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Pb soldering to Pb free finishes

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#60033

Pb soldering to Pb free finishes | 1 October, 2009

Does anyone out there have experience soldering with Pb solder (Sn 63 or Sn 62) to SAC 305 coated PCB lands (about 50um) or Sn-Cu plated lands (about 10um). I know soldering Pb free (Sac based soler) to Pb/Sn coated lands is a no-no, but was waondering what the pitfalls were going the other way. We are trying to convert bare circuits to Pb free, yet be able to use either SAC solder or Sn 63 (or Sn 62) for some lagacy projects where changing solder alloy is out of the question. What should we look out for?

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#60034

Pb soldering to Pb free finishes | 2 October, 2009

> Does anyone out there have experience soldering > with Pb solder (Sn 63 or Sn 62) to SAC 305 coated > PCB lands (about 50um) or Sn-Cu plated lands > (about 10um). I know soldering Pb free (Sac based > soler) to Pb/Sn coated lands is a no-no, but was > waondering what the pitfalls were going the other > way. We are trying to convert bare circuits to Pb > free, yet be able to use either SAC solder or Sn > 63 (or Sn 62) for some lagacy projects where > changing solder alloy is out of the question. > What should we look out for?

We had a problem putting regular solder on unleaded pads. The finish looked grainy and it didn't fillet well. I found that making the profile so that it is at the max allowable temperature and dwell gives the unleaded a chance to diffuse into the leaded paste.

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#60037

Pb soldering to Pb free finishes | 2 October, 2009

If you know "soldering Pb free (Sac based soler) to Pb/Sn coated lands is a no-no," why would soldering with Pb/Sn to Pb-free coated lands be different? If you are going to do this, follow the advice of an earlier poster who recommended higher peak soldering temperature [~230*C] than you would use for leaded assembly.

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#60054

Pb soldering to Pb free finishes | 5 October, 2009

this is what they call hybrid soldering....i missed the discussion at the IPC Show in Chicago...

Can someone with hybrid soldering idea share some?

thanks

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#60116

Pb soldering to Pb free finishes | 15 October, 2009

Plasma Prior to Conformal Coating

Heller Industries Mark 5获得了 2015年中国SMT远见奖 - 回焊炉领域