Calibration problem

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Calibration problem

    I cannot cal any new angles with dcc without going to dcc/man and having to take the first hits manually. When in DCC/DCC after the a0/b0 angle is checked and I want to check a90/b-90 it misses the sphere by .400. Isn't it supposed to measure all subsequent angles based on the a0/b0 first measured sphere location? It always targets a sphere .400 above where it reallt is, why????? I am using ver 3.7mr3 on a BnS Global DCC. I never used to have this problem until 3.7 what's the deal???? I am tired of baby sitting the CMM each time I want to cal a bunch of probe angles and have to manually take the first hit for each and every angle, it's not supposed to be this way.

  • #2
    make sure you have the correct ext listed in the probe description. i hate to admit it but i wasted about an hour one time bcause i had a 2x40 x10 probe in the head and listed a 2x40x20 in the pull down menu. missed the sphere just like you described. 10mm error = .3937
    Last edited by george frick; 03-23-2007, 04:46 AM.
    sigpic
    Southern Man don't need him around anyhow!

    Comment


    • #3
      Originally posted by Robert Squire View Post
      I cannot cal any new angles with dcc without going to dcc/man and having to take the first hits manually. When in DCC/DCC after the a0/b0 angle is checked and I want to check a90/b-90 it misses the sphere by .400. Isn't it supposed to measure all subsequent angles based on the a0/b0 first measured sphere location? It always targets a sphere .400 above where it reallt is, why????? I am using ver 3.7mr3 on a BnS Global DCC. I never used to have this problem until 3.7 what's the deal???? I am tired of baby sitting the CMM each time I want to cal a bunch of probe angles and have to manually take the first hit for each and every angle, it's not supposed to be this way.
      If the A90/B-90 is not reching the calibration tool, most likely you have a configuation problem.
      Double check.
      sigpicIt's corona time!
      737 Xcel Cad++ v2009MR1....SE HABLA ESPAƑOL

      Comment


      • #4
        Another thing to check, is the probe head square to the machine?

        I have had a similar problem in the past, where my probe head was not square to the machine, resulting in missing the cal sphere when trying to calibrate certain tips.

        Regards,
        ZydecoPete
        sigpic

        Comment


        • #5
          If you are absolutely certain everything is defined properly, try this...

          Calibrate A0B0 answering "yes" when it asks if the sphere has moved. Do not move the sphere. Then click "ok" out of the probe window. Re-open the probe window. Select A90B-90 and select "no" when it asks if the sphere has moved. Hopefully A90B-90 will calibrate correctly. If it does, click "ok" out of the probe window. Re-open the probe window. Select A0B0 and A90B-90 and try calibrating both by clicking "no" when it asks if the sphere has moved.

          Comment


          • #6
            The probe build is/was correct, I have also had that same problem in the past so this is the first issue I llok at when ever I have any sort probe cal problem. But I have to use man/dcc to get all the angles to cal correctly. otherwise after the first angle a0/b0 it missed the speher by .400. I say .400 because in the results file, the actual is always approximately .400 below the theo. I have 12 years experience with PC-DMIS, so I always try to cover the basics before ever asking anythihng here. that's why I am not here that often, I usually catch the problem before it gets to the point of needing an answer fro the board here, but this one persists and it's frustrating.

            Comment


            • #7
              Originally posted by Robert Squire View Post
              The probe build is/was correct, I have also had that same problem in the past so this is the first issue I llok at when ever I have any sort probe cal problem. But I have to use man/dcc to get all the angles to cal correctly. otherwise after the first angle a0/b0 it missed the speher by .400. I say .400 because in the results file, the actual is always approximately .400 below the theo.
              Approx .400 below theo for X, Y or Z? Could this be because the probe head isn't square to the machine? Is it .400 off one way with A90B90 and .400 off the other way with A90B-90?

              Comment


              • #8
                Originally posted by Robert Squire View Post
                The probe build is/was correct, I have also had that same problem in the past so this is the first issue I llok at when ever I have any sort probe cal problem. But I have to use man/dcc to get all the angles to cal correctly. otherwise after the first angle a0/b0 it missed the speher by .400. I say .400 because in the results file, the actual is always approximately .400 below the theo. I have 12 years experience with PC-DMIS, so I always try to cover the basics before ever asking anythihng here. that's why I am not here that often, I usually catch the problem before it gets to the point of needing an answer fro the board here, but this one persists and it's frustrating.
                I think, for starters, you need to know if your probe is mechanically square with the machine.

