CNC Plasma Cutting Chassis

[GilaMonsterAlex]

Set up is everything. It's not just about drawing a hole and some lines that will make it work. You need your plasma cutting machine to be setup correctly for your material of choice. If you learn that, your cut and part quality will make it worth the effort.

I would not plasma cut small holes. You could "mark" by blasting the center, this doesn't always work!

Plasma cutting aluminum is very doable. It does create lots of "slag" that sticks to the aluminum, more than steel slag does. On sheets you won't notice it, but in tube or u-channel it will stick to the walls. I find that a twist lock scrotch pad will take that stuff off real easy. Otherwise it's a pain.

[Jim Zondag]

We plasma cut a lot of parts for our robot this year. Normally we have use a waterjet for many of our sheetmetal parts, but our company's waterjet machine broke in early Jan, and was down for the whole build season, so we had to make other plans.

This took a little trial and error, but we were able to make transmission plates, rivet holes and a lot of other fairly precise parts in Aluminum sheet as thin as 0.050" on a plasma cutter. The tolerencing is not nearly as good as a waterjet or laser (but it is good enough for FRC).
A few tips: Use big rivets, we use a lot of 1/4" rivets, so 0.010 tolerence or so on the holes doesn't really matter. Make all bearing holes slighty undersized and ream to fit. Make more simple assembled parts rather than a few complex peices if you are going to form them.