Equate alignment

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  • Equate alignment

    I have never used equate alignment in a program before, but I have a part coming up that I have to measure in two halves and I was wanting to use it instead of having to have two programs. What is the best way to do this?
    DeWain Hodge

  • #2
    Good Luck with that !! I tried it once and never got it to work. I've read that you gotta probe the same features in the second alignment that you did in the first alignment. Honestly, this makes no sense to me. In my case, if I could probe the same features after flipping the part, there'd be no need to flip it in the first place...I've also read that in the second alignment you've gotta recall "startup" and not the previous alignment...Lemme know if you have any success, I'd like to know how to do it correctly myself....
    Sheffield Endeavor3 9.20.8, Tesastar-SM, Leitz LSP-X1s & LSP-X1M, PCDMIS 2011 MR1


    • #3
      You must end whit the alignment that you going to use after you move the part.. that's the key.
      so measure the part.... move the part .... measure the features for second alignment again (the on you ended whit) .......make second alignment..... Equate second alignment whit first alignment...done
      hope this make sense


      • #4
        Originally posted by DeWain Hodge View Post
        I have never used equate alignment in a program before, but I have a part coming up that I have to measure in two halves and I was wanting to use it instead of having to have two programs. What is the best way to do this?
        You have to have features near the center of the part that you can measure after moving the part that you can RELATE back to the original alignments origin (theoretical nominal values should suffice). It doesn't need to be your original alignment features.

        Say you have a 12 foot beam with holes in it every foot, and you can reach 7 feet of the beam in one go. Measure through to just before the 7 foot hole. Then, move the part. Now, immediately after moving the part, measure a plane around the 5.5 to 7 foot mark, the hole at 6 foot and the hole at 7 foot. Create an alignment on these features (LVL/Origin on plane, rotate hole to hole, origin to 6 foot hole, OFFSET back to original origin). The origin point MUST match the origin of the original alignment (theoretically). Then, use equate alignment to equate this alignment to the original alignment.

        PC-DMIS says ok, equate the new 0,0,0 with the old 0,0,0. Since they are theoretically the same PC-DMIS can translate all of the data from before the alignment, into relative position in your current alignment.

        One caveat here. I have never personally programmed AND performed this. I have only done this as the operator, and at the time, I didn't really know what was going on. So, this is all theoretical, based on my incomplete recollection, and my understanding of what the help file is saying. Save a copy of the program at the point where you have finished the entire first half. Then, give it a try.

        ETA: The equate cannot work in the programming stage. You have to actually have moved the part and measured your new alignment features in the new position. So program up to the point where you have to move the part. (It probably works at the programming stage too, in theory, since the new position would just be exactly the old position, but, um, yeah.)
        Last edited by VinniUSMC; 08-08-2014, 07:00 AM.
        "This is my word... and as such is beyond contestation."


        • #5
          I have used the equate alignment with our Romer arm several times. Actually works pretty slick. I have used ( 3 ) 1 inch ball bearings and mounted them to the part with modeling. Measure the three spheres and make an alignment, move the part, measure the bearings again in the same order and make the same alignment and equate them. After you equate, reactivate your original alignment that you set up off your datums. If you can reach all the datums from both set ups, you could just measure the datums and do your equate. In my case I wasn't able to do that.

          You can also use hardware store hexagon nuts and do single point locations. I like the ball bearings better.
          Scott Staral
          Layout Tech.
          Wisconsin Aluminum Foundry


          • #6
            Just came across this thready by search. A while ago I was trying to do an equate alignment on a long part where I was able to reach a set of holes in both locations. I believe I did everything properly, and I was able to get everything to "look right" in the graphics display and it all ran properly but for some reason everything was shifted a bit in my X axis only it seemed. I was sliding the part in Y. My locations were not jiving with my surface plate check. If anyone got this to work would you mind sharing what you did? Hopefully it will shed some light on what I missed. Thanks in advance!


            • #7
              Hey! I just ran across this thread, too, and I like the potential of what I see! What I've done in the past when I have a 10' long tool (we have a ~6 foot long CMM bed), I align from a tooling ball hole at 1' and another at 5' (putting my ALN at the 5' hole), do what I can on the front half, and save it. THEN I do a second program, aligning to the 5' hole (and putting my alignment there, again) and the 9' hole, and program the rear half of the tool. In the end, I relate all dims to the 5' hole, but in 2 programs. Frankly, the tools tend to be simple tools, without complicated callouts, so I am comfy with this strategy. BUT, EQUATE ALIGNMENT might be a better way to go --- especially if there are complicated callouts! I'll have to change my approach/strategy a bit, but the power of this tool (ASSuming I can make it work...) is undeniable! I'll have to play with it. I knew there was a reason I should be reading the threads on this forum! Even if they aren't about my problem-of-the-day. Thanks, guys!


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