Reporting Profile of a surface with U modifier

[rmf180]

Current and new customer have begun specifying profile of a surface using the U modifier as detailed in the latest version of ANSI y14.5. I have had numerous conversations over the years regarding the intent of profile is bet illustrated as attribute but customers insist on variable data. As long as the profile call our is equally distributed, the formula accepted has been: Profile = Max - Min as long as the data straddles the nominal else Profile = Maximum deviation from nominal * 2. Given an unequal profile such as: Prf .004 U .001, the profile zone is defined as +.001 / -.003 inch along the detailed surface. How do you report the "variable data" if all points on a sample range between -.003 to -.002 inch from nominal? Probably a simple solution which I cannot get to.

 

[Proud Liberal]

One option might be to designate the callout as PASS / FAIL and additional report min and max values from nominal. There is no mathematical conversion from point deviations to profile in this scenario.

 

[Kingsld1]

Unfortunately Y14.5 is a design standard, not a inspection or reporting standard. About the best you can do is report individual point deviation from the nominal line.

 

[optomist1]

minor detail,correct designation is ASME Y14.5 19XX or 2XXX....re: Attribute vs Continuous data.....with very few exceptions Continuous Data is best...when analyzed it will give insight as to dimensional trends "before" the typical attribute gages/inspection equipment begins rejecting parts..

 

[JuliaRho]

How do I write a CMM program using a U modifier for profiles?