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Disal
I have engineers here that have basic dimensions to control true position callouts-and they have true position callouts on those basic dimensions also!! They got upset cause i told them it makes no sense.. I have a hole with a TP .005 to A and B, and i have basic dimensions from A and B and then TP .004 of these dimensions to A.. How does that make sense?? how am i supposed to even inspect that ...but what do i know!!

AM I WRONG HERE???
  • I'm seeing your print like this:



    If my interpretation was correct, the only argument I would make would be that once you do out the math, you're allowed AT MAX 0.0017 deviation in each axis on the 0.005 TP.... so I would argue that the bottom composite frame should be 0.0017 OR LESS back to -A-. I'd make it 0.0015.
  • I'm seeing your print like this:

    {"alt":"Click image for larger version Name:\tpic grp.JPG Views:\t0 Size:\t36.8 KB ID:\t480350","data-align":"none","data-attachmentid":"480350","data-size":"full"}

    If my interpretation was correct, the only argument I would make would be that once you do out the math, you're allowed AT MAX 0.0017 deviation in each axis on the 0.005 TP.... so I would argue that the bottom composite frame should be 0.0017 OR LESS back to -A-. I'd make it 0.0015.

    Thank you so much for taking the time to explain!! i've taken a GD&T class but not this advanced. Since they couldn't explain to me how to inspect this-they just took it out of the drawing and made the hole true position tighter (.004 to A and B)
  • in reply to Disal
    Happy to help!

    If the composite DRF that I shared above is what I was working with, I would do this: 

