PC-DMIS - Self Center a hole then recall it to measure diameter and location

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  • PC-DMIS - Self Center a hole then recall it to measure diameter and location

    I am new to PC-DMIS. I've been trained with Zeiss Calypso and a lot of stuff is different! I have a few holes in a part that I am trying to get the diamter and location. These holes float around quite a bit. I often cannot measure the holes because they are too far out from the CAD model. With Calypso, I would use a large probe, do a self center, then use a smaller probe and measure the hole by recalling the self center hole. Is there a way to do this with PC-DMIS? I looked in help, but the only way I can recall something is to recall an alignment.

    Thanks for your help!

  • #2
    Originally posted by Matthew D. Hoedeman
    There are TWO ways, FIND HOLE and READ POS, both in the autofeature menu for circles.

    FIND HOLE makes Pcdmis search for the hole, when it does NOT make contact with the part (in the hole) it will then measure the hole. This can take a LOT of time, I don't use it.

    READ-POS pauses the program, allows you to place the probe over/in the hole, hit a button, then it measures at that location

    BOTH methods should also use RE-MEAS which makes Pcdmis measure the hole a second time, using the first result as the 'target' for the second.
    Just to clarify, the find hole option will measure the hole at first with 3 points (USING THE CENTER FUNCTION) to zero on the hole and then measure the hole using whatever amount of points defined by the programmer. I use it to define my datums on machined parts along with 3 hits on the surface to establish the location the surface of the hole about to be measured.
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    James Mannes

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    • #3
      This list contains these list options. They determine how PC-DMIS proceeds when attempting to find a hole. If a list option is not available, it is not supported for that feature type.

      DISABLED - No Find Hole operation is performed.

      NOCENTER - This item acts as the CENTER item except the probe doesn't take the three hits to find the rough estimate of the hole's center. It merely begins measuring the circle using existing parameters set in the specific auto feature dialog box.

      SINGLE HIT - This setting tells the probe to take one single hit. If it hits the surface and doesn't find the hole, then it automatically switches to the "If the hole is never found" case (for circles and slots) or "If the hole is not found" case (for notches) described in the "Find Hole Specifics" links below. If the probe finds the hole, it proceeds using the NOCENTER option.

      CENTER - This item first causes the probe to move down to the "check distance" depth to make sure it doesn't encounter any material. It then moves to either the feature's depth or to the Check Distance * Percent to search inside the hole for a rough estimate of the hole's center (see "Registry Items" below). The probe does this by taking three hits equally spaced around the hole. Once the probe has the hole's general location, it then proceeds to measure the hole using the parameters set in the specific auto feature dialog box. Unless NOCENTER or SINGLE HIT is selected, this is the default procedure that PC-DMIS follows if the hole is found.
      .
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      James Mannes

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      • #4
        Thanks for the replies. The problem I have is that the hole is out of location, meaning that the probe goes to what it thinks is the center of hole, but it is off quite a bit. It then goes in and hits the surface a lot earlier than expected, throwing a "Parameter out of Tol" error. It seems like CENTER will work, except if the hole is drastically out and causes the machine to error out. Is it not possible to use a 6mm probe to hit tangent to the surface of the hole, record that position, and recall that position as the target value to measure the hole with a 2mm probe?

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        • #5
          Originally posted by supahonkey View Post
          I am new to PC-DMIS. I've been trained with Zeiss Calypso and a lot of stuff is different! I have a few holes in a part that I am trying to get the diamter and location. These holes float around quite a bit. I often cannot measure the holes because they are too far out from the CAD model. With Calypso, I would use a large probe, do a self center, then use a smaller probe and measure the hole by recalling the self center hole. Is there a way to do this with PC-DMIS? I looked in help, but the only way I can recall something is to recall an alignment.

          Thanks for your help!
          Yes & with ease.
          Occasionally I have encountered a similar sort of problem with castings varying one to another………..the remedy is easy for me in V3.2065Mr3………..I drop into the code & alter the ‘target’ values but leave the theoretical ones intact. Pc Dmis will ask if I want to ‘update’ the nominals when I apply a value in the tolerance boxes to which the answer is mostly NO.
          Poleaxe

          Beware the environment you live in for it will shape you
          Be careful the friends you choose for you will become like them.

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          • #6
            I understand what you mean, but my goal is to automate the measurement program. I want to somehow have DMIS find the location of the hole, or at least not throw a "Parameter out of tol" when the CMM a hole that is off from CAD nominal.

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            • #7
              yeah. find hole is the ticket. it hunts out and rough measures, then measures at the off location actual.

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              • #8
                Thanks for the help. I will try the "find hole" function when I get back to work next Monday.

                Is there a way in DMIS to recall a feature when measuring other features? I noticed you can recall an alignment, but I saw nothing about features. I use feature recall in Calypso a lot and miss it dearly.

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                • #9
                  Originally posted by supahonkey View Post
                  Thanks for the help. I will try the "find hole" function when I get back to work next Monday.

