The challenges of Pb-Free Designs

When designing for the latest Lead-free RoHS compliant designs.
What challenges were faced in the Lead-free changes?
I know that pure tin designs had issue with whiskering. But what could cause issues for designs that can still use lead, is going lead-free?

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We run lead-free jobs every day and aside from the material it’s all pretty standard. The list of ROHAS compliant laminates is a bit limited compared to standard materials but that’s about it. We have a dedicated Hot Air Leveler set up for lead-free solder which eliminates the Tin whisker problem. Suggest sending a stack-up and request ROHAS compliant and see what comes back but there won’t be much difference.

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ROHS, although a major change in the electronic manufacturing business, was probably not as much of a shake up as first expected. In particular the granting of exceptions for military and medical helped a great deal. While there were many missteps, the extensive inspections and testing eventually worked out most of the bugs. The industry was also good at producing ROHS versions of components.

Many times I was asked to do “BOM scrubbing”, that is to take someone’s BOM, sit down, verify each part number was ROHS compatible or to find a replacement for it. Most of that sort of thing went quite well.

“Whiskering” was one of the additional problems but was expected when the process began and so work was already being done to find compatible solder alloys and such. A later problem was sulfur contamination, which seems to have been solved and passed on.

Now we are faced with some new banned substances.

According to the REACH regulation, these phthalates are also considered Substances of Very High Concern (SVHC).

The industry is already hard at work in order to comply with this.

As related to board design I don’t expect any issues.

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