[Ja...] Posted June 8, 2020 Share Posted June 8, 2020 Good afternoon everyone. I have a part that has presented an issue that we weren't aware of until now. On the attached part, Datum A is the surface to you. We have been aligning Plane on A, Circle in B and then aligned to the plane of C. As you may know this is causing variation in alignment and True Position callouts. So now they want to use a single point, in the middle of Datum C. This is where i am stuck. I can not for the life of me get the alignment to the Pt to match what i was getting to the plane alignment. It appears that the point I created for C is not actually aligning the part as we are getting the same true position numbers for the large ID to ABC as we are to AB. I tried to create a line from Pt C to B and align to that but I still can't seem to get it to align properly. The line created appears to be off the datum C location and more to where the center of the probe would be when taking that point. Straight distance from Pt C to B is 69.4742mm This thing is driving me nuts. Any help would be greatly appreciated.Point Part.JPG Link to comment Share on other sites More sharing options...
[Ma...] Posted June 8, 2020 Share Posted June 8, 2020 You could take a line on C, then rotate by your basic angle in the alignment. Set X and Y origins to Datum B and Z origin on Datum A. Link to comment Share on other sites More sharing options...
[Ja...] Posted June 8, 2020 Author Share Posted June 8, 2020 Please sign in to view this quote. We tried that too and still found too much variation in the repeatability of it. That is why they want to go with a point now. Link to comment Share on other sites More sharing options...
[Ma...] Posted June 8, 2020 Share Posted June 8, 2020 If you take a single point on datum C, then in SPECIAL you can rotate to angle and rotate to X or Y specific value. Link to comment Share on other sites More sharing options...
[Ke...] Posted June 8, 2020 Share Posted June 8, 2020 Please sign in to view this quote. Did you verify that the evaluation of Point C is *not* using mid-point? Have you verified the location & angle of the feature(s) related to "C", by using "A", the large diameter, and "B"? What is the form of Plane "C"? ...Even just using Point "C" may not be consistant, if the form of the plane is "bad". Link to comment Share on other sites More sharing options...
[Gr...] Posted June 8, 2020 Share Posted June 8, 2020 How exactly did you create Point C and line BC? Link to comment Share on other sites More sharing options...
[Me...] Posted June 8, 2020 Share Posted June 8, 2020 I must be missing something. Since -C- doesn't pass through -B- you may need to create a feature offset from -C- the Basic amount of 8 to get a stable alignment feature to clock to. Have you tried creating a plane, point, line, etc that is offset from the -C- surface and using that or a 3d line through it? Link to comment Share on other sites More sharing options...
[Ri...] Posted June 8, 2020 Share Posted June 8, 2020 As Robert said, you cannot just create a Point, and use that as the tertiary as it needs to be offset. What I typically do, is measure a Plane on the surface for the Base Alignment (for your Planar). Calypso will automatically offset the alignment correctly. Then come back and measure your single point. Create a Theoretical Circle that pulls the actuals for the Point, but for the axis that the Point should be passing through, you will offset the actual value the 8mm. The reason that I say to use a Circle instead of a point is Calypso doesn't like using points for Tertiary Datums. You can make the diameter whatever size you want it to be - that portion doesn't matter. Link to comment Share on other sites More sharing options...
[Ri...] Posted June 8, 2020 Share Posted June 8, 2020 Link to comment Share on other sites More sharing options...
[Ja...] Posted June 8, 2020 Author Share Posted June 8, 2020 Please sign in to view this quote. Unfortunately, I am just figuring this out. I thought it aligned to it and found out it didn't. Meanwhile, we measured 300 pcs through 4 processes and the data is all junk. I don't get why it wouldn't clock to a point. Link to comment Share on other sites More sharing options...
[Ja...] Posted June 8, 2020 Author Share Posted June 8, 2020 Please sign in to view this quote. So, I took points on A, Circle on B and a point on C and then rotated the alignment 46.7713° (40.255+6.5163 where 6.5163 was the difference between B to C and Plane C.) I didn't know Calypso doesn't like using a point as the tertiary. I figured it would rotate on B until it clocked to Point C. Our other software will clock to an individual point. I made the mistake of thinking Calypso would too. Link to comment Share on other sites More sharing options...
