contour that is covered by another contour or by objects that are lying behind another contour, in the 3D sense. A background may be a foreground for an additional contour.

C-line (construction line)

A line that is infinite in both directions or infinite starting at a point which can be inserted into the drawing area. You use C-lines to transfer important points (for example, center points of bore holes) into other views or drawing areas.

countersink

A chamfered hole that allows bolt and screw heads to be flush or below the part surface.

dynamic dragging

The act of determining the size of a standard part with the cursor while inserting it into a side view. The standard part is displayed dynamically on the screen and can be dragged to the next possible size and length. The values (sizes) are taken from the Standard parts database.

Power Command

Summary term for Power Copy, Power Recall, Power Edit, Power Dimensioning, Power Erase and Power View.

Power Copy

A command that copies a drawing object to another position in the drawing. Power Copy produces an identical copy of the copied object.

Power Edit

A edit command for all objects in your drawing.

Power Erase

Command for deleting. Use Power Erase when you delete part reference numbers or when you delete dimensions that were created with Power Dimensioning.

Power Recall

A command that lets you click an existing drawing object and places you in the correct command for creating that object.

Power View

A tool where you can quickly and easily create a standard part top view from a side view.

representation

Standard parts representation in a drawing in normal, simplified, and symbolic mode.

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Working with Standard Parts AutoCAD Mechanical Power Pack provides a large selection of standard parts to work with, including regular and fine threads and many types of holes. With the AutoCAD Mechanical Power Pack, you can insert complete screw connections (screws with holes and nuts) in one step. Some intelligence has been built into this process. For example, if you select a screw with a metric thread, you get only metric threads when you add any additional parts such as threaded holes or nuts. NOTE The ISO standard part standard has to be installed for this tutorial exercise.

Getting Started First, insert the initial drawing. 1 Open the file tut_ex11 in the acadm\tutorial folder. Toolbutton

Open

Menu

File > Open

Command

OPEN

The gearbox is not completed yet. We want to add standard components and show, how easy it is to edit standard parts with an automatic update of the background objects. 2 Zoom in to the differential gear, using the Zoom Window command. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

3 Respond to the prompts as follows: Specify first corner: Specify point P1 Specify opposite corner: Specify point P2

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Inserting a Screw Connection Now, you insert a screw connection at the differential gear housing. 1 Start the Screw Connection command. Toolbutton Screw Connection Menu

Content > Screw Connection

Command

AMSCREWCON

2 In the Screw Connection dialog box, choose the Screw button.

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3 In the Please select a Screw dialog box, select Socket Head Types.

4 Then select ISO 4762 and Front View.

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5 In the Screw Connection dialog box, choose the upper Hole button. Then select Holes, Through Cylindrical, and ISO 273 normal. 6 In the Screw Connection dialog box, choose the lower Hole button. Then select Inner Threads, Blind, and ISO 262. 7 In the Screw Connection dialog box, specify the size M4, and choose Next >.

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8 In the Screw Assembly Grip Representation - Front View dialog box, select Normal, and choose the Finish button.

9 Respond to the prompts as follows: Specify insertion point of first hole: Specify point P1 Specify endpoint of first hole [Gap between holes]: Specify point P2 Drag Size: Drag the screw connection dynamically to the size M4 x 16, and click Drag Size: Enter 12

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Now, you have inserted the screw connection, specified a screw length of 16 mm, and specified a blind hole depth of 12 mm. NOTE During dragging, the size of the screw is shown in the status bar, where the coordinates are usually displayed.

The background is automatically hidden, and your drawing should look like this:

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Copying a Screw Connection with Power Copy With Power Copy, you can copy complete objects, including the information attached to those objects. In the case of a screw connection, you copy the whole screw connection to another location. The background is automatically updated. Now, copy the previously inserted screw connection with the Power Copy command. 1 Start the Power Copy command. Toolbutton Power Copy Menu

Modify > Power Commands > Power Copy

Command

AMPOWERCOPY

2 Respond to the prompts as follows: Select object: Select the previously inserted screw Specify insertion point: Specify the point as shown in the following figure Specify rotation angle: Enter 0

The screw is copied to the specified location. Your drawing should look like this:

Copying a Screw Connection with Power Copy

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Using Power Recall and Performing a Screw Calculation With Power Recall, you can call a function just by clicking an object in a drawing. In this exercise, you click a screw connection, so the Screw Connection command will start. Use Power Recall to recall the screw connection. Edit the screw connection, calculate it, and insert it into the drawing at the cover plate. 1 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

2 Zoom in to the cover plate using Zoom Window. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

3 Respond to the prompts as follows: Specify first corner: Specify point P1 Specify opposite corner: Specify point P2

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4 Start the Power Recall command. Toolbutton

Power Recall

Menu

Modify > Power Commands > Power Recall

Command

AMPOWERRECALL

5 Respond to the prompt as follows: Select object: Select the screw, P1

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6 In the Screw Connection - Front View dialog box, delete the ISO 273 normal hole by clicking the Delete (X) button to the right of the ISO 273 normal field.

