View Full Version : Help, electronics

14-09-2011, 08:52 PM
HI, as i am half way through my build of my A3 cnc machine, im asking you guys for help as i am useless at these kind of electronics, so far my seach has come down to this kit,

is this a good choice? im hoping to machine alluminium, would 3.1nm steppers be powerful enough on 5mm pitch leadscrews?

As you can see i would like a plug and play so i cant connect it all wrong lol

Any help would be appreciated :)

14-09-2011, 09:01 PM
Am I right in thinking by A3 you mean the machine travel is about the size of an A3 sheet of paper? If so the 3nm motors will be plenty big enough. Are you using timing belts and pulleys?

For such a small machine it may not make much difference, but in general you want to use higher voltage stepper motor drivers. The ones on that site appear to be only 30 volts which will significantly limit the torque of the motor at high speeds since the torque at high speed (and thus the speed overall) is roughly proportional to the voltage. This is because the inductance of the motor limits the current into the motor and a higher voltage helps overcome that limit. Those motors work very well on 70 volts and pretty well on 50V. To do that you'll want a driver like this one:


I'm sure we can help if you're not sure about anything with the wiring.

14-09-2011, 09:09 PM
Hi, thanks for the quick reply, and yes sorry, machine travel is about A3 size, and i was only gong to be using a pully on the x axis as i have 2 leadscrews, so one motor connecting both, other than that i was going to be connecting them directly, on the y and z, so by having a lover voltage, 28volts, will this mean it will have more torque at low rpm?, as im only going to be using rapid for fast movement out of cut, ? cheers