MeshCAM Day 2 - Image Machining

Yesterday you got a walkthough of the most common MeshCAM workflow, machining a 3D STL file. Today we'll look at something a little non-traditional: machining an image file.

If you choose to follow along, you can download the PNG file or get it as a ZIP file.

1. Load the File

  • From the top menu, click File->Open
  • Select the image file that you downloaded above and click OK
  • In the Image Settings dialog, enter 300 for Pixels/Inch
  • For the Z Size, enter .1in
  • In the Height Mapping section, click Black is Z-

The 3D view now shoes the image converted to a height map with the lighter parts of the image set at a higher Z level and the darker set to a lower Z level.

2. Create a Toolpath

From the left menu, click the "Generate Toolpath" icon.

3. Global Settings

The Global Parameters part of the toolpath dialog defines a few parameters that affect every toolpath that is generated.

  • Enter a Tolerance value of .001in
  • Click "Machine whole stock"
  • Uncheck "Enable Arc Fitting"

Roughing

For this tutorial, we're not going to cut very deep so we'll skip the roughing pass.

  • Uncheck Enable Roughing

4. Create a Tool

MeshCAM needs to know what tool you plan on using to cut the geometry so it can properly calculate a toolpath.

  • Check Enable Finish Pass
  • Check Cut Along X
  • Click Select Tool
  • In the new dialog, click Add
  • In the Edit Tool dialog, click Balll
  • Copy the settings shown above.
  • Click OK
  • The tool you just created should be selected. Click OK

5. Finishing Settings

The Finishing toolpath is used to remove the last bits of material remaining from roughing and give the part a good finish. Because we have such a shallow geometry, we can skip roughing and go straight to finishing.

  • Uncheck Waterline
  • Uncheck Pencil Cleanup
  • Copy settings above
  • Click OK

6. Preview the Toolpath

Once the toolpath apprears in the 3D window, you can shift the view to get a closer look at any part for the geometry.

7. Save the G-Code

MeshCAM comes with a bunch of post processors that tell it how to format the gcode for your machine controller. When saving the file, it's important to pick the right post processor for your machine. If you have any doubts, pick Basic-Gcode or Mach3. Both are fairly generic and work with most machines.

  • Click Save Toolpath
  • Pick the correct post processor in the Save as type drop down menu.
  • Enter a filename
  • Click Save
  • Go load the gcode into your machine!

Conclusion

You may have never considered using an image as the source for a CNC machining project but the feedback I've gotten over the years is that this is one of the most popular features in MeshCAM.

If you're one of these people then you may want to open up your favorite image editor and see what you can come up with. As you play with it more you may think of projects that would take much longer to complete with a traditional CAD workflow.