Tuesday, October 11, 2011

abusing CNC mills for internet memes

It's official. CNC mills are sexy. Even decades-old bridgeport model ones that take giant floppies.

So a while back I was all like "I'mma mill me some nyancat for my 2.008 paperweight." (http://orangenarwhals.blogspot.com/2011/09/nyancad-correct-motivation-for-learning.html)
Oh yea, my partner for this lab is the awesome Cappie Pomeroy. He did all the lathe work o.o so don't ask me about that.

So I got around to milling it.
look, nyancat got fatter so that you can fit a 1/16'' end mill between it's crevices!
(The way I did it is I did a Tools>Sketch Tools>Sketch Picture, then resized that reference nyancat picture until it looked appropriate. I then put a Tools>Options>Grid>Major Grid 0.07 / minor grid off. System Snaps>check Grid. Also, make sure Units>IPS, InchPoundSomething. Then just trace it with lines).

However, my resizing and retracing ended up not mattering, since I decided to engrave it. This was because we had to make a 15 minute version, and no matter how I tweaked Mastercam (using 0.02'' depth instead of 0.1'', using a wide endmill to clear it and then remachining with the 1/16''), there was no way the full 3D paperweight was milling out in 15 minutes.

Yea so there are really dumb ways to make a path in Mastercam. 
See the X'd out paths to the left -- I was tracing all the paths by hand, essentially. Then Pat, the shop instructor, came by and showed me the magic of the the "polygon" tool which will automatically apply a function (in this case, engraving) to everything within that polgyon. It created some weird paths, like you get on a lasercutter which doesn't recognize your vector as one shape but as individual lines*, but it gets the job done. In other words, he finished in 10 minutes what was taking me hours to do... hah.
*aka it doesn't trace them continuously but rather jumps back and forth between different lines in the drawing

See link below for g-code / mastercam / solidworks files.

The jig was made by the instructors for the class, along with the "offset" used in Mastercam to make sure the blank is positioned correctly.
gahhh technical difficulties. Yes, I used my phone to take a picture of picture on my camera.  You really don't want to know.
Nyanweight documents:
https://docs.google.com/leaf?id=0B9r0HZeoMbmgZjgzMTkyOTEtOTU4OS00MDhjLWJlMmYtNTQzMjc2YmJlMzkx&hl=en_US
where "base/lab1" docs are for the CNC lathe and "engraving" docs are for the CNC mill.


Software used: solidworks (.sldprt, exported to .dwg), mastercam

Todo next: Mill out the actual thing.