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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Contaminate PCB surface

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Contaminate PCB surface | 27 November, 2011


I'm just study PCB in my company. I found many Surface PCB have some contaminate and can not specify what it is. Size is around 2 mm2 . Sometime I send to supplier and they said it is solder paste or some dirty flux. please see contaminate1

and some case is plastic packing burnt but my company have cleaning machine It should not contaminate on PCB's surface or efficiency of cleaning machine is poor. please see contaminate2

Sometime Cu attach on fine pitch and effect to short circuit on board.

So I need some kindly help as below 1) Can I trust supplier result? 2) How I improve cleaning machine? 3) How to check efficiency of cleaning machine? 4) Does this contaminate usually happen on SMT process? SMT have to set cleaner machine. Can I claim to PCB's supplier to improve?

I will wait kindly suggest .

Best regards, Siaomuay


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Contaminate PCB surface | 29 November, 2011


What is your flux and peak reflow/rework temperature?

Do you use chemistry in your cleaner?


Shean Dalton

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Contaminate PCB surface | 30 November, 2011

Dear Shean Dalton

Peak temperature 240'c and we use IPA for cleanning Pcb surface before mounting

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Contaminate PCB surface | 3 December, 2011

We can't tell much from your pictures, except there are rounded gray blobs that could be solder. If that's the case, you need to get that solder hotter. Please give us the temperature readings of those blobs during reflow.

You mentioned that you're using IPA as a cleaning agent. IPA doesn't work. It is a hazardous material and is a fire hazard.

What are you trying to clean from these assemblies?

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Boundary Scan

Plasma Prior to Conformal Coating