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CNC and Me

Our next machine is the CNC. CNC stands for Computer Networked Control, and works kind of like the Hand Router except it is controlled by a computer and not my hands. Our assignment was to build something with this using 'pockets' and 'contours'. The computer aided machining (CAM) software calls a carved out hole a 'pocket' and a cut line a 'contour'.

This was a challenging task. I had to go back and forth between the shop's CAM station and the CNC several times. The first trip back was because I forgot to set the depth levels to a negative number. Without that the CNC will mill the air above my wood. After I got that corrected I had some difficulty setting up the machine. John and Shreiya helped me turn the machine on and attach my wood to the CNC bed.

After zero'ing out the machine, I finally started the job! Here are some photos.

I put a screw into the center of the dot above the 'i' in my name. That screw keeps the finished product in place when the CNC finishes the contour cut.

The job finished but as you can see the contour plot did not go deep enough. I did measure the thickness of the board but I did so with digital calipers that had not been properly zero'ed out. There was an extra ~0.2 inches of material left. I went back to the CAM station to make another job that just did the contour to the proper depth.

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When the CNC finished the board rotated right away, suggesting that if that screw hadn't been there it would have moved farther. In the future I should have two screws keeping everything in place instead of one.

My mill bit was a downward cut bit so the top looks nice but the bottom edge of the contour cut was a bit rough. Nothing that a little sandpaper couldn't fix! Here's the final result:

/images/itp/subtraction/week4/final.jpg

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