Re: Is MSA needed once or once a year for Verniers, Micrometers, Gages, etc?
I would only like to add that if your customer require MSA each year for the tools/equipment on your control plan, it becomes a requirement and you shall comply with it.
Here is how this works.
The is no time function to Gage R&R. I hate to call it MSA, because MSA is actually all functions of gage verification, such as linearity bias, stability, etc. - some of which
are time functions and
do have periodic requirements dealt with in calibration.
Gage R&R answers the question "Is this the right gage for the job?" Logically, you should only have to answer that question once. But, if you did not capture the operator variation adequately by not using a wide enough sample of skill levels, you may have to redo it if the skill levels of the operators drops. If you change the gage, you may have to redo it if the relation of the gage to the operator or part changes. Significant
changes in the
gage system (operator, part, gage, environment) would initate a need for redoing the gage R&R.
There may be two reasons why a customer may require annual gage R&R: 1) they are ignorant to the point of gage R&R and rubber stamp useless requirements to cover up their fear of their ignorance, OR 2) they know their suppliers will mess with the gage and not redo the gage R&R as the should, so to make sure they didn't "break it" when they thought they were "fixing it" they try to catch these problems by forcing periodic gage R&R. Many customer requirements are generated by suppliers messing up - so they stuff more and more requirements on the supplier to try to catch them and keep them from burning the customer again. So, the true basis for the requirement may get lost.