Learning how to use the CNC machine was a lot of fun last week.  It works a lot like the plasma cutter, but it can make way more complicated objects.  Our assignment for the week was to CNC any design we wanted to, so obviously Clark and I made the Batman symbol.

This is how it turned out.  We cut it out of a purple foam because it is a cheap material and very easy to cut.  In case you didn’t notice, the bat that we cut is missing its ears.  Clark and I first made our file in Illustrator and saved it as an SVG.  At this point our bat still had ears, but once we put it through Makercam they unfortunately had to go.  This is because the CNC machine uses a drill bit to cut material, and so you can not make right angles or sharp points in the x- or y- directions (since the drill bit is cylindrical).  That, plus the ears on the bat were to small to be defined by the relatively large drill bit.   Once we created our tool path in Makercam, Clark and I saved the file as a .nc and imported it onto the CNC computer.

At first we tried to cut the logo out on one of the blue wax blocks from class.  Unfortunately we forgot about the scaling issue we ran into during class, and the machine cut out the logo much bigger than it told us it would.  The file size was under 3 inches long, and that is what was displayed on the CNC computer, however when the machine started spinning it cut a lot more than anticipated! Here is our initial attempt:

As you can see only about 2/3 of the logo fit on the block.   The lines in the picture above that are within the pocket are there because Clark and I stopped the CNC machine after it completed all of its rough cuts, so it did not go through with the slower finishing.  This is when Clark and I decided to use foam instead of the wax, both because of its cheapness and because there were larger pieces of it than the wax.

When our foam piece was done cutting, the edges were very rough and there were lots of stringy foam pieces that weren’t cut away by the drill bit.  To get rid of those we used the air hose in the machine shop to blast the loose bits away.  That got rid of the majority of them, and after that it was a simple matter of cleaning it up by hand.

Getting to know another machine in the machine shop was a ton of fun.  I’m excited to incorporate it into our final project.