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Re: Stacking of Bare Boards

Ashok Dhawan


Stacking of Bare Boards | 7 April, 2000

I have come across a number of cases where Solder Mask is chipped off or scratched. I was wondering this has anything to do with :

**Packing of PCBs in stacks and vacuum sealed **Stacking of PCBs prior to print operation

What is general practice in handling boards prior to print operation ?

Can HASL bumps can affect SM on mating board , loosely held in a stack ?

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Re: Stacking of Bare Boards | 11 April, 2000

Hello Ashok I can't recall mask damage through normal handling that did not have an adhesion or cure problem as its root cause. Most of our boards arrive shrink packed in groups of 10. We simply pop off the wrap one pack at a time and leave them in the stack. HASL bumps are generally rounded or mound shaped and will not damage a good mask. All this assumes that you are not allowing any aggravated sliding, grinding or gouging movement of the boards. The first step is to inspect these boards for damage at incoming. If they are OK and clean try a tape adhesion test on the mask. Seach the archives for how. good luck John Thorup

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Re: Stacking of Bare Boards | 11 April, 2000

Ashok: I agree with John. This is not normal. Dave F

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