Ugh...choosing a controller is making me nuts

[strangetanks]

Well, probably a typical new guy here. But here goes. I'm building a CNC router table (duh) 4'x8' thats capable of cutting through cabinet grade plywood.

The mechanical components are no big deal. But I'm having trouble wrapping my head around the controller/driver.

I happen to have 2 Compumotor ZetaA57-102-MO stepper motors. I have some money to spend on the controller unit, I just don't want to have to buy the freakin thing twice.

I basically just want to buy a controller, wire up the motors and use Mastercam to generate tool paths. If I need to increase the size of the steppers later I would like that to be an option also.

Hopefully someone can give me some insight as to whether this

http://cgi.ebay.com/PARKER-COMPUMOTO...item4cec9f3a3d

is an appropriate unit to purchase.

Sorry for being such a noob.

[eloid]

Originally Posted by strangetanks Well, probably a typical new guy here. But here goes. I'm building a CNC router table (duh) 4'x8' thats capable of cutting through cabinet grade plywood. The mechanical components are no big deal. But I'm having trouble wrapping my head around the controller/driver. I happen to have 2 Compumotor ZetaA57-102-MO stepper motors. I have some money to spend on the controller unit, I just don't want to have to buy the freakin thing twice. I basically just want to buy a controller, wire up the motors and use Mastercam to generate tool paths. If I need to increase the size of the steppers later I would like that to be an option also. Hopefully someone can give me some insight as to whether this http://cgi.ebay.com/PARKER-COMPUMOTO...item4cec9f3a3d is an appropriate unit to purchase. Sorry for being such a noob.

personally, it a choice for that size of table ....stepper or servo once u decide
that question? ....next ask should I buy something that i cant kill or the lower cost hobby level brand stuff...

I would spend a a extra 100 - ish buck and get gecko g203v ( for steppers) there almost impossible to kill..... and if you have issues with it ...I have herd, many times they repair or replace there units free of charge... they really stand behind there product... I have g203v and it a great unit...

As for bob, most pc dont have parallel ports any more.... The future is usb
so i would us a smooth stepper with cnc4pc.com bob ie c23 or smaller bob as fits your needs. Any bob will work... yes you can by pp brd and add it to you pc also.

[strangetanks]

Thanks for the advice! The quick reply is appreciated, there is just sooo much information to wade through I was going bananas.

The parrellel vs USB is a good question. I had intended on using an older (ok pretty damn old) PC as a dedicated machine for running the CNC machine. I can't imagine it wouldn't perform well enough to make me a happy camper. From what I've seen most folks are using parellel ports.

The G203V looks super duper. Ok, so here's where I sound like a dummy. That unit not only contains the controller, but also the power supply which drives the stepper motors?

[marzetti]

The G203 is a driver only for a single axis. You would need a breakout board and a power supply to complete the electronics. I am using Keling 4030 drivers with their C10 BOB but I wish I had spent just a bit more and gone with the Gecko G540 which is a complete 4 axis unit which requires no breakout board, only a power supply. Read the documentation on Gecko's support page and you'll find a lot of info there. Keling and MJPA are a good source for power supplies.

[FandZ]

G540. I haven't read anyone ever saying, geez, wish I would have gotten something better than a G540. For the price, convenience, and performance it's hard to beat.

That said, you'll be limited to stepper motors in the 380oz range with the g540. You could use higher torque steppers but once you look at the RPM and power drop off it won't be worth it with a g540. There is plenty of power in 380oz though. Also since you are doing a larger table, don't skimp on the lead screw and get something in the 10tpi range. I'm guessing with a 8 foot table you'll be looking at doing a rack and pinion setup though.

[Crevice Reamer]

Hi ST. Welcome to the Zone.

4 x 8 is a large table. What mechanical means are you using to drive the axes? What size? Threaded rod? Acme rod? Ball screws? Rack & Pinion?

Here is some basic CNC info that should help you:

http://crevicereamer.com/Page_2.html

CR.

[CarveOne]

Originally Posted by strangetanks Well, probably a typical new guy here. But here goes. I'm building a CNC router table (duh) 4'x8' thats capable of cutting through cabinet grade plywood. The mechanical components are no big deal. But I'm having trouble wrapping my head around the controller/driver. I happen to have 2 Compumotor ZetaA57-102-MO stepper motors. I have some money to spend on the controller unit, I just don't want to have to buy the freakin thing twice. I basically just want to buy a controller, wire up the motors and use Mastercam to generate tool paths. If I need to increase the size of the steppers later I would like that to be an option also. Hopefully someone can give me some insight as to whether this http://cgi.ebay.com/PARKER-COMPUMOTO...item4cec9f3a3d is an appropriate unit to purchase. Sorry for being such a noob.

