Step Pulley Term Project Report

3RD SEMESTER, MECHANICAL ENGG;

 SEMESTER TERM PROJECT REPORT ON;

MANUFACTURING PROCESS OF STEP PULLEY BY MACHINING:

PROJECT MEMBERS: 1. :- Syed Anis Badshah 2. :-Shafique Ahmad

UW-09-ME-BE-001 UW-09-ME-BE-032

3. :-Syed Ibrahim Hassan UW-09-ME-BE-036 4. :- Sanaullah Khattak

UW-09-ME-BE-044

SUBMITTED TO: Dr. MUHAMMAD RIAZ BHATTI  ME-09 (MECHANICAL 3rd) Wah Engineering College UNIVERSITY OF WAH 25 JANUARY 2011

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;



ABSTRACT:

Looking at the present situation we often search for devices used for lifting of bodies, changing direction of the motion of a component , driving the shafts and chains through some specific RPM’s, or increasing the circulatory motion of a machine, all these multiple functions are done through pulleys which is itself a simple type of machine. Step pulley is a basic type of pulley having more than one groove and has one concentric unit. Steps are like stairs as we preceded the height of stairs are increases, in engineering drawing language we say the diameter of each step is increases if we go from the small step to the large. Steps may be 3, 4, 5, 6 and as per requirement. Our project is three steps v pulley. The V indicates the belt drive; our project can be used for the application of V belt drives purposes. First we draw a rough sketch on paper then we neatly draw the sketch on AutoCAD with proper dimensions. These step pulleys are many utilized in high speed rotating machines. It is used to increase the speed as per requirement. Working of Step pulley is similar to Gears.

DEDICATIONS:-This

project is dedicated to

our PARENTS AND TEACHERS without whose support and prayers we are nothing.

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;

 ACKNOWLEDGEMENTS 

First of all we would like to thank Allah Almighty for giving us the chance and the courage to carry out this project. we have achieved a lot from this project so we keep on praying to Allah for more.



Secondly, we would like to thank our POFIT instructors for all the support and guidance without which we would have never gone so far.



Thirdly we would like to thank WEC lab Staff for their technical advices.

 INTRODUCTION Pulley is a simple machine commonly used as wheels and axles with a groove around the outside. A pulley needs a rope, chain or belt around the groove to make it do work. Also used for lifting heavy weights easier by redirecting force. Pulleys let you move loads up, down, or sideways. Pulleys are classified on the bases of position, numbers, and grooves.

 ON THE BASIS OF POSITION: On the basis of position pulleys are classified as; 1. FIXED PULLEYS:

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG; A fixed pulley is the only pulley that when used individually, uses more effort than the load to lift the load from the ground. The wheel does not move. Fixed pulleys change the direction of the effort force. It does not increase the size of the effort force. The advantage of the fixed pulley is that you do not have to pull or push the pulley up and down. The disadvantage is that you have to apply more effort than the load.

2. MOVABLE PULLEYS: A movable pulley is a pulley that moves with the load. The movable pulley allows the effort to be less than the weight of the load. The movable pulley also acts as a second class lever. The load is between the fulcrum and the effort. The main disadvantage of a movable pulley is that you have to pull or push the pulley up or down. The main advantage of a movable pulley is that you use less effort to pull the load.

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;

 ON THE BASIS OF GEOMETRY; On the basis of geometry pulleys are; 1. Flat pulley: Rotary motion is the most common type of motion for a shaft or an axle. One way in which an engineer uses rotary motion is by transmitting it from one shaft to another when the shafts are parallel. This can be done by using pulleys and belts. A pulley is a wheel which may or may not have a grooved rim. The figure below shows a stacked vee pulleys and vee belts often used in car engines.

2. TOOTH PULLEY; In machines where a positive drive is essential and no slip between belt and pulleys can be accepted, a toothed belt and pulley is used. Toothed belts are mainly used for timing mechanisms, where quiet, positive (no slip) drive is required. The figure below shows a toothed belt and toothed pulleys used

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG; to drive a camshaft in a motor car engine.

 ON THE BASIS OF NUMBERS On the basis of numbers pulleys are classified as; 1. COMPOUND PULLEYS: Combined pulley makes life easier as the effort needed to lift the load is less than half the weight of the load. The main advantage of this pulley is that the amount of effort is less than half of the load. The main disadvantage is it travels a very long distance. 

ALSO KNOWN AS COMBINED PULLEYS.OR “BLOCK AND TACKLE.”

