Body axis scan question

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

  • Body axis scan question

    Hello everyone, I’m using body axis scan to create 3D lines then intersect the lines. One line horizontal and the other roughly vertical.
    My concern is the lines are not where I expect they would be.
    For example I set a body axis scan for Z-6.000, I carefully scan 2 hits roughly 2 inches apart and create the 3D line. When I analyze the line it’s Z-6.017. Shouldn’t the Z-6.000 be a fixed dimension, am i doing something wrong?

  • #2
    Manually with an arm? You'll never be exact.
    "This is my word... and as such is beyond contestation."

    Comment


    • #3
      Thank you for your response, yes manually with an arm.

      Comment


      • #4
        If you have a laser scanner, you can get it exact. If you need to probe it, pull up your DRO and manually probe the points at the desired Z height.

        Comment


        • #5
          Originally posted by VinniUSMC View Post
          Manually with an arm? You'll never be exact.
          This isn't necessarily true. PCDMIS creates the body axis scan hits by:

          - setting body axis plane
          - capturing scan
          - identifying last hit prior to plane crossing and first hit afterwards
          - drawing a line between the two hits
          - calculating the body axis scan hit as the pierce point between the line and the body axis plane.

          by that logic (and by my experience), it should be exact at Z= -6!! Are you using a CAD model? If so, you should have FINDNOMs turned on, with an appropriate tolerance. The presence of the CAD model will affect how your probe compensation takes place (towards the CAD!).

          Lacking a CAD model, things get trickier. PCDMIS wants to comp your hits, so it will do so in the closest Axis you have the arm pointed in. This is usually bad for me, as I'm scanning a 2D complex surface, and my IJK isn't as simple as <-1,0,0> in this case. In that situation, I tend to turn off Probe Compensation (under F10 > Probing), and capture my scan hits from the center of the ball. Unfortunately, then you are off by the ruby's radius, but you can always construct features (offset by the ruby radius) to represent the actual surface.

          Long story short, doing any sort of scan without a model is tough with a Romer in PCDMIS, mostly due to probe compensation. Try scanning with probecomp off and constructing your features from there. I suspect that's the source of your issue.
          ----------------------------------

          Ex Hex

          Comment


          • #6
            Thank you for your reply. No CAD for this part, I'll give it a try with probecomp off. Thanks again.

            Comment

            Related Topics

            Collapse

            • PowerJunkie
              Scan is off
              by PowerJunkie
              I performed a linear closed scan using a 4mm tip, constructed a line along a straight portion of the scan, and then dimensioned the distance between that...
              10-15-2008, 09:43 AM
            • j.gonzalez
              Nullfilter
              by j.gonzalez
              so I am doing an open linear scan evrything was going good but i noticed it was not working to well scan looked liked lines were distored so i F9 scan...
              05-17-2010, 11:23 AM
            • larrybell
              scan help
              by larrybell
              I am attempting to scan a part across the x axis of a round part to get a profile. Every scan I have tried will not get the points off the model. What...
              09-16-2009, 07:34 AM
            • NMC_CMM
              Patch Scan Help
              by NMC_CMM
              Morning all,

              I'm trying to perform a patch scan on a large flat surface; I have no cad. I pick my start point, direction, and 2-3 boundary...
              08-05-2009, 09:18 AM
            • Tomi530i
              Scan with SP25M nooby question
              by Tomi530i
              Good morning all

              I have a nooby question.
              When I'm using auto feature I can change the measurement strategies to Adaptive Scan...
              02-08-2016, 06:19 AM
            Working...
            X