[Me...] Posted December 8, 2020 Share Posted December 8, 2020 I'm having issues inspecting cylindrical parts as the one shown below & I believe it is everything to do with my Base Alignment. The issue is when I'm checking Positions & Runouts with the part sitting Horizontally instead of Vertically due to datums on the print. Does anyone have any suggestions for the alignments when inspecting Horizontally? For my Horizontal alignment I just used the -A- face & the -B- bore as a simple alignment, same for Vertical. I'm thinking I should be doing multiple circles and then creating a 3D Line to use as my Spatial in the Base Alignment. Please help. Link to comment Share on other sites More sharing options...
[Ri...] Posted December 8, 2020 Share Posted December 8, 2020 Your second suggestion is the way that I always tackle long parts. Try to make the line as long as possible. Also add at least a 1,2,1 loop if you can. Link to comment Share on other sites More sharing options...
[Ri...] Posted December 8, 2020 Share Posted December 8, 2020 You are going to struggle with these runouts though because the features are so far away from the datums. It will be tough. Link to comment Share on other sites More sharing options...
[Cl...] Posted December 8, 2020 Share Posted December 8, 2020 For the Base Alignment I'd use a step cylinder (spatial) from the two OD flanges on either end. Link to comment Share on other sites More sharing options...
[Ri...] Posted December 8, 2020 Share Posted December 8, 2020 Please sign in to view this quote. I was told to be cautious using the Step Cylinder in the Base Alignment as the space axis and inadvertently flip causing a lot of issues. Since the Base Alignment should only be used for part alignment, I'd suggest the 3d Line over the Step Cylinder. Link to comment Share on other sites More sharing options...
[Me...] Posted December 8, 2020 Author Share Posted December 8, 2020 Honestly I've never had any luck using cylinders in Base Alignments...I always use circles planes or lines. Link to comment Share on other sites More sharing options...
[Ch...] Posted December 8, 2020 Share Posted December 8, 2020 Please sign in to view this quote. Richard will be right. Consider using a 3d line constructed from B-D as your spatial and primary datum. Justify this by also reporting the perp of that line back to datum B. Your argument would be that the using B-D as your primary is functionally the same as using AB as primary. And since you are not using the datums as designed, your supporting document for this would be to reference ASME B89.7.2-2014.CMM-GDT_Measurement_Planning_Hand-Out.pdf Link to comment Share on other sites More sharing options...
[Ma...] Posted December 9, 2020 Share Posted December 9, 2020 What makes this a "long" cylindrical part? Datum A appears to be almost as large as the length of the part. This seems like it should be adequate reliably define the orientation and a simple circle in B should adequately define the other two origins for the base alignment. What am I missing here? Link to comment Share on other sites More sharing options...
[Me...] Posted December 9, 2020 Author Share Posted December 9, 2020 I thought so too and I got .0013 on True Position sitting the part Horizontally and .0003 in Vertically. It may have something to do with the accuracy of my probes at 90° as well, they are a little longer than the max requirement. Link to comment Share on other sites More sharing options...
[SH...] Posted December 9, 2020 Share Posted December 9, 2020 Please sign in to view this quote. How do you check baloon number 98 , disc probe?. Link to comment Share on other sites More sharing options...
[Me...] Posted December 9, 2020 Author Share Posted December 9, 2020 No I wouldn't recommend using a disk probe to measure .001 runouts unless you have a disk that is 3MM diameter or below. We don't have disks that small. I manually calibrate my disk probes to within .00001in and I never have accurate results for runout or roundness using a disk. I've tested this by comparing the results on a master ring gage with my 3mm standard probe, which is my most accurate. As far as inspecting it, we have a Jig Bore setup out in the shop that we have the operators use to indicate parts for inspection, it has a DRO and everything, very useful. Link to comment Share on other sites More sharing options...
[SH...] Posted December 9, 2020 Share Posted December 9, 2020 I would have done with disc probe, my customers will not accept manual inspection, as far as they are concerned CMM is the almighty 🤬 . If you were talking about 1/10 rule, you have 0.0254 runout and disc probe will have 3 to 4 micron error, so it will be a see saw condition.... Link to comment Share on other sites More sharing options...
[Me...] Posted December 9, 2020 Author Share Posted December 9, 2020 Please sign in to view this quote. Good luck with that one my friend. I learned as much as I could with disk probes as far as calibrating them and proper usage and when it came to form dimensions, my disk probes are unreliable. The cookbook also states the max sizes per bore for form and location as well. Link to comment Share on other sites More sharing options...
[Ri...] Posted December 9, 2020 Share Posted December 9, 2020 Disc probes are useless. Just make a t or a star. Link to comment Share on other sites More sharing options...
[SH...] Posted December 9, 2020 Share Posted December 9, 2020 I have had good results... Link to comment Share on other sites More sharing options...
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