Weird Concentric circles TP result

Hello all,

I am using a TIGO TP20 setup (PCDMIS 2017 R2) and I am measuring a small cylindrical part (somehow resembling a very short tube). The outer Diameter being 9mm and inner 6 mm. I have it placed vertically on my fixture and trying to true position control the inner circle as to the outer. The problem is that the face I am having the part on Z+ has no rotational datum and as such I only level on the top plane and probing from Z+ the 2 circles. There is no room (part being 4 mm short) for cylinders.

In any case, this is a simple TP callout of 2 circles. The issue is that while without moving the part on the fixture I am getting repeatable results at a few microns in 2 axis resulting in a TP of less than 0.01mm, when I turn the part 180 degs I am getting 0.03 shift in Y axis. Not only that, but rotating the part continuously by 180 Degs, I am getting consistent repeatable results over and over with the same offset...

The circle even being small I am probing as least squares, 360degs full circles and 23 and 17 hits accordingly in order to have a better approach.

Nevertheless, the distance between the 2 circles should always be the same no matter the orientation / rotation which is left unconstrained (actually was constrained externally with a plane of the fixture). The call out is only requesting TP from Datum A (outer dia).

Maybe it is the leveling plane curling (flatness was 0.015-0.020 mm) due to the fixture grip (not really stressing it much tbh), but still... why have consistency between placements?

For me, this is the first time seeing this happening and I am thinking it has to do with the rotation that's left "unconstrained" and this should not be happening imo. Any ideas maybe?

Parents

constadin over 1 year ago

I just purposed to lock the rotation trying to explain the defects. If you re-measure all the features after rotation, does it change anything ? (particulary if you level on the top plane after rotation - just to check, I understand you cannot do it on a lot of parts !!!!!)
I think you should post the code (even if it's in french ), or a picture of the fixturing

oh no I was not referring to your proposal. It was actually a good idea to test (that I did indeed try) but changed nothing (not to our surprise I suppose, but you never know...). The fixture is just a v shaped vice that is griping the part at the lower 2mm out of the 4mm which is the part. I am probing the upper half of the part the remaining 2 mm! I have it stressed a little as possible, barely but (sufficiently enough) touching it indeed. When I place the part the only thing that is changing is the form error of the inner circle (goes from around 10 microns to 18 microns) and the TP of the inner circle.

