Measuring wierd? BASE C

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

  • Measuring wierd? BASE C

    Hello, we are having problem with our buyer regarding measurement deviations. I think its the difference in how we are measuring BASE C on part.

    http://oi64.tinypic.com/30t30bs.jpg

    I'm interested in seeing how would you guys measure this BASE C (14.45mm)?

    This is how we currently doing it.

    http://oi65.tinypic.com/24zf0v6.jpg

    We measure RED lines and create parallel lines (GREEN LINES) to it with 1.5mm offset to compensate for "messkugel" half diameter on both sides. From internal diameter (center of part) we create theoretical circle with diameter 151.6mm and construct point at intersection between theoretical circle and GREEN LINES.

    Create line between two intersection points and use it as BASE C.

    Any help or suggestions on any other methods for measuring this would be appreciated.

    Thanks, best regards.

  • #2
    Datum C is the mid point so you need to create that not a line

    Comment


    • VinniUSMC
      VinniUSMC commented
      Editing a comment
      Yup.

  • #3
    Originally posted by Entey View Post
    Create line between two intersection points and use it as BASE C.
    Datum C, in my interpretation is a midpoint between the two orange points. No line.
    You can create a rotation line from datum B to datum C, presuming datum B is the center of the part's circular/cylindrical datum.

    Comment


    • VinniUSMC
      VinniUSMC commented
      Editing a comment
      Yup.

  • #4
    Originally posted by UKCMM View Post
    Datum C is the mid point so you need to create that not a line
    Mid point between two points? Yeah I tried that aswell, results doesnt change too much.

    Comment


    • VinniUSMC
      VinniUSMC commented
      Editing a comment
      Well, there's the right way, which is a rotating about B to C (a line from B to the midpoint which is C), and there's not the right way, which is anything else.

  • #5
    Datum A is a plane, Level & Origin Z.
    Datum B is a cylindrical feature to Origin X/Y
    Datum C is a point to rotate about Z, while pivoting about B centroid. I typically construct a line from B to C midpoint, then rotate X about Z to the line.
    If your alignment is not very similar to above, it is a factor in the alignment that is causing the difference.

    Another concept is if your buyer is inducing cosine error by probing on the angled faces not perpendicular to the faces.
    Ask them what they are doing to quantify C datum.
    enteypost.jpg
    Last edited by louisd; 11-14-2017, 03:46 PM.

    Comment


    • #6
      Crate a midpoint via the orange points as Datum .C
      Maybe 2 times alignment measured after DCC mode that is more better.

      Comment

      Working...
      X