J
jenboy
An argument about variation using ANOVA method - which one is "right"?
1) We need to dial in our blow molded product to the low end of the spec and the high end of the spec to ensure we have the whole range of variation the gage is required to measure.
2) Based on the capability study, control limits are calculated and the range between those calculations are used as the basis for the variation the gage needs to measure.
I'll admit, I'm the number 2 and I'm not the boss. The boss is dead set on number 1. Problem is, if we run to the low side on wall, we're out of spec on weight and run the risk of going out of spec on wall as well. Our charts show us running with a shifted (to the high side), albeit normal curve. (Why the print specs and tolerances weren't revisited before PPAP I have no idea!) I have a die setter ready to explode because he can't dial in what the QA Manager (and acting QE on this project) wants with out producing a bunch of junk - have I been doing this wrong the whole time? I never had a customer question it, or have a gage go haywire. But I'm stuck now with a whole bunch of frustrated program people over a MSA - and a looming PPAP date. Any suggestons?
1) We need to dial in our blow molded product to the low end of the spec and the high end of the spec to ensure we have the whole range of variation the gage is required to measure.
2) Based on the capability study, control limits are calculated and the range between those calculations are used as the basis for the variation the gage needs to measure.
I'll admit, I'm the number 2 and I'm not the boss. The boss is dead set on number 1. Problem is, if we run to the low side on wall, we're out of spec on weight and run the risk of going out of spec on wall as well. Our charts show us running with a shifted (to the high side), albeit normal curve. (Why the print specs and tolerances weren't revisited before PPAP I have no idea!) I have a die setter ready to explode because he can't dial in what the QA Manager (and acting QE on this project) wants with out producing a bunch of junk - have I been doing this wrong the whole time? I never had a customer question it, or have a gage go haywire. But I'm stuck now with a whole bunch of frustrated program people over a MSA - and a looming PPAP date. Any suggestons?