Terrain Relief Models, Unabridged

How To
9

Notes On Probing

Carving (and possibly engraving) terrain relief models will almost certainly involve a tool change at some point. Probing to reset your Z is therefore something you will be doing (with or without an actual wired probe). Another thing you will be doing is removing the top of the stock, which is the very surface that I highly recommend you use as your Z zero. Obviously, this means that we need to think ahead a bit before chips start flying. What we need is a place to probe that will not disappear and an offset between that and the original stock top. This is actually quite straightforward.

Probing in detail

  1. Set the probe block on the leveled wasteboard next to the stock.
  2. Probe for Z (or manually set Z zero at the surface of the leveled wasteboard).

    In Carbide Motion after probing for Z only, Z zero is set to the surface on which the probe block is resting and the Z axis is jogged up to Z+31mm, i.e. 6mm above the probe block.

  3. Jog to the vicinity of what will be the highest point of your relief model (or just use anywhere if you’re confident the stock is flat and level).
  4. Manually jog down until your tool tip touches the stock (using the paper trick, backlighting, or whatever other method you prefer).
  5. Write down the currently displayed Z value.
  6. Rezero your Z right here, and run your first toolpath.
  7. After changing to a new tool, set the probe block back on your leveled wasteboard, as you did in step 1.
  8. Probe for Z (or manually set Z zero at the surface of the leveled wasteboard).
  9. Jog your Z axis to the value you wrote down in step 5. Your new tool is now at same height as the original stock top.
  10. Rezero your Z right here, and run your next toolpath. Repeat from step 7 as necessary.

Doubling up on probing

If you have enough clearance to use your probe block on top of the stock (including the probe thickness and the post-probe jog – e.g. 31mm total above stock top for Carbide Motion), you can probe for Z on your stock top instead of finding it the manual way.

  1. Set the probe block on top of your stock (ideally, near the highest point of the terrain model, just in case you’re not perfectly level).
  2. Probe for Z.
  3. Jot down the value for your Z axis in machine coordinates.

    In Carbide Motion, click the bold Position header over the X/Y/Z coordinates to switch back and forth between job coordinates and machine coordinates.

  4. Set the probe block on your leveled wasteboard.
  5. Probe for Z.
  6. Subtract the current Z axis value in machine coordinates from the value you jotted down after probing stock top.
  7. Write down the difference between the two Z values.
  8. Jog your Z axis to the value you wrote down in step 7. Your new tool is now at same height as the stock top (if not, check your math).
  9. Rezero your Z right here, and run your first toolpath.
  10. After changing to a new tool, set the probe block back on your leveled wasteboard, as you did in step 4.
  11. Probe for Z.
  12. Jog your Z axis to the value you wrote down in step 7. Your new tool is now at same height as the original stock top.
  13. Rezero your Z right here, and run your next toolpath. Repeat from step 10 as necessary.
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