    LOADPROBE/7107_Y_3X40
            TIP/T1A0B0, SHANKIJK=0, 0, 1, ANGLE=0
MAN_PLN1   =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,NONE,LEAST_SQR
            THEO/<0,0,0>,<0,0,1>
            ACTL/<0,0,0>,<0,0,1>
            TARG/<0,0,0>,<0,0,1>
            ANGLE VEC=<1,0,0>,RADIAL
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
MAN_CIR1   =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,OUT,LEAST_SQR
            THEO/<0,0,-0.1>,<0,0,1>,1,0
            ACTL/<0,0,-0.1>,<0,0,1>,1,0
            TARG/<0,0,-0.1>,<0,0,1>
            START ANG=0,END ANG=360
            ANGLE VEC=<1,0,0>
            DIRECTION=CCW
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
MAN_CIR2   =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,LEAST_SQR
            THEO/<-0.086,0.125,-0.1>,<0,0,1>,0.2
            ACTL/<-0.086,0.125,-0.1>,<0,0,1>,0.2
            TARG/<-0.086,0.125,-0.1>,<0,0,1>
            START ANG=0,END ANG=360
            ANGLE VEC=<1,0,0>
            DIRECTION=CCW
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
MAN_LIN1   =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
            THEO/<0,0,-0.1>,<-1,0,0>
            ACTL/<0,0,-0.1>,<-1,0,0>
            CONSTR/LINE,OFFSET
            SURFACE NORMAL = <0,0,1>,MULTI POINT
            ID = MAN_CIR1,MAN_CIR2,,
            OFFSET = 0,0.125
A1         =ALIGNMENT/START,RECALL:STARTUP,LIST=YES
              ALIGNMENT/LEVEL,ZPLUS,MAN_PLN1
              ALIGNMENT/ROTATE,XMINUS,TO,MAN_LIN1,ABOUT,ZPLUS
              ALIGNMENT/TRANS,XAXIS,MAN_CIR1
              ALIGNMENT/TRANS,YAXIS,MAN_CIR1
              ALIGNMENT/TRANS,ZAXIS,MAN_PLN1
            ALIGNMENT/END
            MODE/DCC
            CLEARP/ZPLUS,PLN_A.Z+0.5,ZPLUS,PLN_A.Z+0.5,ON
PLN_A      =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,NONE,LEAST_SQR
            THEO/<0,0,0>,<0,0,1>
            ACTL/<0,0,0>,<0,0,1>
            TARG/<0,0,0>,<0,0,1>
            ANGLE VEC=<1,0,0>,RADIAL
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
CIR_B      =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,OUT,LEAST_SQR
            THEO/<0,0,-0.1>,<0,0,1>,1,0
            ACTL/<0,0,-0.1>,<0,0,1>,1,0
            TARG/<0,0,-0.1>,<0,0,1>
            START ANG=0,END ANG=360
            ANGLE VEC=<1,0,0>
            DIRECTION=CCW
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
CIR1       =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,LEAST_SQR
            THEO/<-0.086,0.125,-0.1>,<0,0,1>,0.2
            ACTL/<-0.086,0.125,-0.1>,<0,0,1>,0.2
            TARG/<-0.086,0.125,-0.1>,<0,0,1>
            START ANG=0,END ANG=360
            ANGLE VEC=<1,0,0>
            DIRECTION=CCW
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
CNC_LIN1   =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
            THEO/<0,0,-0.1>,<-1,0,0>
            ACTL/<0,0,-0.1>,<-1,0,0>
            CONSTR/LINE,OFFSET
            SURFACE NORMAL = <0,0,1>,MULTI POINT
            ID = CIR_B,CIR1,,
            OFFSET = 0,0.125
A2         =ALIGNMENT/START,RECALL:STARTUP,LIST=YES
              ALIGNMENT/LEVEL,ZPLUS,PLN_A
              ALIGNMENT/ROTATE,XMINUS,TO,CNC_LIN1,ABOUT,ZPLUS
              ALIGNMENT/TRANS,XAXIS,CIR_B
              ALIGNMENT/TRANS,YAXIS,CIR_B
              ALIGNMENT/TRANS,ZAXIS,PLN_A
            ALIGNMENT/END
DIM LOC3= LOCATION OF CIRCLE CIR1  UNITS=IN ,$
GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH  HALF ANGLE=NO
AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
D       0.2000     0.0025     0.0025     0.2000     0.0000     0.0000 ----#----
END OF DIMENSION LOC3
DIM LOC1= POSITION OF CIRCLE CIR1  UNITS=IN ,$
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     -0.0860                                     -0.0860     0.0000           
Y      0.1250                                      0.1250     0.0000           
TP        RFS     0.0050                0.0000     0.0000     0.0000     0.0000 #--------
END OF DIMENSION LOC1
A3         =ALIGNMENT/START,RECALL:STARTUP,LIST=YES
              ALIGNMENT/LEVEL,ZPLUS,PLN_A
              ALIGNMENT/ROTATE_CIRCLE,XMINUS,TO,CIR_B,AND,CIR1,ABOUT,ZPLUS
              ALIGNMENT/TRANS,XAXIS,CIR_B
              ALIGNMENT/TRANS,YAXIS,CIR_B
              ALIGNMENT/TRANS,ZAXIS,PLN_A
            ALIGNMENT/END
DIM LOC2= POSITION OF CIRCLE CIR1  UNITS=IN ,$
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     -0.1517                                     -0.1517     0.0000           
TP        RFS     0.0004                0.0000     0.0000     0.0000     0.0000 #--------
END OF DIMENSION LOC2


  • Shouldn't CIR_B be a cylinder? Can a circle be a datum?
    And A is actually the OD and B is the plane
  • in reply to Disal
    F8ck sorry I don't know how my brain got all crisscrossed like that

    Yes -B- should be a cylinder

    Level thru -B-
    rotate the same way I did
    XY origin is -B-
    Z origin is -A-

    Yes a cirxle can be a datum but it shouldn't be for your circumstance. I'm sorry
  • it's good-i get what you're saying. I mostly use Exact but i still do my alignments properly even though it's not necessary with exact. Thanks again Slight smile
  • in reply to Disal
    I don't use XACT. Obviously it works but I prefer to have a higher level of control over my programs by making my own alignments and recalling them when i dimension stuff.
  • i was mostly taught exact. Legacy i only learned from this forum. I use it too but i'm more comfortable with exact
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