NOTE You have to delete the ISO 273 hole from the screw connection, because otherwise, the built-in intelligence would prevent the selection of a countersink screw since it doesn’ t match with the ISO 273 through hole.

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7 In the Screw Connection dialog box, choose the Screw button. Then Countersink Head Type, ISO 10642, and Front View. 8 In the Screw Connection dialog box, choose the upper Hole button. Then select Holes, Countersinks, and ISO 7721. 9 In the Screw Connection dialog box, choose the lower Hole button. Then select Inner Threads, Through, and ISO 262 (Regular Thread). Now, use the Precalculation function of the Screw Connection dialog box to calculate the screw connection. 10 In the Screw Connection dialog box, choose the Precalculation button.

11 In the Screw Diameter Estimation – VDI2230 dialog box, specify: Material Class: 10.9 Applied Force: 1500 N Nature of Load: Static and Centric applied Axial Force (upper-left icon) Method for Tightening Screw: Mechanical Screw Driver The Result field displays a sufficient diameter of M4.

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12 Choose OK. 13 In the Screw Connection dialog box, the calculation has marked M4. Choose the Finish button.

14 Respond to the prompts as follows: Specify insertion point of first hole: Specify point P1 Specify endpoint of first hole [Gap between holes]: Specify point P2 Drag Size: Drag the screw connection dynamically to the size M4 x 12 and click Drag Size: Enter 8

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Now, you have inserted the specified screw connection with a screw length of 12 mm and a blind hole depth of 8 mm. Your drawing should look like this:

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Editing a Screw Connection with Power Edit Instead of having to use different editing commands for different objects, you can use just one command, Power Edit, for editing all objects in a drawing with built-in intelligence. Using Power Edit on a screw connection, the whole assembly can be edited and will be updated in your drawing with an automatic background update. Now, edit the second screw at the cover plate to get the same countersink screw. 1 Start the Power Edit command. Toolbutton Power Edit Menu

Modify > Power Commands > Power Edit

Command

AMPOWEREDIT

2 Respond to the prompt as follows: Select object: Select the lower screw at the cover plate, P1

3 In the Screw Connection dialog box, delete the ISO 273 normal hole by clicking the delete (X) button to the right of the ISO 273 normal field. 4 In the Screw Connection dialog box, choose the Screw button. Then Countersink Head Type, ISO 10642, and Front View. 5 In the Screw Connection dialog box, choose the upper Hole button. Then Holes, Countersinks, ISO 7721. 6 Select M4 and choose the Finish button.

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7 Respond to the prompts as follows: Specify insertion point of first hole [Gap before hole]: Specify point P1 Specify endpoint of first hole [Gap between holes]: Specify point P2 Drag Size: Drag the screw connection dynamically to the size M4 x 12 and click Drag Size: Enter 8

The edited screw connection is inserted. Your drawing should look like this:

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Working with Power View With Power View, you can quickly generate a top or bottom view of a side view of a standard part and vice versa. Now, use Power View to insert the screws into the top view of the coverplate. 1 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

2 Zoom in to the coverplate, using Zoom Window. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

3 Respond to the prompts as follows: Specify first corner: Specify point P1 Specify opposite corner: Specify point P2

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4 Start the Power View command. Toolbutton Power View Menu

Modify > Power Commands > Power View

Command

AMPOWERVIEW

5 Respond to the prompts as follows: Select object: Select the screw at the cover plate, P1 Specify insertion point: Specify the centerline cross at the top view of the cover plate, P2

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The top view of the screw connection is inserted into the top view of the coverplate. Your drawing should look like this:

NOTE Since you made the Power View to a screw connection, you can insert a top view of the screw connection. If you select a screw that is not part of a screw assembly, you can insert a top view or a bottom view. 6 Repeat steps 4 and 5 to insert the top view of the screw at the other three centerline crosses of the top view of the coverplate. The coverplate should look like this:

Deleting with Power Erase Power Erase is an intelligent erase command. It detects the object information of a part. If you delete a screw connection with Power Erase, the representation of the background is automatically corrected. Now, delete a screw using the Power Erase command.

