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Best fit calculation errors 2024.1

jgiff18

Having an issue with all 3 of our CMMs. Today's example is a program I wrote yesterday. Program was written offline on 2024.1, is being ran on 2024.1 using a Global S 15.30.10 and all holes are being taken by adaptive circle scan. Part has 50-60 holes of varying sizes ranging from .251" to .594". On the smaller holes, I am getting occasional best fit calculation errors. What fixes it is F9 the feature, reselect the hole, and run again. I was running it with a 5mm probe but changed to a 3mm thinking it might fix the problem but it didn't. It is not happening on every hole. It'll run a few of one size then throw the error, I'll fix it, then it'll run a few more with no issues then throw the error again.

Also note that the part is completely clean and the probes used have a fresh calibration. My biggest gripe is that I have a backlog of programs I'm trying to get done but they want me to run this part too. I should be able to let this program run while I program (different computers) but I have to babysit the CMM to keep it going.

Why is this happening and has anyone else run into this issue?

EDIT: Something I noticed is that, before execution, the .376" holes show 48 hits, when it errors it shows one hit, and when it executes successfully it shows 124 hits. Not sure if it helps or not, I'm just passing along as much information as I can.

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    Hello Jgiff18, 

    Recently after looking at similar issue routine, I would like to share my thoughts with you:

    1. Circles measured by adaptive sacnning may be threaded holes. Use pitch input in such a case. For threaded holes, adaptive line strategy with cylinder may be better choice.  

    2. The scan speed is very high. Point density used is low. In your case, it looks that point density you may be  4 pts per mm for 0.376 inch holes with problem. 

    3. If you use very high speed then it can cause issue.  For 0.376 inch hole, perimeter would be about 30 mm. If you use speed of 20mm/s, the scan time will be about 1.5 sec. In this much time, you can collect  about 124 points with point density of 4. 

    4. Not knowing any speed, point density and other parameters as well as hole is threaded or not and does it move a lot, as well as how big diameter devaitaion you expect, as well as location deviation you expect, I would suggest to lower your speed or optimize it for your need - position, form, diameter. 

    5. It looks to me that this error occurs when numbe of points collected are less that 3 for circle. I can not be positve on this but bases on your description that when error happens there is only 1 point. It can be combination of high speed, hole position moved and diamter having bigger deviation.. just a thought. 

    Hope this helps. Beyond this, you may want to capture debug file with this error and collect your routine, prb files, CAD file if possible and work with Tech support.  

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  • 0

    Hello Jgiff18, 

    Recently after looking at similar issue routine, I would like to share my thoughts with you:

    1. Circles measured by adaptive sacnning may be threaded holes. Use pitch input in such a case. For threaded holes, adaptive line strategy with cylinder may be better choice.  

    2. The scan speed is very high. Point density used is low. In your case, it looks that point density you may be  4 pts per mm for 0.376 inch holes with problem. 

    3. If you use very high speed then it can cause issue.  For 0.376 inch hole, perimeter would be about 30 mm. If you use speed of 20mm/s, the scan time will be about 1.5 sec. In this much time, you can collect  about 124 points with point density of 4. 

    4. Not knowing any speed, point density and other parameters as well as hole is threaded or not and does it move a lot, as well as how big diameter devaitaion you expect, as well as location deviation you expect, I would suggest to lower your speed or optimize it for your need - position, form, diameter. 

    5. It looks to me that this error occurs when numbe of points collected are less that 3 for circle. I can not be positve on this but bases on your description that when error happens there is only 1 point. It can be combination of high speed, hole position moved and diamter having bigger deviation.. just a thought. 

    Hope this helps. Beyond this, you may want to capture debug file with this error and collect your routine, prb files, CAD file if possible and work with Tech support.  

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