CAD Synchronization Issues

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  • CAD Synchronization Issues

    I'm a new CMM user, having recently taken the PC-DMIS 101 training, and I'm having difficulty synchronizing my imported CAD with the machine. I've searched through the forum for similar issues, but nothing has helped yet. I may simply be skipping a step, as I'm inexperienced. Here's my issue:

    I import a CAD (STEP) file into PC-DMIS, and it shows up on the cad view. I create features for an alignment (plane, cylinder, plane in this case) using the program mode by selecting points with the mouse, and then I create the alignment feature itself. When I execute the program, I move the stylus with the joystick to manually probe those features on the part. However, when I'm finished, the graphics of the features appear at different locations on the screen and don't "jump" to the CAD like I recall from training. If I try to run any other movements in DCC after that, I get an out-of-stroke error, since the targets (e.g., other features I programmed using the CAD) are far away from the probe-measured features, and the machine doesn't like that.

    I've tried simple fixes like restarting the CMM, the computer, and the software a few times. I've also tried using an iterative alignment with a plane, line, and point, as well as other alignments. I also tried re-exporting the CAD from our CAD software and then re-importing it into PC-DMIS. I've considered that I could manually move the CAD by offsetting it, but that seems like a cheat that would work once and now for future files.

    Am I way off base, or am I just missing a simple step? I'd appreciate any suggestions and help. Thanks!

  • #2
    Good afternoon! Welcome to PC-Demon! for starters, copy and paste you code so that we can see what's going on. We can read the code line for line and help you clean up anything we see wrong. Copy and paste you code and we will go from there.


    • #3
      Welcome Andy M !

      If I understand you correctly, it sounds like you've imported your model and the trihedron isn't facing the way you'd like it to be (which is making your program all types of messed up). If that is the case, here's what you do:

      1) Work with whomever designed this CAD model/whomever can alter this CAD model for you. Have them move the location of the trihedron on the model so that way it is where you want it to be/oriented how you want it to be when you open up the CAD in pc dmis.
      2) If option 1 is something you can't do......then import your CAD into PC DMIS
      3) Imagine in your head how you want your part sitting on the CMM table. Get a very clear image of this.
      4) You have buttons you can click to rotate your model around. Click "Graphics Window in Y-". This will show you from the Y- perspective how your trihedron is currently set to your model.
      5) Think of how you want it to be sitting again...vs how it imported for you...then go into "Edit/Graphic Display Window/Transform". This window will allow you to rotate as well as move (translate) the model around your trihedron. Don't be scared, play around with this until you understand what its doing. Use this window to rotate & translate as needed then hit apply & okay.
      6) Once your trihedron is oriented how you want it to be on your model, THEN begin your programming. Everything should look normal.

      If I completely misunderstood you, sorry! Would still love to try & help...please post your code & we'll really start digging into this for you.
      Beep beep beep..


      • #4
        First things first your out of stroke error is simply your moves are out past where the CMM can travel. As far as the measurements away from the part, remember where actually you home the machine to be 0,0,0 in the X,Y,and Z in the upper left hand corner, that's where it PC-DMIS thinks its starting, and when you put the part in the middle of the table, and you start to establish your manual alignment, based off the reference points created from the CAD. DO NOT TREAT YOUR CAD MODEL AS AN ACTUAL PART, REFERENCE ONLY. If you done everything correct, normally if you put your cursor anywhere past your alignments. You'll see the features go back to the CAD model
        (In Memory of my Loving wife, "Ronda" who I lost March 7, 2016. I love you baby.)
        They say "Nobody's Perfect." I must be Nobody.


        • #5
          The CAD's XYZ axes match the machines XYZ axes?

          Any chance that you leveled to a plane, but forgot to set the origin to that plane? The alignment should have 5 lines to be complete, something like:

          Did you do a CAD=PART? I write exclusively offline, and I don't have to do this, but sometimes....


          • #6
            Wow, thanks for the quick replies everyone! My code's on another computer offline, so I'll work on getting that moved over so I can post it here. Are CAD files embedded in the code if I post it? The CAD is proprietary, so I'd have to remove it before posting.

            I had used the orient options in the Part/Machine Setup before to get my orientation correct, but not the transform. I played around with it a bit, and I can re-position my CAD so it's close to where the features are appearing after I manually probe them. It looks better, but I'm not sure quite what that gets me, as the measured features still don't sync up exactly with the CAD.

            When I manually probe a "previous created using CAD" feature (say, a plane), a graphic plane shows up on my screen at the real position, not the CAD position, as it should. I understand that the real measurements come from my physical part, not the CAD. Here's what I think is supposed to happen: When I create an alignment with those manually probed features, the CAD should snap to that alignment, so I can now program future features for DCC without having to manually do everything first. Is this correct? That's the part that I can't get working.

            I'll work on moving my code over so I can post it. Thanks again!


            • #7
              And....that was it! RandomJerk figured it out. I leveled to Z, rotated, and set the X&Y origin, but forgot the Z origin for my alignments! And alignment theory is like the first lesson we studied at training, so I feel stupid. I fixed that up, and on the next run, my alignment immediately snapped to the CAD after the alignment and the DCC portion started running correctly (albeit at minimum speed because I'm nervous). I'll probably start more newbie threads when I get to debugging, but this fixed my issue. Thanks for the help, everyone!


              • RandomJerk
                RandomJerk commented
                Editing a comment
                The not setting the Z zero to the leveling plane is extremely common early on, and still will bite the experienced programmer on occasion, so consider it a rite of passage...

