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Hi All,
I've been reading a lot about (and have conducted a few) Gage R&R lately and have noticed that even in a measurement system with very good Equipment and Appraiser variaition, we can still not meet acceptable % Gage R&R numbers if the spec is tight.
Along those lines I was wondering if some general guidelines, or even a chart, exisit that correlate machine shop inspection tools with tolerances that realistically can be measured, both for product specs and statistical processes.
We have Micrometers, Calipers, Height Gages, CMM's, 2 and 3 pt bore mics and such in our precision machine shop.
Our mic's have both resolution and accuracy of .00005 inches, (Mit 293-340), Calipers .0005 resolution, accuracy?
I realize in general we want 10 units of discrimination so I probably could take resolution and mulltiply x 10? I'm thinking it's not really that simple though.
Ultimately I'm looking to have a 'good feel' for what tolerances can and can not be measured per tool on the floor reliably for SPC. Our tightest part is +.0002, -.0001. Typical tolerances are +/- .005 and our key features are commonly +.001, -0 or +0, -.001
These include ID's, OD's and lenght & width.
I hope this makes sense and seems like a reasonable question - Thanks!
I've been reading a lot about (and have conducted a few) Gage R&R lately and have noticed that even in a measurement system with very good Equipment and Appraiser variaition, we can still not meet acceptable % Gage R&R numbers if the spec is tight.
Along those lines I was wondering if some general guidelines, or even a chart, exisit that correlate machine shop inspection tools with tolerances that realistically can be measured, both for product specs and statistical processes.
We have Micrometers, Calipers, Height Gages, CMM's, 2 and 3 pt bore mics and such in our precision machine shop.
Our mic's have both resolution and accuracy of .00005 inches, (Mit 293-340), Calipers .0005 resolution, accuracy?
I realize in general we want 10 units of discrimination so I probably could take resolution and mulltiply x 10? I'm thinking it's not really that simple though.
Ultimately I'm looking to have a 'good feel' for what tolerances can and can not be measured per tool on the floor reliably for SPC. Our tightest part is +.0002, -.0001. Typical tolerances are +/- .005 and our key features are commonly +.001, -0 or +0, -.001
These include ID's, OD's and lenght & width.
I hope this makes sense and seems like a reasonable question - Thanks!