Iterative Alignment, FCF, B Points Won't make nice Rotational Feature.

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  • Iterative Alignment, FCF, B Points Won't make nice Rotational Feature.

    Hey all, so I'm struggling through using Iterative alignments for the first time. (level 2 class can't come fast enough).

    I found more than enough info on here to get the Iterative alignment working but now I need to report out some GD&T. Long story short I was using legacy but now I actually have dimensions so I would like to use Xact and be able to show the FCF.

    I can create a Plane from A1-A3, C1 is just a point, but B1 and B2 aren't oriented in a way that I can create a nice line that will match with my Trihedron/ vector of A. I've attached a quick drawing to show the datum targets. How should I go about this?

    20190612_142003.jpg

    Thanks in advance for your advice.

  • #2
    Stumped again.
    20190612_1420033.JPG

    In this instance A is the rotational feature and B is tertiary. But how am I supposed to use only 1 point for rotation.

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    • A-machine-insp
      A-machine-insp commented
      Editing a comment
      We interpret notes like that all the time here. The way I see it is you can level and rotate using all/any datum target point but you can only use A3 and B1 to translate to (and C1 obviously).

      My opinion on the whole thing is that you don't need to use an iterative alignment assuming the part is as square as the pic shows.

    • Loon4ever
      Loon4ever commented
      Editing a comment
      It is not sadly. However that just answered this part of the questions. Thank you so much!!

  • #3
    A is primary. B is used as rotation but its saying that B 0.00 is point B1. B is an offset line ( or point ) thats why you have the the BASIC listed between B! & B2

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    • #4
      You don't create a line. Use auto feature to key in the XYZ IJK for all points and then you can use iterative alignment. Add move to's and or Avoidance moves so it wont crash. You can also just use any corner for your manual alignment and then go after your datum scheme using iterative.
      sigpicSummer Time. Gotta Love it!

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      • #5
        Yes, but how am I supposed to use a single point for a rotational feature when a minimum of 2 features are needed?
        If I just translate the B2 point the BASIC amount then the Line's vector still isn't perp or parr to A's vector so I can't just make it a datum feature with Xact and align to it right?


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        • #6
          I have a model with the datum targets already on it. The iterative alignment isn't the problem. It's using these datum targets to create the feature control frame when the Line that B creates is not Perp or parr to A's Vector.

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          • #7
            You need to create an offset or generic point for your B2 target point.

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            • Loon4ever
              Loon4ever commented
              Editing a comment
              Assuming you mean offsetting the B2 point both the amount of the basic dimension and the amount not given, but that can be interrogated from the model, to make a line with a vector that is perp to A. Then I can use that line to Define my B Datum with Xact to dimension with?

            • andrewb91
              andrewb91 commented
              Editing a comment
              You are correct.

            • Loon4ever
              Loon4ever commented
              Editing a comment
              This ended up working. Thanks Mate!

          • #8
            If you are satisfied with your iterative alignment, you can construct datum features *from* the alignment:

            construct plane, method "alignment"
            construct line, method "alignment"
            construct point, method "origin".

            If you do it only by the dialogs, you need to think about the workplane before each construction, but I find it easier to edit the command text directly after creating it with the dialog.

            Code:
            PLN2       =FEAT/PLANE,CARTESIAN,TRIANGLE,NO
                        THEO/<0,0,0>,<0,0,1>
                        ACTL/<0,0,0>,<0,0,1>
                        CONSTR/PLANE,ALIGN,ZPLUS
            
            LIN2       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
                        THEO/<-0.5,0,0>,<1,0,0>
                        ACTL/<-0.5,0,0>,<1,0,0>
                        CONSTR/LINE,ALIGN,1,XPLUS
            
            PNT2       =FEAT/POINT,CARTESIAN,NO
                        THEO/<0,0,0>,<0,1,0>
                        ACTL/<0,0,0>,<0,1,0>
                        CONSTR/POINT,ORIGIN
            AndersI
            SW support - Hexagon Metrology Nordic AB

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            • Loon4ever
              Loon4ever commented
              Editing a comment
              Thanks I will play around with this sometime!

          • #9
            That is what Iterative Alignment is for. Its so you can use 2 feature not on the same axis to align to. There are a lot of parts that have offset alignment for rotations
            sigpicSummer Time. Gotta Love it!

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            • Loon4ever
              Loon4ever commented
              Editing a comment
              Ah sorry I should have titled the post better. I already have the alignment, I needed to know how to use the 2 point not on the same axis to create a Datum feature so that I could use Xact Measure to report out my Dimensions. I ended up doing what andrewb91 suggested and it worked.

          • #10
            Originally posted by Loon4ever View Post
            Stumped again.
            20190612_1420033.JPG

            In this instance A is the rotational feature and B is tertiary. But how am I supposed to use only 1 point for rotation.
            construct a plane from the point make that your ref,, hard to tell from your sketch but if [2,23] (boxed in), is something that are on the drawing you have somthing there that should be evaluated, i guess a surface or position from A|B?......

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