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Low volume quality PCBs (how to)

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Low volume quality PCBs (how to) | 14 July, 2005

Hi. In the past years I had made dozens of PCBs but now I am trying to get a professional finishing on them. The main problem is oxidation of the copper traces. Basically I use the silkscreen method to make the pattern in both layers and then etch. Later, I apply soldermask (by silkscreening too) in both layers and since I have to heat cure the soldermask in an oven, the copper oxidates too. I do not know which method will be better, if applying some kind of laquer, varnish, etc., (which also would be solderable too) and then apply the soldermask, or how I could stop the copper oxidation. Thank you very much for any help.

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Low volume quality PCBs (how to) | 15 July, 2005

Few of us here on SMTnet fabricate our bare boards. Most of us are assemblers. So, the solderability of the connections of our boards is a BIG issue with us.

Our suppliers protect the solderability of the copper by coating the copper to limit the effects of corrosion. Common types of solderability protection that we see are: * Hot Air Solder Leveled [HASL} * Electroless Nickel / Immersion Gold [ENIG] * Organic Solderability Protection [OSP] * Immersion tin * Immersion silver

The latter three are proprietary processes. We can give you contacts if you'd like. HASL and ENIG have been around and is fairly well documented.

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Low volume quality PCBs (how to) | 14 August, 2006

Can you just coat them with solder?


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Board House


Low volume quality PCBs (how to) | 15 August, 2006

Bake your solder mask and then solder coat.

If you are going to put an immersion finish like Osp, gold, tin or silver you would have to do a Micro etch to clean the copper prior to placing the surface finish.


Board House

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