LOADPROBE/PROBE1
TIP/T1A0B0, SHANKIJK=0, 0, 1, ANGLE=0
RECALL/ALIGNMENT,EXTERNAL,APS-PDEA-103722425_A
MODE/DCC
PREHIT/1.5
RETRACT/1.5
CLEARP/ZPLUS,200,ZPLUS,0,OFF
MOVE/CLEARPLANE
MOVE/POINT,NORMAL,<0,0,200>
CER1 =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,LEAST_SQR
THEO/<0,0,-2>,<0,0,1>,5.55
ACTL/<-0.6152,-0.271,-2>,<0,0,1>,5.5548
TARG/<0,0,-2>,<0,0,1>
START ANG=0,END ANG=360
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=NO
CLEARP/ZPLUS,5,ZPLUS,0,ON
A1 =ALIGNMENT/START,RECALL:APS-PDEA-103722425_A,LIST=YES
ALIGNMENT/TRANS,XAXIS,CER1
ALIGNMENT/TRANS,YAXIS,CER1
ALIGNMENT/END
MOVE/CLEARPLANE
CER2 =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,OUT,LEAST_SQR
THEO/<0,0,-0.5>,<0,0,1>,8.99,0
ACTL/<-0.0008,0.0641,-0.5>,<0,0,1>,8.9976,0
TARG/<0,0,-0.5>,<0,0,1>
START ANG=180,END ANG=540
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=YES
VOID DETECTION=NO
REMEASURE=NO
SURFACE=THICKNESS_NONE,0
MEASURE MODE=NOMINALS
RMEAS=NONE,NONE,NONE
CIRCULAR MOVES=CIRCULAR
GRAPHICAL ANALYSIS=NO
FEATURE LOCATOR=NO,NO,""
SHOW CONTACT PARAMETERS=YES
NUMHITS=7,DEPTH=0,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=10
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
ASSIGN/V1=CER2.R-0.20
MOVE/CLEARPLANE
PNT1 =FEAT/CONTACT/VECTOR POINT/DEFAULT,POLAR
THEO/<V1,90,0>,<0,0,1>
ACTL/<4.2989,89.9965,0.3247>,<0,0,1>
TARG/<V1,90,0>,<0,0,1>
SNAP=NO
SHOW FEATURE PARAMETERS=YES
SURFACE=THICKNESS_NONE,0
MEASURE MODE=NOMINALS
RMEAS=NONE,NONE,NONE
GRAPHICAL ANALYSIS=NO
FEATURE LOCATOR=NO,NO,""
SHOW CONTACT PARAMETERS=YES
AVOIDANCE MOVE=NO,DISTANCE=10
SHOW HITS=NO
A4 =ALIGNMENT/START,RECALL:A1,LIST=YES
ALIGNMENT/TRANS,ZAXIS,PNT1
ALIGNMENT/END
PLN1 =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,TRIANGLE,LEAST_SQR
THEO/<0,0,0>,<0,0,1>
ACTL/<-0.0004,-0.019,0.1625>,<-0.0037827,0.0390827,0.9992288>
TARG/<0,0,0>,<0,0,1>
ANGLE VEC=<0,-1,0>,RADIAL
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=7,NUMROWS=1
SPACER=V1
AVOIDANCE MOVE=NO,DISTANCE=2
SHOW HITS=NO
DIM PLAT1= FLATNESS OF PLANE PLN1 UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=100.00 ARROWDENSITY=100 OUTPUT=BOTH
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
M 0.0000 0.0150 0.0000 0.0195 0.0195 0.0045 >
A2 =ALIGNMENT/START,RECALL:A1,LIST=YES
ALIGNMENT/LEVEL,ZPLUS,PLN1
ALIGNMENT/TRANS,XAXIS,CER2
ALIGNMENT/TRANS,YAXIS,CER2
ALIGNMENT/TRANS,ZAXIS,PLN1
ALIGNMENT/END
MOVE/CLEARPLANE
CER8_99 =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,OUT,LEAST_SQR
THEO/<0,0,-0.5>,<0,0,1>,8.99,0
ACTL/<-0.0003,-0.0014,-0.5>,<0,0,1>,8.9912,0
TARG/<0,0,-0.5>,<0,0,1>
START ANG=-90,END ANG=270
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=23,DEPTH=0,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=10
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
A3 =ALIGNMENT/START,RECALL:A2,LIST=YES
ALIGNMENT/TRANS,XAXIS,CER8_99
ALIGNMENT/TRANS,YAXIS,CER8_99
ALIGNMENT/END
MOVE/CLEARPLANE
CER5_55MI =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,MAX_INSC
THEO/<0,0,-3>,<0,0,1>,5.55
ACTL/<-0.0056,0.0004,-3>,<0,0,1>,5.544
TARG/<0,0,-3>,<0,0,1>
START ANG=0,END ANG=360
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=17,DEPTH=0,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=10
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
SCN1 =FEAT/SET,CARTESIAN
THEO/<0,0,-3>,<0,0,1>
ACTL/<-0.0024,0.0008,-2.9992>,<0,0,1>
CONSTR/SET,BASIC,CER5_55MI.HIT[1..CER5_55MI.NUMHITS],,
CER5_55LS =FEAT/CIRCLE,CARTESIAN,IN,LEAST_SQR,NO
THEO/<0,0,-3>,<0,0,1>,5.55
ACTL/<-0.005,0.0017,-2.9992>,<0,0,1>,5.5525
CONSTR/CIRCLE,BF,2D,SCN1,,
OUTLIER_REMOVAL/OFF,3
FILTER/OFF,UPR=0
MOVE/CLEARPLANE

