Circular Construct Issue

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Circular Construct Issue

    Good morning people. I have some need of your skills. I have attached here a sketch showing a cross section of a part that resembles an inverted dog bowl with a radial cut feature (all around the centerline) inside on the wall. I can't snip-it the actual CAD model shot as the part is military in nature. My issue is this. I'm having a "locked horns drag out" with a government inspector who does not care how I measured the feature I am going to describe. On the print the callout is for a basic diameter on the curved surface (relative to R basic) and they call out the Z depth of that basic circle as +/- .01 from the top lip. Well, using the CAD I went the other way and went to the called Z depth nominal and measured polar points at that depth and using the CAD model, calculated the diametric tolerance parameters allowed over the +/- .01 Z depth tolerance. Kind of the same technique used in measuring CAM lobes. The points on the curve are toleranced and the location of the points of tangency are basic. Anyway, the government guys are anal and want it backwards. So, the question: the best way to "find" that basic Radial point on the curve and give a readout of it's Z parameter based on where it exists within +/- .01. I think there is a circular construction feature based on creating a basic circular diameter of a scan set which I can do as I use SM-25 scanning head probes but I'm unfamiliar with the technique. If you see an easier methodology I'm all ears. Thanks! Sketch1.pdf
    Physics dictates to man why his world acts the way it does....Chemistry tells him why it smells the way it does.

  • #2
    Maybe using "fixed rad" here could be the solution ?
    I didn't look at the right radius.
    I would measure the radius R1 as a circle, then create a generic plane X=R basic, I=1, and create a pierce point between the circle and the plane, then copy / paste with pattern and create a circle from all pierce points if necessary, and dimension them.
    Last edited by JEFMAN; 05-31-2019, 10:44 AM.

    Comment


    • #3
      I would measure R1 then create a generic Z+ line at the R basic X value then construct an intersection point between R1 and the line this would give the Z value.

      Comment


      • JEFMAN
        JEFMAN commented
        Editing a comment
        +1 ! could work only if R1 is a 2d circle. If it's a 3d circle, not perfectly aligned, the intersection could not exist...

      • UKCMM
        UKCMM commented
        Editing a comment
        Agreed I believe the shape could be a torus but I do not have that on our version of DMIS so unsure if you can intersect a line to torus.

      • JEFMAN
        JEFMAN commented
        Editing a comment
        You're right, it could be a torus, but I believe that torus is only in measured features, whatever the version

    • #4
      Looks like they're basically asking for the Z value of the radius center. As JEFMAN said, use FIXED_RAD, it's the only possible way you'll get a repeatable center.

      Code:
      CIR1       =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,OUT,LEAST_SQR
                  THEO/<16.5,0,-3.9>,<1,0,0>,17.4,0
                  ACTL/<16.5,0,-3.9>,<1,0,0>,17.4,0
                  TARG/<16.5,0,-3.9>,<1,0,0>
                  START ANG=0,END ANG=360
                  ANGLE VEC=<1,0,0>
                  DIRECTION=CCW
                  SHOW FEATURE PARAMETERS=NO
                  SHOW CONTACT PARAMETERS=YES
                    NUMHITS=7,DEPTH=5,PITCH=0
                    SAMPLE METHOD=SAMPLE_HITS
                    SAMPLE HITS=3,SPACER=0
                    AVOIDANCE MOVE=NO,DISTANCE=10
                    FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
                  SHOW HITS=NO
      CIR2       =FEAT/CIRCLE,CARTESIAN,IN,FIXED_RAD,YES
                  THEO/<21.5,0,-3.9>,<0,0,1>,17.4
                  ACTL/<21.5,0,-3.9>,<1,0,0>,17.4
                  CONSTR/CIRCLE,BF,2D,CIR1.HIT[1..CIR1.NUMHITS],,
                  OUTLIER_REMOVAL/OFF,3
                  FILTER/OFF,UPR=0
      If I'm mistaken, and the Z value is a different point on that radius, try something like this.