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1 Start the Power Erase command. Toolbutton Power Erase Menu

Modify > Power Commands > Power Erase

Command

AMPOWERERASE

2 Respond to the prompt as follows: Select objects: Select the screw, P1, as shown in the following drawing Select objects: Press ENTER

The screw connection is deleted and the lines and hatch are restored. Your drawing should look like this:

Inserting a Hole Now, you replace the previously deleted screw connection with a pin. Insert a blind hole for the pin. 1 Start the Blind Hole command. Toolbutton Blind Holes Menu

Content > Holes > Blind Holes

Command

AMBHOLE Inserting a Hole

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2 In the Select a Blind Hole dialog box, select acc. to ISO 273 and Front View. 3 Respond to the prompts as follows: Specify insertion point: Specify point P1 Specify rotation angle: Specify point P2

4 In the acc. to ISO 273 - Nominal Diameter dialog box, select a size of 5, and choose the Finish button.

5 Continue to respond to the prompt as follows: Drag Size Enter 20 The blind hole is inserted. Your drawing should look like this:

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Inserting a Pin Now, insert a pin into the blind hole. 1 Start the Cylindrical Pins command. Toolbutton Cylindrical Pins Menu

Content > Fasteners > Cylindrical Pins

Command

AMCYLPIN

2 In the Select a Cylindrical Pin dialog box, select ISO 2338 and Front View. 3 Respond to the prompts as follows: Specify insertion point: Specify point P1 Specify rotation angle: Specify point P2

4 In the ISO 2338 - Nominal Diameter dialog box, select a size of 5, and choose the Finish button.

5 Continue to respond to the prompt as follows: Drag Size Drag the pin to size 5 h8 x 18 and click the left mouse button 6 In the Select Part Size dialog box, select 5 h8 x 18, and choose OK.

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The pin is inserted. Your drawing should look like this:

Hiding C-Lines For a better overview, you can hide the C-lines by turning them off temporarily. 1 Zoom to the extents of the drawing. Toolbutton Zoom Extents Menu

View > Zoom > Extents

Command

ZOOM

2 Start the C-Line On/Off command. Toolbutton C-Line On/Off Menu

Assist > Layer / Layergroup > C-Line On/Off

Command

AMCLINEO

All C-lines are turned off temporarily.

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Simplifying the Representation of Standard Parts In some cases, for example in complex assemblies, it is helpful to have a simplified representation of the standard parts for a better overview. With AutoCAD Mechanical Power Pack, you can switch between different representation types without losing object or part information. Now, you change the representation of the differential gear screws. 1 Start the Change Representation command. Toolbutton Change Representation Menu

Content > Change Representation

Command

AMSTDPREP

2 Respond to the prompts as follows: Select objects: Select the differential gear with a window Select objects: Press ENTER

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3 In the Switch Representation of Standard Parts dialog box, select Symbolic, and choose OK.

The representation of the selected standard parts is simplified. Your drawing should look like this:

The standard parts library of AutoCAD Mechanical 2000 is not only a simple block library, but also an intelligent library, that helps you design with standard parts in a very effective way.

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Chain Calculation

In This Chapter

In this tutorial, you calculate a chain length and insert sprockets and chain links into a drawing.

12

„

Performing a length calculation

„

Optimizing the chain length

„

Inserting Sprockets

„

Inserting a Chain

175

Key Terms Term

Definition

partition

Distance in mm or inches between centers of adjacent joint members. Other dimensions are proportional to the pitch. Also known as pitch.

pitch diameter

The diameter of the pitch circle that passes through the centers of the link pins as the chain is wrapped on the sprocket.

roller chain

A roller chain is made up of two kinds of links: roller links and pin links alternately and evenly spaced throughout the length of the chain.

sprocket

A toothed wheel that transfers the power from the chain to the shaft or the other way round.

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Chain Calculation NOTE The ISO standard part standard has to be installed for this tutorial exercise.

Getting Started First, load the initial drawing. 1 Open the file tut_ex12 in the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

2 Zoom in to the area of interest, marked with W1 and W2. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

3 Respond to the prompts as follows: Specify first corner: Specify W1 Specify opposite corner: Specify W2

The drawing contains a chain housing, sprocket positions, and Getting Started

| 177

points.