and

DIM LOC1= LOCATION OF CIRCLE CER8_99 UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
D 8.9900 0.0150 -0.0150 8.9912 0.0012 0.0000 #
RN 0.0000 0.0300 0.0000 0.0044 0.0044 0.0000 #
END OF DIMENSION LOC1
DIM LOC2= LOCATION OF CIRCLE CER5_55MI UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
D 5.5500 0.0500 -0.0500 5.5440 -0.0060 0.0000 #
RN 0.0000 0.1000 0.0000 0.0111 0.0111 0.0000 #
END OF DIMENSION LOC2
DIM LOC3= POSITION OF CIRCLE CER5_55LS UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH FIT TO DATUMS=OFF DEV PERPEN CENTERLINE=OFF DISPLAY=DIAMETER
AX NOMINAL +TOL -TOL BONUS MEAS DEV OUTTOL
X 0.0000 -0.0050 -0.0050
Y 0.0000 0.0017 0.0017
TP RFS 0.1000 0.0000 0.0106 0.0106 0.0000 #
END OF DIMENSION LOC3

Reply

constadin over 1 year ago

I just purposed to lock the rotation trying to explain the defects. If you re-measure all the features after rotation, does it change anything ? (particulary if you level on the top plane after rotation - just to check, I understand you cannot do it on a lot of parts !!!!!)
I think you should post the code (even if it's in french ), or a picture of the fixturing

LOADPROBE/PROBE1
TIP/T1A0B0, SHANKIJK=0, 0, 1, ANGLE=0
RECALL/ALIGNMENT,EXTERNAL,APS-PDEA-103722425_A
MODE/DCC
PREHIT/1.5
RETRACT/1.5
CLEARP/ZPLUS,200,ZPLUS,0,OFF
MOVE/CLEARPLANE
MOVE/POINT,NORMAL,<0,0,200>
CER1 =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,LEAST_SQR
THEO/<0,0,-2>,<0,0,1>,5.55
ACTL/<-0.6152,-0.271,-2>,<0,0,1>,5.5548
TARG/<0,0,-2>,<0,0,1>
START ANG=0,END ANG=360
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=NO
CLEARP/ZPLUS,5,ZPLUS,0,ON
A1 =ALIGNMENT/START,RECALL:APS-PDEA-103722425_A,LIST=YES
ALIGNMENT/TRANS,XAXIS,CER1
ALIGNMENT/TRANS,YAXIS,CER1
ALIGNMENT/END
MOVE/CLEARPLANE
CER2 =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,OUT,LEAST_SQR
THEO/<0,0,-0.5>,<0,0,1>,8.99,0
ACTL/<-0.0008,0.0641,-0.5>,<0,0,1>,8.9976,0
TARG/<0,0,-0.5>,<0,0,1>
START ANG=180,END ANG=540
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=YES
VOID DETECTION=NO
REMEASURE=NO
SURFACE=THICKNESS_NONE,0
MEASURE MODE=NOMINALS
RMEAS=NONE,NONE,NONE
CIRCULAR MOVES=CIRCULAR
GRAPHICAL ANALYSIS=NO
FEATURE LOCATOR=NO,NO,""
SHOW CONTACT PARAMETERS=YES
NUMHITS=7,DEPTH=0,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=10
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
ASSIGN/V1=CER2.R-0.20
MOVE/CLEARPLANE
PNT1 =FEAT/CONTACT/VECTOR POINT/DEFAULT,POLAR
THEO/<V1,90,0>,<0,0,1>
ACTL/<4.2989,89.9965,0.3247>,<0,0,1>
TARG/<V1,90,0>,<0,0,1>
SNAP=NO
SHOW FEATURE PARAMETERS=YES
SURFACE=THICKNESS_NONE,0
MEASURE MODE=NOMINALS
RMEAS=NONE,NONE,NONE
GRAPHICAL ANALYSIS=NO
FEATURE LOCATOR=NO,NO,""
SHOW CONTACT PARAMETERS=YES
AVOIDANCE MOVE=NO,DISTANCE=10
SHOW HITS=NO
A4 =ALIGNMENT/START,RECALL:A1,LIST=YES
ALIGNMENT/TRANS,ZAXIS,PNT1
ALIGNMENT/END
PLN1 =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,TRIANGLE,LEAST_SQR
THEO/<0,0,0>,<0,0,1>
ACTL/<-0.0004,-0.019,0.1625>,<-0.0037827,0.0390827,0.9992288>
TARG/<0,0,0>,<0,0,1>
ANGLE VEC=<0,-1,0>,RADIAL
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=7,NUMROWS=1
SPACER=V1
AVOIDANCE MOVE=NO,DISTANCE=2
SHOW HITS=NO
DIM PLAT1= FLATNESS OF PLANE PLN1 UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=100.00 ARROWDENSITY=100 OUTPUT=BOTH
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
M 0.0000 0.0150 0.0000 0.0195 0.0195 0.0045 >
A2 =ALIGNMENT/START,RECALL:A1,LIST=YES
ALIGNMENT/LEVEL,ZPLUS,PLN1
ALIGNMENT/TRANS,XAXIS,CER2
ALIGNMENT/TRANS,YAXIS,CER2
ALIGNMENT/TRANS,ZAXIS,PLN1
ALIGNMENT/END
MOVE/CLEARPLANE
CER8_99 =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,OUT,LEAST_SQR
THEO/<0,0,-0.5>,<0,0,1>,8.99,0
ACTL/<-0.0003,-0.0014,-0.5>,<0,0,1>,8.9912,0
TARG/<0,0,-0.5>,<0,0,1>
START ANG=-90,END ANG=270
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=23,DEPTH=0,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=10
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
A3 =ALIGNMENT/START,RECALL:A2,LIST=YES
ALIGNMENT/TRANS,XAXIS,CER8_99
ALIGNMENT/TRANS,YAXIS,CER8_99
ALIGNMENT/END
MOVE/CLEARPLANE
CER5_55MI =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,MAX_INSC
THEO/<0,0,-3>,<0,0,1>,5.55
ACTL/<-0.0056,0.0004,-3>,<0,0,1>,5.544
TARG/<0,0,-3>,<0,0,1>
START ANG=0,END ANG=360
ANGLE VEC=<0,-1,0>
DIRECTION=CW
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=17,DEPTH=0,PITCH=0
SAMPLE METHOD=SAMPLE_HITS
SAMPLE HITS=0,SPACER=0
AVOIDANCE MOVE=NO,DISTANCE=10
FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
SHOW HITS=NO
SCN1 =FEAT/SET,CARTESIAN
THEO/<0,0,-3>,<0,0,1>
ACTL/<-0.0024,0.0008,-2.9992>,<0,0,1>
CONSTR/SET,BASIC,CER5_55MI.HIT[1..CER5_55MI.NUMHITS],,
CER5_55LS =FEAT/CIRCLE,CARTESIAN,IN,LEAST_SQR,NO
THEO/<0,0,-3>,<0,0,1>,5.55
ACTL/<-0.005,0.0017,-2.9992>,<0,0,1>,5.5525
CONSTR/CIRCLE,BF,2D,SCN1,,
OUTLIER_REMOVAL/OFF,3
FILTER/OFF,UPR=0
MOVE/CLEARPLANE

