Christmas comes early to my CNC machine

Yesterday, I thought I’d tackle a quick project. Earlier this year, I designed a Christmas ornament based on the South Carolina flag and some other Christmas ornaments I’d seen. I modeled the design in Autodesk Fusion 360 using mainly splines and extruded it to 8 mm since that was the thickness of stock I had lying around. Then I used the software to generate G-code for the contour cuts, using a spiral cut going down about a millimeter every time around the design.

After the design was done, I used CAMotics to visualize what the cuts would look like on some virtual stock. I’ve found this to be a very useful step, ensuring that everything is where it is supposed to be and not wasting any wood in the process. It is still easy to miss something (like in this case, I missed the hole where the hanger should fit) but it is better than nothing.

The following is a picture of my first cut in progress on the machine. I was using a 1.5 mm flat end router bit running at 5000 RPM and a cut feedrate of 100 mm/min. This speed caused some burning (smoke), so I changed the feedrate for the second one I made to 300 mm/min and that took care of the burning (for the most part) — and I didn’t even break a bit.

Here is a picture of the final part, before it was sanded, to take off the whiskers.

I think I now have the 2D contour cutting down fairly well. The ornament is cut from 115 mm x 80 mm x 8 mm, so there are some tight tolerances in the design, but it worked out. I’ve now cut a second one out of walnut as well (this time with the hanger hole at the top). Now on to a more complex object that has both a silhouette, contour cut as well as more ornamental cuts.

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