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To: TheBusDriver who wrote (3196)	12/19/2000 5:32:53 PM
From: Don Lloyd	Read Replies (1) \| Respond to of 8010

wayne - I worked for many, many years as an elec. tech. used to hold solder in my mouth all the time (didn't have 3 hands). Hate to think of all the lead in my system...then again I handle Radioactive sources on a regular basis now so I probably don't have anything to fear from the lead! The radioactive sources are probably neutralized by your internal lead shielding. If not, you probably WILL end up with 3 hands. -g- Regards, Don

To: TheBusDriver who wrote (3196)	12/19/2000 8:31:31 PM
From: The Vet	Read Replies (1) \| Respond to of 8010

Wayne there are more than rumblings - lead based solders will be completely outlawed in Europe within a few years and that will force the Asian manufacturers to comply and eventually the US will have to go along with it or be banned from the European markets. It's not just electronic solder, but plumbing applications that are under the gun as well and that uses a lot of solder. Leaded solder is going down the same road as leaded gasoline - soon it will be gone. Check the URL's from my post 3162 a couple of days ago or just type "lead free solder" into any search engine.

To: TheBusDriver who wrote (3196)	12/19/2000 10:22:48 PM
From: Aloysius Q. Finnegan	Respond to of 8010

<< I worked for many, many years as an elec. tech. used to hold solder in my mouth all the time (didn't have 3 hands). Hate to think of all the lead in my system...then again I handle Radioactive sources on a regular basis now so I probably don't have anything to fear from the lead!>> While ingesting lead is not healthy for anyone, it is particularly harmful to children. During the early years of a child's development, the body utilizes calcium in the formation of synaptic nerve connections in the brain. Unfortunately it cannot distinguish between lead and calcium.

To: TheBusDriver who wrote (3196)	12/20/2000 9:34:39 AM
From: long-gone	Respond to of 8010

No global unity for new lead-free solder By Jack Robertson Electronic Buyers' News (01/18/00, 12:03:11 PM EST) The lead-free solder dilemma is adding to CEMs' and OEMs' long list of worries. No, it's not the environmentalists' rallying cry to ban lead-solder fluxes. The IPC isn't trying to preserve venerable lead soldering, and sees a switch to new alloys as inevitable. What upsets the U.S. trade association and its members in the interconnect industry is the lack of a unified global program to phase in new lead-free solder. Research and initiatives are scattered all over the place. It'll be a nightmare if companies, industries, and nations come up with a mish-mash of new alloys and processes with no global consensus, warned Dave Bergman, IPC's vice president of technology. “The worst-case scenario is contract manufacturers facing a bewildering array of solder-free recipes with various customers insisting on their own particular technique,” he said. The IPC would rather see a global program than scattered regional efforts. So far, however, that doesn't appear to be in the cards. Japan is perhaps the furthest along in lead-free solder manufacturing, and its efforts illustrate the quagmire. Many Japanese consumer-electronics companies are starting to use lead-free soldering, but they differ widely in material and techniques. The materials used include tin-bismuth, tin-copper, tin-silver-copper, and tin-zinc alloys. Some have a proprietary alloy. The National Electronics Manufacturing Initiative in the United States is working with OEMs and CEMs to zero in on a few alloys that can replace lead. But competition from Japan may not give U.S. contenders enough time to build consensus. If Japan's new lead-free products take off, U.S. companies may not be able to wait for industry standards and may jump into the alloy mixing bowl with their own solder brew, adding to the global confusion. Lead-solder replacement is complicated compared with previous efforts to eliminate toxic chemicals, such as chlorofluorocarbons, from high-tech manufacturing. Solder alloys affect components and printed-circuit boards they come in contact with. With all potential substitutes, there are tradeoffs concerning contaminant resistance, cost, ease of manufacturing, operating temperatures, and tooling and equipment changes. Politicians also aren't waiting for the global industry to get its act together. The European Union is soon expected to publish its final rule eliminating lead solder by 2004. There is a World Electronics Circuits Council of national interconnect associations, but that body has no plan yet to tackle the lead-free hot potato. Finding a new solder isn't a cinch. buyersnews.com

To: TheBusDriver who wrote (3196)	12/20/2000 9:37:55 AM
From: long-gone	Read Replies (1) \| Respond to of 8010

