Hey everyone,
I'm, building a cnc lathe/mill of sorts, and Im looking for help designing.
I've been trying to find a stepper motor for the main motor that can spin an object as it's
getting cut. There will also be a second motor with a cutting bit on it, but that's a different problem.
The stepper needs to be able to make small increments of a rotation and hold the object still while it's getting cut.
Does anyone have any suggestions for beefy stepper motors that fit the bill?
Also, I saw that a lot of people use the BigEasy Stepper driver.
Any suggestions are welcome. Thanks for your time,
-devin
You might want to try google. There are groups out there that already do this stuff so they would know the requirements already. A lath spindle normally requires a substantial motor. Not sure you need a stepper for that axis.
You will need a backlash-free gear system to get accurate positioning on the axis, stepper motors are good to only
about 0.5 degrees or so (and that's without allowing for high torque loads)
Resolution is not the same as accuracy, and microstepping isn't the answer since you have to allow for off-axis
error on the motor spindle and non-linear angle response to microsteps. (You still need to use microstepping to
control vibration and resonance during fast movement)
Something like a 36-fold reduction gear from a Nema23 motor ought to be able to provide good positioning
(perhaps 1/50 degree, given 20 full steps per degree)
I presume this is more of a mill than a lathe, so you don't need high speed on the main axis?
It sounds like what you are trying to do is build a lathe with "live" tooling whereby the workpiece revolves slowly and is cut with a milling cutter. A stepper motor can indeed accomplish this though you will likely need to gear it down via timing belts to get sufficient resolution. I would go to http://cnczone.com/forums/forum.php. It's a very large site and can be intimidating at first but you will find all you need to know there.