Hi ezekietemple, your opinion is quite new to me. IMO, manafaturing process does not always stay unchanged. If the manufacturing pocess has been improved significantly, the variation of its output i.e. products would be largely decreased. In this case, though the gage is still in its good condition, the result of Gage R & R would not stay the same, the result would get worse. And the gage may not be suitable to measure this improved process. Moreover it is possible that the operators who use this gage would be also changed. In order to know whether this measuring system works well or not, the Gage R＆R should be run again, right?
"Manufacturing process does not always stay unchanged"...
(The entire POINT of
ISO 9000 - and many other standards -
IS TO ENSURE THAT YOUR PROCESS / PRODUCTS DO NOT CHANGE...) Now, when there is a significant change - whether planned or not - there are many ways to address that change and this may include a Gage R&R study and/or possibly something else...)
"
If the manufacturing pocess has been improved significantly... And the gage may not be suitable to measure this improved process."...
(If there is a "significant change" then yes, maybe a new Gage R&R is necessary, but also maybe not. It depends on what "changes" have occured - they may or may not effect the validity of that gauge and what it measures.
PLEASE NOTE: Your comment "
the manufacturing process has been improved significantly" is too vague and not capable of giving a direct answer.
If you have specifics, then please list them.)
"
Moreover it is possible that the operators who use this gage would be also changed."
(Please see this quote from my post above(in the square brackets below]... I have already stated that this may be a case where a new Gage R&R would be used/beneficial... but also may not...].
[[
Gage R&R is a test to see if a measurement method (Gage and use of that gage) is appropriate for measuring a particular feature/characteristic.
It either is appropriate or is not appropriate...period.
Three years of waiting will not chage its appropriateness. Heavy use will not change its appropriateness.
A new customer will not change its appropriateness.
Based on this alone, Gage R&R is a one time proof.
When operators change, it may be worthwhile to verify that the new ones are using the same method. This does not require Gage R&R, though you may choose to use that tool.
When a gage is used heavily and may drift, it may be worthwhile to verify that the gauge is still accurate and repeatable. This does not require Gage R&R, though you may choose to use that tool.
Bottom line is that Gage R&R does not have to be run again...the test method is appropriate for that which is being tested.
You may choose to run it again for some other purpose...but there is no need to check for appropriateness again.
]]
"
In order to know whether this measuring system works well or not, the Gage R＆R should be run again, right? "
(Maybe. You can choose to do a Gage R&R every time a new person is hired/replaced etc... But that does not mean that you
have to... In summary, Gage R&R is not the only way to perform MSA (Measurement System Analysis) it is one of many tools and is not subject to time itself. If other things change in your process (environment, operators, methods, materials, measurement specifications etc...), then you may decide a new Gage R&R is needed. However, if these things change and it is decided that they will not have an effect on the Gage R&R (by you performing some sort of MSA) then you do not have to perform the Gage R&R. {{{ but you better be able to give good reasons to your customer / auditor...!!!}}}
