KB314: RoHS / Lead Free Production Q&A

This article was last updated on May 14, 2012, 7:40 p.m. | Print Article | Leave Feedback

Q: What is RoHS?

A: The RoHS Directive stands for "the restriction of the use of certain hazardous substances in electrical and electronic equipment".

This Directive bans the placing on the EU market of new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants.

Q: When did the directive become effective in the EU?


A: July 1, 2006

Q: How does this affect products shipped to countries outside the EU?


A: The United States and Canada have not yet instituted RoHS as of January 2008 but, there is a movement to implement the restrictions in California.

So far, Japan does not ban the use of the listed hazardous substances but they do require labeling disclosing their use in products.

China RoHS took effect on March 1, 2007 and is more like the EU RoHS directive in that it prohibits the use of the hazardous substances.

Q: If this is not required in all countries, why did Digitrax choose to implement RoHS?


A: Digitrax ships significant amounts of products to international destinations such as the EU and Japan where the directive is in place.

So, in order to continue servicing these markets, the conversion to RoHS was necessary.

In addition, we feel that over time, these restrictions will be put in force in most countries around the world (including the US).

We also believe that consumers would rather purchase products from environmentally friendly companies.

2006 was a good time for Digitrax to convert because we were ready to completely re-tool our surface mount production facility.

We were in the process of purchasing new equipment and because we could see RoHS beginning to be implemented, we chose to go ahead with the conversion.

Q: When did Digitrax become RoHS Compliant?


A: Digitrax phased in the RoHS production process during 2005 & 2006.

By the end of 2006 all production with the exception of the radio equipped products were RoHS compliant.

The radio equipment is only sold in countries where RoHS has not yet been mandated.

Q: Is there a down-side to RoHS/Lead Free production processes?


A: Most RoHS printed circuit board assemblies must be processed at higher temperatures because of the materials that replace lead in the soldering process.

Generally other consumer product industries have reported a slight increase of infant mortality and lower production yields due to this requirement.

Q: I noticed differences in the fit of Plug N' Play decoders that are RoHS compliant. Why is this and how can I install RoHS decoders to that they make better contact?


A: In an effort to achieve the best fit in locomotive installations, Digitrax had several iterations of RoHS compliant Plug-N-Play decoders during 2006.

The pre-RoHS lead Hot Air Solder Leveled (HASL) finished printed circuit boards had pads that were approximately 26.5 mils (thousandths of an inch) thick on average.

The HASL finish on these boards was soft, and allowed a snug fit, since the solder finish was thick and malleable and flowed easily around the contact points.

The RoHS compliant finish is a solid and unyielding finish of gold plating over nickel and copper.

It has a much harder surface finish than the pre-RoHS HASL finish.

During 2006, Digitrax tried laminates/processes from 5 different circuit board manufacturers across many of the decoders produced during 2006.

Most of the decoders produced during 2006 were installed and are in use today.

In some cases the thickness and rigidity of the RoHS compliant boards caused issues.

Most users who encountered problems, simply put lead solder on pads where the contact was loose to make them fit more reliably.

The earliest gold plated RoHS printed circuit boards made for Plug N' Play decoders by Digitrax averaged about 24 mils.

The current RoHS laminate/finish we are using is about 27 mils.

This seems to be working well in most locomotive installations so, we plan to keep this thickness for future production.

The RoHS finish is solid with NO malleability, so PCB thickness and casting tolerances are very critical for a secure fit inside the locomotives.

The extra few mils of thickness makes the PCB's noticeably more rigid.

These challenges have been mostly with the DN163Ax series decoders.

The DN163Kx series decoders are generally easier to work with since there is more support in the casting engagements of the locomotives.

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