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1、LOGOSMTSMT工艺工艺工艺工艺 1010SMT PROCESS TRAINING 10SMT PROCESS TRAINING 10Simao Yang Education Simao Yang Education Group Co.LtdGroup Co.Ltd.YS-U.comIntroduction, Technology Introduction, Technology Trends, Assembly Types and Trends, Assembly Types and SMT Component TechnologiesSMT Component Technologies
2、LOGOModule 4 Module 4 Unit 3 Unit 3Placement Considerations Placement Considerations and Flexibilityand FlexibilitySimao Yang Education Simao Yang Education Group Co.LtdGroup Co.Ltd.YS-U.com3 3Considerations for Placement - Board SizevEquipment adjusts to min/max PCB or panel size for various SMT pr
3、oductsvIn-line conveyor fixturing is utilizedvEdge margin requirements must be designed into PCB or panelvThickness of PCB is process considerationvWork envelope needs to include PCB size, feeders, and placementvFiducials on PCB are used by camera and computer for accurate placement4 4Considerations
4、 for Placement - ComponentsvEach placement tool usually handles a range of component sizesVacuum nozzle size defined by dimensional range of componentsvZ-strokes refers to component movement in up-down locationsvComponent alignment on pick-up head utilizes visionChips: outline & centroidICs: centroi
5、d, individual leads, coplanarity, etc.vComponent verification is done “on the fly”, checking for correct component valuesvEquipment detects missing parts5 5Considerations for Placement - FeedersvComplexity of changeover of feeders is process considerationvNumber of feeders required equals number of
6、different components in bill of materialsvFeeder must be compatible with component packaging from vendorvTape cover peel-back capabilities built into feedersvEase of loading - pin locators and electrical connections affect process timevOperator awareness necessary for feeder selection accuracy6 6Com
7、ponent Placement SystemvFlexibilityThe wider the variety of components a machine can place, the more flexible it isv Most common feeder types:Tape and reelBulkMatrix trays and waffle packsMagazines or tubesVibratory feedersSurf tapeDirect Die feeder7 7Tape and ReelvPreferred for large quantity produ
8、ctionAbility to hold large quantities of partsLower downtime required for reloadingControlled Orientation and position for partsLot number traceability controlvThe tape is available in varying widths ranging from 8 mm to 72 mmvThe component carrier in tape is made of punched cardboard or thermoforme
9、d plasticvSuitable for passive components, discrete actives, SOJs, PLCCs, SOICs, Standard pitch QFPs, Bare Dies, BGAs & other SMDs that do not have fragile leads8 8Siemens: 3x8 mm Feeder 0201v3x8 mm Feeder golden edition“ specialized for 0201 and 0402vIncreased accuracy / repeatabilityvNo tape shutt
10、er, eliminates mechanical influence on the component3x8 mm StandardfeederTape shutter3x8 mm Feeder Golden edition“Fixed tape removal edge9 9Bulk PackagingvProsSmall, no wasteHigh capacityFast refillvConsNew feeders requiredNew component reference numberPossible damage to end terminations1010Matrix T
11、ray and Waffle PackvThese are useful for smaller production runs with customized productsvLargely used for Integrated Circuit packagesvAvailable in sizes of 2” x 2” and largerFor Fine Pitch QFPs, BGAs, etc.For Bare Dies & CSPs1111Suitable for SOICs, SOJs & PLCCs Feeder TubesvBoth flexible and rigid
12、sticks are available for several sizes of integrated circuits and other componentsvA reasonable number of devices can be handled in each stickvThe parts will remain oriented and protected, once loaded1212Vibratory FeedersFeeder TubesSource: US VIBRA, Inc.1313Surf TapevA pressure-sensitive sticky tap
13、e fixed to the base of the punched plastic carriervComponents adhere with their back-side to the sticky tapevNo cover tape is used vUsed for bare dies and flip chipsvFlip chips have to be flipped inside the feeder 1414Source: Chip Scale ReviewDirect Die Feeder1515Smart Feeders1616Retrofitable Smart
14、Feeder - Utilizing RFID1717Programming1818Vision SystemLOGOModule 4 Module 4 Unit 3 Unit 3Pick and Place Process StepsPick and Place Process StepsSimao Yang Education Simao Yang Education Group Co.LtdGroup Co.Ltd.YS-U.com2020Pick and Place Process StepsvStep 1Boards from the screen print operation m
15、ove into the Pick and PlaceSMT lines may utilize 1 or more Pick and Place machines to populate PCBsThe Pick and Place assembles large and small SMT components onto the printed circuit board (PCB) with correct orientation, polarity and placement locationvStep 2Components are loaded onto the Pick and
16、Place using feedersvStep 3The Pick and Place is controlled by software, using a computer mouse and monitorvStep 4A vision system verifies the PCB is aligned properly in the Pick and Place, using fiducial markings Software, monitor and mouseComponent PlacementFeederFiducials2121Pick and Place Process StepsvStep 5Nozzles “pick up” and “place” componentsvStep 6A camera takes a picture of the component being placed, this picture is compared to the component description in the machine programvStep 7T
