Lead Free Wave Soldering

Do a search on it there are some old listings of it im sure.

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I have been LF wave soldering for well over a year now.

Yes, yes, no, maybe....What exactly are you looking for?

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Notes from an AIM No-Lead Presentation ...

Wave Soldering * May require a higher pot temperature than tin/lead: 255-265*C * May require a change in liquid fluxes to compensate for the poor wetting of some alloys and high thermal stresses of the wave process. * Makes OSP a bad choice for wave soldered boards.

Solder Maintenance * Certain lead-free alloys, such as Sn/Cu, suffer from high copper dissolution rates. * Unfortunately, whether Sn/Cu or Sn/Ag/Cu is implemented for wave soldering, the density of both alloys is less than Sn63/Pb37. Therefore, instead of the intermetallic floating off and easily being removed as when in Sn63/Pb37, the intermetallics sink and are dispersed through the lead-free alloy in the pot. This could result in additional solder maintenance and pot dumps. * The good part of this density issue is: it takes less more expensive solder to fill your pot. [Maybe that's not so good after all, erzit?] * Probably have to watch copper concentration more closely than with SnPb.

Wave Soldering Equipment * Most modern wave solder machines can provide the necessary heat (preheat and wave) for lead-free soldering. * Nitrogen blanket may be required, depending upon the alloy selected. * High-tin alloys rapidly dissolve the materials often used in wave solder equipment. SS pots, nozzles, impellers, etc will need to be replaced with cast iron, titanium, or a special coating. * Wave soldering equipment manufacturers have had success using a Melonite coating over SS. ["Equipment Impacts of Lead Free Wave Soldering" Morris and O�Keefe. APEX 2003] * Converting a SnPb filed cast iron pot to lead-free requires removing the SnPb, then two cycles of filling, running, and removing pure Sn. [Recyclers dream.]

We have no relationship, nor receive benefit from the company referenced above.

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Many trials conducted so far from single sided to Mixed technology dual wave with our LFB227/S 0.3Ag silver Lead free. Results are excellent, some say better than 63/37. One continueing problem though is the age old area of undercured resist and running at 260C pot temp is causing some major concerns. A problem only ever rectified when flux change to low solids rosin then problem is sorted immediately. About time the PWB vendors sorted this issue out. Best regards Greg York Technical Sales Manager BLT Circuit Services Ltd England

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We manufacture conversion kits for lead free wave solder machines. We recommend that all component parts be manufactured from grade 1 / 2 Titanium which is far superior to any coatings applied to stainless steel and not as expensive as people think. There are currently seven machines sucessfully in production at Sony Pencoed.

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