hexagon logo
Register Sign in
  • Replies 32 replies
  • Subscribers 225 subscribers
  • Views 505 views
  • Users 0 members are here
Options
Related

Iterative alignment and using XactMeasure

BWIZZLE
Alright here is my problem/question.
I have a part where Datum -A- (Z axis) is not prismatic, however datum -B- (X axis) and -C- (Y axis) are.

I do not have much experience with Iterative alignments other than that I have been to the Level 2 Hexagon class (Just don't use them or have the need too).

My thoughts were, this is a good time, to try an Iterative alignment.
I believe I have that part of the program correct:
I created 6 auto vector points on top (Datum -A-),
then 5 auto vector points on left side (Datum -B-)
then finally 5 auto vector points on the front of the part (Datum -C-).

When I create the Iterative alignment I pick top 6 points as level (Datum -A-),
5 points on left rotate (Datum -B-),
then 5 points on front as origin (Datum -C-).

After completing this Iterative alignment my trihedron doesn't move from before the alignment.
So I constructed planes out of the five points for datum -B- and -C- respectively.
I then origin my "X" to Datum -B- and my "Y" to datum -C-.
How do I origin my "Z", and how do I assign my datum -A- for exact measure? Where did I go wrong? Please any help would be greatly appreciated.
Parents
  • Ignore the trihedron. Iterative alignment is a CAD alignment, or PART alignment.

    A 3-2-1 alignment uses features to align, and YOU tell Pcdmis what those features need to be, nominal-wise.
    An Iterative alignment uses features to align, but the CAD data tells Pcdmis what those features need to be, nominal-wise.

    The ONLY way to "level" to a non-planar, non-flat surface is ITERATIVE alignment. EVERY PART has datums, even car position parts. There are "A" datums, "B" datums, "C" datums, as many datums as you want, just like for every other part out there.

    DATUM does NOT EQUAL ZERO. It never has, it never will. A datum CAN BE zero, but it does not have to be zero. Datums are the "START POINTS" for inspection.

    The top of a flat, square 123 block that is the "A" datum can be Z0, Z1.0, Z523.984. It makes NO DIFFERENCE. DATUM <> 0, it never has. The trihedron is nothing more than a visual aid for you to see which way each axis is pointing in the current alignment, NOTHING more. The trihedron <> 0 anymore than DATUM.

    'top, curvy, non-flat' surface = "A Datum". Pick 3, 4, 5,000 points on that surface, from the CAD DATA (and the "B" and "C" datums as well). BEFORE you measure them, OPEN the alignment utility, go to iterative alignment, select all those points on the "A DATUM" surface for the "LEVEL" features, pick the "B" feature for the rotate, pick the "C" features for the origin.

    Pcdmis will then "level" and "origin" to those "A" features. It will 'rotate' and 'origin' to the "B" features. It will origin to the "C" feature. And guess what? You are NOW origined to ALL your datums, no matter what their numerical value is, be it Z127.398 or Z-1928.392. Pcdmis will have them as close as possible to the nominal values as can be done.

    I guess if you don't get it after all this, you either need to find some other calling or go to Pcdmis classes.

    First off, HOW RUDE!!!!!!

    I do not necessarily want my Datums to be Zero, (don't believe I ever said that) but I do need my dimensions to come from the Datums, not the CAD trihedron. What part of this am I not explaining well enough for you to understand. If we were talking real world inspection, not with PC-DMIS, if I set Datum "A" down on a datum feature simulator it would set on the three highest points. What I did is found the three highest points on datum "A" and created a plane out of those three points?
Reply
  • Ignore the trihedron. Iterative alignment is a CAD alignment, or PART alignment.

    A 3-2-1 alignment uses features to align, and YOU tell Pcdmis what those features need to be, nominal-wise.
    An Iterative alignment uses features to align, but the CAD data tells Pcdmis what those features need to be, nominal-wise.

    The ONLY way to "level" to a non-planar, non-flat surface is ITERATIVE alignment. EVERY PART has datums, even car position parts. There are "A" datums, "B" datums, "C" datums, as many datums as you want, just like for every other part out there.

    DATUM does NOT EQUAL ZERO. It never has, it never will. A datum CAN BE zero, but it does not have to be zero. Datums are the "START POINTS" for inspection.

    The top of a flat, square 123 block that is the "A" datum can be Z0, Z1.0, Z523.984. It makes NO DIFFERENCE. DATUM <> 0, it never has. The trihedron is nothing more than a visual aid for you to see which way each axis is pointing in the current alignment, NOTHING more. The trihedron <> 0 anymore than DATUM.

    'top, curvy, non-flat' surface = "A Datum". Pick 3, 4, 5,000 points on that surface, from the CAD DATA (and the "B" and "C" datums as well). BEFORE you measure them, OPEN the alignment utility, go to iterative alignment, select all those points on the "A DATUM" surface for the "LEVEL" features, pick the "B" feature for the rotate, pick the "C" features for the origin.

    Pcdmis will then "level" and "origin" to those "A" features. It will 'rotate' and 'origin' to the "B" features. It will origin to the "C" feature. And guess what? You are NOW origined to ALL your datums, no matter what their numerical value is, be it Z127.398 or Z-1928.392. Pcdmis will have them as close as possible to the nominal values as can be done.

    I guess if you don't get it after all this, you either need to find some other calling or go to Pcdmis classes.

    First off, HOW RUDE!!!!!!

    I do not necessarily want my Datums to be Zero, (don't believe I ever said that) but I do need my dimensions to come from the Datums, not the CAD trihedron. What part of this am I not explaining well enough for you to understand. If we were talking real world inspection, not with PC-DMIS, if I set Datum "A" down on a datum feature simulator it would set on the three highest points. What I did is found the three highest points on datum "A" and created a plane out of those three points?
Children
No Data
© 2024 Hexagon AB and/or its subsidiaries. Privacy Policy | Cloud Services Agreement