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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
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  • Unfortunately we didn't cover any of these topics in class. I'm not familiar with read points, although I've seen them mentioned several times in this forum. We do have threaded gridplates. Currently cmm 2 is mainly used for checking the part with the fixture that my original question involved. Occasionally we check service parts there which do not have fixtures, so I usually set them up the best I can with the fixturing tool set we have from Te-co and run a manual alignment. Cmm 3 is currently being used primarily to measure a new part we are running, and that fixture rarely moves. We are in the process of having a threaded gridplate built for that machine (which I'm thoroughly excited about Smiley). I have noticed better position outputs on machine 2 after adding the second dcc alignment. I used to talk about being able to hear the positional difference from part to part when an ID was measured, but apparently I was the only one who noticed. I no longer hear such a huge difference. I'm also unfamiliar with iterative alignments, although I've seen them mentioned here as well. This has brought to mind one more small question while I'm here. On cmm 3 (PCDMIS 2014.1) it seems like I remember the probe retracting automatically when a manual point was taken. It no longer does this. Now you have to manually back the probe away from the part. We've done a lot of digging into the settings, although I really didn't change any, and I wonder if this may be due to a box accidentally being unchecked. Any ideas?

    And thanks for the fix Josh. It's a blessing and a curse. Which one just depends on which day I'm asked Wink.
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  • Unfortunately we didn't cover any of these topics in class. I'm not familiar with read points, although I've seen them mentioned several times in this forum. We do have threaded gridplates. Currently cmm 2 is mainly used for checking the part with the fixture that my original question involved. Occasionally we check service parts there which do not have fixtures, so I usually set them up the best I can with the fixturing tool set we have from Te-co and run a manual alignment. Cmm 3 is currently being used primarily to measure a new part we are running, and that fixture rarely moves. We are in the process of having a threaded gridplate built for that machine (which I'm thoroughly excited about Smiley). I have noticed better position outputs on machine 2 after adding the second dcc alignment. I used to talk about being able to hear the positional difference from part to part when an ID was measured, but apparently I was the only one who noticed. I no longer hear such a huge difference. I'm also unfamiliar with iterative alignments, although I've seen them mentioned here as well. This has brought to mind one more small question while I'm here. On cmm 3 (PCDMIS 2014.1) it seems like I remember the probe retracting automatically when a manual point was taken. It no longer does this. Now you have to manually back the probe away from the part. We've done a lot of digging into the settings, although I really didn't change any, and I wonder if this may be due to a box accidentally being unchecked. Any ideas?

    And thanks for the fix Josh. It's a blessing and a curse. Which one just depends on which day I'm asked Wink.
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