Performing a Length Calculation 1 Start the Length Calculation command. Toolbutton Length Calculation Menu

Content > Chains / Belts > Length Calculation

Command

AMCHAINLENGTHCAL

2 In the Belt and Chain Length Calculation dialog box, choose the Library button.

3 In the Library, select ISO 606 metric. 4 In the Select Part Size dialog box, specify: Standard: ISO 606 – 05B – 1

5 Choose OK.

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6 In the Belt and Chain Length Calculation dialog box, choose OK, and respond to the prompts as follows: Specify 1st point for tangent or [Undo] : Select circle a at point 1 Specify 2nd point for tangent: Select circle c at point 2 Specify 1st point for tangent or [Undo] : Select circle c at point 3 Specify 2nd point for tangent: Select circle b at point 4 Specify 1st point for tangent or [Undo] : Select circle b at point 5 Specify 2nd point for tangent: Select circle a at point 6 Specify 1st point for tangent or [Undo] : Press ENTER Select circle to store tangents: Select circle a

The tangent definition is finished, and the length of the chain is calculated. Because the length is divided into whole numbers of links, one sprocket has to be moved to achieve such a length. 7 Continue responding to the prompts as follows: Select pulleys or sprockets to be moved. Select objects: Select circle b Select objects: Press ENTER Specify base point or displacement: Select the center of circle b Specify second point of displacement: Select the center of the cross at point 8 Select pulleys or sprockets to be moved. Select objects: Press ENTER

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AutoCAD has calculated the new length, which is still not a multiple of the chain division. Therefore, the chain arrangement has to be optimized: Number of links in chain:121 Distance to next link: 6.88567 mm

Optimizing the Chain Length Now, optimize the chain length. 1 Start the Length Calculation command. Toolbutton Length Calculation Menu

Content > Chains / Belts > Length Calculation

Command

AMCHAINLENGTHCAL

2 In the Belt and Chain Length Calculation dialog box, check Optimization, Translation, and Direction >>, and specify: Required number of links: 122

3 Choose OK. 4 Respond to the prompts as follows: Select pulleys or sprockets to be moved. Select objects: Select the relocated circle b Select objects: Press ENTER Specify direction angle to move: Enter 90 Sprocket b is moved until a chain length of 122 links is achieved.

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5 In the Belt and Chain Length Calculation dialog box, choose Cancel, to cancel the optimization. Now, your drawing looks like this:

Inserting Sprockets Now, insert the sprockets. 1 Start the Draw Sprocket/Pulley command. Toolbutton Draw Sprocket/Pulley Menu

Content > Chains / Belts > Draw Sprocket/Pulley

Command

AMSPROCKET

2 In the Pulleys and Sprockets dialog box, specify: Number of teeth: 19 Number of Teeth to Draw: 19

3 Choose OK.

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4 Respond to the prompts as follows: Specify center of wheel: Select the center of circle a With Centerlines : Press ENTER Insert part reference: Press ENTER The sprocket is isnerted into the drawing. Now, insert the next two sprockets. 5 Start the Draw Sprocket/Pulley command again. Toolbutton Draw Sprocket/Pulley Menu

Content > Chains / Belts > Draw Sprocket/Pulley

Command

AMSPROCKET

6 In the Pulleys and Sprockets dialog box, specify: Number of teeth: 13 Number of Teeth to Draw: 13

7 Choose OK. 8 Respond to the prompts as follows: Specify center of wheel: Select the center of circle b With Centerlines : Press ENTER Insert part reference: Press ENTER 9 Start the Draw Sprocket/Pulley command again. Toolbutton Draw Sprocket/Pulley

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Content > Chains / Belts > Draw Sprocket/Pulley

Command

AMSPROCKET

Chapter 12 Chain Calculation

10 In the Pulleys and Sprockets dialog box, specify: Number of teeth: 51 Number of Teeth to Draw: 3 Insertion Angle for Sprocket/Pulley: 180

11 Choose OK. 12 Respond to the prompts as follows: Specify center of wheel: Select the center of circle a With Centerlines : Press ENTER Insert part reference: Press ENTER The last sprocket is inserted as a simplified representation with only three teeth, as specified in the dialog box. Now, your drawing looks like this:

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Inserting a Chain Finally, insert a chain. 1 Start the Draw Chain/Belt Links command. Toolbutton

Draw Chain / Belt Links

Menu

Content > Chains / Belts > Draw Chain/Belt Links

Command

AMCHAINDRAW

2 In the Draw Chain dialog box, specify: Number of Links to Draw: 122

3 Choose OK. 4 Respond to the prompts as follows: Select polyline and starting point: Select the polyline near point 9 Please wait ... calculating chains Number of links in chain:122 Distance to next link: 0 mm Please wait ... calculating chains Is position of link correct [Y/N=Rotation] : Press ENTER Insert part reference: Press ENTER The chain is inserted. Your drawing looks like this:

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Inserting a Chain

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186

Calculating a Spring

In This Chapter

In this tutorial, you calculate a spring for existing boundary conditions and insert the spring into a drawing. You also copy and edit the spring, using the Power Copy and Power Edit commands.

13

„

Starting the spring calculation

„

Specifying the spring layout

„

Calculating and selecting the spring

„

Inserting the spring

„

Copying the spring with Power Copy

„

Editing the spring with Power Edit

187

Key Terms Term

Definition

belleville spring washer

A washer-type spring that can sustain relatively large loads with small deflections. The loads and deflections can be increased by stacking the springs.

compression spring

A spring type that can be compressed and can absorb pressure forces.

dynamic dragging

The act of determining the size of a standard part with the cursor while inserting the part into a side view. The standard part is displayed dynamically on the screen and can be dragged to the next possible size and length. The values (sizes) are taken from the Standard parts database.

extension spring

A spring type that can absorb tension forces.

Power Copy

A command that copies a drawing object to another position in the drawing. Power Copy produces an identical copy of the copied object.

Power Edit

A single edit command for all objects in a drawing.

torsion spring

A spring type that can absorb torque forces.

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Chapter 13 Calculating a Spring

Calculating a Spring With the AutoCAD Mechanical Power Pack spring function, you can insert compression, extension, torsion, and Belleville washer springs. The calculation is carried out in accordance with DIN 2098 or ANSI. The standard sizes of the springs can be selected from DIN ® 2098/Gutekunst/SPEC catalogs. To make the operation as simple and as clear as possible, the same methods are used to insert all the spring types. NOTE The ISO standard part standard has to be installed for this tutorial exercise.

Getting Started In this tutorial, you create a compression spring in two different compression situations. You calculate and insert the spring in an existing drawing. First, you insert the initial drawing. 1 Open the file tut_ex13 in the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

Zoom in to the area with the springs. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

2 Respond to the prompts as follows: Specify first corner: Specify first corner Specify opposite corner: Specify opposite corner

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The drawing shows two views (A and B) of the lever and spring housing, to reflect two different states of compression.

Starting the Spring Calculation First, you specify the spring to calculate. 1 Start the Springs command. Toolbutton Springs Menu

Content > Springs

Command

AMSPRING

2 In the Select Springs dialog box, specify: Compression Springs: On Select from Table: On

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3 Choose OK. 4 Respond to the prompts as follows: Specify starting point or [Existing Spring]: Specify point P1, as shown in the following figure Specify direction: Specify point P2

®

5 In the Browser, choose SPEC Catalog B. The Compression Springs dialog box is displayed.

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Specifying the Spring Layout Now, you specify the spring layout. 1 In the Compression Springs dialog box, specify: Standard Cases: Select the icon on the right in the first row Exact Match for: Lengths

2 Choose Next. Now, you specify the geometric boundary conditions. 3 In the Compression Springs - Select dialog box, select the options as shown below, and click the < button to the right of the Da Power Commands > Power Copy

Command

AMPOWERCOPY

2 Respond to the prompts as follows: Select objects: Select the spring in view A /Multiple: Select the upper-right corner of the spring housing in view A Second point of displacement: Select the upper-right corner of the spring housing in view B

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3 Continue responding to the prompts as follows: Select rod (only closed contours) : Select objects: Press ENTER Insert part reference: Press ENTER The spring is copied into view B. However, you need to adjust the length of the spring in view B.

Editing the Spring with Power Edit TIP You can also start Power Edit by double-clicking the object you want to edit - in this case the spring. 1 Start the Power Edit command. Toolbutton Power Edit

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Menu

Modify > Power Commands > Power Edit

Command

AMPOWEREDIT

Chapter 13 Calculating a Spring

2 Respond to the prompt as follows: Select object: Select the spring in view B The Compression Spring - Drawing dialog box is displayed. 3 Choose the < button to the right of the Lx= field, and specify the spring length.