      Code:
                  COMMENT/OPER,NO,FULL SCREEN=NO,AUTO-CONTINUE=NO,
                  Assume they want the Z value at a basic diameter of Ø40
      ORIGIN_POINT=FEAT/POINT,CARTESIAN,NO
                  THEO/<0,0,0>,<0,0,1>
                  ACTL/<0,0,0>,<0,0,1>
                  CONSTR/POINT,ORIGIN
      OFFSET_PT1 =FEAT/POINT,CARTESIAN,NO
                  THEO/<20,0,0>,<0,0,1>
                  ACTL/<20,0,0>,<0,0,1>
                  CONSTR/POINT,OFFSET,ORIGIN_POINT,20,0,0
      OFFSET_PT2 =FEAT/POINT,CARTESIAN,NO
                  THEO/<0,20,0>,<0,0,1>
                  ACTL/<0,20,0>,<0,0,1>
                  CONSTR/POINT,OFFSET,ORIGIN_POINT,0,20,0
      OFFSET_PT3 =FEAT/POINT,CARTESIAN,NO
                  THEO/<-20,0,0>,<0,0,1>
                  ACTL/<-20,0,0>,<0,0,1>
                  CONSTR/POINT,OFFSET,ORIGIN_POINT,-20,0,0
      OFFSET_PT4 =FEAT/POINT,CARTESIAN,NO
                  THEO/<0,-20,0>,<0,0,1>
                  ACTL/<0,-20,0>,<0,0,1>
                  CONSTR/POINT,OFFSET,ORIGIN_POINT,0,-20,0
      PART_ZAXIS =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
                  THEO/<0,0,-0.5>,<0,0,1>
                  ACTL/<0,0,-0.5>,<0,0,1>
                  CONSTR/LINE,ALIGN,1,ZPLUS
      CIR2       =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,FIXED_RAD
                  THEO/<16.5,0,-3.9>,<0,1,0>,8
                  ACTL/<16.5,0,-3.9>,<0,1,0>,8
                  TARG/<16.5,0,-3.9>,<0,1,0>
                  START ANG=0,END ANG=360
                  ANGLE VEC=<0,0,1>
                  DIRECTION=CCW
                  SHOW FEATURE PARAMETERS=NO
                  SHOW CONTACT PARAMETERS=YES
                    NUMHITS=7,DEPTH=5,PITCH=0
                    SAMPLE METHOD=SAMPLE_HITS
                    SAMPLE HITS=3,SPACER=0
                    AVOIDANCE MOVE=NO,DISTANCE=10
                    FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
                  SHOW HITS=NO
      CIR3       =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,FIXED_RAD
                  THEO/<0,16.5,-3.9>,<1,0,0>,8
                  ACTL/<0,16.5,-3.9>,<1,0,0>,8
                  TARG/<0,16.5,-3.9>,<1,0,0>
                  START ANG=0,END ANG=360
                  ANGLE VEC=<0,0,1>
                  DIRECTION=CCW
                  SHOW FEATURE PARAMETERS=NO
                  SHOW CONTACT PARAMETERS=YES
                    NUMHITS=7,DEPTH=5,PITCH=0
                    SAMPLE METHOD=SAMPLE_HITS
                    SAMPLE HITS=3,SPACER=0
                    AVOIDANCE MOVE=NO,DISTANCE=10
                    FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
                  SHOW HITS=NO
      CIR4       =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,FIXED_RAD
                  THEO/<-16.5,0,-3.9>,<0,1,0>,8
                  ACTL/<-16.5,0,-3.9>,<0,1,0>,8
                  TARG/<-16.5,0,-3.9>,<0,1,0>
                  START ANG=0,END ANG=360
                  ANGLE VEC=<0,0,1>
                  DIRECTION=CCW
                  SHOW FEATURE PARAMETERS=NO
                  SHOW CONTACT PARAMETERS=YES
                    NUMHITS=7,DEPTH=5,PITCH=0
