Hi all,
Thanks for the clarification on the external controllers. If those don't interpret G-code directly, they probably nearly do. It'd be great to understand the Mach (for example) protocol. If Mach4 no longer generates the timing pulses, it would have to tell the external controller how many steps and in what direction it needs to move, and at what speed each movement is made. Plus it probably sends other things like curve radii. Anyway, I'm mostly speculating here; need to read more on this.
I'm still trying to decide on the machine design. One day fixed bridge wins, others vertical column wins. Right now, I'm going through what/ifs with vertical columns. It's hard to figure out how all would go together without having critical things like the spindle and its motor. The spindle cartridge (pictured previously) arrives in the next day or two. That will give me a chance to take measurements, figure out how I'm going to drive it, and build the support box/head for it. Of course, I can't finalize that until I have a spindle motor....
I have been obsessing the past few days over the spindle motor. What I want and what I can get at a reasonable cost don't seem to intersect. I want a servo motor that can do about 8,000 RPM at the top. There are a million different high speed, VFD driven spindles everywhere. But I want to rigid tap, thread mill, maybe even automatic tool changing one day. Sure, there are tricks to get an induction machine to do these things but a servo has all that it needs natively.
What I can get that meet my requirements is a 3.7kW servo package, like this:
The darn thing is way too large for the small machine I'm planning. It's also 100lbs (46kg)! I can get a 2.2kW that's slightly lighter but it costs the same to ship and only about $80 cheaper than the 3.7kW. The Chinese are so imprecise with their quotes and leave so much details out. I wish they posted the complete specs of whatever they're selling, post the manual online so you can read it *before* buying and have a good explanation why a smaller servo package costs the same to ship as a larger one.
Back to the Alibabas and their express train of confusion.
Regards,
JR