ISO Plots vs. Gage R&R - Do ISO plots meet intent of MSA?

[Steven Sulkin]

Anyone know if ISO plots meet intent of MSA? I am not familiar with ISO plots, but it appears to address all the issues (repeatibility, reproducibility, stability, linearity, bias), if designed appropriately. Any comments as to how it stacks up to GRR? Any expected difference in sample size (our measurements are very costly)?

Thanks in advance.

 

[Marc]

As long as you are plotting (QS9000) certain 'trends'. They want to meke sure trends are being observed and that instruments are understood. Some of the stuff you need for overall compliance will come from Design Engineering in so far as to why certain equipment was chosed with respect to 'sensitivity' and such.

Over the last two years MSA has come into play more than ever before. Earlier focus was mainly on a coherent calibration system. UL sorta started a focus more in depth - an understanding of the technology of measurement systems must be demonstrated and some auditors and registrars are being more - uhhhh - picky and want to see actual plots. I would first check with your registrar and gain an undrrstanding as to their expectations. Registrars and auditors are not all asking for the same degree of evidence of MSA. In fact, a lot of auditors do not understand MSA.

Again - check with your registrar.

Since I'm on the soap box, I may as well also point out that you have to be careful - what would be required for an instrument measuring to a tolerance of +/- 0.25 inch is not going to be as critical as measuring where you have +/- 0.0001mm.

[This message has been edited by Marc Smith (edited 12-03-98).]