| Dear all, | | We've got a curious problem. We have had a major problem with BGA's occasionally being placed one to several rows or columns off the pads. We are using Universal's GSM2 platform for our general purpose placements. Our Universal rep here didn't have a ready answer for us and even after we followed their advice, we were still not getting any improvements. We've checked our component database settings, our lighting levels, our BGA's, the pickup tolerance, and nothing helped. Then the problem went away for about a half year. we never did find the answer to it. But now it's back again. We've had two boards with BGA's shifting on us in the past week. | | Has anyone any idea what may be the cause of this problem? I'm open to any suggestions because we are baffled! | | Thanks, | Hon | Amazing coincidence. I just had such a conversation with our pnp tech. She had the same problems repeating recently both with plastic types and our ceramic BGA's and CCGA's.
The first problem was oxidized solder balls. This, as you already know, has the affect on cameras and lighting of not allowing proper recognition, alignment, and placement - of a row or two sometimes.
For the ceramic types, some operators were not aligning to edges properly and at times even picking up adhesive "creep" oozed out from under metal heat sinks on top. This too caused serious problems - though neither may apply to your concerns.
Earl Moon
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