Need Help!- Picking out a servo drive for EMC2

[gbowne1]

Hi All!

I am going to be building a new cnc milling machine. Not a gantry/router type. I am going to be using EMC2. The machine's table will be 13.25" wide (front to back) and 56" long (left to right) and about 1.75" thick.. but may be up to 2.25" thick and T-Slotted. I have no idea what the table travel I will use.

I want to make it a minimum of 3 axis and use servos not steppers.. perhaps NEMA34. I have been told that AC servos are good. 4th Axis would be a rotary table as an option.

I was looking at all sorts of servo drives on ebay "business and industrial". There is Mitsubishi, Allen Bradley, Siemens, Yaskawa, Indramat, Omron, Kollmorgen, Emerson, Electro-Craft, Parker Compumotor, Panasonic, Pacific Scientific, Glentek, Moog, Vexta, NSK, Galil, Samsung, Baldor, Gettys, Bosch Rexroth, FANUC and a few others. I need something easy to set up and run with EMC2.. but something more than a Gecko. I see a ton of Yaskawa, Mitsubishi and Allen Bradley on there out of all of those. Anyone have any ideas? I also see a lot of Yaskawa servos.

Anyone have any ideas or suggestions on which ones work well with EMC??

I am going to have some inputs/outputs to some switches, lights, etc. as sort of a operator panel/HMI. plus limit switches, etc. such as Cycle Start, Cycle Stop, Emergency Stop, Jog, a Jog MPG handwheel, Coolant On/Off/Auto, Jog, Home, MPG, Spindle controls (jog, etc).

The build will include THK linear rails and blocks (HSR &SHS), Rockford Ballscrews and a custom built spindle for a small BT30 or CAT30.

Again, any suggestions comments etc. are welcome.

[epineh]

If you are going to use EMC then you don't really need a servo drive as such, you could make a H-Bridge and use EMC to read the encoders, and take care of the PID tuning.

This takes a little effort, and there are a few people out there doing the same thing (myself included) Search for Samco here on the zone and have a look at his large brushed servo on the cheap thread, there is a lot of information there, may give you an idea of a roll your own drive. His power stage is a fairly high power version and may be bigger than you need, worth a look though.

Some kind of pulse generating/encoder reading card would be helpful, do some research on the MESA 7I43 or 5I20 for use with EMC, this will give you faster pulse speeds than a parallel port can.

For my money the good old brushed DC servo's work very well, I know that AC or BLDC servo's may pack more punch for the same size but are a bit harder to build drivers for, or if buying the drives are more pricey.

For your IO have a look at HID Comp, this is a tool that allows configuration for USB based HMI devices :

http://hidcomp.sourceforge.net/

These are just suggestions, I am in the middle of doing something similar so I can't really give you any experience based advice. I have built a router that runs off EMC2 but it is using servo drives with step/dir input so not really the same as I have mentioned.

Good Luck !

Russell.

[gbowne1]

I really would not like to build my own drive. I was hoping I could pick something other than what you might expect, like a Gecko, Xylotex, etc.

I've built four different FANUC systems including a Series 15 all built from parts sold on eBay.

I wanted to pick something off the shelf that was also available on ebay.

Greg