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Best fit error on one CMM and not others

dwade
What I'm struggling with is a best fit error on one cylinder (DAT_N) on one CMM only and only when running through Inspect. I've ran the program on 4 CMMs all through Inspect (5.1) and on 3 I have no problems but on 1 CMM this error comes up. I can exit Inspect and run the program in Online mode and have no problems with this cylinder (DAT_N). I've deleted and rebuilt the probe, I've deleted the cylinder and recreated it and changed algorithms and stop / start angles and nothing I've done will let me run it through Inspect without the best fit error popping up. We are currently walking half way across the shop to run the part on 1 of the CMMs that we don't get the error. 

DAT_M =FEAT/CONTACT/CYLINDER/DEFAULT,CARTESIAN,IN,LEAST_SQR
THEO/<-37.9,-17.89,2.314>,<-1,0,0>,3.65,21.49
ACTL/<-37.9,-17.89,2.314>,<-1,0,0>,3.65,21.49
TARG/<-37.9,-17.89,2.314>,<-1,0,0>
START ANG=10,END ANG=115.5
ANGLE VEC=<0,0,1>
DIRECTION=CCW
SHOW FEATURE PARAMETERS=YES
VOID DETECTION=NO
REMEASURE=NO,USE THEO=YES
SURFACE=THICKNESS_NONE,0
MEASURE MODE=NOMINALS
RMEAS=NONE,NONE,NONE
AUTO WRIST=NO
CIRCULAR MOVES=STRAIGHT
GRAPHICAL ANALYSIS=NO
FEATURE LOCATOR=NO,NO,""
SHOW CONTACT PARAMETERS=YES
NUMHITS=5,NUMLEVELS=3,DEPTH=1,END OFFSET=10,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=0
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
DATDEF/M,FEATURES=DAT_M,,
$$ NO,
=================================================
MOVE/POINT,NORMAL,<-50,-17.89,2.3>
MOVE/POINT,NORMAL,<-50,2,-15.23>
$$ NO,
=================================================
DAT_N =FEAT/CONTACT/CYLINDER/DEFAULT,CARTESIAN,IN,LEAST_SQR
THEO/<-37.9,2,-15.23>,<-1,0,0>,3.65,21.49
ACTL/<-37.9,2,-15.23>,<-1,0,0>,3.65,21.49
TARG/<-37.9,2,-15.23>,<-1,0,0>
START ANG=30,END ANG=150
ANGLE VEC=<0,0,1>
DIRECTION=CCW
SHOW FEATURE PARAMETERS=YES
VOID DETECTION=NO
REMEASURE=NO,USE THEO=YES
SURFACE=THICKNESS_NONE,0
MEASURE MODE=NOMINALS
RMEAS=NONE,NONE,NONE
AUTO WRIST=NO
CIRCULAR MOVES=STRAIGHT
GRAPHICAL ANALYSIS=NO
FEATURE LOCATOR=NO,NO,""
SHOW CONTACT PARAMETERS=YES
NUMHITS=5,NUMLEVELS=3,DEPTH=1,END OFFSET=10,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=0
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
DATDEF/N,FEATURES=DAT_N,,


I'm open to any and all suggestions.

TIA,
Duane​​
Parents
  • So, you are saying that the specific CMM can run other parts and not have the problem AND it runs this part with no problems EXCEPT for ONE specific hole?
    If this is what you are saying, it has to be something with one of the involved features, the feature you are measuring (if the math is failing best-fit immediately after measurement) or the feature or one of the datums if it is failing best fit during True Position reporting. Remember that in GeoTol (if you are using it) datums and features are recalculated, at least if you are using ASME. I don't know about ISO and you are in metric, so maybe you are in ISO and that wouldn't apply.
    If this is immediately after the measurement, try dragging the middle level so that it is either near the top or bottom level rather than equally spaced. Five hits, three levels should be fine, but you have less than 180 degrees (unless I'm envisioning direction backwards, from 30 to 150 CCW is 120... I believe, but your axis is -1, so maybe I'm backwards), so stranger things have happened. Maybe with the way THAT machine moves, htis are a little more wonky and the point distribution doesn't resolve into any cylindrical shape. Changing hit pattern can help that.

    If you have this problem on hole 1 on part number A (every piece of part number A, hole 1 fails), and hole 7 on Part number B, etc. etc. I would think (making assumptions about the way Hex programs and operates here) there could be some issue in the way that data is passed between applications through the stack. That could be hardware or software. Most likely soft, as hardware issues on the stack usually give you a blue screen of death or just a hard reboot without asking.
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  • So, you are saying that the specific CMM can run other parts and not have the problem AND it runs this part with no problems EXCEPT for ONE specific hole?
    If this is what you are saying, it has to be something with one of the involved features, the feature you are measuring (if the math is failing best-fit immediately after measurement) or the feature or one of the datums if it is failing best fit during True Position reporting. Remember that in GeoTol (if you are using it) datums and features are recalculated, at least if you are using ASME. I don't know about ISO and you are in metric, so maybe you are in ISO and that wouldn't apply.
    If this is immediately after the measurement, try dragging the middle level so that it is either near the top or bottom level rather than equally spaced. Five hits, three levels should be fine, but you have less than 180 degrees (unless I'm envisioning direction backwards, from 30 to 150 CCW is 120... I believe, but your axis is -1, so maybe I'm backwards), so stranger things have happened. Maybe with the way THAT machine moves, htis are a little more wonky and the point distribution doesn't resolve into any cylindrical shape. Changing hit pattern can help that.

    If you have this problem on hole 1 on part number A (every piece of part number A, hole 1 fails), and hole 7 on Part number B, etc. etc. I would think (making assumptions about the way Hex programs and operates here) there could be some issue in the way that data is passed between applications through the stack. That could be hardware or software. Most likely soft, as hardware issues on the stack usually give you a blue screen of death or just a hard reboot without asking.
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