So, during my time as a intern with Bosch I got some experience playing with a fairly old model CNC Plasma Cutting machine. It had some issues and I never got it to hold any kind of tolerances needed for FRC, but I was also a novice operator.
Recently I’ve been looking into different precision cutting methods for sheet metal and plate because I might lose access to the Waterjet I have at USC. Plus, I’ll be honest our Waterjet is pretty old and tough to work with. We lose a lot of time even trying to get parts made on it.
Is there a CNC Plasma machine any team uses that can hold tolerances good enough for FRC use? What price did you pay for yours if you did and what sort of things did you have to budget for in terms of consumables etc.
There are plasma cutters that can hold a high enough tolerance but they are far far more expensive than a good cnc router. 177 is the only team I know that regularly uses a plasma cutter but they go through a lot of hoops and post processing just to get the tolerances they need. My team has a plasma cam and its become a $13,000 scrap storage table.
Define ‘good enough’. I don’t know passes your sniff test here.
95 uses plasma cut parts extensively and our table is not a particularly good example. Tolerances run about +/- .015" in aluminum sheet using a really nice torch consumables from Hypertherm (and a Hypertherm engineer on the team making sure it’s all put together right). That’s obviously still not good enough for something like a press fit bearing pocket, but plenty good enough for a lot of sheet metal parts.
For us .015" is fine, but that’s largely because we know that’s what the tool we have will do, and plan around it. When we need to do something like cut a bearing pocket or precisely locate a hole we’ll do those features on a mill after blanking the part on the plasma cutter.