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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Pad dissolution on Thick PCB's

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#41197

Pad dissolution on Thick PCB's | 26 April, 2006

Hi all,

Has anyone any experience they can share with regard to pad dissolution on PTH's on thick boards. We are using lead free SAC305 on both OSP and Immersion silver finishes and are experiencing difficulties when removing and replacing connectors in boards typically 0.125" and over. By the time the solder has flowed enough for us to remove and replace the connector the pads on the underside of the board are gone.

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#41244

Pad dissolution on Thick PCB's | 27 April, 2006

you can either use an alloy that has a higher copper content to reduce dissolution or the better option is to have a Nickel plating barrier. both have there problems. Bu remember the dissolution of copper by tin carries on at a slower rate a ambiant temperatures.

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#41249

Pad dissolution on Thick PCB's | 27 April, 2006

This is similar to a previous posting here on SMTnet, where, as we recall, one response suggested using a solder alloy with less tin.

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