[Ri...] Posted June 9, 2020 Share Posted June 9, 2020 It will clock to an individual point inside of an alignment, but in a DRF, it will not. Link to comment Share on other sites More sharing options...
[Ja...] Posted June 9, 2020 Author Share Posted June 9, 2020 Please sign in to view this quote. Ok, so next question on this. I am noticing an issue with my point. I have it programmed to be taken 70.4932mm from B and the vector is perpendicular to the surface. Can anyone tell me why it would still be measuring the actual over a millimeter shorter? I can understand a little variation but not this much.point.JPG Link to comment Share on other sites More sharing options...
[Ma...] Posted June 9, 2020 Share Posted June 9, 2020 Look at your actual vectors. It is being measured as a Y point. Link to comment Share on other sites More sharing options...
[Ja...] Posted June 9, 2020 Author Share Posted June 9, 2020 How do I fix that? The CMM appears to be approaching the point at the proper vector during the program run. Link to comment Share on other sites More sharing options...
[Da...] Posted June 9, 2020 Share Posted June 9, 2020 Look under "evaluation" of this "Point1". Is it a touch point? Link to comment Share on other sites More sharing options...
[Ja...] Posted June 9, 2020 Author Share Posted June 9, 2020 Please sign in to view this quote. Yes. Link to comment Share on other sites More sharing options...
[Ja...] Posted June 9, 2020 Author Share Posted June 9, 2020 Please sign in to view this quote. So, Changing in the evaluation from a touch point to a plane point and having it set to probing direction, ( i had no idea about all of these options for points) it switches it to the proper vector and takes the point within 20 micon of the location specified. This has also corrected my other positional errors i was having. Link to comment Share on other sites More sharing options...
[Ri...] Posted June 9, 2020 Share Posted June 9, 2020 If you extract it from the model with the define points it tends to define it as a touch point. Link to comment Share on other sites More sharing options...
[Ja...] Posted June 10, 2020 Author Share Posted June 10, 2020 so I have noticed there is some more variation when taking this point on the same part while using Plane-Point up to .08mm in its location. It is causing variation in the TP of the large bore. I have been messing with the different options for points and looking in the help file and am not quite getting the full understanding of each point type and how it applies to its use. When I use a net point or a space point, the point appears to end up exactly where I programmed it to be. But how do I know that this is or is not correct? Being this point is being used for the alignment which option would you guys use? I appreciate all the information you all have given me so far. It has been very helpful. Link to comment Share on other sites More sharing options...
[Ri...] Posted June 10, 2020 Share Posted June 10, 2020 Majority of my single points are Space Points. I do use Mid-Points, but typically only when using Self-Centering. The only time that I use Plane Point is when I'm working with an RPS or 3d Best Fit Alignment. Link to comment Share on other sites More sharing options...
[Da...] Posted June 10, 2020 Share Posted June 10, 2020 Different way of doing it.Capture.PNG Link to comment Share on other sites More sharing options...
[Ke...] Posted June 10, 2020 Share Posted June 10, 2020 Please sign in to view this quote. My defaults are also to use Space Points for single points, and Midpoints for Self-Centering... but, I have also been using Space Points for RPS/3D Best Fit... is there a specific benefit to using Plane Points? Link to comment Share on other sites More sharing options...
[Ri...] Posted June 10, 2020 Share Posted June 10, 2020 The Space Point gets projected out, while the Plane Point doesn't When working with the 3d Best Fit, it will caution you if you try to use Space Points. Link to comment Share on other sites More sharing options...
[Ke...] Posted June 10, 2020 Share Posted June 10, 2020 Please sign in to view this quote. Oooh... I don't use these much, but (luckily) 98% of the time, I'm using these types of alignments as a Base Alignment... and you get the warning, with the opportunity to automatically convert the points (which I do); but it looks like you get no such warnings, when using these as a secondary alignments. Link to comment Share on other sites More sharing options...
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