Profile of Cone

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  • Profile of Cone

    See attached drawing. It is basically a truncated cylinder, with the smaller OD as Datum_A, with a profile callout on the conic feature. Can this profile be measured on a CMM without scanning capability? If so, how? (Not software specific, just basic methodology). Oh, the 30° is basic.

    Thanks!
    Last edited by keego; 09-01-2009, 04:15 PM.
    sigpic
    Global Advantage 12-22-10
    TESASTAR M SP25 4.3mr2

  • #2
    If you have CAD:
    Vector points.
    Create a set with the points.
    Profile the set.
    Lately, it occurs to me
    What a long, strange trip it's been.

    2017 R1 (Offline programming)

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    • #3
      You will have to control the location but only radially, the axial location of the profile needs to float. How do you do that in PCDMIS?
      Links to my utilities for PCDMIS

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      • #4
        If you do not have cad & you know what the larger od is & it also appears to be on the same centerline you can rotate along the y axis 15 degrees per side and check points along the surface....That is if your -A- is standing up in the Z +......I think that would work
        sigpic.....Its called golf because all the other 4 letter words were taken

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        • #5
          You could measure it with an autocone and then extract the hits to generic points and apply profile to those. The advantage of this is the ability to easily change the placement of the hits.
          sigpic 1.61803399Δ
          ASSIMILATE INTERGRATE SYNTHESIZE

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          • #6
            Yes, but how do I report the points? What are my nominals? Do I rotate my alignment 15° prior to reporting?
            sigpic
            Global Advantage 12-22-10
            TESASTAR M SP25 4.3mr2

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            • #7
              The profile would have to float along the axis.
              It is sort of like Conicity
              Links to my utilities for PCDMIS

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              • #8
                Originally posted by slesholdofthreep View Post
                You could measure it with an autocone and then extract the hits to generic points and apply profile to those. The advantage of this is the ability to easily change the placement of the hits.

                Thats not a bad idea..easier then what i suggested
                sigpic.....Its called golf because all the other 4 letter words were taken

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                • #9
                  I never report nominals when reporting profile.
                  I report deviation from nominal.
                  Lately, it occurs to me
                  What a long, strange trip it's been.

                  2017 R1 (Offline programming)

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                  • #10
                    So each point taken has to be a certain distance from Datum_A axis? Do I use the z coordinate and the basic 30° angle to calculate nominals and approach vectors? What if the cone is actually 28°, do I use this actual in my calculations or still the basic?

                    I'm so confused!
                    sigpic
                    Global Advantage 12-22-10
                    TESASTAR M SP25 4.3mr2

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                    • #11
                      Don't sweat it, I am totally lost as well.
                      How do you know what the nominal of a certain point is?
                      You may not report nominal but to get the deviation you still need to know what nominal is.
                      IF I measure the part and obtain the points they deviate from ...what???
                      (I have almost the same part except it is 45 degrees and .4 )

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                      • #12
                        Originally posted by keego View Post
                        So each point taken has to be a certain distance from Datum_A axis? Do I use the z coordinate and the basic 30° angle to calculate nominals and approach vectors? What if the cone is actually 28°, do I use this actual in my calculations or still the basic?

                        I'm so confused!
                        Ok you have your part set up with the -A- datum in the z+
                        Lets say your od is 10.0mm
                        Your angle for both sides is 30 degrees or 15 per side. (You said its a basic angle so 30 degrees period)
                        You would be in Y- & then do a offset angle rotate of +15 or -15 depending which side your on
                        You would then come in & touch along the cone shape using 1 x vector approach for right side & -1 x vector approach for left side

                        Your x point would be either 5.0 or -5.0 (depending if its negative or positive side of centerline)
                        Your y would be set at 0 ( center of part)
                        you would then play with your z height for best results. (its only used for height)

                        I would use auto point too...alot easier to play with

                        Hopefully this confused you even more
                        sigpic.....Its called golf because all the other 4 letter words were taken

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                        • #13
                          Originally posted by bw_bob View Post
                          Ok you have your part set up with the -A- datum in the z+
                          Lets say your od is 10.0mm
                          Your angle for both sides is 30 degrees or 15 per side. (You said its a basic angle so 30 degrees period)
                          You would be in Y- & then do a offset angle rotate of +15 or -15 depending which side your on
                          You would then come in & touch along the cone shape using 1 x vector approach for right side & -1 x vector approach for left side

                          Your x point would be either 5.0 or -5.0 (depending if its negative or positive side of centerline)
                          Your y would be set at 0 ( center of part)
                          you would then play with your z height for best results. (its only used for height)

                          I would use auto point too...alot easier to play with

                          Hopefully this confused you even more
                          Would you use an auto surface point and sample hits to nail the approach vector given the basic angle is not perfect?
                          Perry
                          B&S Mistral
                          3.207 Beta on XP

                          Older'n dirt

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                          • #14
                            Ok, now I think I've got it. So after I rotate the 15° my nominal y is the nominal radius of datum_A? This can only work if I take a point on the cone, bring my z origin down to that, then rotate, right? So here's what I'm thinking. Strike a 3d line down one side of the cone and get its angle to A. Then rotate about x that angle so I can use approach vector 0,1,0. Now take a vector point. Recall original alignment, bring z origin down to that point, rotate 15 about x, then report the vector point's y value with a nominal of datum_A raduis. I'll try this tomorrow when I get back in unless one of you sees a flaw in my logic. Let me know please! And thanks!
                            sigpic
                            Global Advantage 12-22-10
                            TESASTAR M SP25 4.3mr2

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                            • #15
                              I'm going on the assumption that you are measuring this in the +Z working plane

                              1. Measure Datum A. Level and origin to Datum A Cylinder. Origin to the end of the Datum A cylinder for Z (for now).
                              2. Measure the cone using the cone autofeature. Allow enough clearance from the cone ends to allow for "float" along the Datum A axis, because you don't yet know where the cone is with much precision.
                              3. Construct a circle at the intersection of the cone and the cylinder.
                              4. Realign to Datum A Cylinder. Establish X,Y origin on the cylinder. Establish Z origin on the constructed cone/cylinder intersection.
                              5. Measure the cone AGAIN using the new datum reference frame. Use the nominal information from the print. XYZ all = 0. depth and height = whatever is basic, Angle = 30 degrees, starting circle diameter = whatever Datum A's diameter is (you might consider using the measured value for Datum A, depending on what else on this print is basic).
                              6. Click on the Profile button. Report Form and Location of the considered feature (the second cone you measured). Don't forget to put in .0015 in both the plus and minus tolerance boxes since the profile specification is bilateral.

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