Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Clean raw bds

Pat Copeland

#14692

Clean raw bds | 14 August, 1998

Where can I find a spec to put on my fab drawing, to call out the cleanliness of the board, before I recieve it. These boards will require a tight spec after they are assembled, so I want to know that they are clean when I get them. Any suggestions. Also does a clean spec for an assembled board, (5 micrograms per sq. centimeter), sound acheivable?

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Earl Moon

#14693

Re: Clean raw bds | 14 August, 1998

| Where can I find a spec to put on my fab drawing, to call out the cleanliness of the board, before I recieve it. These boards will require a tight spec after they are assembled, so I want to know that they are clean when I get them. Any suggestions. Also does a clean spec for an assembled board, (5 micrograms per sq. centimeter), sound acheivable? Pat, It is written, in ANSI/J-STD-001B, and so shall it be, etc.. Check out Section 8.0 starting on page 14 and go from there. Who wants 5? Earl Moon

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Bob Willis

#14694

Re: Clean raw bds | 17 August, 1998

| | Where can I find a spec to put on my fab drawing, to call out the cleanliness of the board, before I recieve it. These boards will require a tight spec after they are assembled, so I want to know that they are clean when I get them. Any suggestions. Also does a clean spec for an assembled board, (5 micrograms per sq. centimeter), sound acheivable? | Pat, | It is written, in ANSI/J-STD-001B, and so shall it be, etc.. Check out Section 8.0 starting on page 14 and go from there. Who wants 5? | Earl Moon With a bare board you should be able to get the boards with a higher cleanliness level than 5. When I was working in fabrication we were providing boards for no clean assembly processes with a maximum of 2ug/cm2. Much of the problem with bare boards is the resist type as I commented on a week ago. Some solder masks when they are developed trap ionic material in thire surface which can be released when tested. The hot test Alpha is more prone to show up this issue. If you want a no clean process to achive < 10-15ug/cm then the first issue is the board. We could also debate the whole relevence of ionic testing but that is another day. Well off to work now !!!!!

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