For those of you not familiar with RoHS, it is a European Union directive. RoHS stands for Restriction of Hazardous Substances (or Restrictions on Hazardous Substances, depending on who is writing). It bans the use, with certain exemptions, of the following substances:
- lead (Pb)
- mercury (Hg)
- cadmium (Cd)
- hexavalent chromium (Cr VI)
- poly-brominated bi-phenyls (PBBs)
- poly-brominated diphenyl ethers, specifically penta- & octa- (PBDEs)
These substance are being banned as part of WEEE, Waste Electrical & Electronic Equipment. To make a long story short, the authorities in Europe noticed that as electronics get shorter and shorter product life cycles, more and more of the landfill is WEEE. The purpose of the WEEE directive is to encourage recycleing, reuse and general reduction of electrical & electronic waste in landfills. While that is a laudible goal, the execution of said goal stinks – another rant for another time.
But because there will still be some WEEE that will wind up in landfills and some more of it will be handled and processed and recycled, the EU is concerned about what substances are used in WEEE and want to reduce the use of certain substances so they will not contaminate landfills, contaminate the people reusing the electronics, etc. etc.
And that is why, even though many estimates are that it only accounts for 0.1-0.5% percent (yes, that’s right, 1 to 5 thousandths) of the lead used, regular tin-lead solder (63Sn37Pb) is going to be banned from use in most electronics. WEEE & RoHS only apply to Europe, but (a) that is a large enough market and (b) there are a lot of other countries and even some U.S. states following suit, so most manufacturers are working to comply with WEEE & RoHS anyway.
Of the six substances banned, there are good reasons why they are used in electronics in the first place. VERY good reasons, depending on what the substance can do.
Today, I had a co-worker ask me just how much lead and cadmium do the folks in Europe is actually going to get into someone from the lead solder on circuit boards or the cadmium in relay contacts. Both my co-worker and I agreed that there is probably only very minute amounts of lead that are going to migrate from solder, into water, through the landfill liner and into the groundwater. We also both agreed that there is probably even LESS cadmium that is going to migrate out of the relay contact, out of the relay case, out of the overall product enclosure, into water, through the landfill liner and into the groundwater.
But because there might POSSIBLY be some MEASURABLE amount that might POSSIBLY get into the environment IN SOME WAY, the use of those substances needs to be stopped.
So the electronics industry is moving back to the 1960s when solder technologies were NOT mature and reliability, endurance, workability, etc. had to figured out by trial and error for each new solder chemistry & alloy. And the relay industry is moving back to the . . . . how long have they been using cadmium in relay contacts, since at least the 1930s? . . . . . the relay industry is moving back to the 1930s or earlier to figure out how to get the same longevity and endurance from non-cadmium containing alloys. And it probably won’t be possible, not in packages that are the same size as are being used now.
How it is that reducing the reliability & power-handling of products, through solder chemistries that run hotter (thereby stressing the soldered components more) and relays that can’t switch as much, will reduce the amount of products that get thrown away, is a leap of logic I can’t follow.