[Cl...] Posted August 23, 2021 Share Posted August 23, 2021 Short cylinder or circle for primary datum? All you have is a cylinder .528 Ø x .220 deep. Link to comment Share on other sites More sharing options...
[Da...] Posted August 23, 2021 Share Posted August 23, 2021 ASME 14.5 2018 section 7 doesn't list a circle as a PRIMARY datum. The cylinder is listed and will control 4 degrees of freedom, 2 translational and 2 rotational. Link to comment Share on other sites More sharing options...
[Cl...] Posted August 23, 2021 Author Share Posted August 23, 2021 I am having a hell of a time with a type-1 GRR for a position callout using this short (.220 depth) cylinder as the primary and only datum. Link to comment Share on other sites More sharing options...
[Da...] Posted August 23, 2021 Share Posted August 23, 2021 How many circles are you using to make the cylinder? Are you able to check all 360°? Link to comment Share on other sites More sharing options...
[Ri...] Posted August 23, 2021 Share Posted August 23, 2021 You can use a Circle, but Calypso is most likely pulling the Spatial Rotation from the Base Alignment. Link to comment Share on other sites More sharing options...
[Cl...] Posted August 23, 2021 Author Share Posted August 23, 2021 Please sign in to view this quote. That would explain why the position deviations are nearly perfect (five decimal places) The Datum -A- surface is used as one half of a step cylinder for the Base Alignment. BTW a customer program. Link to comment Share on other sites More sharing options...
[Cl...] Posted August 23, 2021 Author Share Posted August 23, 2021 Please sign in to view this quote. This is a customer program. They use two circles at 420 each. Link to comment Share on other sites More sharing options...
[Me...] Posted August 24, 2021 Share Posted August 24, 2021 Please sign in to view this quote. This is correct but a huge issue. The statement below about sufficient length cannot be ignored in certain situations where a cylinder that is shorter in length than its diameter size is used as the PRIMARY datum. "All Datums must be of sufficient length" - this includes very small planes as a primary datum as well. Our company has purchased AGI's training courses, which Mark Foster teaches and he goes into very specific detail about this exact issue. Link to comment Share on other sites More sharing options...
[Cl...] Posted August 24, 2021 Author Share Posted August 24, 2021 I can't pass a type-1 GRR using a cylinder as Datum -A-. I use a circle and I pass. Link to comment Share on other sites More sharing options...
[ch...] Posted August 24, 2021 Share Posted August 24, 2021 Please sign in to view this quote. You are cheating yourself 😃 😃 Link to comment Share on other sites More sharing options...
[ch...] Posted August 24, 2021 Share Posted August 24, 2021 Please sign in to view this quote. I have faced this with Perpendicularity... Link to comment Share on other sites More sharing options...
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