Home Alloys Solder Alloys and the Industries They Serve ALLOY MELTING RANGE (°C) INDUSTRY SERVED SnAg 221 -226 Automotive SnAgBi 206 - 213 Military/Aerospace Consumer SnAgBiCu - Military/Aerospace SnAgBiCuGe - Consumer SnAgBiX 206 - 213 Consumer SnAgCu 217 Automotive Telecommunications SnBi 138 Consumer SnCu 227 Consumer Telecommunications SnZn 198.5 Consumer -------------------------------------------------------------------------------- Some Industry Organizations and the Alloys They're Investigating ORGANIZATION ALLOY NEMI SnCu0.7 SnAg3.5 SnAgCu NCMS SnAg3.5 SnBi58 SnAg3.2Bi2.0 CASTIN SnAg3.4Bi4.8 SnIn20Ag2.8 (Indalloy) SnAg3.5Cu0.5Zn1.0 ITRI SnAgCu SnAg2.5Cu0.8Sb0.5 SnCu0.7 SnAg3.5 SnBiAg SnBiZn -------------------------------------------------------------------------------- Alloy Material Cost, As Compared to Eutectic Tin-Lead Solder ALLOY PRICE MULTIPLIER REFERENCED TO TIN-LEAD* USE SnAgCu 2.2 to 2.7 Considered a benchmark SnCu 1.5 Low-cost alternative for wave soldering SnAgBi 2.2 to 2.7 Possible Pb replacement (especially for SMT). Bi concern for SnPb finish boards. Avoid any Pb! SnZn 2.2 to 2.7 Concerns with corrosion resistance. Requires special fluxes. No long-term reliability data available. SnAg 2.2 to 2.7 Extensive data *NOTE: Price is compared to SnPb at current metals market price. -------------------------------------------------------------------------------- Lead-Free Solder Alloys Potential alloys with high percentage of tin: +silver (Ag) 0.1 to 5.0% +bismuth (Bi) 1.0 to 5.0% +antimony (Sb) 0.2 to 5.0% +copper (Cu) 0.2 to 2.0% +zinc (Zn) 0.5 to 9.0% +indium (In) 0.5 to 20.0% +magnesium (Mg) 0.5 to 2.0% -------------------------------------------------------------------------------- Common Alloys Being Used or Evaluated to Replace Lead & Their Melting Points Sn96.5Ag3.5 (221 C) Sn95Sb5 (232-240 C) Sn95.5Ag3.8Ci0.7 (~217 C) Sn95.8Ag3.5Cu0.7 (~217 C) NIST Alloy Sn99.3Cu0.7 (227 C) Sn96.2Ag2.5Cu0.8Sb0.5 (213-218 C) Sn97Cu2.0Sb0.8Ag0.2 (226-228 C) Sn91.8Ag3.4Bi4.8 (202-215 C) Sn42Bi58 (138 C) -------------------------------------------------------------------------------- Physical Properties of Lead-Free Alloys: I High tin content alloys like Sn90+: + Typically have much higher melting points than traditional Sn63Pb37 + Are stronger and less ductile than lead or Indium-bearing alloys + Typically exhibit poor wetting when compared to Sn63Pb37 Moderate bismuth content alloys: + Typically have lower melting points than Sn63Pb37 + Typically are very brittle + Wetting and joint appearance is relatively poor Physical Properties of Lead-Free Alloys: II Effect of certain elements such as copper on high tin content solder: (as in Sn95.5Ag3.8Cu0.7): + Retards the dissolution rate of copper. + Can improve the wettability. + Can improve the thermo-mechanical properties of solder joints. + Reduces the melting point slightly. Indium-bearing solders compare favorably to lead-bearing solders. Both are ductile materials. Typically, indium-bearing solders (e.g., Sn48In52) tend to be slightly expensive compared to other alternatives. Indium-bearing solders are often used when soldering to gold substrates. Note that where Sn-Au intermetallics are brittle, Au-In intermetallics are relatively thin and much more tolerant of thermal cycling. Bi-containing Alloys Fatigue life is reduced when soldered to hot air solder leveled (HASL) boards. Lead from Hot Air Leveling (HAL) coatings can diffuse through the grain boundaries of alloy. This lead can form a eutectic composition of Bi52Pb32Sn16 in the grain boundaries. The melting point of the eutectic alloy is 95 °C. The overall result is a large decrease in the strength of the joint. Fillet lifting of PTHs due to pasty range (206-213 °C) Avoid any Pb!! The Effect of Lead on Sn42Bi58 Lead from hot air leveling (HAL) coatings can diffuse through the grain boundaries of the alloy. This lead can form a eutectic composition of Bi52Pb32Sn16 in the grain boundaries. The melting point of the eutectic alloy is 95 °C. The overall result is a large decrease in the strength of the joint. In-containing Alloys In reduces the melting temperature of an alloy In alloys offer good strength and physical properties In very expensive and in short supply Also forms a ternary compound with SnPb finishes that has a phase change at 114°C. kester.com