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Solderability problem II

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#57800

Solderability problem II | 16 January, 2009

We are encountering similar problem as yesterdays posting, with solder not sticking to the pads but wicking to the leads on Leaded HAL finish boards, except we have tried two different solder paste lots with similar result. The oven profile and paste works on other similar board. If we rough the pad surface the solder sticks.Our board are from China, and we feel there is some contamination on the surface. Any cleaning sugestion?

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#57801

Solderability problem II | 16 January, 2009

HI ,

A LOT OF SIMILAR ISSUES WERE DISCUSSED LATELY. MOST OF THE TIME THE PROBLEM IS IN THE BOARD FINISH. THE BEST OPTION IS GOLD FINISH(ENIG). MAKE A SAMPLE AND TRY IT WITH BOTH PASTES YOU HAVE. ANOTHER THING I DID BEFORE AND IT HELPED ME PARTIALLY IS THE PROFILE. GO ON SLOW SPEED MAKE LONGER SOAK AND SHORTER REFLOW ZONES. THIS REALLY IMPROVES WETTING AND YOUR SOLDER WILL NOT JUST STAY ON THE LEAD. THE EASIEST WAY IS TO TRY IT MANUALLY. SOLDER ONE PART MANUALLY AND YOU WILL BE ABLE TO SAY IF YOU HAVE BAD CONTAMINATION AND HOW IS YOUR SOLDERABILITY.

REGARDS, EMIL

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#57802

Solderability problem II | 16 January, 2009

Had the same problem with boards from China. Try using Scotch Brite medium duty pad. It worked for us.

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#57804

Solderability problem II | 16 January, 2009

Thanks, we tried using some very fine sand paper and did improve. Any one know of any chemical that would work.

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#57805

Solderability problem II | 16 January, 2009

i would not try to chemically clean the finish, you would just be asking for other problems.

1) I would ask your supplier their Hasl mix. Standard Lead hasl is 63/37 - it almost sounds like your boards have a higher content of Tin and your experiencing some tarnishing or they have been finishing your boards with Lead free hasl.

2) I would recommend Enig or Immersion Silver.

Regards, Boardhouse

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#57837

Solderability problem II | 21 January, 2009

Try a typical Stencil Cleaner with Glycol ether mix as probably solder resist residue depositing back onto the pads during levelling. Cheers Greg

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#57857

Solderability problem II | 22 January, 2009

try making your boards in the USA. There's better QC, and if any problems do happen, they can be solved easily and quickly saving you money in the run. You get what you pay for. Good luck.

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#57860

Solderability problem II | 22 January, 2009

Hi Jeff,

Unfortunately there is just as many bad shops in the US. Communication & doing your Due diligence is the best solution.

I sell for Taiwan now but sold for a US shop for 10 years. Taiwan Quality is as good or better than most US Shops and dealing with QC issues is no different then dealing with them State side. If paying more means better quality, I guess I should raise my prices. In this Market if you offer poor quality product on a steady basis, you won't be around long.

Regards, boardhouse

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