BGA dead bug pick and place

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I'm currently dealing with an design of an end effector that... - Oct 24, 2002 by

If I understand correctly you want to pick BGAs from the bal... - Oct 28, 2002 by gregp

Thankyou very much for the information. Another question... - Oct 29, 2002 by kent

Larger tighter spaced balls will present a problem in sealin... - Oct 30, 2002 by gregp

Base on the PORON foam rubber recommended, is it possible to... - Jun 09, 2004 by

I think it depends on the thickness of the PORON sheet. For... - Jun 18, 2004 by gregp

Kent

#22126

BGA dead bug pick and place | 24 October, 2002

I'm currently dealing with an design of an end effector that need to pick n place a BGA dead bug package. The design is using peumatic system to do the task. Any advise or suggestion on this kind of design?

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gregp

#22165

BGA dead bug pick and place | 28 October, 2002

If I understand correctly you want to pick BGAs from the ball side using some type of vacuum arrangement. You will find that the reliability of this is dependant on the size of the balls and the pitch. The larger the balls and tighter the pitch, the more difficult the application. For smaller balls with loose pitches, you have a couple of off the shelf options. A company called Small Precision Tools in Petaluma,CA makes a variety of molded suction cups. One in particular is FCTR-C-320 developed for flip chip applications. SPT website:www.smallprecisiontools.com Another option is a company called PISCO. They make a series of sponge type vacuum cups. They are basically foam rings that will seal well on uneven surfaces. If you search the web for PISCO you will probably find information for your local distributor. That last option is the one I ultimately decided upon for the best results. It is a homemade version of the pisco stlye vacuum cups. We opted for a softer durometer PORON foam rubber and made a punch to punch out some thin wall rings out of a sheet. We then stretch the ring over a vacuum nipple. This works well for the vast majority of BGAs. You can email me directly if you have any questions.

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kent

#22168

BGA dead bug pick and place | 29 October, 2002

Thankyou very much for the information. Another question, what are the difficulty of dealing with the larger ball and tighter pitch? What is size of the ball is consider large and how far the distance for pitch is consider tight? Currently I have a product with pitch to pitch 1mm distance and ball size with diameter of 0.5mm. Thankyou very much if you can answer my question.

from, Kent

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gregp

#22192

BGA dead bug pick and place | 30 October, 2002

Larger tighter spaced balls will present a problem in sealing the vacuum cup. There will be more leakage in this case. It really depends upon the application. The BGA you mention should not be a major concern. The bigger problems are with bigger balls. It also depends on what acceleration you plan on moving the picker. Your cup diameter should be as larger as possible. Your vacuum system should be designed with high flow characteristics to account for inevitable leakage. If you need to vacuum sense the BGA for presence, you may require analogue sensors. Realize that the BGA may not be super stable on this type of cup.

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Bernard

#29024

BGA dead bug pick and place | 9 June, 2004

Base on the PORON foam rubber recommended, is it possible to apply on small BGA chip of 4x4 ball size 0.3mm. Any specific part no and supplier for this type of foam and is it a anti-static material? Would it be possible to punch out at dia. 3mm?

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gregp

#29168

BGA dead bug pick and place | 18 June, 2004

I think it depends on the thickness of the PORON sheet. For .3mm balls you could probably get away with a pretty thin sheet (maybe 1/16"). I don't know how thin it comes offhand. For the part you are describing I woulf try maybe a 3.5mm OD and a 1.5mm ID. This will give you a 1mm wall thickness to the ring which is about a 1:1 ratio of ring wall width and thickness.

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