External alignment help (idiots guide)

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  • External alignment help (idiots guide)

    I am looking for some help on how to create and run using an external alignment, I have tried once before with what can only be described as disastrous effects. Basically I trashed a probe and was lucky it ended with just that.

    It looks as though we are going to have to use the CMM to measure production parts as well as handing over the controls to the finely educated shop floor people. Many of you have experience in this and know the consequences especially if they have access to the program and use the controls too much so I am trying to mitigate this problem with operator mode and an external alignment.

    So I have a program that we use to measure the part already, it has manual alignment and a DCC iterative alignment.

    I have many questions that follow and hopefully you can answer some of them.

    1. using an external alignment can I do away with both the manual and DCC alignments or is it still best to leave the DCC in as well?
    2. do you leave the alignment in there still just in case you need it or do you delete the unneeded alignments?
    3. Do I run the manual alignment only (no program) and then go into insert > alignment > Save or are there more steps or different steps required?
    4. again refers back to if I delete the other alignments. When I recall the alignment how do you guys do this, do you have an option to recall the alignment or just block the other alignments and just have the recall one in there?

    I am sure there are other steps I need but cant think at the moment what

    thanks for an help

  • #2
    I'm not sure I'll be able to help, but I'll try...I frequently use external alignments at the beginning of my programs. A lot of the parts I run are round so we bought a self-centering chuck for a lathe and built a base for it to mount to the granite slab.

    Then a program was written that aligns to the center of the chuck and the alignment was saved as an external alignment. Now, anytime I write a program for a part that will be setup on the chuck, at the beginning of the program I "Insert>Alignment>Recall and pick my chuck alignment.

    Now, at this point, since my chuck is self-centering and fairly repeatable I could just go on and take the points and features needed to report to print but since I'm somewhat OCD I do go ahead and perform a DCC alignment to the part. And yes, External Alignments can be recalled throughout the program just like any other alignment using the steps in the second paragraph.

    Now, if I'm reading your post correctly, and I may not be, it seems that you wanna take a program that you already have that is utilizing a Man & DCC alignment and convert it to use an External Alignment. Well, this should be easy enough but most likely will be tricky also. In my experience with PCDMIS, you gotta be really careful when screwing around with alignments or things can go South real fast...First you'll need to create an alignment program to align to the set-up the part is gonna use and save the alignment as an external alignment. That's the easy part. Now go to where you wanna insert it ( Beginning of program I assume ) and do just that....And here's where the fun begins... Most likely your gonna get that confusing pop-up about the alignment changing and points beyond being transformed, yada yada yada...Whether you choose Yes or No depends on whether or not the point of origin is moving but be it known the wrong choice will hose the program quicker than it takes a second hand to think about moving so be sure you have a backup copy or three...

    Maybe this answered some of your questions, maybe not but I tried. Holler if I can help any more...




    Sheffield Endeavor3 9.20.8, Tesastar-SM, Leitz LSP-X1s & LSP-X1M, PCDMIS 2011 MR1

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    • #3
      I think I got it working late on Friday, Took me a while till I realized the saved external alignment had to be in the part program folder to recall.

      Mite have to leave the experiment here for a while as I am waiting on some new fixings to bolt down the fixture which will move the position.

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      • #4
        Take existing program. (Use a copy obviously)

        After manual alignment, insert > alignment > save (give it a meaningful name)

        Straight after that, recall the external alignment you've just saved so you have this

        Man features
        Man Alignment (Recalls Startup)
        Save Ext Alignment
        Recall Ext Alignment
        DCC Features
        DCC Alignment (Recalls Man Alignment)

        Now, change the Recall alignment for the DCC alignment from the original Man Alignment, to the External Alignment so you end up with this


        Man features
        Man Alignment (Recalls Startup)
        Save Ext Alignment
        Recall Ext Alignment
        DCC Features
        DCC Alignment (Recalls External Alignment)

        As long as you have no further recalls of either the original Man Alignment, or Startup (which doesn't lock down all 6 DOF) you can Cut and Paste the first three bits into a new program so you have


        Original Program

        Recall Ext Alignment
        DCC Features
        DCC Alignment (Recalls External Alignment)


        New Alignment Program

        Man features
        Man Alignment (Recalls Startup)
        Save Ext Alignment
        Applications Engineer
        Hexagon UK

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        • #5
          Thanks for the straightforward steps.


          Originally posted by NinjaBadger View Post
          Take existing program. (Use a copy obviously)

          After manual alignment, insert > alignment > save (give it a meaningful name)

          Straight after that, recall the external alignment you've just saved so you have this

          Man features
          Man Alignment (Recalls Startup)
          Save Ext Alignment
          Recall Ext Alignment
          DCC Features
          DCC Alignment (Recalls Man Alignment)

          Now, change the Recall alignment for the DCC alignment from the original Man Alignment, to the External Alignment so you end up with this

          I don't think I did this step, will have to check. It was probably just running the DCC alignment from the last position like I had unmarked the manual alignment.


          Man features
          Man Alignment (Recalls Startup)
          Save Ext Alignment
          Recall Ext Alignment
          DCC Features
          DCC Alignment (Recalls External Alignment)

          As long as you have no further recalls of either the original Man Alignment, or Startup (which doesn't lock down all 6 DOF) you can Cut and Paste the first three bits into a new program so you have


          Original Program

          Recall Ext Alignment
          DCC Features
          DCC Alignment (Recalls External Alignment)


          New Alignment Program

          Man features
          Man Alignment (Recalls Startup)
          Save Ext Alignment

          I was also thinking of doing this with a separate alignment program.

          Comment


          • #6
            Your external alignments can be saved anywhere you want them to be saved, you just have to setup the SET SEARCH PATHS to look in the right place.
            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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            • #7
              We have a yes/no comment at the beginning of each routine, asking if a manual alignment is necessary. In light of recent disasters caused by auditors running calibrations and alignments (think 'too many cooks in the kitchen'), we are proposing a comment:input in each routine, asking for a "Metrology Password" before manual alignment can occur.
              I was thinking to hide the password validation script within a group. Anyone not intelligent enough to expand the group shouldn't be manually operating the machine.

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              • #8
                quick question about external alignments. Do you prefer to use minimum number of points to establish the part alignment or generous amount of point?

                I would think use the minimum number of points in the external alignment program and then when recalled in the inspection program, cmm finds the part, then use more points for the dcc alignment?

                Comment


                • #9
                  Yeah, I use the minimum for the external (Indeed I often omit the level & rotate and just set an XYZ origin) but I then have a DCC 'manual' alignment (minimum num hits to lock all 6DOF) before a full DCC alignment.

                  Applications Engineer
                  Hexagon UK

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                  • acgarcia
                    acgarcia commented
                    Editing a comment
                    Good to know, thanks.

                • #10
                  I also use very few points in an external. I really just treat an external alignment as an internal alignment saved somewhere else; it's completely the same thing. The only difference is nomencalture and location.
                  This one is saved here, where the other is saved.. well, over there.
                  If I created a full manual/DCC alignment system for one part, I could save it as an exernal alignment, open a new program, recall that external alignment, and continue as if nothing happened.
                  I prefer the methods stated above; an external "quick and dirty" alignment that can't possibly be screwed up *knocks on wood* followed by the internal fine alignment procedures.
                  As long as the probe finds the part with relative accuracy, and there's a finer alignment procedure later on, you can have as bare-bones an alignment as will actually run

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