Right now if you fixture a relatively thin item using the mini vise, or possibly any clamp or vise, the Nomad starts the run by lowering the tool to a set point forward and to the left of the piece, just above the z height of the piece, then jogs to the piece from that low Z position. As a result, you run the risk of crashing the tool into the left jaw of the vise or any left side fixturing you have. My vise has a couple rat bites from this already
I suppose this could also affect work pieces that happen to be taller on the left side of the milling area.
A fix would be to jog at initial height and only lower the tool once it is in the starting location for the cuts.
You can control this by setting the safety height in meshcam - so the height above z that you want the cutter to obey. Set it at something above the height of the vise and it wonât hit it.
I also do this when Iâm machining a piece in the vice that is higher than the top of the vice but requires a plunge below the height on the vice into the material.
In MeshCAM it is Set Retract Height in the CAM menu. This is the height at which all rapid lateral moves happen, and from which height the tool plunges down into the material. But this brings the tool up to this height at each retract, which on a 3D job can increase time considerably especially with a slow plunge feed.
I like to keep a low retract height, often below the height of the hold-down screw heads. As you discovered, dr_g, MeshCAMâs behavior is to move the tool to X0 Y0, down to retract height, and then to the actual X-Y point where the initial plunge is:
I rearrange the initial moves using a text editor to eliminate the move to X0 Y0, and substitute the move to the initial plunge point before moving to retract height and then plunging:
From that point on, the retracts and plunges take place within or just at the edge of the actual geometry, where it is safe to use the low retract height. This behavior is only with the first tool (or only tool) in a job. Subsequent tools in the same job do not have the move to X0 Y0 so this editing is only necessary at the beginning of the gcode.
This initial move to X0 Y0 is hard-coded into MeshCAMâit isnât something that can be changed in the postprocessors. I have asked Robert to eliminate this initial move in the past but there was some reason it wasnât possible. Maybe he can revisit the matter.
The rawstock on this job was 1" x 1" x 3mm. I used a retract height of .05", which was below the fixture pins and hold-down screw heads. This is the first side of a two-sided job. Program Zero in top left front corner (between the dowel pins) The gcode fragmens above were from this job, which was a way too small (for some reason I accidentally scaled it by 50%) dish antenna for my âHello Galaxyâ MIllenium Falcon piece.
Thank you both so much for the information and solution! For some reason or another I thought this was a behavior of Carbide Motion. I raised the retract height and it clears fine now!
