Hi Jamie,
I've done a G0704 conversion to AC servo (Allen Bradley), Mach 4, Smoothstepper and have offered engineering designs services to people looking to use Acorn + Clearpath on CNC routers, so I'm intimately familiar with them.
Happy to answer specific technical questions if you run into anything.
General thoughts:
- Mach 4 is likely the best system for low cost + highly customizable IMO. I built a custom drive interface through LUA and streaming serial to display drive diagnostics on the screen.
- Ethernet Smoothstepper is the best Mach 4 motion controller IMO. Lots are unstable or have poor IO performance
- Mach 4 is probably 98% stable. Some things, usually bleeding edge features, break if you test them to their limits. Not going to bother a casual user.
- Mach 4 is constantly being worked on - big plus.
- LUA scripting, painful learning curve but very capable. You're able to do almost anything other than edit the core motion controller.
- Acorn is pretty easy to setup and seems to work well. My customer seems happy with his choice.
- Acorn is all supplied by one company. Concise and easy to follow documentation and directions. Good technical support.
- Acorn control board is sensitive to electrical noise. This could be an issue if you want to put a VFD in the box with it. Hard to troubleshoot
- You're stuck with Centroid's ecosystem if you go Acorn. Adding IO is quite expensive. $400 per 16 inputs and 16 outputs.
- There is some limited scripting available with the Acorn.
- I used to preach DMM servos. I've had mixed feelings lately. They have some of the lowest cost systems that aren't import junk, but they still lack some features I consider to be important to a hobby guy (good GUI setup utility, autotuning , etc.)
- AutomationDirect has some reasonably priced AC servo packages now as well with A+ customer support.
- Stay away from eBay/China AC servos. Horrible documentation. Not worth it for any cost savings.
- Clearpath is more expensive than some lower cost servos thanks to the "on motor" servo drive. To me, this isn't really a huge benefit, but their product seams to work very well and is easy to set up.