and

DIM LOC1= LOCATION OF CIRCLE CER8_99 UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
D 8.9900 0.0150 -0.0150 8.9912 0.0012 0.0000 #
RN 0.0000 0.0300 0.0000 0.0044 0.0044 0.0000 #
END OF DIMENSION LOC1
DIM LOC2= LOCATION OF CIRCLE CER5_55MI UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
D 5.5500 0.0500 -0.0500 5.5440 -0.0060 0.0000 #
RN 0.0000 0.1000 0.0000 0.0111 0.0111 0.0000 #
END OF DIMENSION LOC2
DIM LOC3= POSITION OF CIRCLE CER5_55LS UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH FIT TO DATUMS=OFF DEV PERPEN CENTERLINE=OFF DISPLAY=DIAMETER
AX NOMINAL +TOL -TOL BONUS MEAS DEV OUTTOL
X 0.0000 -0.0050 -0.0050
Y 0.0000 0.0017 0.0017
TP RFS 0.1000 0.0000 0.0106 0.0106 0.0000 #
END OF DIMENSION LOC3

Children

constadin over 1 year ago in reply to constadin

This is actually the very first code that got more complicated with my testings later on :P The number of point increased, added cylinders etc.
Cancel
Vote Up 0 Vote Down

Sign in to reply

Cancel