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;

 ON THE BASIS OF GROOVES: On the basis of grooves pulleys are classified as; STEP PULLEYS: A step pulley is a system of pulleys made up of many different sizes. The typical step pulley consists of a two- to four-pulley configuration. This type of step pulley is found on equipment such as a drill press where different operational speeds can be produced simply by changing the belt to a different pulley size. The step pulley is always operated in pairs, and when the belt is changed on one pulley, it is also changed on the corresponding pulley on the other side of the belt.  PROCESS FOR MANUFACTURING STEP PULLEYS: Most step pulley assemblies are cast from liquid materials; some of the very highend pulleys, however, are forged from solid billet material such as aluminum or steel. The billet step pulley is much more true when spinning than a cast version; there is a great cost difference between the two, however, with the billet costing

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG; much more. Some designs utilize separate and independent pulleys to make up the arrangement, although this is not a true step pulley.

While most of the step assemblies are configured for V-belt use, there are also some step pulleys which utilize flat belts. This type of step system can be switched or changed on the fly and is found in lathe transmissions or some milling machines. The flat belt pulleys are typically always forged from billet stock and operate much more smoothly than the V-belt design. The V-belt type of pulley is favored in higher torque applications, though, due to the ability of a V-belt to grip the pulley with more strength.  BASIC PURPOSE (ADVENTAGEs) OF STEP PULLEY: 1.

When it has been determined that the speed should be regulated on a particular step pulley equipped machine, the process of adjusting the speed is usually an easy one. With the motor in the off position, open the belt cover. Take note of where the belt is currently positioned on the pulleys. Remember, a large pulley driving a smaller pulley will result in more power but less speed output. Conversely, a small pulley driving a large pulley will have more speed output but less power.

2. Once the proper pulley system has been determined for the

desired outcome, the belt cover can be closed and the machine once again turned on. Now the machine can be operated at the proper speed for the desired effect. Sanding projects, for example are typically conducted at a faster speed than a cutting or shaping project. On a typical wood lathe project, the pulleys may be changed several different times. 3. When it has been determined that the speed should be

regulated on a particular step pulley equipped machine, the process of adjusting the speed is usually an easy one. 4. One exercise that strengthens the coracobrachialis is the

incline cable chest fly. To perform the incline fly, one should set

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG; both pulleys on a dual cable column machine to their lowest setting and stand midway between them and slightly in front.

 Wood lathe machine

5. The other practical example in which step pulley used is drill

press. Where different operational speeds can be produced simply by changing the belt to a different pulley size. The step pulley is always operated in pairs, and when the belt is changed On one pulley, it is also changed on the corresponding pulley On the other side of the belt.

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;



TYPICAL DRILL PRESS.

Close look------

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;

Above are the various parts in drill press where step pulley is inserted.  MANUFACTURE STEP PULLEY BY CASTING: TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG; 

Casting requires proper pattern and mould.



Proper molten metal and proper arrangement of gating system that is riser, runner and sprue.



Giving proper time to the molten metal to solidify and careful about shrinkage and shrinkage allowance.



Before casting calculate all the factors acting during the process to get a good cast.



After cast proper finishing through autos and other equipments. FLOW CHART DIAGRAM IS BELOW:



Pattern of wood is made.

(B) proper sand mould is prepared

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;

(C) Cast is obtained. Side view

(d) top view of the cast

If there is any mistake in pattern, gate system, molten metal properties then cast will be,

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;

 OUR PROJECT DESIGN: I remind that material used for our project is Aluminum. And we manufacture this project through machining. Machines involved are CNC, LATHE AND DRILL MACHINES. 

First we draw a drawing in AUTOCAD specifying the top and front view of our project having three grooves or steps.



Three steps are manufactured on CNC and Lathe machines. 

First step have 22mm length and have diameter of 114mm (4.5 inches approximately).



2nd step have 20mm length and have diameter of 76mm.

 

3rd step have 20mm length and diameter is 38mm.

Through Drill machine having drill of 13mm (approximately half inch) diameter, we drill at the center of the circular job. This hole is done for passing of shaft or spindles etc.



In each step the depth of groove is constant i.e. 9mm. and the grooves are for vee.belt drive having angle of 45.

TERM PROJECT REPORT

3RD SEMESTER, MECHANICAL ENGG;

 Question:

why

we

choose

machining

manufacturing method instead of casting?  We choose machining method because it is

easier than

casting. For project point of view machining method is better than casting. Casting requires much equipment. First pattern is required then mould of the required pattern is required. After this suitable metal free of hazards are melted and pour through the sprue into the mould goes through gating system. Then time of solidification requires, so have lengthy process but casting is better process in point of production point of view.

 Merits of machining method is only one reason, Step pulleys through machining manufacturing method have well finish than casting.

Step pulley with 4 grooves steps

TERM PROJECT REPORT