[To...] Posted March 16, 2022 Share Posted March 16, 2022 I have created a Best Fit Bore Pattern on 3 circles to Datum A (top of part). From the attached plot, you can see that rotation and translation have been applied but the top circle is just out of tolerance. However, the 2 lower circles clearly have room to shift. Any thoughts? . . CADcube Example_PlotProtocol.pdf Link to comment Share on other sites More sharing options...
[SH...] Posted March 16, 2022 Share Posted March 16, 2022 It must have more deviation compared to other circles.. Link to comment Share on other sites More sharing options...
[Ch...] Posted March 16, 2022 Share Posted March 16, 2022 This might be wrong but here are my thoughts: When rotating and translating, Calypso looks at minimizing total deviation from nominal (not deviation from its upper spec limit). If you shift the two lower circles, then they both get worse while only the top circle gets better. Even though the shifting would cause all features to be in tolerance, you would actually have more deviation from nominal. I think. Link to comment Share on other sites More sharing options...
[To...] Posted March 16, 2022 Author Share Posted March 16, 2022 Please sign in to view this quote. I'm using circles so it is only looking at the center point. What other deviation are you referring to? Link to comment Share on other sites More sharing options...
[To...] Posted March 16, 2022 Author Share Posted March 16, 2022 Please sign in to view this quote. If I use a functional gage, it doesn't matter if one feature has more deviation that the others, right? Link to comment Share on other sites More sharing options...
[Ro...] Posted March 16, 2022 Share Posted March 16, 2022 Hi Tom, Have you tried a different fitting method for the bore pattern, Minimum, for example? Link to comment Share on other sites More sharing options...
[Ch...] Posted March 16, 2022 Share Posted March 16, 2022 Please sign in to view this quote. I agree with this. My point is that are we sure that Calypso 100% agrees with the functional gage? Link to comment Share on other sites More sharing options...
[Th...] Posted March 16, 2022 Share Posted March 16, 2022 I would guess fit method is the problem here? The trainers stressed using view tolerance in pretty much every use case. Actually Chad's initial post sums it up. The Gauss fit won't intentionally make individual element deviations worse in order to bring all elements within their spec limits, while view tolerance does, I think. Link to comment Share on other sites More sharing options...
[SH...] Posted March 16, 2022 Share Posted March 16, 2022 Please sign in to view this quote. No. Link to comment Share on other sites More sharing options...
[No...] Posted March 17, 2022 Share Posted March 17, 2022 Chad nailed it. I've used bore pattern best fit for a long time and that's exactly what Gauß best fit does. It doesn't care about the tolerances, it just creates an evenly distributed fit. With more bores in the pattern, it might have even shown its insensitivity for single outliers. Link to comment Share on other sites More sharing options...
[To...] Posted March 17, 2022 Author Share Posted March 17, 2022 Thomas, you are right again.... Thanks to you and everyone for your input.PlotProtocol_BFBP.pdf Link to comment Share on other sites More sharing options...
[Ch...] Posted April 25, 2022 Share Posted April 25, 2022 I was going thru old reference documents and found this. Scroll to slide 17 which covers exactly this. Gauss will NOT simulate how part fits on hard gage.Algorithms.pdf Link to comment Share on other sites More sharing options...
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