Need motor recommendation

[Robotics Guy]

I'm planning to build a little PCB drilling machine, using a dremel as the drill. I think unlike most CNCs, it would be better to have two stepper motors moving the board (not the drill assembly) on the x & y axis, and just have some other mechanism to dip the drill down into the PCB.

I have absolutely no knowledge of stepper motors and would appreciate any recommendations as to what kind of hardware I need to purchase, the cheaper the better.

The boards that will be drilled are small, only about 4" by 6".


Thanks for the advice!

[Kelinginc]

Check some package here

http://www.kelinginc.net/CNCNEMA23Package.html

or small machine

http://www.kelinginc.net/CNCmachines3030.html

[Robotics Guy]

Thanks for the reply.

I'm actually not looking for an entire package like that, just the two motors. I was hoping to get the motors cheaply as well.

Would one of these work, perhaps?

http://www.alltronics.com/cgi-bin/ca...brand&start=30

I don't know things like what shaft size is standard, or how to tell if it will be precise and accurate enough for CNC. That's where I'd really appreciate the advice.

Thank you.

[jschmitt]

You need to decide how big you need these sites will help
http://zone.ni.com/devzone/cda/ph/p/id/223
http://www.orientalmotor.com/product.../TecMtrSiz.pdf
http://pminmo.com/PMinMOwiki/index.p...chanical_Power

That being said If you are just using it to move the table for drilling placement and not milling, most of those motors are plenty big enough for a small pcb drill. The 5709 have 400 steps/rev compared to the 5618 and 5718 have 200 steps/rev which is standard. If you used 1/2-8 2 start acme for your lead screw, the table would move .250 inch each turn of the screw. Divide that by the number of steps it takes to turn the motor one rev. If your drive multi steps you have even lower resolution. If you need even more resolution you can go to 1/2-10 2 start or even 1/2-10 single start. Be cautioned that steppers have more torque at slower speeds. I am currently running a 1/2-10 single start with 200 in-oz motors on a 24 x 36, and my rapids are 60 ipm max, but I haven't had trouble milling a 1/4 x 1/4 slot in oak.

[Robotics Guy]

Thanks for all the info! I wasn't able to access the last to links for some reason though.

Is the "Lin Engineering - 5709" that you said looked good from that page a decent motor for it's price range? I have no preference about which site to order from, I just found that page through google.

Is there some place else I should buy from?

[jschmitt]

Thanks for all the info! I wasn't able to access the last to links for some reason though.

I had trouble with The pminmo link but was able to access it: http://pminmo.com/PMinMOwiki/index.p...chanical_Power
The Oriental motor link has moved, they were old links I bookmarked

Is the "Lin Engineering - 5709" that you said looked good from that page a decent motor for it's price range? I have no preference about which site to order from, I just found that page through google.

I am assuming you are just making a single purpose xy table with little travel so rapids aren't a big deal, and you seem to be looking for resolution, which I would do with a higher pitch leadscrew, which would also give you more torgue, so you could even use smaller motors and plain treaded rod if you are want to save money. The nut for the leadscrew is what costs, Depending on accuracy and precision. I would use a 200 step/rev motor 5718 or 5618. You need to know what kind of driver you want to use either unipolar or bipolar. Unipolar is generally a cheaper driver to make, has less parts. Bipolar drivers generally have more torque. I don't know if you are buying drivers or making your own.

Is there some place else I should buy from?

I have bought motors from ebay and alltronics, I happen to check your link regularly. mpjones and allelectronics are also ones I check.