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How strong does a motor need to be to run a CNC? Answered

I'm looking to build a CNC, then use that CNC to mill parts for a 3D printer. What I need to know is how strong the motors need to be. I'm going to be using my

https://www.sparkfun.com/products/11286?

connected to three

https://www.sparkfun.com/products/10267?

all powered by

https://www.sparkfun.com/products/9442

Would i be able to run a CNC or my eventual 3D printer with

https://www.sparkfun.com/products/10551

I'm hoping to be able to, becuase this would be the cheapest thing. But would this motor be strong enough to move around the axes? Thanks for input.

8 Replies

user
4lifenerdfighter (author)2012-09-14

Would this one work?

https://www.sparkfun.com/products/9238

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user

That may be good enough for a basic 3D printer but not for a mill. You need motors with a holding torque of more then 5kg/cm.

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user

Well, the

https://www.sparkfun.com/products/10846

is 4.89. Will that be enough?

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user

5kg/cm or greater is what you need. Preferably more then 5 kg/cm. Sparkfun isn't going to carry the kind of motor you need. Start looking at other retailers and start looking at NEMA 23 motors. You'll be spending about $28 to $35 per motor.

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user
bwrussell (author)2012-09-14

Those motors are too small. What sort of material will you be milling? If you want to be able to cut dense materials, like most metals, you will need much more powerful motors.
Also, what sort of configuration are you using on the mill? Moving table or moving spindle?

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user

I think I'm going to have a moving spindle.

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user
bwrussell (author)bwrussell2012-09-14

I'm guessing the printer will require a little less torque but still probably greater than you have here. If you use those motors for the mill it will just stall or skip steps as the torque from cutting overpowers the torque of the steppers.

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user
mpilchfamily (author)2012-09-14

The motor your looking at won't power much beyond a basic robot. Even the cheapest available 3D printers call for a Stepper motor with 5kg/cm holding torque or better. Most every 3D printer i've see all use NEMA 17 motors. Cheap and basic CNC mills tend to use NEMA 23 motors and a lot more holding torque.

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