                  Is there a way in DMIS to recall a feature when measuring other features? I noticed you can recall an alignment, but I saw nothing about features. I use feature recall in Calypso a lot and miss it dearly.
                  Not personally used 'Collapso' software but I know the 'incremental' measure function you mean. In Pc dmis I go into 'Utilities' & high light the relevant feature & assign fresh datums to it (name it properly) which mimics the incremental or temporary datum quite nicely.

                  When done just recall your (properly named) program or drawing datum & proceed as normal.
                  Poleaxe

                  Beware the environment you live in for it will shape you
                  Be careful the friends you choose for you will become like them.

                  sigpic

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                  • #10
                    Originally posted by supahonkey View Post
                    Thanks for the help. I will try the "find hole" function when I get back to work next Monday.

                    Is there a way in DMIS to recall a feature when measuring other features? I noticed you can recall an alignment, but I saw nothing about features. I use feature recall in Calypso a lot and miss it dearly.
                    I think you might be looking for relative measure. put that in the search area in the help

                    From my hTc EVO
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                    I am IronMan!!!!

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                    • #11
                      What size holes are you measuring? One trick I use is to first define the hole by its correct nominal location, but with a much smaller ID - say 6mm for a 30mm hole and set the search distance to about 30mm - and measure with three hits and no sample hits. (Name it Cir1). Just keep in mind the hole dia must always be larger then your ruby. Then measure the hole again with sample hits and as many measure hits as needed with the correct nominals for the Theo and Cir.x, Cir.y for Target.

                      HTH
                      v2013 MR1, v2015.1
                      B&S Global 544, 555
                      Mitutoyo A504 w/PC-DMIS

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                      Since 1994

                      Never force anything. Get a bigger hammer.
                      (Advice from my dad.)

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                      • #12
                        Thanks for all of the replies. I have identified what a good part of the problem is. The CAD model for the part we are measuring is a bit weird in that AutoCircle doesn't recognize a few of the holes in the model as circles. You have to create three points, then manually define them as a circle. This means that the probe goes first approach the center, then go to the first point; rather it goes into the hole a certain distance above the first point. If the hole floats then the probe crashes against the part. Is there a way to make DMIS go into the center of the hole rather than just above the first point?

                        Per the thread above, the hole is only .125 and we are using a 1mm probe tip. I will try telling DMIS that is is a much smaller hole.

                        I used the "Find Hole" function and it works beautifully. I export an .IGES file for a fella in design. He told me that two circles are now in the hole in the .IGES file. He told me this started happening after I added the "Find Hole" function. He doesn't know which hole is correct. Both are not nominal, they are both shifted. How can I make it so UG only reports it's measurement for the Actual measurement?

                        Thanks,
                        Brenton

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                        • #13
                          Originally posted by supahonkey View Post
                          Thanks for all of the replies. I have identified what a good part of the problem is. The CAD model for the part we are measuring is a bit weird in that AutoCircle doesn't recognize a few of the holes in the model as circles. You have to create three points, then manually define them as a circle. This means that the probe goes first approach the center, then go to the first point; rather it goes into the hole a certain distance above the first point. If the hole floats then the probe crashes against the part. Is there a way to make DMIS go into the center of the hole rather than just above the first point?

                          Per the thread above, the hole is only .125 and we are using a 1mm probe tip. I will try telling DMIS that is is a much smaller hole.

                          I used the "Find Hole" function and it works beautifully. I export an .IGES file for a fella in design. He told me that two circles are now in the hole in the .IGES file. He told me this started happening after I added the "Find Hole" function. He doesn't know which hole is correct. Both are not nominal, they are both shifted. How can I make it so UG only reports it's measurement for the Actual measurement?

                          Thanks,
                          Brenton
                          Use an Avoidance move before probing the hole. The probe will travel the the defined hole location, and pause at a pre-set (by you) distance away from the surface. That is also a selection in Autofeatures.
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                          • #14
                            Please ignore the last post about the two holes showing up. It turns out that the second hole was from the old method (before I used "Find Hole").

                            On another note, how do I delete actuals from previous measurements? Deleting the actuals before running my program would have prevented this problem.

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                            • #15
                              Originally posted by supahonkey View Post
                              Please ignore the last post about the two holes showing up. It turns out that the second hole was from the old method (before I used "Find Hole").

                              On another note, how do I delete actuals from previous measurements? Deleting the actuals before running my program would have prevented this problem.
                              The Actuals are the result of the previous measurement and have no influence on future measurements. It is the only field you cannot edit. Theo supplies the Nominals for reported features while Target tells the CMM where to look for the feature.
                              v2013 MR1, v2015.1
                              B&S Global 544, 555
                              Mitutoyo A504 w/PC-DMIS

                              sigpic
                              Since 1994

                              Never force anything. Get a bigger hammer.
                              (Advice from my dad.)

                              Comment

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