Re: G320X Drive question
I'm going to have to respectfully disagree with Andrew and Craig on this one. I would be lost without a CNC/manual machine in my shop. You have the best of both worlds with that Webb machine. I have one identical to it, but it's branded as an Eagle. Made by Topwell in Taiwan, and imported under a few different brand names. I'm still using the original brushed Baldor DC servos and Servo Dynamics drives, powered by a 75V power supply.
Mine started out life as a 2 axis machine with an Anilam control and is now a 4 axis machine that can be operated as a full manual, 2 axis with manual quill, 3, or 4 axis CNC, all with manual knee. Switches between modes in seconds, and I do so frequently right in the middle of a setup. For the kind of work I do, I find it very useful to be able to perform manual operations either mid job, or perform an entire job in manual mode. Just depends on what I am doing at the time.
Rather than using rotary encoders, I opted to use linear magnetic scales. They have proved to be more or less bullet proof for the last 7 years. This gives me 1 micron resolution on all axes, I have scales on both the knee and the quill. Using scales attached to the load pretty much eliminates any backlash or ball screw errors. I have about 0.004'' backlash in my Y axis which causes about a 0.001'' out of round error on a circular pocket that doesn't get compensated for. There is no substitute for a mechanically tight machine.
The heart of my system is a Galil motion controller. From what I understand, these are compatible with Mach4, I know they are compatible with Mach3. I have very little experience with the Mach products, but I know the DRO on the screen is still active in manual mode when connected to the Galil controller, at least it was in my very brief excursion into Mach3. Although, as far as I know, Mach products do not use the encoder feedback at all, a completely open loop system. Somebody correct me If I'm wrong here. The Galil controller however is closed loop, and can close the loop at the controller level even when used with Mach products.
Using a Galil controller, you can use the original analog servo drives, or step & direction with different drives if you like. Galil will handle either. In fact on my machine I use analog control on X, Y, and Z, and stepper control on the 4th axis.
You have a really nice machine there, so spending a bit of extra money to make it top of the line is worth it.
Jim Dawson
Sandy, Oregon, USA