Summary for rohs rack plating Discussion
RoHS compliance and rack plating are not the same thing, according to the thread. Ken Tenney asked whether a small stamped steel part with zinc and trivalent chromium had to be rack plated because one vendor claimed racking was required for RoHS compliance, and he noted the cost difference was significant. James Watts replied that rack vs. barrel has nothing to do with RoHS, though a separate customer specification might forbid barrel plating for quality reasons such as edge dings. Brian Terry said RoHS applies to the finished item, not the manufacturing method, and that barrel plating is perfectly acceptable if the finished part meets the substance restrictions. He added that RoHS does not specify plating technique. Ken later suggested the vendor may simply be steering work to a rack line that had been converted to trivalent chromating while the barrel line still used hexavalent chromate.
Q. I am having a small stamped and bent sheet metal part fabricated from AISI 1008-1018 CRS in the US. I have a specification for zinc with trivalent chromium. One vendor who has outside finishing applied, has given me feedback that the parts must be racked (hung) to be RoHS compliant.
This is the first time I’ve encountered this in 5 years of specifying this finish. I cannot find anything definitive. Is barrel application acceptable? The pricing difference for such a small part (22 x 13 x 1.5 mm, with a hole) is tremendous, thus the question.
Ken Tenney
engineer – Winchester, Virginia, USA
May 18, 2010
First of two simultaneous responses —
A. Rack vs barrel has nothing to do with RoHS. There could be something in someone’s spec that forbids barrel plating, and that would more likely be for dings on the edges.
James Watts
– Navarre, Florida
May 19, 2010
Second of two simultaneous responses —
A. Ken,
RoHS applies to the finished item, not on how the part is manufactured. There is nothing in RoHS that restricts plating to only rack plating, barrel plating is perfectly fine.
RoHS is concerned with hazardous substances on the finished item, not on the process, and certainly doesn’t go so far as to specify plating techniques.
Brian Terry
Aerospace – Yeovil, Somerset, UK
May 20, 2010
A. Hi. I think I would hazard the theory that the plater wants to steer you toward rack plating because his rack line has been converted to RoHS-compatible trivalent chromating whereas his barrel plating line is still running a hexavalent chromate 🙂
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
May 20, 2010
I appreciate the responses here and will convey them back to the vendor who made the suggestion that racking was required for RoHS compliance. (We have not selected them for this part, but they need a fair chance at gaining business on future jobs.)
Ken Tenney
– Winchester, Virginia, USA
May 21, 2010