Where theworld gathers for metal finishing
Q&As since 1989
-----
Ra or RMS (Rq)
I have seen in print that RMS (Rq) has become obsolete for specifying surface roughness and that it has been replaced by Ra. Our engineering manager insists that RMS (Rq) is still the standard that is used in sealing applications and that he is unwilling to change. Our supplier do not always have equipment that will read in Rq which has led to rejected parts
Is there a definitive document or publication that would clear up this issue for me?
Quality Manager of a purchaser of Ground components - Island Lake, Illinois
May 29, 2009
June 2, 2009
For North America, I've long considered ASME B46.1 to be the defining document on surface finish and how it should be measured, reported, and analyzed. Interestingly, a quick Google search showed two things: first, cstools.asme.org/csconnect/FileUpload.cfm?View=yes&ID=20001
-
is a powerpoint discussion of what changed in going from the 1995 to the 2002 versions, and
http://www.asmeconferences.org/B46Seminar/
suggests that ASME will be releasing an updated version this year.
(I'd likely not buy the old one unless they promised to include the update when it's published.) Stay tuned!
Lee Gearhart
metallurgist - E. Aurora, New York
Q, A, or Comment on THIS thread -or- Start a NEW Thread