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Pb % contaminant allowed in Pb/Free Solder

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GS

#37810

Pb % contaminant allowed in Pb/Free Solder | 11 November, 2005

HI all, which is the last "though" about the max Pb % allowed/acceptable into a Pb Free Alloy ? For istance inside : - HASL Process Solder Pot Alloy - Wave Solder Pot Alloy ( 400Kg mass average) - Static Wave Solder Pot Alloy - Etc

IPC-J-STD-001D talks only about Solder Purity Limits for Tin/Lead Alloys, nothing jet regarding Lead Free Alloys. Did I have seen correct?

Thank you

Best Regards.............GS

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#37817

Pb % contaminant allowed in Pb/Free Solder | 11 November, 2005

By country [swiped from an AMD presentation]: * EU: Chemical (lead-free) date: July 1, 2006 for products �put on the market�; affects lead, mercury, cadmium, hexavalent chromium, PBB, PBDE, except for exempted applications. [0.1% for lead, mercury, hexavalent chromium, PBB and PBDE and 0.01% for cadmium] * China: Chemical (lead-free) date: July 1, 2006, same chemicals as EU RoHS. * Japan: Product scrap with lead (>0.3 mg/l) is a �hazardous substance containing waste�. Disposal permitted only in controlled landfills, mfrs. pay extra costs (Waste Disposal and Public Cleansing Laws). * South Korea: Korean Electronics Industry Declaration to Manufacture Environmentally Friendly Products, March 2004; Ministry of Environment has commissioned study of RoHS/WEEE regulations. * Taiwan: Green mark requirements tied to EU WEEE/RoHS. * Thailand: industry/government Thai RoHS Alliance, as a result of Sep. 04 Ecomaterials seminar. * California: State Bill SB20, Electronic Waste Recycling Act of 2003, passed Sep. 03, amended by State Bill SB50. Lead-free date: 1/1/07; mirrors EU RoHS Directive heavy metal restrictions.

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GS

#37829

Pb % contaminant allowed in Pb/Free Solder | 11 November, 2005

Thank you Davef,

If I am not wrong in understanding, your answer is mainly related to the Legal point of view according to several different Countries who adopted Rohs or equivalent.

My question, sorry for my poor English, is mainly related to the limit of Pb % (allowed by process) above that we could meet soldering problems. Like, for istance: bad solder joint, dross build up, brittle solder gioint,bridges, icing, etc. Like what we could meet today with Sn/Pb alloy when too much Cu, Fe,Ni,Sb,Ag,Bi,. see IPC-J-STD-001D Table 3-1

I know, with new alloy like SACs or similar, the scenario in terms of contamination % limits have changed a lot comparing to Sn/Pb 63/37, but just courios to know what is coming on in this matter when moving to Lead Free solder inside pot of wave soldering machines . And what they (those who already have L-F wave process) take care weekly or monthly when analyzing the solder alloy samples from wave pots and how they re-balance the values if out from limits, but which limits ?

Thank you

Best Regards..........GS

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#37831

Pb % contaminant allowed in Pb/Free Solder | 12 November, 2005

Those limits of allowable impurities have been set over many years of practical experience.

People area talking about lead contamination of lead-free solder connections, but I can't find specific numbers in my notes. Places to start are: * One of Tom Woodrow's papers shows that less than 1% lead isn't going to get us. * A Swedish report, highlighted on the front page of the recent NPL circular, that suggests that around 2% is bad and above and below that is OK. I don't know the details. * A Sandia report shows little solder joint degradation from 0% to 8% Pb additions for two different lead free solder alloys. The Sandia report also shows that both a chemistry effect (what types of metallurgical phases are formed) and a physical effect (what shape are the phases and how do they interact with stress/strain) can be found. * AIM, in a David Suraski presentation, talks about lead collecting in dynamics similar to �zone refining� [ http://www.aimsolder.com/techarticles/Lead%20Contamination%20in%20Lead-Free%20Electronics%20Assembly.pdf ]

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GS

#37834

Pb % contaminant allowed in Pb/Free Solder | 12 November, 2005

In other words it should mean that Lead Free Soldering Process (this SACs era, and not for istance classic Lead Free Sn/In used since many years ago) is still a "Baby Technology" and so we need experience and feedback from the field before to issue a reliable Standard like it could be considered the IPC-JSTD-001C ??

Thanks again

Regards .............GS

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