Motors for PCB Milling CNC

[roboticsound]

Hi everyone,

I hope this is in the right place (please move if not).

OK well after months of researching I want to finally start building my first CNC machine.

It will mainly be for milling PCBs and so I was thinking along the lines of the Mantis 30 or the Pleasant Mill. Anyway, I have managed to source most of the parts and I was just wondering about motors.

Does anyone have any recommendation about which motors to use? The mantis mentions nema 17 motors but am I right in saying that "nema 17" is just to do with the size? I have seen many different ones with different specs.

Any input would be very much appreciated.

Thanks

[doorknob]

Does anyone have any recommendation about which motors to use? The mantis mentions nema 17 motors but am I right in saying that "nema 17" is just to do with the size? I have seen many different ones with different specs.

You are correct in saying that NEMA 17 is a physical size specification for the motor rather than a torque specification.

I have not built such a machine, so I am reluctant to give you a specific recommendation, but my own preference would be to get motors with higher-torque ratings than necessary "just in case". So if I had a choice between going with 20 oz. in. motors or 100 oz. in. motors, I'd get the 100 oz. in. ones. But YMMV...

[roboticsound]

OK, thanks for your reply so do you think southing like this looks good?

Zapp Automation

[doorknob]

Well, here's an example of a guy who built a Mantis using 3.1 kg-cm NEMA 17 steppers, which if I've done the conversion correctly is about 40 oz. in. (whereas your linked motor has a higher holding torque rating of 4.4 kg-cm or closer to 60 oz. in.):

http://www.cnczone.com/forums/diy-cn...tml#post899493

In the linked thread, the OP complained of the motor stalling when going at speeds of above 150mm/min (using full steps).

Your mechanical setup may be different from his, though...