                Easy way to check. Set your head at A0/B0 and place right angle iron on surface plate and tram the face in square with your A0/B0 tool.
                Set Angle iron on plate so the front face of the angle iron is facing Y minus ( toward you when standing at the front of the machine) and parallel to X axis.

                Now move clear of the angle iron and swing the probe to A90/B-90 and take a touch on the face of the angle iron and set a zero on the face.

                Get clear of the angle iron and set the head to A90/B90.

                Touch the face of the angle iron again. You should be within .001/.003 or better.

                If you are not very close, you will have to begin taking one half of the error out and starting this process all over. If you have the old DEA type probe collet, it is possible your probe COULD be significantly out of square.

                If you have a PH10 and the base of the probe fits up into the Z ram, I would be surprised if you had more than a .001/.002 in. error.

                HTH

                H
                Hilton Roberts

                "Carpe Cerveza"

                Comment


                • #9
                  Sounds like an physical offset (along the z-rail) not accounted for in the probe buildup. What machine / probeing do you have. Is the PH10 attached to the z-rail or through a mounting plate?

                  It shouldn't be that way, and can be corrected. Just need to know where the offset is coming from so you can add it to the .dat file.

                  Comment


                  • #10
                    It is .400 in the z axis. There is an AM2 plate between the quill and the PH10MQ, this is all accounted for. the squareness is not in question at least not by .400. I could see it being off .010-.025 but other than that, that isn't the direction that is giving me the problem. It's not a lateral(side to side) error it's in the z axis. But that's whats frustrating is that all components are accounted for in the probe build in PC-DMIS. It just doesn't remember where the a0/b0 first sphere measured location for the subsequent probe angles. It will miss it, by trying to measure it as if it's .400 taller(The qual. sphere, in the z axis). I have tried just about every combination to get this to "see" and remember the a0/b0 first location so it won' miss the following angles by that .400. About the only sure fire way for me to get this to measure ALL needdd probe angles is by selecting man/dcc when measuring the angles. This is most noticeable in the a90/bxx, obviously.

                    Comment


                    • #11
                      I assume you have deleted your probe file and created another one by now right?
                      <internet bumper sticker goes here>

                      Comment


                      • #12
                        Yes. This is starting with a new probe file, both. New ones and existing ones.

                        Comment


                        • #13
                          I want to make sure I fully understand. You select A0B0 and A90B90 for calibration. You take your manual hit for A0B0 and it runs through the calibration just fine. Then, it switches to A90B90 and tried to take the first hit (moving 1,0,0) .400 above the center of the sphere. Does it crash into the spere or not touch it and kick up an unexepected end of move error?

                          So, we can either make the assumption that it isn't "remembering" where the sphere is or that it is measuring wrong with A0B0. I think it is more likely that it is measuring it wrong.

                          For example, if you tell it you have a 4X10 mm tip but actually loaded 4X30mm it will measure A0B0 just fine. But, it will think the sphere is located 10mm higher than it actually is. Then, when it switches to A90B90, it will miss the sphere by 10mm! 10 mm is awfully close to .400 in BTW.

                          Has your machine always been like this or is it a new problem? What kind of probe build up are you doing. Try the simplest one you can. Just a 2X20 tip attached to the probe with no extensions or anything.

                          Sorry to kind of beat a dead horse here and only tell you what has been said before.

                          Comment


                          • #14
                            I assumed it was an issue with the AM2 plate, because we have four programers here, some were building probes without the AM2 plate and some were building it with the AM2 plate. I have given explicit instructions to all to always build using the AM2 plate, because that's what is there. Now that you mention .400 being so close to 10mm you have me second guessing my probe builds. because we do have 10, 20 and 30mm extensions here. maybe someone keeps mistaking the 30 for a 20. I will investigate this and let you know and I appreciate all of the help. 95% of all PC-DMIS problems always seem to be operator error regardless of the amount of experience and I am not above that statement either. I will get back, thanks!!!

                            Comment

                            Related Topics

                            Collapse

                            Working...
                            X