[wlsn.chrs]

Hey guys. I'm looking for an inexpensive drive board for 3 nema 23 425 oz-in motors. I'm open to the idea of building my own. Please let me know ASAP. I'm going back to college in a month and need to get my harbor freight x2 retrofitted before then.

Thanks

[jalessi]

Bipolar or unipolar?

How many amps?

[wlsn.chrs]

It is a bipolar and draws 2.8 amps. The specs sheet is available at http://www.kelinginc.net/KL23H286-20-8B.pdf

[jalessi]

Wlsn.Chrs,

If you get a eight wire Keling motor like the one you posted it can be wired bipolar or unipolar.

Gecko has there four axis G540 stepper drive on sale for $210.00, it is a bipolar drive.

http://geckodrive.com/product.aspx?c=3&i=14469

HobbyCNC has a unipolar three axis drive on sale for $64.00

http://www.hobbycnc.com/

Jeff...

[wlsn.chrs]

Hmm, ok. If I wire the motor as unipolar though I will effectively have dropped the holding torque from 425 oz-in to 305 oz-in. Is this enough torque to direct drive the x2 Harbor Freight x,y and z axis(I'm going to direct drive the micro precision adjustment wheel for this axis)? If so, should I invest in cheaper motors with less holding torque that would require a cheaper drive board? Is there a midrange drive board I could use? Could I simply wire the motors as bipolar for the hobbyCNC board, it seems to support 3 amps?

Sorry for all the questions. I'm torn between spending more money now so I don't waste money on a cheaper board I will eventually have to upgrade and keeping it simple and cheap with the HobbyCNC Bipolar board.

Thanks for all the help

[jalessi]

Wlsn.Chrs

305 ounce motors will be fine with a X2, are you replacing the stock lead screws with ball screws?

The HobbyCNC drive is unipolar only, it will not work if you wire the motors bipolar.

You may need to add harmonic dampers when using a HobbyCNC driver, if your machine develops mid band resonance issues and the motors start stalling at higher feed rates.

See the You Tube video.

[ame="http://www.youtube.com/watch?v=8Am69_F93yA"]YouTube - 65 ipm[/ame]

The Gecko G540 has mid band resonance compensation built in to the drive.
It will not require mechanical dampening.

Jeff...

[wlsn.chrs]

Some time in the future I may replace the axis with ball screws, but at the moment I don't have the money to do that and convert it to a cnc. In your opinion, is there an noticeable performance loss between the Gecko and Hobby boards? The extra 120 oz-in gain with the Gecko may just be overkill. However, I do plan to use the machine to mill aluminum and steel.

[jalessi]

Wlsn.Chrs,

Lack of torque wont be a problem.

305 ounces with a 20 tpi leadscrew will generate plenty of torque.

Jeff...

[wlsn.chrs]

alright. Thanks for all the help.

[wlsn.chrs]

One last question. It looks like John from kelinginc.net is out of the nema 23 425 oz-in motors ($49) I mentioned. Would you recommend any websites that would carry these motors new or used? I've checked ebay, cnczone classifieds, and google to no avail.

[jalessi]

http://www.hobbycnc.com/products/stepper-motors/