4 Respond to the prompt as follows: Specify spring length Lx (L1 = 32): Select a point, as shown in the following picture

5 Choose Next, to insert the spring.

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6 Continue to respond to the prompts as follows: Select rod (only closed contours) : Select objects: Press ENTER Insert part reference: Press ENTER AutoCAD Mechanical reinserts the spring in its new compressed length into the housing.

TIP If there is a rod in the center of the compression spring, you have to select the rod so that the representation of the background will be displayed correctly. The Spring command provides a very useful tool for generating complex springs in your design.

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Using FEA to Calculate Stress

In This Chapter

In this tutorial, you calculate stresses in a lever, using the finite element analysis, and use the results to improve the design of the lever.

14

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Calculating the stress in a lever

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Defining loads and supports

„

Evaluating and refining the mesh

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Improving the design

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Recalculating the stress

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Key Terms Term

Definition

distributed force

A force that is spread over an area.

FEA

Finite Element Analysis. A calculation routine, or method. Calculates stress and deformation in a plane for plates with a specified thickness, or in a cross section with individual forces, stretching loads, and fixed and/or movable supports. The FEA routine uses its own layer group for input and output.

fixed support

A support that is fixed to a part and is fixed in axial direction.

load

Forces and moments that act on a part.

movable support

A support that is not fixed in axial direction.

Power Edit

A single edit command for the objects in your drawing.

stress

Force or pressure on a part. Stress is force per area.

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2D FEA Getting Started Design sophistication in the area of mechanical engineering and construction is increasing. Therefore, the calculations relating to these designs have to be performed using more advanced tools in order to assure reliability. To determine the stability and durability of a given structure under various loading situations, you need to observe the stress and deformation in the components while they are being loaded. A structure is considered to be durable if the maximum stress is less than what the material permits. Various computational methods have been developed for calculating deformation and stress conditions. One of these methods is called the Finite Element Analysis. The knowledge gained from this stress rating may lead to changing the structure in certain areas, which in turn necessitates changes to the design. The FEA routine uses its own layer group for input and output. Note that FEA is not designed for solving all special FEA tasks. Its purpose is to provide you with a quick idea of the stress and deformation distributions. NOTE The ISO standard part standard has to be installed for this tutorial exercise.

Calculating the Stress in a Lever 1 Open the file tut_ex14 in the acadm\tutorial folder. Toolbutton Open Menu

File > Open

Command

OPEN

The drawing contains a lever, which is the basis for your calculations. 2 Zoom in so that the lever fits on your screen. Toolbutton Zoom Window Menu

View > Zoom > Window

Command

ZOOM

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3 Activate the FEA calculation. Toolbutton FEA Menu

Content > Calculations > FEA

Command

AMFEA2D

4 Respond to the prompts as follows: Specify interior point: Specify a point inside the contour The FEA 2D Calculation dialog box opens so that you can define border conditions and perform calculations.

Select the thickness and the material of the lever. 5 In the Default section, enter a thickness of 10.

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6 Choose Table, and select the material from your preferred standard table: Select Al. alloys die-cast if you prefer to use ANSI materials. Select AlMg5F25 if you prefer to use DIN materials. NOTE The results will differ slightly from the tutorial, depending on the selected material.

Defining Loads and Supports To perform calculations, you need to define the loads and supports. 1 Choose the moveable line support button, and respond to the prompts as follows: Specify insertion point : Specify point 1 Specify endpoint: Specify point 2 Specify side from endpoint: Specify a point above the contour

2 Choose the moveable line support button again, and respond to the prompts as follows: Specify insertion point : Specify point 3 Specify endpoint: Press ENTER to define the starting point as the endpoint

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3 Choose the line force button, and respond to the prompts as follows: Specify insertion point : Specify point 5 Specify endpoint: Specify point 4 Specify side from endpoint: Specify a point to the right of the specified points Enter a new value : Enter 500

4 Choose the line force button, and respond to the prompts as follows: Specify insertion point : Specify point 6 Specify endpoint: Specify point 7 Specify side from endpoint: Specify a point to the right of the specified points Enter a new value : Enter 500

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Calculating the Results To calculate the results, you need to generate a mesh. TIP If you calculate results without creating a mesh in advance, the mesh will be created automatically. 1 Choose the mesh button. 2 Choose the isolines (isoareas) button. 3 In the FEA 2D Isolines (Isoareas) dialog box, select the Graphic Representation button on the right, and choose OK.

