Hi guys, I need some help understanding my crossed ANOVA gage R&R results and what to tell the customer.
So we are currently doing a PPAP for a new customer on a part that we’ve been making for a decade.
The production process has a detection machine that 100% tests each part and interlocks and rejects it if it fails. The detection machine takes 10 minutes to test the part and provides variable values as results. The machine then takes those variable values and compares them against a spec and interlocks if it fails outside that spec. Even though the detection machine provides variable data, we functionally use it as an attribute gage, pass/fail results only. No SPC is done using this detection machine.
Our new customer requires us to do a Gage R&R on the detection machine in order to make sure it is an effective measurement system. We have never done this before.
Even though it’s functionally an attribute gage i decided to do a crossed anova Gage R&R since the machine provides variable data and I didn’t want to do 450 measurements for a attribute gage R&R.
According to the results of the gage R&R, it failed. Study variation R&R results are like 90% and the number of distinct categories is 1.
So it failed. However the tolerance variation gage R&R hovers around 20%.
From my understanding, study variation Gage R&R is more driven by SPC requirements while tolerance Gage R&R is more about the effectiveness of the measuring system to detect pass vs fail.
Since this machine is more of a functional attribute gage in our process, could I argue that it passes gage R&R?
Am I understanding all of this correctly. Is there anything in the AIAG MSA manual to support my argument.
I really don’t want to do an attribute gage R&R study. That would be 50 parts X 3 operators X 3 trials for a total of 450 measurements and 4500 minutes of testing at the very least.
Thoughts?
So we are currently doing a PPAP for a new customer on a part that we’ve been making for a decade.
The production process has a detection machine that 100% tests each part and interlocks and rejects it if it fails. The detection machine takes 10 minutes to test the part and provides variable values as results. The machine then takes those variable values and compares them against a spec and interlocks if it fails outside that spec. Even though the detection machine provides variable data, we functionally use it as an attribute gage, pass/fail results only. No SPC is done using this detection machine.
Our new customer requires us to do a Gage R&R on the detection machine in order to make sure it is an effective measurement system. We have never done this before.
Even though it’s functionally an attribute gage i decided to do a crossed anova Gage R&R since the machine provides variable data and I didn’t want to do 450 measurements for a attribute gage R&R.
According to the results of the gage R&R, it failed. Study variation R&R results are like 90% and the number of distinct categories is 1.
So it failed. However the tolerance variation gage R&R hovers around 20%.
From my understanding, study variation Gage R&R is more driven by SPC requirements while tolerance Gage R&R is more about the effectiveness of the measuring system to detect pass vs fail.
Since this machine is more of a functional attribute gage in our process, could I argue that it passes gage R&R?
Am I understanding all of this correctly. Is there anything in the AIAG MSA manual to support my argument.
I really don’t want to do an attribute gage R&R study. That would be 50 parts X 3 operators X 3 trials for a total of 450 measurements and 4500 minutes of testing at the very least.
Thoughts?