Generic Features

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  • Generic Features

    Has anyone seen the measured values of generic features change by themselves? I use Generic features for locating basic dimensions like gage points and recently have chased down a repeatability problem to find that the MEAS part of the generic feature was changed from the original programmed value. (Yes they were DEPENDENT)

    How can this value possibly change?

    (v.3.7.3)
    Last edited by cmmguy; 09-01-2009, 11:30 PM.
    Links to my utilities for PCDMIS

  • #2
    What value is loaded in the the MEAS part of the generic? In other words what is it supposed to be and how much is it changing? How are you loading it?

    Bill

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    • #3
      Originally posted by Bill McCafferty View Post
      What value is loaded in the the MEAS part of the generic? In other words what is it supposed to be and how much is it changing? How are you loading it?

      Bill
      Because I was using as a Basic Target, the Nominal and the Measured values were identical for both XYZ and IJK.

      I cant pinpoint the moment it changed so not sure what triggered the change. The nominal stayed the same but the measured changed.

      I create the generic features right after an alignment. I used regular numbers in the values. The change was in the range of .025mm but not an even amount or the same.

      My fix was to use a variable with a fixed value but still cant understand why the software would change the values
      Links to my utilities for PCDMIS

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      • #4
        I always use variables to fix both the nominal and measured value of generic features as you are correct, they simply change when they feel like it. I also assign I and O as 1 and 0 to fix my vectors.
        sigpic

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        • #5
          Originally posted by cmmguy View Post
          Because I was using as a Basic Target, the Nominal and the Measured values were identical for both XYZ and IJK.

          I cant pinpoint the moment it changed so not sure what triggered the change. The nominal stayed the same but the measured changed.

          I create the generic features right after an alignment. I used regular numbers in the values. The change was in the range of .025mm but not an even amount or the same.

          My fix was to use a variable with a fixed value but still cant understand why the software would change the values
          I find that I have this problem constantly(and now with generic features too apparently). My usual approach is to use the variables ONE=1 and ZERO=0 to lock down the vectors and other nominals. This changing of nominals is an unacceptable issue with pcdmis. I dont know if the later versions do it or not but 3.7.3 is supposed to be the most stable so I dont know what that says about other versions.

          I am still hoping someone will tell me I am doing something wrong to cause these to change. No I dont use CAD.
          Links to my utilities for PCDMIS

          Comment


          • #6
            Originally posted by cmmguy View Post
            I find that I have this problem constantly(and now with generic features too apparently). My usual approach is to use the variables ONE=1 and ZERO=0 to lock down the vectors and other nominals. This changing of nominals is an unacceptable issue with pcdmis. I dont know if the later versions do it or not but 3.7.3 is supposed to be the most stable so I dont know what that says about other versions.

            I am still hoping someone will tell me I am doing something wrong to cause these to change. No I dont use CAD.
            Nope you are doing nothing wrong unless I am doing the exact same "wrong" thing. I have had this problem from V3.5 at least and still have it in V4.3. As per my previous post I always hard code ALL of my generic features with variables, bit of a pain but at least I know they will not change.
            sigpic

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            • #7
              Originally posted by jon_dav_uk View Post
              I always use variables to fix both the nominal and measured value of generic features as you are correct, they simply change when they feel like it. I also assign I and O as 1 and 0 to fix my vectors.

              +1 started doing this several months ago after being bitten by the bug many times. I have also had the THEO and TARGET values change in some of the rough alignment features in some programs and have started using variables there also and now they no longer change....

              Code:
                          ASSIGN/ZERO = 0
                          ASSIGN/ONE = 1
              CIR_MAN    =AUTO/CIRCLE,SHOWALLPARAMS = YES,SHOWHITS = NO
                          THEO/0.305,0.3375,0.125,0,0,-1,0.316
                          ACTL/0.305,0.3375,0.125,0,0,-1,0.316
                          TARG/0.305,0.3375,0.125,0,0,-1
                          THEO_THICKNESS = 0,RECT,IN,STRAIGHT,LEAST_SQR,ONERROR = NO,$
                          AUTO MOVE = NO,DISTANCE = 0,RMEAS = None,None,None,$
                          READ POS = NO,FIND HOLE = NO,REMEASURE = NO,$
                          NUMHITS = 3,INIT = 3,PERM = 3,SPACER = 0.06,PITCH = 0,$
                          START ANG = 0,END ANG = 0,DEPTH = 0.06,$
                          ANGLE VEC = -1,0,0
              MAN        =ALIGNMENT/START,RECALL:STARTUP, LIST= YES
                          ALIGNMENT/LEVEL,YPLUS,CIR_MAN
                          ALIGNMENT/TRANS,XAXIS,CIR_MAN
                          ALIGNMENT/TRANS,YAXIS,CIR_MAN
                          ALIGNMENT/TRANS,ZAXIS,CIR_MAN
                          ALIGNMENT/ROTATE_OFFSET,90,ABOUT,YPLUS
                          ALIGNMENT/END
                          WORKPLANE/YPLUS
                          MODE/DCC
                          MOVE/POINT,NORMAL,0,2,0
              CYL_B      =AUTO/CYLINDER,SHOWALLPARAMS = YES,SHOWHITS = NO
                          THEO/ZERO,ZERO,ZERO,ZERO,ONE,ZERO,ZERO
                          ACTL/0,0,0,0,1,0,0.316
                          TARG/ZERO,ZERO,ZERO,ZERO,ONE,ZERO
                          THEO_THICKNESS = 0,RECT,IN,STRAIGHT,LEAST_SQR,ONERROR = NO,$
                          AUTO MOVE = BOTH,DISTANCE = 0.1,RMEAS = None,None,None,$
                          READ POS = NO,FIND HOLE = CENTER,REMEASURE = NO,USE THEO = NO,$
                          NUMHITS = 4,NUMROWS = 3,INIT = 1,PERM = 1,SPACER = 0.06,PITCH = 0,$
                          START ANG = 0,END ANG = 180,DEPTH = 0.06,$
                          ANGLE VEC = 1,0,0
              ST1        =ALIGNMENT/START,RECALL:MAN, LIST= YES
                          ALIGNMENT/TRANS,XAXIS,CYL_B
                          ALIGNMENT/TRANS,YAXIS,CYL_B
                          ALIGNMENT/TRANS,ZAXIS,CYL_B
                          ALIGNMENT/END
              Last edited by dwade; 09-02-2009, 06:19 AM.
              Xcel & MicroVal Pfx & Global 37mr4 thru 2012mr1sp3
              Contura Calypso 5.4

