Results???

[jkb_mcg]

Take a look at this...Notice the Theo and Actual for Cir 3....X is .0012 off and Y is -.0008 off. Now look at the True Position X and Y Actuals. What's the deal here?


CIR3 =FEAT/CIRCLE,RECT,OUT,LEAST_SQR
THEO/0,0,0.7468,0,0,1,5
ACTL/0.0012,-0.0008,0.7468,0,0,1,4.9833
MEAS/CIRCLE,5,WORKPLANE
MOVE/POINT,NORMAL,2.8428,1.2012,0.757
MOVE/POINT,NORMAL,2.8427,1.2011,1.8004
MOVE/POINT,NORMAL,2.7909,-0.7536,1.8097
MOVE/POINT,NORMAL,2.5481,-0.9753,0.7445
MOVE/CIRCULAR
MOVE/CIRCULAR
MOVE/CIRCULAR
MOVE/CIRCULAR
MOVE/POINT,NORMAL,-2.7945,-1.3987,0.7442
ENDMEAS/
DIM LOC1= TRUE POSITION OF CIRCLE CIR3 UNITS=IN ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH DEV PERPEN CENTERLINE=OFF DISPLAY=DIAMETER
AX MEAS NOMINAL +TOL -TOL BONUS DEV OUTTOL
X 0.0012 0.0000 0.0012
Y 0.0102 0.0000 0.0102
DF 4.9833 5.0000 0.0000 0.0300 -0.0167 0.0000 #
D1 PLANE PLN1 AT RFS
D2 LINE LIN1 AT RFS
D3 4.9973 5.0000 0.0100 0.0100 0.0127 CIRCLE DAT_B AT MMC
TP RFS 0.0000 0.0104 0.0205 0.0101 >
END OF DIMENSION LOC1

[JamesMannes]

You are using the datum modifiers right? You are recalling them incorrectly. It should be like a 3-2-1 alignment hence pln, circle, line.

[jkb_mcg]

I'm not sure I follow you...Yes, I have use datums checked...i clicked my feature first...then plane, then, line, then my origin.

[Matthew D. Hoedeman]

Did you use DATUMS in the TP? Don't. Make an alignment to the datums for the TP dimension, then just do the TP dimension. And, at the same time, report a regualr dim-locaiton of the hole. They will match. Pcdmis will slide and shift your alignment around when using datums/MMC in the TP dimension.

[jkb_mcg]

Did you use DATUMS in the TP? Don't. Make an alignment to the datums for the TP dimension, then just do the TP dimension. And, at the same time, report a regualr dim-locaiton of the hole. They will match. Pcdmis will slide and shift your alignment around when using datums/MMC in the TP dimension.

So, uncheck Use Datums? Yes, I am aligned to my datums already. This is a MMC TP. What if its out of tol. and the MMC would bring it in?

[JamesMannes]

I'm not sure I follow you...Yes, I have use datums checked...i clicked my feature first...then plane, then, line, then my origin.

Sorry I typed too fast. It should be plane, circle, line. Edited other post to fix my fux pux.
3=primary(plane levelind/origin 1 axeis), 2=secondary(circle 0,0), 1=tertiary(rotation?)

[Matthew D. Hoedeman]

FIX IT!

Well, that is one option. If you are that border-line, it probably SHOULD get fixed.

HOWEVER, you can add teh MMC from the datum by using assignments. Assign the bonus from the datum hole to V1 and assign V2=TP tol + V1 and when you tolerance the TP, after the dimension is created, put V2 in for the tolerance. I think that should work. HOWEVER, when looking at the dimension in ANYTHING other than report mode, it will show you V2 for the tolerance, report mode should show the value. The assignment will need to be marked.

[jkb_mcg]

FIX IT!

Well, that is one option. If you are that border-line, it probably SHOULD get fixed.

HOWEVER, you can add teh MMC from the datum by using assignments. Assign the bonus from the datum hole to V1 and assign V2=TP tol + V1 and when you tolerance the TP, after the dimension is created, put V2 in for the tolerance. I think that should work. HOWEVER, when looking at the dimension in ANYTHING other than report mode, it will show you V2 for the tolerance, report mode should show the value. The assignment will need to be marked.

I don't hardly ever use assignments but I'll give it a shot! THX!

[jkb_mcg]

Sorry I typed too fast. It should be plane, circle, line. Edited other post to fix my fux pux.
3=primary(plane levelind/origin 1 axeis), 2=secondary(circle 0,0), 1=tertiary(rotation?)

That worked! Thanks! It's just hard to believe that by putting them in a different order is going to change them .018!!!

[JamesMannes]

Here take a look at this.

[dwade]

HOWEVER, you can add teh MMC from the datum by using assignments. Assign the bonus from the datum hole to V1 and assign V2=TP tol + V1 and when you tolerance the TP, after the dimension is created, put V2 in for the tolerance. I think that should work. HOWEVER, when looking at the dimension in ANYTHING other than report mode, it will show you V2 for the tolerance, report mode should show the value. The assignment will need to be marked.

While this is not correct GD&T it is one of the "DEMON work arounds" that you can use to get MMC bonus. I had a part in an older program that give perfect, zero deviation on the features toleranced using datums and applying MMC. It would show no deviation from nominal until I quit using the datums.

[jkb_mcg]

Here take a look at this.

Cool. Thanks! Do these Newsletters still come out? I haven't gotten one for quite some time.

[JamesMannes]

Cool. Thanks! Do these Newsletters still come out? I haven't gotten one for quite some time.

It's like quarterly at best.

[Matthew D. Hoedeman]

While this is not correct GD&T it is one of the "DEMON work arounds" that you can use to get MMC bonus. I had a part in an older program that give perfect, zero deviation on the features toleranced using datums and applying MMC. It would show no deviation from nominal until I quit using the datums.

That is because Pcdmis, when using MMC on the datums, treats it like a hard-gage and slides the alignment around so that the deviation of the TP feature is as close to zero as possible. So, if your datum holes are (and CAN BE!) 0.5mm bigger than minimum, then your alignment could be shifted up to 0.25mm in either direction, placing the EDGE of the datum holes on the edge of a minimum-size locator pin, more or less.