Probe Problem (maybe)

I have had several issues with running the same gcode multiple times.

I have gcode to flatten aboard. In this example a 14”x18”. The code works and is set to a depth of .02”

Here are the steps that has caused a problem.

Install a v-grove bit upside down in order to set 0.
Run the XYZ proved command. I do this because the bit does not align nicely with the probe.

Install flatten bit.

I place the probe upside down and select the highest point on the board.

Ru the flatten gcode

So far this has worked.

After the code is done, I will reset the z point using the probe, again upside down.

Sometimes this works and more than once when I run the gcode the 2nd, third or fourth time, it will drive the bit deeper into the wood.

This time, I may have burned up the router, it works but a lot of smoke came out before I hit the estop.

Also, I lost a a descent chunk of walnut, so much that I need to go buy more.

Also lost the bit.

Very frustrating and I’m not sure what would cause the problem. I never have issues when running the code the first time, only when I run a second or third time.

Code is generated from Fusion 360, I was wondering is there a reset that needs to happen or should I look at reset everything between runs?

Run flattening gcode

I can’t think of what is causing you the issue but I can offer my workflow.

I think I do similar when I surface boards which generally take several passes - but rather than probe I set the z down by the amount the tool path cut in prior pass. (I do this by mdi to z -depthOfCut and rehome z to make this the new zero. Clearly I move to an x y position in space).

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I am bringing back a bunch of high density foam that I can test with and make sure I have a working procedure before moving forward. This one is costing me a bit as I think the router is toast.

Again Thanks

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A couple thoughts.

  1. Are you saying your probe Z-height is returning the wrong code? Your calibration of the probe might be off.
  2. If you are using fusion 360, and your “Box point” is on top of the material and you have your setup “stock top offset” greater than 0 than rezeroing off the top of the material is going to screw things up.

I use Fusion 360 for about half my projects. I always home off the waste board for multi operational cuts. Only time I zero off the top is for flattening.

Here is my work flow for flattening only in Fusion 360.

  1. Have the material top offset, set to how much I want to take off. Typically I do 2 mm and set my depth of pass to 1 mm.
  2. I eyeball the center point or reference corner. (Flattening you don’t need to be that specific)
  3. Install my flattening bit and probe to get Z.
  4. Run the code
  5. If I need to take more off than lower it by the material top offset with the screen and set that to the new zero.

If you are combing flattening with another operation. You need to zero off the waste board.

Hope this helps.