For learning how to use the CNC mill, I decided to keep it simple and pull a shape from the Noun Project to mill into my wood. The shape I chose was a little plant/sprout thing, which I cleaned up in Adobe Illustrator before sending it to Carbide Create. In Carbide Create I followed the steps to input my wood dimensions and adjust the settings before carving the first piece. My design was pretty tight, just barely fitting to the edge of the wood, but I figured it was good enough. What I didn’t account for was that the second piece was very very slightly smaller, making the second sprout off the wood on both edges: booooo. Upon rereading the assignment and discovering that I was also to carve out the shape using the max depth function, I decided to switch gears and start over.

For my second (and final) design, I decided to carve two ornaments, and was lucky enough to get some beautiful walnut to carve them out of. I pulled a pine tree design from the Noun Project and transferred it over to Adobe Illustrator to turn the design into an outline and give it a circle around to serve as the final cut to separate the ornaments into their discrete pieces, as well as a hole at the top to thread a string through. This outer shape was 3”x3” as dictated by the assignment and my limitations in the sizing of the wood.

I next transferred to Carbide Create where I began with inputting the wood size and settings before getting to the toolpaths. I started with the 1/16” bit to get the detailed cut of the tree, which wouldn’t have been accomplished with the thicker 1/8” bit. I did this 1/8” deep as a pocket toolpath, then moved on to the others. Next, I created a drill hole path using the 1/8” bit down to the max depth (string hole), which worked perfectly as I had created my hole diameter to be exactly 1/8”. My final toolpath was the outer cut, which I did as a contour using the 1/8” to the max depth to cut out the ornament fully.

I did both the ornaments in a single run side-by-side and had to organize them on the screen to ensure they wouldn’t overlap with each other in any way. I also ensured the toolpath was set to do the same thing to each ornament before moving to the next (aka pocket, pocket, hole, hole, contour, contour). This order was important for stability and precision, as the pocket may not have turned out as well if the outer cut had been done first since the piece may be inclined to move around the newly created space. In all, it worked out well and I was able to do a nice sanding to the outer edges of the ornaments and around the outline of the tree to smooth it out. One it was smoothed and ready to go, I glazed it with Danish oil before leaving it to dry.

 

 

 

 

 

 

 

 

In sum, this was a cool assignment and I’m glad to now know how to CNC mill. Some takeaways:

• I’m appreciative of the extra practice I got when redoing the pieces
• I can confirm through getting cut by a bit (and still having the scar on my hand to prove it) that they are very sharp and it’s best to be careful around them
• The CNC mill can only cut as detailed as the endmill or ballnose available
  • AKA cutting lines thinner than the mill piece will be unsuccessful!
• Make sure to keep the probe reference plate and its connected ground piece separate or the software will get confused and be unable to probe for length
• Try to have everything set up beforehand because resetting often means going back again through the motions of zeroing all over again (and having to replace the endmill with the probing pin again)
• Make sure to secure the right tape to the bottom of the piece or else it might move (as seen in my group training session, although to be fair we were also using the wrong tape)
• Hold the probe reference plate in place at the edge of the wood when zeroing it’s position on the build plate because although the square has edges to sit around the corner, it will easily move when the probing pin goes to hit each edge
• Once you learn how to use the CNC mill, it isn’t too bad!

Cost: ~$53 for practice and 2 clean ornaments

Materials:

Scrap wood: $3.48 for 2″x4″x8ft Whitewood board  @ 35″^2 = $0.317

Walnut: $58 for 1″x4″x2ft 5 pk @ 21″^2 = $2.54

Danish oil: $13.98 for the 473mL canister @ 10ml = $0.0087

Labor: $7.5/hr @ 4 hrs = $30 total

Overhead/machine use = $5/hr @ 4 hrs = $20