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

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Drying PCBoards

Michael F.

#20579

Drying PCBoards | 3 July, 2002

Need some info regarding the terms and conditions of drying bare boards before the assy. process (if need it at all). We encountered latly with delimination in some boards and I'm not sure that it is a product failure.

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#20585

Drying PCBoards | 3 July, 2002

First, we have talked about drying / baking / demoisturizing / whatevering bare board previously. Search the fine SMTnet Archives to get started on recipes.

Second and more importantly, you gotta fix this delamination problem. If it is delamination, it is bad news. Even if it isn�t delamination, that YOU think it�s delamination indicates a serious problem at least with the appearance of your board. Have you done any sections? Can you post pix?

Next, delamination can be attributed to several factors: * Entrapped moisture, processing solutions, and �what not� that expands when heated to normal soldering temperature. * Excessive soldering temperature. * Excessive laminating temperature. * Defective laminate material. * Problem in oxide treatment of innerlayer. * Contamination at the laminate interface.

Comments are: * Pressure from water rapidly out-gassing from a board under normal soldering conditions can cause delamination in poorly fabricated boards. * Pressure from water rapidly out-gassing from a board under normal soldering conditions can NOT cause delamination in properly fabricated boards. * If you did some bad things to the board [Abby Normal soldering conditions], most likely delamination will among the problems with the appearance of the board. Beige silkscreen ink will be the least [but initially the most obvious] of the remainder of the problems.

I think I hear someone saying �road trip�, 'Mike', the buyer's name, and then laughing. Sorry.

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