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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


QFP Coplanarity

Peterson

#18970

QFP Coplanarity | 25 February, 2002

We are using a Panasonic MPAV2 to place some QFP's. Can someone please help me with a problem we are having with coplanarity!

The machine is "dropping" parts due to coplanarity issues.

What settings should we be looking at in order to eliminate the machine (nozzle, vacuum, etc) as a cause? In other words, how can we assure the part vendor that it is their problem (from the factory) and not ours.

THANKS!

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Stephen

#18971

QFP Coplanarity | 25 February, 2002

When you say "dropping" I assume you mean "rejecting" them because co-planarity is outside the tolerance you have set and the machine is putting them on the reject belt or tray as the case may be. I worked for a CM with an MPA-G3. One customer supplied one of the QFP's on their board, that had co-planarity issues. We could set the tolerance so low it rejected everything or so big it let everything pass. We found the happy medium one of two ways, I forget which exactly. We either put it very tight and loosened it up untill the inspectors complained of unsoldered pins, or put it loose and tightened up untill the inspectors stopped complaining. I believe the tolerance we settled on was around .15 mm (it might have been higher). At this level the machine accepted most of the QFP's and we didn't have any unsoldered leads after reflow. It would be nice if you could get the panasonic machine to give you the measurements and not just a pass/fail.

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Matt N-Stott

#19002

QFP Coplanarity | 27 February, 2002

We can fully inspect your parts and give you the actual measurements of coplanarity, this will let you know if they are within spec.

Regards Matt

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