If you want to buy drives that have the torque to run anything like NEMA 34 size motors on a MechMate type machine in the future buy the Gecko G203V first and be done with it. I bought my four drives during their Customer Appreciation Sale and saved on the cost. They can use up to 7A motors with up to 72v power supplies. These drives are the best protected drives available.

You will need a breakout board for them. C11G is specifically designed for the Gecko drives and has fully opto isolated I/O pins. PMDX is a popular source for breakout boards also. They also have a modular design version that allows mounting up to four G203V drives on it for an integrated assembly similar to the G540.

The G540 is the best drive currently available for 3A and smaller motors. It has all the other best features of the G203V, and you don't need to buy a breakout board.

CarveOne

[ger21]

OK, after some digging, I found out that your motors are 3.5amps when wired bipolar parallel. Good news is they'd work very well with the G540.


Bad news is they are roughly 150 oz motors, about 1/4 the size you'd want on a 4x8 machine.

Typically, for a machine that size, you'd go with Gecko G203's and minimum 400 oz-in motors.

Might be a good idea to spend some time at the Mechmate forum and see what they are using. I think it's Rack and Pinion, and minimum 400 oz motors geared at least 3:1.

www.mechmate.com



EDIT: after a little more digging, it appears these Compumotor motors have an inductance between 5 and 10 mH. So for maximum performance, you'd want to supply them with 70+ Volts. The G540 would only give about half of what they are capable of. You can buy much more powerful, modern motors that will easily outperform those Compumotor motors for about $30-$40.

[Crevice Reamer]

Without knowing your drive system, I hesitate to recommend any electronics. But most likely the G540 and some N34 906 motors would fix you up:

$289 (1) G540 unkillable 4 axis drive. This IS a deluxe, advanced features breakout board also--COMES WITH 4th axis drive
and spindle-speed controller already installed.
$297 (3) Keling KL34H295-43-8A 906 oz N34 motors (Detunes to 520 oz W/G540.)
$060 (1) Keling KL-350-48 48V/7.3A PSU. (This will handle 3 motors & probably 4th axis also. If not, use: http://www.antekinc.com/details.php?p=209 )
-------
$696

Or maybe you only need the N34 on the long axis, and could use $50 N23 381s on the others.

http://kelinginc.net/

CR.

[strangetanks]

Wow!!! You guys rock! Basically, this is the information I was looking for.

To give a bit more information on what I had intended to set up. The y direction (8ft run) will be a chain drive. With the chain being stationary and a sprocket pulling the entire assembly back and forth. I've seen some similar set ups and its an attractive set up to me because I can easily extend my table even further than 8' someday if I want. There will be a drive shaft coupling either side together so the carriage is drivin equally on both sides. I'll probably use a toothed belt to gear the motors down.

I wasn't certain yet if my motors were up to the task, I wanted to get some of the carriage assembled so I can measure some actual weights and resistances. But luckily these stepper motors have a shaft stickin out on both sides. If I calculate one won't do the job it should be a very simple matter to couple them up on the same drive shaft.

For the X direction (4ft run) I was going to go with a ball screw assembly. These appear to be readily available on Ebay. I'll have to score some type of ball screw assembly for the Z axis as well.

Its sounding like what I'll need is a G540, a power supply and a bunch of cables. At the very least this gives me a good point of focus for further research. I was getting pretty confused as it feels pretty difficult to compare apples to apples among manufacturers.

[Crevice Reamer]

Originally Posted by strangetanks I'll probably use a toothed belt to gear the motors down.

This is not really feasible because steppers lose torque as speed increases. By gearing them down any more than slightly, you will lose whatever torque is gained in speed losses.

I wasn't certain yet if my motors were up to the task, I wanted to get some of the carriage assembled so I can measure some actual weights and resistances. But luckily these stepper motors have a shaft stickin out on both sides. If I calculate one won't do the job it should be a very simple matter to couple them up on the same drive shaft.

This is not feasible because the two motors will fight each other more than move the load.

For the X direction (4ft run) I was going to go with a ball screw assembly. These appear to be readily available on Ebay. I'll have to score some type of ball screw assembly for the Z axis as well. Its sounding like what I'll need is a G540, a power supply and a bunch of cables. At the very least this gives me a good point of focus for further research. I was getting pretty confused as it feels pretty difficult to compare apples to apples among manufacturers.

I fear you will not be able to use the motors you have for this. I think the 906/381 combo will work best for you.

You will also need some other stuff with the G540:

http://crevicereamer.com/Page__57.html

CR.

[eloid]

Originally Posted by marzetti The G203 is a driver only for a single axis. You would need a breakout board and a power supply to complete the electronics. I am using Keling 4030 drivers with their C10 BOB but I wish I had spent just a bit more and gone with the Gecko G540 which is a complete 4 axis unit which requires no breakout board, only a power supply. Read the documentation on Gecko's support page and you'll find a lot of info there. Keling and MJPA are a good source for power supplies.

reread my post there is a bob (c23) from cncforpc.com its a full bob.....