Alignment help

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

  • Alignment help

    I have never had to make an alignment such as the one in the attachment.
    Datum C is to be added and will be the axis of the 10MM screw hole on the left.
    I thought it would go something like this:

    Level to the datum A cylinder ( Which workplane do you level to ?? )
    Rotate to 2 points taken on datum B surface.

    For the origin point I am not sure of the intent of the drawing nor do have any idea of how to create it.

    Help with the drawing would be greatly appreciated
    Attached Files
    ["Paper is poverty,... it is only the ghost of money, and not money itself." --Thomas Jefferson ][/SIGPIC]

  • #2
    The origin will be determined by the FCF you are solving for. I would set the part so -A- was running up/down ( or parallel to Z rail ) then measure the cylinder going from z- to z+ then lvl z+ axis. Switch to y- ( or plus ) run a line on -B- going x- to x+ and rotate tox+ about z.

    Comment


    • #3
      You mean Datum C will be the M6 threaded hole with the 10mm boss on one side right? Not the 10mm thread, or am I the confused one?

      Anywho, It does not matter which work plane you choose to level to Datum A, but Sean's suggestion of Z is as good as any. Once you do that, by the views shown, Datum B can not constrain the remaining rotation. Datum C would have to do that. But unless there are FCFs you are concerned with that I don't see in the pdf, it does not matter. All you need is Level to A, if z then set X & Y origins on A. Measure plane Datum B and set Z origin on that.

      For the perpendicularity and concentricty callouts, all that is needed is level & origin to A, as that is the only Datum specified in the FCFs.

      HTH
      sigpic"Hated by Many, Loved by Few" _ A.B. - Stone brewery

      Comment


      • #4
        Originally posted by wes cisco View Post
        you mean datum c will be the m6 threaded hole with the 10mm boss on one side right? Not the 10mm thread, or am i the confused one?

        Anywho, it does not matter which work plane you choose to level to datum a, but sean's suggestion of z is as good as any. Once you do that, by the views shown, datum b can not constrain the remaining rotation. Datum c would have to do that. But unless there are fcfs you are concerned with that i don't see in the pdf, it does not matter. All you need is level to a, if z then set x & y origins on a. Measure plane datum b and set z origin on that.

        For the perpendicularity and concentricty callouts, all that is needed is level & origin to a, as that is the only datum specified in the fcfs.

        Hth
        +1
        Lately, it occurs to me
        What a long, strange trip it's been.

        2017 R1 (Offline programming)

        Comment


        • #5
          B will lock rotation if you draw a line on it. I only chose z cuz something had to be chosen...

          Comment


          • #6
            Originally posted by Wes Cisco View Post
            You mean Datum C will be the M6 threaded hole with the 10mm boss on one side right? Not the 10mm thread, or am I the confused one?

            Anywho, It does not matter which work plane you choose to level to Datum A, but Sean's suggestion of Z is as good as any. Once you do that, by the views shown, Datum B can not constrain the remaining rotation. Datum C would have to do that. But unless there are FCFs you are concerned with that I don't see in the pdf, it does not matter. All you need is Level to A, if z then set X & Y origins on A. Measure plane Datum B and set Z origin on that.

            For the perpendicularity and concentricty callouts, all that is needed is level & origin to A, as that is the only Datum specified in the FCFs.

            HTH
            Judging by the looks of the part it may be easier to clamp in a vise with A Datum aligned with X + workplane, use a star probe set-up so you can have easy access to both cylinders. +1 to Cisco's interpretation, the callouts do not require constraint in all rotations.
            Is this a pastic part (you could have difficulty with deformation when clamping)?
            sigpic
            Originally posted by Ironhoe
            I got something under my sporran for you, take care of it and you got my vote.

            Comment


            • #7
              Thanks for the responses
              Yes I incorrectly stated datum C, I will be more careful in the future.
              Should I not try to intersect the datum A cylinder axis with axis with datum B surface and set XY origin at that point?
              I will say that when I do that I am having difficulty getting a good alignment to CAD.
              I have been taught in GD&T class that XYZ should intersect forming a single point for the origin, thus the idea of piercing or intersecting the axis and plane.
              Sorry for gatting back with everyone so late, I was out on Friday.
              ["Paper is poverty,... it is only the ghost of money, and not money itself." --Thomas Jefferson ][/SIGPIC]

              Comment


              • #8
                Originally posted by Bob Pierce View Post
                Thanks for the responses
                Yes I incorrectly stated datum C, I will be more careful in the future.
                Should I not try to intersect the datum A cylinder axis with axis with datum B surface and set XY origin at that point?
                I will say that when I do that I am having difficulty getting a good alignment to CAD.
                I have been taught in GD&T class that XYZ should intersect forming a single point for the origin, thus the idea of piercing or intersecting the axis and plane.
                Sorry for gatting back with everyone so late, I was out on Friday.
                Bob,
                Per your print requirements it doesn't specifically indicate to do this. I would level to A, skip rotation, make your cylinder origin to 2 of your axes and B datum (plane) the origin of the 3rd axis. Note that you can orient this part to any workplane, thats why I didn't specify alignment axes.
                HTH
                sigpic
                Originally posted by Ironhoe
                I got something under my sporran for you, take care of it and you got my vote.

                Comment


                • #9
                  I have successfully aligned the part using most of your recomendation, I did rotate to the 10MM boss as suggested by Wes. It aligned great and I am currently measuring the part.
                  The discussion of creating a single point, which I did not, for the origin based upon the datums might need to continue. Which, in this case seems to make a great difference in the location of the origin point.
                  Thanks for getting me headed in the direction required to measure the part.
                  ["Paper is poverty,... it is only the ghost of money, and not money itself." --Thomas Jefferson ][/SIGPIC]

                  Comment


                  • #10
                    That single point for your origin will vary greatly depending on the perp of -A- to -B-. The perp will be affected ( on the CMM ) greatly by the form of -A- and the form of -B-.

                    Comment


                    • #11
                      Originally posted by Ironhoe View Post
                      That single point for your origin will vary greatly depending on the perp of -A- to -B-. The perp will be affected ( on the CMM ) greatly by the form of -A- and the form of -B-.
                      Well said, Sean. +1
                      sigpic
                      Originally posted by Ironhoe
                      I got something under my sporran for you, take care of it and you got my vote.

                      Comment


                      • #12
                        Originally posted by Bob Pierce View Post
                        I have successfully aligned the part using most of your recomendation, I did rotate to the 10MM boss as suggested by Wes. It aligned great and I am currently measuring the part.
                        The discussion of creating a single point, which I did not, for the origin based upon the datums might need to continue. Which, in this case seems to make a great difference in the location of the origin point.
                        Thanks for getting me headed in the direction required to measure the part.
                        I am glad we could help. For the record I did NOT recommend aligning to the boss, but to the datum, which is not labeled on the drawing section you posted. Most likely the thread and the boss are in line with each other closely enough that it won't make a significant difference , but maybe not!

                        To the best of my knowledge, unless it is somehow specified that there must be a single origin point constructed by intersecting datums, it is not required. (Most likely this would be a note on the drawing if it were a requirement.) If I were aligning this I would allow the software to the use the centroid of Datum A for the origin, but I would make sure I collected data from as much of Datum A as practical.

                        HTH
                        sigpic"Hated by Many, Loved by Few" _ A.B. - Stone brewery

                        Comment

                        Related Topics

                        Collapse

                        Working...
                        X