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

Printed Circuit Board Assembly & PCB Design Forum

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White Tin PCB - Hand soldering

Mark Miller


White Tin PCB - Hand soldering | 25 January, 2000

Has any one experienced hand soldering through hole components to white tin plated PCB's using no-clean wire solder?

Our facility is presently evaluating white tin vs Sn/Pb coatings. Our only difficulty at this time has been hand soldering of wires and other through hole components to meet IPC-610B class II fillets. We get a great solder fillet on the primary side of the PCB, the secondary pad 20-50% of joints do not form. The solder stops at the edge of the hole and does not flow around the lead and over the pad. Our surface monunt and wave solder lines are running with out problems.

We can achieve 100% fillets on secondary pads with an RMA flux and applying a liquid no-clean flux prior to soldering the wire. The PCB's are clean and less than 1 month from our internal PCB shop.

We would prefer not to add additional process time to this operation like adding more no-clean flux or removing RMA.

The maufacturer of the white tin solution warns of oxidation with too high a heat in hand soldering, but I have not been able to create that problem intentionally.

Any suggestions would be helpful.

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Re: White Tin PCB - Hand soldering | 26 January, 2000

Mark: It sound like one or more of the following is happening:

* Previous heat cycles (ie, reflow, reflow, wave) are degrading the surface protectant * Wire solder flux doesn't have enough stomp to burn through the corrosion. That poor ol' stuff is spent by the time it gets to the end of the tube.

Good luck

Dave F

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