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

Printed Circuit Board Assembly & PCB Design Forum

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pcb plating



pcb plating | 13 June, 2002

I opened a two product boxes which are similar and have PCBs. The PCB in one box is gold plated. Can anyone explain why it needs gold plating? Thanks in advance

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pcb plating | 14 June, 2002

Assuming you are talking about solderable surfaces:

People specify various materials to protect the solderability of the pads on the board. Gold, actually, Electroless Nickel - Immersion Gold [ENIG], is popular. * Board fabricators like it because they get rich. * Assemblers like it because it has a �flat surface�. Flat surfaces are important when assembling complicated boards. [And they like complaining about poor solderability. And they�re too lazy to evaluate imm tin and imm silver.]

The Merix site [ ] has a pretty good comparison of various materials used in protecting the solderability of board surfaces.

Assuming you are talking about wear surfaces [yano, edge connectors, button contacts, etc.]: Search for discussion on �fretting corrosion� in a recent �OnBoard Forum� hosted by Jim Zanolli from Teka.

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pcb plating | 15 September, 2002

Hi Dave, Immersion Ag has poor surface appearances after reflow or rather tarnished, while Immersion Tin requries higher temp. Probably that's why Immersion Ag is more preferred.

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