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Manual vs DCC alignment

I have taken the basic 1 week PCDMIS course from Hexagon.

Currently I have only modified part programs written by the programmer at our parent company location to run on our cmms.

I work with version 3.7 on cmm 2 and 2014 on cmm 3.

Cmm 1 has Measuremax which I am not sure how to program. This question is regarding cmm 2.

I think I may be a little confused about the purpose of running the dcc alignment after the manual alignment has run. I was under the impression that the manual alignment was to locate the part on the cmm, and the dcc alignment was the "fine tuning" and would adjust for very slight placement changes.

We have a fixture that is bolted to the fixture plate. The part is then mounted on the fixture and screwed into place using 1 screw. The part is secure, but due to different cavities with different die conditions may sit slightly different in the fixture each time. We are measuring the true position of a bore on the x minus side of the part with respect to the plane and bore at the x/y/z 0 position that is used to set the part alignment.

What we have noticed is that when we run the first part with the manual alignment the true position is within tolerance (.04mm). When we run a second part, if I mark all but choose not to mark the manual alignment portion, we see true position values between 0.1mm and 0.2mm.

If I then run the program on that same part again using the manual alignment without moving the part the true position values are again within tolerance. From what I read online yesterday after lots of digging it looks like the dcc alignment serves only to ensure the alignment features are properly probed and defined.

Is there any way around running the manual alignment each time? I don't mind if it's necessary for different cavities or runs, but for a 300pc cpk it's quite time consuming. Thanks in advance for any answers and/or suggestions. Oh, and I'm well aware of the noob hazing here. I have thick skin Slight smile.

Amber
Parents
  • We run higher volume automotive parts in many of the machines and if you're lucky and have rayco, or threaded gridplates, you can do what I call drop an go programs.

    "Find" the part using your check distance set to 4" or 100mm, then do a rough DCC alignment (fixture to part), then a refined alignment 2nd DCC on part, and go from there.

    Operators just have to set up fixtures per instructions (and pictures) in program and press execute - NO moving of the probe head manually AT all!

    Works awesome to keep the cave monkey's from wrecking TP20's. Went from 22K last year in TP20's to 2K this year to date. Plus it speeds up the number of parts you can check a shift when you're not needing to take all the time to manually align parts.

    Also, when you do the 2 DCC alignments you'll find that on especially tight positional tolerance parts (say .030mm) you'll usually gain a few microns when doing this and those extra microns make the difference between scrapping good parts!

    My .02 cents

    4/1/96

    +1
Reply
  • We run higher volume automotive parts in many of the machines and if you're lucky and have rayco, or threaded gridplates, you can do what I call drop an go programs.

    "Find" the part using your check distance set to 4" or 100mm, then do a rough DCC alignment (fixture to part), then a refined alignment 2nd DCC on part, and go from there.

    Operators just have to set up fixtures per instructions (and pictures) in program and press execute - NO moving of the probe head manually AT all!

    Works awesome to keep the cave monkey's from wrecking TP20's. Went from 22K last year in TP20's to 2K this year to date. Plus it speeds up the number of parts you can check a shift when you're not needing to take all the time to manually align parts.

    Also, when you do the 2 DCC alignments you'll find that on especially tight positional tolerance parts (say .030mm) you'll usually gain a few microns when doing this and those extra microns make the difference between scrapping good parts!

    My .02 cents

    4/1/96

    +1
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