Using a dual ball calibration sphere???

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  • Using a dual ball calibration sphere???

    First time using one of these. I have a special probe made up so that i can check these extra long parts. I have a 5 way installed with one pointing to
    A0B0 and the other pointing to A90B180. I calibrated both of these in A0B0,
    A90B180, and A90B0. Set up my alignment with the #1 probe in the A0B0 position. Then I rotated to A90B0. And was using the #2 tool to check some holes out near the end. My probe is off about .100 in one direction. Can someone give me some help on how to actually use a dual ball sphere or possibly tell me what I'm doing wrong? Thanks!
    ~Josh~ Giles Rescue "Ut ceteri vivant"

  • #2
    Well, first of all, BOTH balls need to be defined. THEN, you need to calibrate tip1 A0 B0 on the first ball, telling the machine that the tool has moved, then calibrate that same tip on the second ball, once again telling it that thte tool has moved. You can NOW use either ball to calibrate any tip.
    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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    • #3
      I guess I'm going to have to always answer yes because they don't have their sphere mounted to the table. They just lay it up there when they need to calibrate. I'll give this a shot.
      ~Josh~ Giles Rescue "Ut ceteri vivant"

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      • #4
        Is it best to turn the artifact sideways, like on a 45* angle?
        ~Josh~ Giles Rescue "Ut ceteri vivant"

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        • #5
          Originally posted by jkb_mcg View Post
          Is it best to turn the artifact sideways, like on a 45* angle?
          You have to set the artifact up so that the VECTORS of the shanks of the balls are pointing in the correct direction or it will try to drive through the shank.
          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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          • #6
            Originally posted by Matthew D. Hoedeman View Post
            Well, first of all, BOTH balls need to be defined. THEN, you need to calibrate tip1 A0 B0 on the first ball, telling the machine that the tool has moved, then calibrate that same tip on the second ball, once again telling it that thte tool has moved. You can NOW use either ball to calibrate any tip.
            Matt,
            Will it handle collision issues or is that an operator/programmer issue?
            Links to my utilities for PCDMIS

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            • #7
              Originally posted by Matthew D. Hoedeman View Post
              You have to set the artifact up so that the VECTORS of the shanks of the balls are pointing in the correct direction or it will try to drive through the shank.
              And the correct direction would be....????
              ~Josh~ Giles Rescue "Ut ceteri vivant"

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              • #8
                Originally posted by cmmguy View Post
                Matt,
                Will it handle collision issues or is that an operator/programmer issue?
                Ya know, that is a [email protected] good question. I have never had to use the bottom ball, even when using a star probe. HOWEVER, I took the ball-mount off the B&S base and put it on a custom base so that they point straight up and down. It will handle collision with the shank for the tip it is using, but other than that, I am not sure and I would SERIOUSLY doubt it.
                sigpic
                Originally posted by AndersI
                I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

                Comment


                • #9
                  Originally posted by Matthew D. Hoedeman View Post
                  Ya know, that is a [email protected] good question. I have never had to use the bottom ball, even when using a star probe. HOWEVER, I took the ball-mount off the B&S base and put it on a custom base so that they point straight up and down. It will handle collision with the shank for the tip it is using, but other than that, I am not sure and I would SERIOUSLY doubt it.
                  So, it's not 100% necessary to use the bottom ball? I calibrated my probes as stated above on just the top ball. And still, .100 variance.
                  ~Josh~ Giles Rescue "Ut ceteri vivant"

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                  • #10
                    Originally posted by jkb_mcg View Post
                    ... And still, .100 variance.
                    .100 variance what?

                    Try this if you need to use both

                    HERE
                    sigpic

                    James Mannes

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                    • #11
                      Originally posted by JamesMannes View Post
                      .100 variance what?

                      Try this if you need to use both

                      HERE
                      well, unfortunately the great IT dept. doesn't allow access to this page.
                      ~Josh~ Giles Rescue "Ut ceteri vivant"

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                      • #12
                        Originally posted by JamesMannes View Post
                        .100 variance what?

                        Try this if you need to use both

                        HERE
                        I set up my alignment using T1 in A0B0. And then i rotated to A90B0 and used T2. my first hole i checked was off .100 in one direction.
                        ~Josh~ Giles Rescue "Ut ceteri vivant"

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                        • #13
                          Originally posted by jkb_mcg View Post
                          And the correct direction would be....????
                          Well, if your 'tool' has a vector of 0,0,1, then the ball sits on top of the shaft, with the shaft pointing straight up.

                          If your vector for the tool is 0.707, 0, 0.707, then it points UP and to the RIGHT (45 degree shaft, standard B&S double-ball setup). The vector of the tool shaft has the ball sitting on it in the direction of the vector. This vector is MAINLY for cal-tip-shaft-avoidance. If your tips misses the shaft on all calibrations, then you are close enough.
                          sigpic
                          Originally posted by AndersI
                          I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

                          Comment


                          • #14
                            Another possibility (just in case!)

                            After you do the initial calibration of T1 A0 B0, after telling it the sphere has moved, when you measure the other tip, are you telling it that it has NOT moved? After you 'locate' the tool, tell it NO it has NOT moved until you move the tool, otherwise the tips will NOT be in relationship to each other. When you 'find' the tool after it has been moved, it locates the tool in the measurement envelope ASSUMING that the tip you are using is 'perfect'.
                            sigpic
                            Originally posted by AndersI
                            I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

                            Comment


                            • #15
                              Originally posted by JamesMannes View Post
                              .100 variance what?

                              Try this if you need to use both

                              HERE
                              That's awesome James! When we first got PC-DMIS a few years ago I experimented with it because I hated giving up my two-ball artifact (and the boss didn't want to purchase a Renishaw articulating artifact). Now, when I get some time I'll have to give this a shot...
                              sigpic
                              Xcel 15-20-10 - PFXcel 7-6-5 - Merlin 11-11-7 - Romer Absolute 7525SI
                              PCDMIS 2012
                              Windows Office XP

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