                    SAMPLE METHOD=SAMPLE_HITS
                    SAMPLE HITS=3,SPACER=0
                    AVOIDANCE MOVE=NO,DISTANCE=10
                    FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
                  SHOW HITS=NO
      CIR5       =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,FIXED_RAD
                  THEO/<0,-16.5,-3.9>,<1,0,0>,8
                  ACTL/<0,-16.5,-3.9>,<1,0,0>,8
                  TARG/<0,-16.5,-3.9>,<1,0,0>
                  START ANG=0,END ANG=360
                  ANGLE VEC=<0,0,1>
                  DIRECTION=CCW
                  SHOW FEATURE PARAMETERS=NO
                  SHOW CONTACT PARAMETERS=YES
                    NUMHITS=7,DEPTH=5,PITCH=0
                    SAMPLE METHOD=SAMPLE_HITS
                    SAMPLE HITS=3,SPACER=0
                    AVOIDANCE MOVE=NO,DISTANCE=10
                    FIND HOLE=DISABLED,ONERROR=NO,READ POS=NO
                  SHOW HITS=NO
      LIN2       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
                  THEO/<20,0,-1>,<0,0,1>
                  ACTL/<20,0,-1>,<0,0,1>
                  CONSTR/LINE,PLTO,PART_ZAXIS,OFFSET_PT1,1
      LIN3       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
                  THEO/<0,20,-1>,<0,0,1>
                  ACTL/<0,20,-1>,<0,0,1>
                  CONSTR/LINE,PLTO,PART_ZAXIS,OFFSET_PT2,1
      LIN4       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
                  THEO/<-20,0,-1>,<0,0,1>
                  ACTL/<-20,0,-1>,<0,0,1>
                  CONSTR/LINE,PLTO,PART_ZAXIS,OFFSET_PT3,1
      LIN5       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
                  THEO/<0,-20,-1>,<0,0,1>
                  ACTL/<0,-20,-1>,<0,0,1>
                  CONSTR/LINE,PLTO,PART_ZAXIS,OFFSET_PT4,1
      PNT2       =FEAT/POINT,CARTESIAN,NO
                  THEO/<20,0,-5.836>,<0,0,1>
                  ACTL/<20,0,-5.836>,<0,0,1>
                  CONSTR/POINT,PIERCE,LIN2,CIR2
      PNT3       =FEAT/POINT,CARTESIAN,NO
                  THEO/<0,20,-5.836>,<0,0,1>
                  ACTL/<0,20,-5.836>,<0,0,1>
                  CONSTR/POINT,PIERCE,LIN3,CIR3
      PNT4       =FEAT/POINT,CARTESIAN,NO
                  THEO/<-20,0,-5.836>,<0,0,1>
                  ACTL/<-20,0,-5.836>,<0,0,1>
                  CONSTR/POINT,PIERCE,LIN4,CIR4
      PNT5       =FEAT/POINT,CARTESIAN,NO
                  THEO/<0,-20,-5.836>,<0,0,1>
                  ACTL/<0,-20,-5.836>,<0,0,1>
                  CONSTR/POINT,PIERCE,LIN5,CIR5
      THE_ANSWER =FEAT/CIRCLE,CARTESIAN,IN,LEAST_SQR,NO
                  THEO/<0,0,-5.836>,<0,0,1>,40
                  ACTL/<0,0,-5.836>,<0,0,1>,40
                  CONSTR/CIRCLE,BF,2D,PNT2,PNT3,PNT4,PNT5,,
                  OUTLIER_REMOVAL/OFF,3
                  FILTER/OFF,UPR=0

      Comment


      • #5
        Thanks everyone! Some good ideas here. I'm grateful for the assist!
        Physics dictates to man why his world acts the way it does....Chemistry tells him why it smells the way it does.

        Comment

        Related Topics

        Collapse

        Working...
        X