Very Basic questions on Motor Control

[canyon289]

I've just entered the world of CNC manufacturing and I wanted to build a small machine to learn the basics. I found one that meets my needs but I've got a few questions.

The machine I'm going to build is the Mantis V9.1
Mantis 9.1 CNC Mill - Make Your Bot!

On the site the author provides schematics for his own custom control boards and serial boards but does not provide specific motors to use. He also provides drivers and configuration files for EMC.

My question is how do I know which motor to buy or am I supposed to buy any motor and then configure the software?

My second question is could I just buy a premade control board and motors from ebay and mount them in the machine? And if so how can I be sure that the computer "knows" how to correctly send signals to the control board.

Thanks for any responses in advance!

[ger21]

My question is how do I know which motor

He lists the supplier and part number in the Excel file he has on his site.
If you can't get help from the designer, make sure you know what you're doing.

That's a much smaller machine than most that you'll see here. It uses Nema 17 motors, while just about all here use Nema 23 or larger.

[canyon289]

That was stupid of me. Thanks for pointing that out.

For the second question though, if I was to pick my own motor because I wanted more torque or speed, or buy a complete motor and controller kit how would I be sure that the digital signals are correctly correspond to mechanical movement? Would it be some configuration in the EMC software?

[ger21]

Just about any stepper drives that accept step and direction signals should work. If you're not sure, post a link here and ask.

[canyon289]

I was considering getting a cheap Ebay Kit like this one

3 Axis Nema23 Stepping Motor 185oz-in,Driverboard,Power - eBay (item 140494781724 end time Jan-03-11 17:31:41 PST)

or this one
http://cgi.ebay.com/3-Nema17-Stepper...ht_4983wt_1139

It would eliminate the need for me to make a custom board and for me to solder surface mount components. I just wasn't sure what would happen with the controls aspect, if I'd have to custom make drivers or change a configuration.

Sorry for all the basic questions and hand holding. I appreciate the help

[ger21]

Personally, I'd avoid the Chinese stuff on Ebay. Spend the $50 shipping costs on better stuff.

A good quality, easy to solder kit is available from HobbyCNC | CNC for the desktop machinist and hobbyist.
Check out http://www.kelinginc.net/NEMA23Motor.html for cheaper motors.

[canyon289]

Thank for very much for the link Gerry!

With so many options I don't what I need and what I don't. I'll look into these boards!