              Lord, keep Your arm around my shoulder and Your hand over my mouth. Amen.

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              • #8
                I also was using variables to lock a generic feature that was changing in V3.7MR3. I likie the variables above they look so much cleaner that mines.
                sigpic

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                • #9
                  Originally posted by AuRules View Post
                  I also was using variables to lock a generic feature that was changing in V3.7MR3. I likie the variables above they look so much cleaner that mines.
                  I think what is happening is tied in with the way alignments are being done (V3.5 and up) and when you re-home the machine OR re-align the part, these generic features are "stuck" to the machine co-ordinates" and are NOT being "re-set" to the new alignment. I have long since learned to use variables in generic features (except when I slap something together real quick to help someone on here).
                  sigpic
                  Originally posted by AndersI
                  I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

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                  • #10
                    Another option is to use an equation in the feature. (0+0) PC-DMIS does not touch equations.

                    Comment


                    • #11
                      This is not good ~ I am using generic features and random alterations would mean programs that are supposed to be frozen must now be considered suspect. Where's the security. Stuff like this could cause non-conformances to get by and a notification from Pc-dmis would be in order. Any caveats anywhere?
                      Last edited by Gary Fitzgerald; 09-02-2009, 09:46 AM.
                      sigpicThanks a Millionth

                      Comment


                      • #12
                        I also use a +0 after the theo. & targ. to lock the numbers down.They will not change then.

                        Code:
                        PNT_A2_    =AUTO/VECTOR POINT,SHOWALLPARAMS = YES
                                    THEO/-1.0275+0,0+0,-1.6+0,-1+0,0+0,0+0
                                    ACTL/-1.0275,0,-1.6,-1,0,0
                                    TARG/-1.0275+0,0+0,-1.6+0,-1+0,0+0,0+0
                                    THEO_THICKNESS = 0,RECT,SNAP = YES,$
                                    AUTO MOVE = NO,DISTANCE = 0
                        PNT_A3_    =AUTO/VECTOR POINT,SHOWALLPARAMS = YES
                                    THEO/-1.0275+0,0+0,-1+0,-.9+0,0+0,0+0
                                    ACTL/-1.0236,0,-1,-1,0,0
                                    TARG/-1.0275+0,0+0,-1+0,-.9+0,0+0,0+0
                                    THEO_THICKNESS = 0,RECT,SNAP = YES,$
                                    AUTO MOVE = NO,DISTANCE = 0

                        Comment


                        • #13
                          Hey Dwade,

                          I have a comment:

                          Level constrains 2 degrees of rotation right?. I always use a 3D features with vector (Plane, cylinder, cone...etc).
                          I see you're using a 2D feature (circle) is that correct?

                          Code:
                          MAN        =ALIGNMENT/START,RECALL:STARTUP, LIST= YES
                                      ALIGNMENT/LEVEL,YPLUS,CIR_MAN
                                      ALIGNMENT/TRANS,XAXIS,CIR_MAN
                                      ALIGNMENT/TRANS,YAXIS,CIR_MAN
                                      ALIGNMENT/TRANS,ZAXIS,CIR_MAN
                                      ALIGNMENT/ROTATE_OFFSET,90,ABOUT,YPLUS
                                      ALIGNMENT/END
                          sigpicIt's corona time!
                          737 Xcel Cad++ v2009MR1....SE HABLA ESPAŅOL

                          Comment


                          • #14
                            Originally posted by Roberto View Post
                            Hey Dwade,

                            I have a comment:

                            Level constrains 2 degrees of rotation right?. I always use a 3D features with vector (Plane, cylinder, cone...etc).
                            I see you're using a 2D feature (circle) is that correct?

                            Code:
                            MAN        =ALIGNMENT/START,RECALL:STARTUP, LIST= YES
                                        ALIGNMENT/LEVEL,YPLUS,CIR_MAN
                                        ALIGNMENT/TRANS,XAXIS,CIR_MAN
                                        ALIGNMENT/TRANS,YAXIS,CIR_MAN
                                        ALIGNMENT/TRANS,ZAXIS,CIR_MAN
                                        ALIGNMENT/ROTATE_OFFSET,90,ABOUT,YPLUS
                                        ALIGNMENT/END

                            If surface points are used a circle becomes a 3D feature and it will work to level to it. But if you are going to do this you should make sure to use 3 surface hit as opposed to 1(almost useless).
                            Saving the world, one bad part at a time.

                            Comment


                            • #15
                              Originally posted by EHines View Post
                              If surface points are used a circle becomes a 3D feature and it will work to level to it. But if you are going to do this you should make sure to use 3 surface hit as opposed to 1(almost useless).
                              Once the alignment has embraced the theo's at program creation why would this impact or alter the generic feature on its own? One would think the generic is now tied to wherever homebase aligns to. Am I wrong in this thinking?
                              Last edited by Gary Fitzgerald; 09-02-2009, 10:32 AM.
                              sigpicThanks a Millionth

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