4 Respond to the prompts as follows: Specify base point : Press ENTER to place the isoareas in the boundary Insertion point: To the left of the part, select a suitable location for the table : Press ENTER to return to the dialog box The result looks like this:

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After calculation, the support forces are displayed near the support symbol.

Evaluating and Refining the Mesh The stress table allocation relative to the lever shows heavy concentration of local stress near drawing points 8 and 9. Refine the mesh near these points to obtain more exact calculation results for the points of interest. 1 Choose the refining around point button, and respond to the prompts as follows: Specify center point 1 : Specify several points near points 8 and 9 Specify center point 1 : Press ENTER to continue meshing : Press ENTER to return to the dialog box

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After this step, you get a refined mesh at the specified points. Recalculate the stress representation. 2 Choose the isolines (isoareas) button. 3 In the FEA 2D Isolines (Isoareas) dialog box, choose the Graphic Representation button on the right, and choose OK.

4 Respond to the prompts as follows: Specify base point : Press ENTER to place the iso-areas in the boundary Insertion point: To the left of the part, select a suitable location for the table : Press ENTER to return to the dialog box

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Improving the Design The results show a critical area around point 8 that can be improved by applying a larger radius. Before changing the geometry, the results and solutions have to be deleted. 1 Choose the Delete Solution button. 2 In the AutoCAD Question dialog box, choose Yes to delete the solutions and results.

3 In the AutoCAD Question dialog box, choose No to keep the loads and supports.

4 Start Power Edit to change the radius, and respond to the prompt as follows: Toolbutton Power Edit Menu

Modify > Power Commands > Power Edit

Command

AMPOWEREDIT

Select objects: Select the radius at point 8

5 In the Fillet Radius dialog box, specify: Input: 10

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6 Choose OK. Select objects: Press ENTER to cancel the command The radius of the fillet is changed to 10.

Recalculating the Stress Before recalculating the stress division of the lever, calculate and display the deformation. 1 Restart the FEA routine. Toolbutton FEA Menu

Content > Calculations > FEA

Command

AMFEA2D

2 Respond to the prompt as follows: Specify interior point: Specify a point inside the contour 3 In the FEA 2D Calculation dialog box, select material and the thickness as described earlier in this chapter (see steps 5 and 6 on page 4). 4 Choose the deformation button. 5 In the FEA 2D - Deformed Mesh dialog box, choose OK.

6 Respond to the prompts as follows: Specify base point : Press ENTER to place the deformed mesh in the boundary

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Insertion point: To the right of the part, select a suitable location for the table : Press ENTER to return to the dialog box The result looks like this:

Recalculate the stress division of the lever. 7 Choose the isolines (iso-areas) button. 8 In the FEA 2D Isolines (Iso-areas) dialog box, choose the Graphic Representation button on the right, and choose OK.

9 Respond to the prompts as follows: Specify base point : Press ENTER to place the iso-areas in the boundary Insertion point: To the left of the part, select a suitable location for the table : Press ENTER to return to the dialog box The final result looks like this:

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Index

A

C

acceleration................................. 104, 107 angular dimensioning ........................... 41 annotations...................................... 34, 43 associative detail................................... 87 automatic dimensioning.................. 36, 38

calculate results...................................207 calculation result block .......................122 cam......................................................104 cam configuration ...............................106 cam geometry......................................111 cam plate calculations.........................106 cam plates and cylindrical cams .........105 centerline...............................................34 chain....................................................184 chamfer .......................................126, 131 change representation .........................173 C-line ............................................14, 150 C-line options........................................19 collect balloon.......................................79 compression spring .....................188, 190 construction geometry...........................14 construction lines ....................14, 17, 150 contour ..................................................21 copy objects ..........................................58 countersink..........................................150 countersunk .................................161, 164

B background ................................. 150, 156 balloon ............................................ 62, 67 base layer .................................... 6, 50, 86 base layer group.................................. 100 baseline dimension ............................... 34 bearing calculation...................... 126, 127 belleville spring washer ...................... 188 bill of material ...................................... 62 blind hole ............................................ 156 BOM attribute....................................... 62 BOM database ...................................... 65

