dgatwood said:
The best part is looking at the list of companies that scream in pain versus those that basically didn't blink. It's really quite telling....
FWIW, lead-free solder doesn't really make much difference in mass production. Most products are either soldered with wave soldering or with BGA soldering.
Wave soldering occurs by putting a solder-resistant coating (e.g. a peelable latex coating) on the board wherever solder shouldn't stick, pouring a wave of molten solder across it (hence the name), then peeling away the protective coating. The composition of the solder makes little difference for that, as the solder is plenty hot.
The other technique, BGA, involves balls of cool solder being attached either in dimples in the board or in dimples in the chip or other device to be soldered. After gluing the part into place, the board is placed in a reflow oven, wherein it is brought up to a sufficiently hot temperature to melt the solder. Barring it getting hot enough to melt the traces in the chips (which is at least two or three times as hot as is needed to melt lead-free solders), it really isn't an issue there, either.
Lead-free solder is mainly a problem for hobbyists doing stuff in their garages. For mass manufacturing, it's usually barely a blip on the radar, though I wouldn't be surprised if some companies use it as an excuse.
(Note: there are some aspects of RoHS that can be a little problematic... just not that one.)
While your description of the two soldering techniques is correct, you've forgotten the rest of the story.
All the equipment previously used for lead-soldering has to be replaced; it's contaminated with lead. That means all the wave soldering equipment, all the solder paste masks for the circuit boards, All the BGA ovens and repair stations, and all the through-hole repair station equipment. And if that's not enough, lead-free solder requires that all the soldering points (pads, vias, etc.) on the bare circuit boards must be changed from a "pre-tinned" coating of leaded solder to pure silver, pure gold flashing, or some other non-lead coating. Some manufacturers are trying to go the "cheaper" route by using silver... unfortunately, there are many newly discovered problems using silver (as an example : little silver "whiskers" growing out of the deposited silver, which cause shorting and other failures). Gold flashing hasn't had these issues, but it's much more expensive (look at the cost of gold versus silver).
Then there's the added cost of identifying, marking, and moving all the leaded components into a separate warehouse location to keep them apart from the lead-free components... two separate warehouse locations, that need to be maintained instead of one. Then there's the cost of writing off all the leaded components that can't be used after June 30 for products headed for Europe, or California (the date is still up in the air, but it looks like sometime in 2007).
Then there's the cost of dual warehouse locations for leaded and lead-free subassemblies and finished goods. And also the cost of creating and maintaining the leaded and lead-free bills of materials, purchasing documents, finished goods RoHS compliance documentation for shipping, and on and on. And we're only talking about one substance and one type of material.
Add in all the screws, nuts, washers, connectors, plated sheetmetal parts, painted sheetmetal and plastic parts, hell - even the cartons, paper and other materials used for packaging the products, and you can begin to understand the impact.
Another thing impacting these manufacturers is that RoHS-compliant parts are difficult to get (the typical turn-around time for many RoHS-compliant I.C.s and discrete components has gone from a week or two to 6-9 months!), and the cost of RoHS-compliant parts is anywhere from 50% to 600% higher than the non-compliant parts.
We're talking billions of dollars of impact here.
And the ironic part of this program is this : because the RoHS compliant lead-free soldering is much less dependable than leaded soldering, the U.S government has waived the requirement to use RoHS compliant components in military and medical-field electronics!
Sure - RoHS si great for the long-term health of this planet, and I'm all for it personally, but there is a huge initial monitary impact involved.
And IMHO, many first and second generation RoHS compliant electronic devices will be problematic because of the less-dependable solder joints caused by the lead-free solder and the lead-free PCB pad "tinning" coatings.
I hope I'm wrong about this dependability issue ... I truely am.
