The stepper motors have arrived! I went with the same brand that ProMiCA used in their kit, but the higher torque version.
Still need to order my stepper drives – probably going with the bulletproof Gecko G203V. I did briefly consider designing and building my own, but that wouldn’t be free either, and the point here is to get the machine up and running some time soon. I’ve also narrowed down my power supply I think – a 1500W 70VDC supply from Antek. Beefy, but it gives me plenty of margin left over for a 4th axis for a rotary table, and I should be able to have all axes driving simultaneously.
I’ve been doing a bit of digging into machine control software. The obvious first choice is what nearly everyone seems to use – Artsoft Mach3. I knew of the Linux EMC2 project, which I had initially dismissed as being worthless like so many superficially promising open source projects. This one, however, seems like it is at least worth trying out. It was originally created by NIST, so there’s some heavyweight effort behind it. It uses actual realtime extensions to the Linux kernel, which is a lot more than I can say for Mach3, which runs on very non-realtime Windows. I’ve seen many YouTube videos of it running real machines, including some crazy 5-axis machines as shown below.
They have a live CD, so it’s very easy to try it out. Seems like it’s at least worth the effort to investigate it more closely.