Alignment problem

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  • Alignment problem

    I have a part that is set up in a way that I have seen before, but, I can't seem to think for the life of me how I want to do it. I know there are a couple of options available to me, but, for some reason, I keep shooting my own theories down. Time to get some backup.

    The part is a bracket which is approximately 14 inches long. The bracket has a bend at each end about 2 inches from the edge, which starts the part going to a "C" formation. I have to surface datums which are the two ends, so I have something like Datum A is on a 45 deg bent surface and Datum B is on the 30 degree bent surface on the opposite end of the part. Datum C is drawn as a relationship of a slot on one face and a hole on the other face. I am thinking about doing an iterative alignment to the part and then a CAD=Part, but, for some reason, something is telling me to do a 3D best fit with these two surfaces to allow me to align back to print coordinates easier. I guess it is that I am thinking if I use iterative and then try to align the model to print coordinates, I won't be utilizing both surfaces as intended. Or, can I do best fit after iteratives?

    Thanks in advance.

  • #2
    Well, if part of your A-Datum is a 45 degree surface and the other part is a 30 degree surface, with the 2 surfaces trying to make a irght angle (but missing by 15 degrees) you will NEVER get Pcdmis to solve the iterative using BOTH of those surfaces as an A-Datum. ALL the points for a 'level' of the iterative MUST have close to common vectors, not vectors that are almost 90 degrees off from each other.
    Originally posted by AndersI
    I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.


    • #3
      You "can" do a best fit after iterative
      just look at the results before you make your final decision
      DR Watson shut me down again !!!! :mad: Smoke break:eek:


      • #4
        Thanks Matt. Both surfaces are not Datum A, but Datums A and B. The reason why it is tricky is because I know both of these surfaces have influence on how the holes align in the assembly because they nest into a corner shaped piece which both surfaces rest against, that is what has my head jammed. I have used it on round surfaces before utilizing datum targets.

        Maybe I will just treat one as a gage point as the locations of the holes on Datum B are being dimensioned from the hole center and surface intersection. I could probably get away with that, since that is almost the same thing anyway. If the center and surface intersection points fall within the surface profile specification, then theoretically, the form should be correct. Right??

        ****, I need to go home!


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