true postion

[Ken379128]

Hey all
I was wondering if I am doing True postion right
I am doing the TP of a Hub my 1st and 2nd datums are a plane and another ID

I pick the Hub 1st then the plane and last the other ID the feature control frame has a MMC in the callout for the true postion as well as the other ID. My answer cam out greem but am just wondering if mythinking is correct?

DATUMA =FEAT/PLANE,RECT,TRIANGLE
THEO/-5.344,1.427,-0.774,-0.0024347,-0.0048803,0.9999851
ACTL/-5.349,1.417,0.396,0.0000352,-0.0000655,1
MEAS/PLANE,4
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,9.693,-4.535,-0.743,-0.0024347,-0.0048803,0.9999851,9.687,-4.545,0.395,USE THEO = YES
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,9.66,8.163,-0.728,-0.0024347,-0.0048803,0.9999851,9.654,8.153,0.396,USE THEO = YES
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,-20.383,8.081,-0.757,-0.0024347,-0.0048803,0.9999851,-20.387,8.071,0.397,USE THEO = YES
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,-20.347,-6,-0.868,-0.0024347,-0.0048803,0.9999851,-20.351,-6.01,0.396,USE THEO = YES
ENDMEAS/
BOTHUB =FEAT/CIRCLE,RECT,OUT,LEAST_SQR
THEO/-13.08,-0.032,11.406,0,0,1,3.736
ACTL/-13.063,0.005,11.408,0,0,1,4.035
MEAS/CIRCLE,4,WORKPLANE
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,-14.791,-0.478,11.404,-0.9675808,-0.2525615,0,-15.007,-0.525,11.405,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-13.215,1.914,11.406,-0.0695455,0.9975788,0,-13.217,2.018,11.406,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-11.335,-0.283,11.408,0.9897422,-0.1428652,0,-11.071,-0.31,11.413,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-12.854,-2.009,11.406,0.1135116,-0.9935367,0,-12.847,-2.003,11.407,USE THEO = YES
ENDMEAS/
TOPHUB =FEAT/CIRCLE,RECT,OUT,LEAST_SQR
THEO/-13.192,-0.05,13.826,0,0,1,3.562
ACTL/-13.061,0.001,13.83,0,0,1,4.024
MEAS/CIRCLE,4,WORKPLANE
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,-14.971,-0.359,13.825,-0.985207,-0.1713688,0,-15.039,-0.363,13.829,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-13.112,1.707,13.826,0.0455712,0.9989611,0,-13.054,2.014,13.828,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-11.396,-0.259,13.828,0.9933112,-0.1154684,0,-11.069,-0.275,13.834,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-13.133,-1.8,13.827,0.0337217,-0.9994313,0,-13.081,-2.012,13.828,USE THEO = YES
ENDMEAS/
BOTID =FEAT/CIRCLE,RECT,IN,LEAST_SQR
THEO/-0.045,-0.074,1.632,0,0,1,4.423
ACTL/0.008,-0.012,1.631,0,0,1,4.239
MEAS/CIRCLE,4,WORKPLANE
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,0.081,2.143,1.632,-0.0567651,-0.9983876,0,0.031,2.11,1.634,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,0.092,-2.29,1.632,-0.0619194,0.9980812,0,0.026,-2.135,1.633,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,2.157,-0.057,1.632,-0.9999711,-0.0076044,0,2.122,-0.112,1.632,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-2.248,-0.071,1.631,0.999999,-0.0013942,0,-2.106,-0.125,1.628,USE THEO = YES
ENDMEAS/
TOPID =FEAT/CIRCLE,RECT,IN,LEAST_SQR
THEO/-0.07,-0.085,8.291,0,0,1,4.454
ACTL/-0.013,-0.008,8.294,0,0,1,4.226
MEAS/CIRCLE,4,WORKPLANE
MOVE/CLEARPLANE
HIT/BASIC,NORMAL,-2.287,-0.061,8.291,0.999944,-0.0105868,0,-2.13,-0.13,8.297,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,2.146,-0.048,8.292,-0.9998592,-0.0167823,0,2.104,-0.115,8.296,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-0.048,2.152,8.29,-0.0099095,-0.9999509,0,-0.101,2.097,8.293,USE THEO = YES
MOVE/CIRCULAR
HIT/BASIC,NORMAL,-0.037,-2.321,8.291,-0.014998,0.9998875,0,-0.099,-2.113,8.291,USE THEO = YES
ENDMEAS/
CYLHUB =FEAT/CYLINDER,RECT,OUT,LEAST_SQR
THEO/-13.136,-0.042,12.617,-0.0455563,-0.0010119,0.9989613,3.647,2.58
ACTL/-13.062,0.003,12.62,0.0006927,-0.0013164,0.9999989,4.03,2.432
CONSTR/CYLINDER,BF,BOTHUB,TOPHUB,,
CYLID =FEAT/CYLINDER,RECT,OUT,LEAST_SQR
THEO/-0.058,-0.079,4.961,-0.0037114,-0.0015998,0.9999918,4.438,6.675
ACTL/-0.003,-0.01,4.964,-0.0030692,0.0006253,0.9999951,4.233,6.678
CONSTR/CYLINDER,BF,BOTID,TOPID,,
DIM ITEM21= 2D DISTANCE FROM CYLINDER CYLHUB TO CYLINDER CYLID (CENTER TO CENTER), NO_RADIUS UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH
AX NOMINAL +TOL -TOL MEAS MAX MIN DEV OUTTOL
M 13.000 0.250 0.250 13.059 13.059 13.059 0.059 0.000 -----#---
DIM PERP2= PERPENDICULARITY OF CYLINDER CYLHUB,RFS TO PLANE DATUMA,RFS EXTENDLENGTH=0.000 UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH
AX NOMINAL +TOL -TOL MEAS MAX MIN DEV OUTTOL
M 0.000 0.100 0.000 0.003 0.002 0.002 0.003 0.000 #--------
DIM ITEM19= PERPENDICULARITY OF CYLINDER CYLID,MMC TO PLANE DATUMA,RFS EXTENDLENGTH=0.000 UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH
AX NOMINAL +TOL -TOL BONUS MEAS MAX MIN DEV OUTTOL
DF 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ----#----
M 0.000 0.200 0.000 0.000 0.021 0.011 0.011 0.021 0.000 #--------
DIM ITEM24= TRUE POSITION OF CYLINDER CYLHUB USE AXIS=AVERAGE REF LENGTH=0.000 UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH DEV PERPEN CENTERLINE=OFF DISPLAY=DIAMETER
AX NOMINAL +TOL -TOL BONUS MEAS DEV DEVANG OUTTOL
X -13.136 -13.074 0.063
Y -0.042 -0.028 0.014
DF 4.000 0.050 0.050 0.020 4.030 0.030 0.000 -------#-
D1 PLANE DATUMA AT RFS
D2 4.200 0.100 0.000 0.045 4.245 CIRCLE DATUMB AT MMC
TP MMC 0.200 0.020 0.128 12.580 0.000 -----#---
END OF DIMENSION ITEM24

