Unexpected Toolpaths

[mcdavidr (Ron McDavid)]

Cut my first part on Nomad using MeshCam.
Used these settings:

Part cut well but toward the end it made some unexpected moves. When I thought it was done it started doing a “adaptive toolpath” a circular pattern. Then it went across part in the x axis dropping down into the cutouts and machining across the recessed area in the center? this left a nasty scalloped pattern in the lip of the recess. The it made a full depth light pass out the outside and in the pockets. At this point the cutter had started to load up with chips and the adhesive of the double stick tape. Luckily it didn’t break the bit. What parts of my selections are causing these behaviors?

[PhilG (Phil Gorsuch)]

Hey Ron,

Not exactly sure this is what you are after but here goes.

Fisrt things first - not sure what the circling adaptive thing is - MeshCAM as far as I know does not do adaptive.

MeshCAM by default is set up for 2 passes - a roughing pass and a finishing pass. The roughing pass is set up on the bottom left part of the window in your screenshot. The Finishing pass is the larger right hand side of the window with the fancy pictures…

If the finishing pass is enabled (checkbox at the top) the CNC machine will go over the part a second time, removing a small layer of material to get the part down to the final size.

The idea is the first ‘roughing’ pass removes a majority of the material and leaves a rough surface finish and the finishing pass, moving more slowly and with less stepover, delivers a finer surface finish.

The bottom right of the window which has the ‘pencil cleanup’ and ‘cutout only’ is probably is what is responsible for the last part of what you describe - it is ‘cutting out’ the shape at full depth.

Once you generate the toolpath by clicking ‘ok’ at the bottom you should be able to preview it. Suggest rerunning it sevaral times with different options enabled and checking out the preview tool to get an idea of what the different options do.

Hope thats what you were looking for!

[mcdavidr (Ron McDavid)]

Here are links to short video clips of the behaviors in question.