                Now, this is unorthodox, and some will bite back, but here's the deal. You've been taught 1) level, 2) offset (rotate), 3) origin. That's solid advice, you'll never go wrong following that. However, you can set your Z zero to a plane immediately after leveling to it.

              • bigtallanddopey
                bigtallanddopey commented
                Editing a comment
                it seems to be the new way of teaching the alignment. Level, rotate, and then origin the three axis. I much prefer Level, origin, rotate, origin and then the final origin. I find that people are less likely to forget the origin if they do it right after the level or rotate of the same feature.

            • #8
              hey guys so I am having similar problems and pretty convinced that the align is right not sure what is goin on... the dcc align goes to -8 for theo. I tried running the manual and then the dcc so then dcc would update but it is not working so well

              PART NAME : AR_MND_141_2018
              REV NUMBER :
              SER NUMBER :
              STATS COUNT : 1

              LOADPROBE/AR PROBE BUILD 3-12-18
              TIP/T1A0B0, SHANKIJK=0, 0, 1, ANGLE=0
              HIT/BASIC,NORMAL,<9.1678,10.7168,-19.9846>,<-0.0052123,-0.0004789,0.9999863>,<9.1678,10.7168,-19.9846>,USE THEO=YES
              HIT/BASIC,NORMAL,<9.1147,11.8935,-19.9845>,<-0.0052123,-0.0004789,0.9999863>,<9.1147,11.8935,-19.9845>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.5269,11.997,-19.9873>,<-0.0052123,-0.0004789,0.9999863>,<8.5269,11.997,-19.9873>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.5269,11.3768,-19.9878>,<-0.0052123,-0.0004789,0.9999863>,<8.5269,11.3768,-19.9878>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.2268,10.9147,-19.8163>,<-0.999931,0.0106038,-0.0050535>,<8.2268,10.9147,-19.8163>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.2276,10.908,-19.9609>,<-0.999931,0.0106038,-0.0050535>,<8.2276,10.908,-19.9609>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.2419,12.3083,-19.8475>,<-0.999931,0.0106038,-0.0050535>,<8.2419,12.3083,-19.8475>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.2429,12.3083,-20.0728>,<-0.999931,0.0106038,-0.0050535>,<8.2429,12.3083,-20.0728>,USE THEO=YES
              HIT/BASIC,NORMAL,<9.0805,10.4668,-20.0189>,<-0.0103879,-0.9946831,0.102458>,<9.0805,10.4668,-20.0189>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.7322,10.4705,-20.0188>,<-0.0103879,-0.9946831,0.102458>,<8.7322,10.4705,-20.0188>,USE THEO=YES
              HIT/BASIC,NORMAL,<8.7324,10.4679,-20.044>,<-0.0103879,-0.9946831,0.102458>,<8.7324,10.4679,-20.044>,USE THEO=YES
              HIT/BASIC,NORMAL,<9.0506,10.4646,-20.0439>,<-0.0103879,-0.9946831,0.102458>,<9.0506,10.4646,-20.0439>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.129,-10.6507,20.3361>,<0.0052073,0.0005305,0.9999863>,<-8.129,-10.6507,20.3361>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.0755,-12.6851,20.3369>,<0.0052073,0.0005305,0.9999863>,<-8.0755,-12.6851,20.3369>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.7317,-12.1078,20.3401>,<0.0052073,0.0005305,0.9999863>,<-8.7317,-12.1078,20.3401>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.7381,-11.4574,20.3397>,<0.0052073,0.0005305,0.9999863>,<-8.7381,-11.4574,20.3397>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.9795,-12.6314,20.476>,<-0.9999374,-0.0099038,0.0052123>,<-8.9795,-12.6314,20.476>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.9805,-12.6352,20.2825>,<-0.9999374,-0.0099038,0.0052123>,<-8.9805,-12.6352,20.2825>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.9978,-10.9063,20.2385>,<-0.9999374,-0.0099038,0.0052123>,<-8.9978,-10.9063,20.2385>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.9968,-10.9072,20.432>,<-0.9999374,-0.0099038,0.0052123>,<-8.9968,-10.9072,20.432>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.0998,-12.8423,20.3109>,<0.0117822,-0.9928386,0.1188814>,<-8.0998,-12.8423,20.3109>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.3945,-12.8451,20.3139>,<0.0117822,-0.9928386,0.1188814>,<-8.3945,-12.8451,20.3139>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.3957,-12.8517,20.2609>,<0.0117822,-0.9928386,0.1188814>,<-8.3957,-12.8517,20.2609>,USE THEO=YES
              HIT/BASIC,NORMAL,<-8.1106,-12.8466,20.273>,<0.0117822,-0.9928386,0.1188814>,<-8.1106,-12.8466,20.273>,USE THEO=YES


              • #9
                I did do some translating for the cad model to be correct according to the trihedron


                • DAN_M
                  DAN_M commented
                  Editing a comment
                  Your logic is soound in the real world...but in PC DMIS World..I'm pretty sure your error lies with you using planes for your alignment. Planes have a centroid and when you're using planes to align, they should all have the exact same centroid otherwise the error will extrapolate down the length of your part. Make sense?

                  I'd recommend trying a plane-line-point alignment and see if that works better for you. Also, your vectors look funky. I'd recommend that you force the nominal values to 0,0,1 and then let the actuals be whatever they end up being.

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