[JamesMannes]

First off I am going to assume a few things. First being that this is RFS. Secondly you do have 3 datums containing this part(via alignment). So, with that said are you dimensioning this feature within your current alignment? If so, you do not have to choose the other features that are called as your datums(only for RFS and/or MMC and LMC on the feature itself(not including datum modifiers)). If this dimension is not already within your current alignment and you do have to recall datums, make sure that you recall all the 3 of the datums(unless it is a "Best Fit" alignment).
With that being said, if this is a callout that is a plane/ID as you stated, it is more than likely that you may want to report this as a span. because that is what the engineer is really looking for.

An upload of the print section is always helpful. Extra info ok, not enough is not.

[Ken379128]

tried to put the print view could not do it will try later

[Jan d.]

It seems to me that you are short 1 datum. Looking at your code, your primary is a plane, your secondary is a circle (where in your code do you measure Datum B???).

The problem with this call is that Datum A establishes the plane and datum B sets the rotation point. Nothing in your datuming is stopping rotation though (there is no clocking datum!). This gives PC-DMIS free reign to minimize TP by freely rotating around datum B. Which it clearly does.

By the way, I was told that versions before V4.0, do not even take the MMC behind datum B into effect (I am new to PC-DMIS and never used anything prior to V4.0). If you run this through V4.1 and put MMC on B, your TP numbers will be even better, because it gives PC-DMIS even more room to wriggle. The nice thing about >V4.0 is that it gives you all information as to how much it moved the hard gauge in order to get the best TP number.



Jan.

[Ken379128]

CYLID is the B datum I will try to post the print if I can.