D
I have completed and expanded GRR study, 15 parts, 3 operators, 3 runs, 2 measurement systems.
Each measurement system returns acceptable results on it's own, %Contribution levels below 10% and %Tolerance levels in the mid 20% range.
When the data is process through the expanded tool (using Minitab 16) the results are less than stellar. the %Contribution levels are still acceptable but the %Tolerance levels are at 41% and 56% (testing two points during each run)
The %Tolerance level is based on my required Process Tolerance of course. What I need to determine is, if I run both systems as is, what is my Process Tolerance effectively increased to. In other words, if my P/T is .25 to start, would I, in reality be letting go items in a tolerance range of .35? .45? .75?
I tried to work backwards by repeating the analysis with an increasingly larger P/T range but after several iterations, I graphed the results and the curve flattens out so I can never put in a large enough tolerance to get to a zero %Tolerance. So obviously this method is not valid.
What I need is a method to use the results from the expanded GRR to let me know if I run product across both systems, how much will my range grow for the units that pass? I know this won't give me new limits as that is a question of accuracy, a different test altogether. But knowing the range will let me present the information to management to allow an executive decision to be made.
Many thanks to anyone who can assist me on this.
Doug
Each measurement system returns acceptable results on it's own, %Contribution levels below 10% and %Tolerance levels in the mid 20% range.
When the data is process through the expanded tool (using Minitab 16) the results are less than stellar. the %Contribution levels are still acceptable but the %Tolerance levels are at 41% and 56% (testing two points during each run)
The %Tolerance level is based on my required Process Tolerance of course. What I need to determine is, if I run both systems as is, what is my Process Tolerance effectively increased to. In other words, if my P/T is .25 to start, would I, in reality be letting go items in a tolerance range of .35? .45? .75?
I tried to work backwards by repeating the analysis with an increasingly larger P/T range but after several iterations, I graphed the results and the curve flattens out so I can never put in a large enough tolerance to get to a zero %Tolerance. So obviously this method is not valid.
What I need is a method to use the results from the expanded GRR to let me know if I run product across both systems, how much will my range grow for the units that pass? I know this won't give me new limits as that is a question of accuracy, a different test altogether. But knowing the range will let me present the information to management to allow an executive decision to be made.
Many thanks to anyone who can assist me on this.
Doug