215

cross-hatching....................................... 26 current layer.......................................... 59 curve path ................................... 104, 111 cylindrical pins ................................... 171 cylindrical shaft section ...................... 129

fit description ........................................42 fit name .................................................34 fixed support .......116, 121, 140, 143, 202

D

gear..............................................126, 140 geometric tolerance...............................34 graphic representation.........................207

datum identifier............................... 34, 44 define border conditions ..................... 204 deflection ............................................ 147 deflection line ............. 116, 119, 120, 140 deflection moment ...................... 116, 140 deformation......................................... 211 delete solution..................................... 210 detail ................................... 14, 29, 86, 90 dimensioning tools................................ 36 direction of the loads .......................... 118 distance snap......................................... 14 distributed force.......................... 116, 202 drawing ................................................. 86 drawing border................................ 34, 46 drawing limits ....................................... 10 drawing mode ....................................... 86 drawing title.......................................... 34 dynamic calculation............................ 126 dynamic dragging ............... 126, 150, 188 dynamic stress..................................... 195

E edit balloon ........................................... 72 edit part list ........................................... 72 edit part reference ................................. 65 editing dimensions................................ 39 effective loads..................................... 144 exact match ......................................... 192 extension spring.................................. 188

F FEA............................................. 202, 203 FEA calculation .................................. 204 feature control frame ...................... 44, 45 feature control frame symbol................ 34 feature identifier symbol....................... 34 fillet....................................... 23, 126, 131 filters..................................................... 81 fit .......................................................... 34

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Index

G

H hiding c-lines.......................................172

I initial spring length .............................193 inserting a pin......................................171

L layer group ..................................6, 50, 86 layer groups...........................................53 layout ..............................................86, 87 library............................................14, 178 load......................116, 121, 140, 202, 205

M material ...............................................120 mechanical options .................................9 merge ....................................................75 model space...........................................87 moment of inertia........116, 117, 140, 202 movable line support...........................205 movable support..................................121 move to another group ..........................55 move to another layer ...........................52 movement diagram .............................104 movement sections......................104, 108 multi edit .........................................34, 41 multiple balloon ....................................67

N NC data .......................................104, 112

O optimization ........................................180 optimize chain length..........................180

P part layers ......................................... 6, 50 part reference .................................. 62, 64 parts list........................................... 62, 71 perform calculations ........................... 204 point force................................... 116, 140 point load ............................................ 145 Power Commands................... 14, 39, 150 Power Copy ................ 150, 157, 188, 197 Power Dimensioning .... 14, 27, 34, 86, 95 Power Edit ..150, 164, 188, 198, 202, 210 Power Erase .............. 35, 39, 76, 150, 168 Power Pack ............................................. 2 Power Recall............................... 150, 158 power snap settings............................. 127 Power View ................................ 150, 166 precalculation...................................... 161 projecting edges.................................... 24

R radius reflection line ........................... 126 recalculate stress representation ......... 209 recalculating stress division................ 211 refined mesh ....................................... 209 representation...................................... 150 resolution ............................................ 104

S scale area......................................... 86, 88 scale monitor......................................... 86 screw assembly grip representation.... 155 screw connection ................................ 152 screw diameter estimation .................. 161 Selection Set ......................................... 60 set value ................................................ 73 shaft break................................... 126, 132 shaft calculation.......................... 141, 142 shaft contour ....................................... 141 shaft generator .................... 126, 127, 141 shaft generator configuration.............. 128 shaft section ........................................ 134 side view ............................................. 166 side view of the shaft .......................... 133 simplified representation .................... 173

snap settings..........................................16 sort parts list..........................................80 specifying material..............................143 spline profile .......................................130 split........................................................75 spring ..................................................189 spring layout .......................................192 spring representation...........................196 standard parts ......................................151 standard parts library ..........................174 starting layer ...........................................8 step width ............................................104 stress............................................140, 202 support forces......................................208 supports .......................................121, 205 surface texture symbol ....................35, 43 symbolic..............................................174

T template.........................................6, 7, 10 thread ..................................................134 title block ........................................35, 47 tolerance................................................35 top view...............................................166 torque ..................................................146 torsion moment ...................................146 torsion spring ......................................188 transition .............................................108 translation............................................180

U uniform load........................................121 user through hole ..................................93

V velocity........................................104, 107 velocity and acceleration calculation..110 view scale..............................................86 viewport ....................................86, 87, 91 viewport auto create..............................89 visibility enhancement ..........................58

W working layer ..............................6, 50, 86

Index

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