Difference between revisions of "End-Scan Using End Targets"

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* The image at the right shows the end of a copper tube with a sharp burr and a highly reflective end-wall.  It is very difficult to aim the laser at this end wall and ensure no outliers at the same time.<br><br>
 
* The image at the right shows the end of a copper tube with a sharp burr and a highly reflective end-wall.  It is very difficult to aim the laser at this end wall and ensure no outliers at the same time.<br><br>
 
*The solution is to use white targets on the end of the tubes.  The example here shows white poly labels that measure at 0.004" thick and provide an excellent flat target for the laser.<br><br>(Note: Use the Plane-Point measurement in the built-in computer of the FARO Edge to confirm the thickness of the target.)<br><br>
 
*The solution is to use white targets on the end of the tubes.  The example here shows white poly labels that measure at 0.004" thick and provide an excellent flat target for the laser.<br><br>(Note: Use the Plane-Point measurement in the built-in computer of the FARO Edge to confirm the thickness of the target.)<br><br>
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* The offset from the target to the tube end is entered as a negative value in the Part Setup menu for either end.  In this case, we use -0.004" offset.
 
*Any shape of target works well as long as it is LARGER than the diameter of the tube.  Apply the target so that none of the end-wall can be scanned by the laser.
 
*Any shape of target works well as long as it is LARGER than the diameter of the tube.  Apply the target so that none of the end-wall can be scanned by the laser.
 
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Revision as of 22:14, 27 January 2012

Vtube-laser logo.jpg How to perform super high accuracy end-scans using an end target.

Vtube-laser 1 73.jpg


Why the End-Scan technique is important

The quick End-Scan Using the Scissor Motion technique is not always precisely repeatable if you use any of the AUTO exposure settings to set the LASER exposure in real-time. The reason is that as he laser drops off the end of the tube, the automatic exposure feature impacts which of the points are kept where the tube drops off (at the end).

The solution to this issue is to use the End-Scan Using the End Wall technique - which works well for tubes that have end-walls that are easy to aim at - AND end-walls that are not highly reflective with deformations like burrs.

For tubes that don't qualify for either of the above techniques, we recommend end targets for ultra-precise measurements.

Apply the Target



  • The image at the right shows the end of a copper tube with a sharp burr and a highly reflective end-wall. It is very difficult to aim the laser at this end wall and ensure no outliers at the same time.

  • The solution is to use white targets on the end of the tubes. The example here shows white poly labels that measure at 0.004" thick and provide an excellent flat target for the laser.

    (Note: Use the Plane-Point measurement in the built-in computer of the FARO Edge to confirm the thickness of the target.)

  • The offset from the target to the tube end is entered as a negative value in the Part Setup menu for either end. In this case, we use -0.004" offset.
  • Any shape of target works well as long as it is LARGER than the diameter of the tube. Apply the target so that none of the end-wall can be scanned by the laser.

EndWithTarget.jpg

Measure the Target

When it is time to perform and end-scan, use the following technique to scan the target:

  • Aim the laser at the target so that it strikes the target as perpendicular to the surface as possible. Avoid returning any points other than the target.

  • Hold the laser still when collecting the stripes across the target.
  • Consistently place the line across the same area of the target from measure to measure.

EndWithTargetAndLaser.jpg


Approve the Measurement On the Screen



  • The resulting geometry on the screen should appear like the image at he right.

  • The end point generated on the screen should perfectly coincide with the stripes.

EndScanAfterTarget.jpg


Using End Target Plugs



  • If you prefer using more durable end target plugs, then they can be manufactured to fit in the end of the tube for repeatable measurements.

  • The end target should be a flat white or near-white target.

  • The offset from the target to the tube end is entered as a negative value in the Part Setup menu for either end.

EndTargetPlugDesign.jpg

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