Lecture SMEMA SMT Conveyors Student Version

Modern Electronics Manufacturing SMT Line Configuration •SMT Line Configuration Basis •Full Single Pass Double Sided Type 1 Line Configuration •SMEMA Interface

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration Basis SMT lines are configured based on the following: The level of automation. The type of SMT style to be made. The line volume based on actual CPH. The board component mix. Components on one or both sides. PCB to be assembled in one or two passes. The level of in-line inspection. AOI at each step or just after

reflow, or offline. And last but not least, the amount of funding available.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan

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SMT Line Configuration by Dr. Shahid Khan Conductive PCB Magazines

Off Line X-Ray Inspect ion

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration Line Throughput Calculations Pick and Place Machine Throughput The total catalog CPH of all six mounting machines in

the line is (40K+40K+20K+40K+40K+20K)=200K CPH theoretical. In reality, based on the component mix, this would translate into approximately half of this, or 100K CPH actual. If we assume a double sided PCB panel with 4 repeats. Each repeat has 300 components on the top and 300 on the bottom. Each panel thus has 1200 components on the top and 1200 on the bottom. Placement time for a side would be 1200/100,000 hours or 43 seconds.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan Line Throughput Calculations Printer Throughput: In a typical production printer, the PCB IN/OUT time is approx 15 seconds. And the print time is typically 15 seconds. So, if the printers are producing a print every 30 seconds, they would keep up with the placement machines as it typically takes a few seconds to input and register a panel on the mounters. To increase the printing throughput, the PCB panel size could be increased by increasing the number of repeats, from 4 to 6 or even 8, within the limits of the max. PCB size that can be handled on the conveyors and the machines.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration Line Throughput Calculations Reflow Oven Throughput: Typical solder paste has to be in the oven for around 270 seconds (due to the profile). A large oven is typically 5 meters long. So the PCB would travel 5M in 270 secs or 18mm /second. If the PCB panel was 300mm by 150mm and it was traveling with direction of travel parallel to the 150mm side, with 30mm between each panel. The time for a panel to exit the oven would be (150+30)mm / 18mm/sec = 10 secs. So, if the mounters are producing a panel every 86 secs, the ovens can easily keep up.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan Line Throughput Calculations Total Line Throughput: This would be based on the limiting throughput, which is of the Pick and Place Mounters. They are producing a 4 repeat panel every 43 seconds. So panels produced in an eight hour shift is 8x3600/43 = 670 panels per shift, or 2680 PCBAs per shift. Or 8,040 PCBAs per day on a 3 shift basis. Or 192,960 per month based on a 24 day month. Or 2,315,520 PCBs per year.

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Modern Electronics Manufacturing by Dr. Shahid Khan

Shahid Khan How to Connect them Altogether?  We have just configured this huge double sided SMT line.  These machines will be made by a number of different machine

manufacturers on different sides of the globe.  How is it ensured that they work together and seamlessly pass PCBs from one to the next?  Enter the “Surface Mount Equipment Manufacturers Association”.  To cover this issue and make all the machines work together, they came up with a standard called IPC-SEMA-9851.  This defines a very simple but highly effective way of getting disparate conveyorized machines to hand off to and receive PCBs from each other.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan SMEMA Interface Introduction: The SMEMA machine interface standards were

developed to facilitate the interface of equipment used in the assembly of surface-mounted printed circuit boards. The mechanical specifications that follow are for single board transfer systems with conveyor transports. Conveyor Height Each machine shall have the trans-port conveyor height adjustable from 940 to 965 mm [37 to 38 in] from the floor to the bottom of the PC board. Fixed Rail For the purposes of this standard, the front rail is defined as the fixed rail.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMT Line Configuration by Dr. Shahid Khan SMEMA Interface Conveyor Width For equipment with an adjustable

conveyor width, the front rail is fixed and the rear rail is adjustable. The range of adjustment will vary with the equipment manufacturer. Edge Clearance The conveyor should require no more than 5 mm of clear board space at the side edges. Tooling Pins Tooling pins, if used, should be on the front edge of the board (next to the fixed transport rail). A recommended hole diameter is 4 mm. Distance from the edge should be 7.6 mm.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMEMA Interface

The maximum unsupported gap as

defined by G in above figure is 19 mm.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMEMA Interface

Lead-in The minimum lead-in on the track

ends of the conveyor is 3 mm and the angle shall not be greater than 30° as shown.

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SMT Line Configuration by Dr. Shahid Khan SMEMA Interface ELECTRICAL

INTERFACE REQUIREMENTS: A machine-to-machine electrical interface is required to insure proper sequencing of PC boards. The interface is used for "Local" control and shall operate independently of the cell controller. Inter-Machine Control To sequence boards properly from machine-to-machine, the "Board Available" and "Machine Ready" signal lines will he used and "Board Pass/Fail" signal line is optional. Connectors All interface connectors on a machine shall he female.

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMEMA Interface EL

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Modern Electronics Manufacturing by Dr. Shahid Khan

SMEMA Interface Connecto Function r Cable Pair 1 -2 Machine (Note 1) Ready to Receive Pair 3-4 Board (Note 1) Available

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Condition Contacts Closed (Notes 2,3) Contacts Closed (Notes 2,3)

Modern Electronics Manufacturing by Dr. Shahid Khan

Description Machine is ready to receive next board. Machine has a good board ready to send. All boards are considered to be "good" if the Board Fail option is not being used.

SMEMA Interface Pair 5-6 Auxiliary Interface Power (optional)

Available: user to document purpose and operating parameters.

Pair 7-8 Failed Board Contact Default (no connection or. (Note Available s if used, contacts are 1) (Optional) Closed open) is that the incoming (Notes board is good and suitable 2,3) for use. Optional use is to provide closed contacts when it has been determined Modern Electronics Manufacturing by Dr. 20

Shahid Khan

SMEMA Interface Pair 7-8 Failed Board Contacts (Note Available Closed 1) (Optional) (Notes 2,3)

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Modern Electronics Manufacturing by Dr. Shahid Khan

that the board should stop transfer or be diverted. In such cases, these contacts shall be closed in lieu of (and not in addition to) the normal Good Board Available contacts.

SMT Line Configuration by Dr. Shahid Khan, SMEMA Interface

Pin-out of SMEMA Connector

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SMEMA Interface – Logic Signals

Board transfer occurs when Machine A has a BOARD AVAILABLE (contact closed) And Machine B is MACHINE READY TO RECEIVE (contact closed). The signals can occur at any time, but board transfer does not occur until both contacts are closed. The BOARD AVAILABLE signal from Machine A will remain closed until the board has left Machine A. The MACHINE READY TO RECEIVE signal will remain closed until Machine B has positive control of the board. Board transfer cannot occur again until each signal opens for at least 50 ms. Optional: Once both Machine A and Machine B signals are closed, and the board has neither left A nor arrived at B. an Modern Electronics Manufacturing by Dr. 23 Khan will be generated (to be defined by users). error Shahid message

SMEMA Interface – Timing Diagram for Normal Transfer

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SMEMA Interface – Timing Diagram for NG Board Option

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SMT Line Configuration by Dr. Shahid Khan

End of Lecture (Reading: Posted Lecture Notes on SMT Line Configuration and SMEMA Interface) 26

Modern Electronics Manufacturing by Dr. Shahid Khan