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QFP Coplanarity Error

Views: 3333

#61333

QFP Coplanarity Error | 10 March, 2010

We have these standard pitch QFPs, for which we found some coplanarity error issues. The issues surfaced during BLT. We do not have any instrument to measure the coplanarity error before the component is loaded on the placement machines. Is there any economical and quick method to check for coplanarity error?

Also, we have YesTech AOIs. Can that help in detecting coplanarity error?

Please advise.

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#61334

QFP Coplanarity Error | 10 March, 2010

I am sorry, they are fine-pitch QFPs (20 mils)

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#61352

QFP Coplanarity Error | 11 March, 2010

Poor man's approach to assessing coplanarity issues: * Get two pieces of 2X4 wood that are the same length, about three inches long * Cut the end of one of the pieces at a 45* angle, so that the 45* angle cut leaves a face on the four inch side of the piece of wood * Glue the two pieces together on the four inch sides, so that the 45* cut faces outward. * Do something to the surfaces of the wood do de-ESDify them, making it easier for the ESD-person to maintain composure when he / she catches you doing this thing * Glue a mirror to the 45* face

Tada!!! You have made a Dave's Wonder Coplanarity Meaurementometer & Assesserer. Here's how you use it: * Position the tool [assesserer] so that the 45* mirrored face is is at a 45* angle to the table and the flat surface that was the piece of 2X4 that was not cut is away from the table. * Place the component [assessee] on the top [the flat surface that was the piece of 2X4 that was not cut] of the tool [assesserer] * Scoot the component [assessee] so that leads are hung-out over the edge along the mirrored face. * Look into the mirror and assess the assessee

Anyone not confused raise your hand.

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#61356

QFP Coplanarity Error | 12 March, 2010

Dave's mirror should work. If you're not up to building it, check out http://www.fancort.com/smt/aids_mirror.html

Regards, Mike

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