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 shows 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 Tool

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

• In the top left side of the window, click Setup
• Click List Tools

• Click Add to add a new tool

• Copy the settings shown above.
• Click OK
• Close the tool list window

3. Global Settings

The global settings part of the toolpath dialog defines a few items that affect every toolpath that is generated.

• On the left hand side of the screen, click on the Tolerance value
• Enter a tolerance value of .001 in
• On the left hand side of the screen, click on the Area to Machine value
• Click Geometry Only
• On the left hand side of the screen, click on the Distance Around Geometry value
• Enter a value of .25 in

4. Create a Toolpath

Since this project is a low-relief, without a great deal of material to be removed, we have the option to skip the roughing toolpath. To be complete, we’ll include it here but it’s not always necessary.

• From the top menu, click the Toolpaths->Roughing button.

• Click Select Tool
• Select the #1 Ball Mill that you created above
• MeshCAM will fill in approximate speed and feed values based on the machine and material you’ve selected. Feel free to change these as necessary.
• Set the “Options” section to match the image above.

• Click Ok

• From the top menu, click the Toolpaths->Parallel Finishing button.

• Click Select Tool
• Select the #1 Ball Mill that you created above
• Set the “Options” section to match the image above.
• Click Ok

5. Calculate Toolpaths

On the left pane you’ll see your roughing and finishing toolpaths listed.

• Click Calculate Toolpaths

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
• 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.