When shopping for components it's common to find a lead-free or RoHS-compliant version of the part along side one that is not. Under what circumstances does it matter that I chose exclusively lead-free or RoHS (or whatever other lead-free designation is out there) parts? What would motivate me to pick a lead-free part over a cheaper non-lead free part?
On a side note, some explanation of what all this lead-free business is about would be interesting to me.
Aside from the RoHS stuff mentioned, in our lab we use lead free solder for high temperature circuit work, we tend to operate diodes and JFETs up to around 450degC and we've found leaded solder can't take the heat. Of course without the lead the solder is harder to work with but the result is that we can test circuits at high temperature without having to make mechanical joins between components, which is the alternative.
Oh, and although you can't use leaded solder in Europe for commercial products you can in military stuff - I think the theory is that military people don't tend to lick circuit boards but there is always the risk that a toddler will in consumer stuff :-)
RoHS (Restriction of Hazardous Substances Directive) covers a number of hazardous substances, not just lead. Google RoHS for a list.
You can not sell an electronic product in Europe if it contains any of the listed toxins. It seems likely that other parts of the world will follow suit.
The main challenge with RoHS is that you can not use solder that contains lead. Lead-free solder has a higher melting point and is generally a bit more tricky to work with.
On the bright side, you are less likely to cause lead poisoning to yourself or anyone else manufacturing or recycling your product :-)
The RoHS directive is not an absolute ban, it specifies the max concentration. You can for example have 0.1% lead in your product. Industrial products may not require RoHS compliance, you can for example use NiCd batteries in medical equipment even if it is banned for consumer use. But the batteries have to be brought in to recycling stations after use.
As an individual you are welcome to lick lead all day long or to import non-compliant products for your own use. You can use solder containing lead as long as you don't sell what you make.
These are the substances prohibited by the RoHS legislation (copied from the UK Government leaflet):
RoHS restricts the use of mercury, lead, hexavalent chromium, cadmium and a range of flame retardants notably polybrominated biphenyls and polybrominated diphenyl ethers.
As others have already pointed out, RoHS requirements generally forbids the use of components with hazardous materials (with some exceptions made for batteries and other specialty components where alternatives do not exist).
As a manufacturer of your product, you'll need to certify your product is RoHS compliant (amongst many other regulatory and industry requirements like emissions, safety, recyclability) in order to satisfy your customers and (in increasing number of markets) to be legally sold. Because of this, the entire "supply chain" from the components, to the printed circuit board, to the board assembly (i.e. soldering) will need to be documented as being RoHS.
Not being "RoHS" doesn't necessarily mean that the item contains a hazardous substance. Sometimes, the products are given the RoHS designation to confirm their process compatibility with no-lead manufacturing. Because lead-free solder has a higher melting point, the components must also withstand higher temperatures during board assembly.
to be legally sold in the EU. Other regions (notably including most of the USA) have less stringent requirements for electronics.
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Commented
May 5, 2011 at 16:07