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Stepper motor size for power feed?

This is what I used before I went full CNC. Large power supply from a different CNC setup. Gecko Stepper Motor Driver. And my ELS Z axis step direction providing the motion.

Z-AxisPowerSupply.webp

I would just look at a treadmill motor, variable speed control for that if you don't want positioning.

Enter "treadmill motor dc" into the amazon.ca search window. Princess auto probably has something too.
 
My rig.

> NEMA 34 1600 oz/in stepper direct-coupled to lead screw
> Wall-mounted panel with DM860A driver, 60v 5a power supply, and a small 5v power supply for an Arduino configured to provide variable speed pulses
> small remote operator console with speed dial, pilot light, left-off-right direction switch, jog pushbutton, and run pushbutton. This console houses the Arduino.

I didn’t implement limit switches, mostly because my DRO scale is mounted on the front of the mill table and I don’t have any room.

It’s not 100% satisfactory, my Arduino coding skills are sketchy so the motor stuttters a bit. I suspect I need to spend some time tweaking the duty cycle of the pulse generator but it’s project #43.

IMG_7451.webp
IMG_7452.webpIMG_7453.webpIMG_7454.webp
 
Wow we just can’t seem to get off the stepper servo cnc merry go round. The OP just wants power feed. No position controllable motor is needed. On my first mill I used a Princess auto surplus automotive window motor and it was already geared. Power feed on x and y is probably best addressed with a commercial power feed unit. Vevor has some other forum members have posted about. The knee is harder as you need more power and those units are more money.

To start I’d say make adapters to let you connect your drill to the different axis and see what you think. You can make a variable speed switch out of a hose clamp on the trigger. I think some used plug in drills and some limit switches would be a good home brew solution and cheap too.
 
There are so many ways to skin a wombat. I agree with @Janger that a simple DC motor with speed control is the easiest and simplest. Here's one I designed and built in 1999. Used a 555 timer to create the PWM.
But that was when it was cheaper to build rather buy.
 

Attachments

mbond said:
if you just want power feed that you control with a switch operated by hand, you don't want a stepper motor. Stepper motors have to be controlled by electronics. you just want a regular AC or DC motor
Click to expand...
The problem with a regular motor is it needs to be geared down to reduce the speed. Then you need some type of clutch to engage and disengage it in order to use the hand wheel.
 
A motor from a power window assembly or a windshield wiper usually has gears already attached. Treadmills are another good source I think.

all of these solutions need a way to engage / disengage the motor regardless of the type you choose.
 
Megar arc 5040dd said:
How would you control the speed on this? This might work for lifting the head since I don't see myself using the crank once it has power. The table on the other hand I want to avoid the complication of engaging and disengaging it from the lead screw.
Click to expand...
www.progressiveautomations.ca

10A Compact DC Speed Controller - Progressive Automations

Control the speed of your linear actuator with the adjustment knob on this 10A DC speed controller. Allows for 0-100% speed control of your linear actuator.
www.progressiveautomations.ca www.progressiveautomations.ca
Just an example, Aliexpress will be much cheaper!

You either disengage and engage as others have said, or keep it coupled at all times.
For NC, or CNC you want steppers or servos, engaged at all times. For a power feed I think this is the best idea. Disengaged when not in use.

Youtube guru sensational old fart did exactly this!

Gluck on your project!
 
Keeping a motor of any kind attached to the screw will increase reactance if you want to move it by hand. keeping a stepper motor attached makes that worse in two ways ***. It depends on the kind of stepper motor and its exact internal geometry, but generally the resistance with a stepper motor attached will be higher, and it won't be even.

Stepper motors have the ability to hold their position. Even up to their maximum torque in some cases. You will have to overcome that resistance before you can turn the screw at all manually.

There will be parts of the circle that are offer more resistance to turning by hand, and other parts that the motor will want to push you into. Even when the motor isn't actively resisting your motion, the internal construction makes certain angles

I wrote this and planned to edit it
 
mbond said:
Keeping a motor of any kind attached to the screw will increase reactance if you want to move it by hand. keeping a stepper motor attached makes that worse in two ways ***. It depends on the kind of stepper motor and its exact internal geometry, but generally the resistance with a stepper motor attached will be higher, and it won't be even.

Stepper motors have the ability to hold their position. Even up to their maximum torque in some cases. You will have to overcome that resistance before you can turn the screw at all manually.

There will be parts of the circle that are offer more resistance to turning by hand, and other parts that the motor will want to push you into. Even when the motor isn't actively resisting your motion, the internal construction makes certain angles

I wrote this and planned to edit it
Click to expand...
That sound like it has a permanent magnet in it? I thought they would turn when there was no power going to them. I might try to reach out to Ades workshop on youtube and ask him exactly what type of motor he used. I had thought that he said in the videos, that I got this idea from, that he used a stepper motor. Here is the video I am referring to
I basically just want to do the exact same thing but with a motor sized for my mill that is larger that the one he did this on.
 
mbond said:
Stepper motors have the ability to hold their position. Even up to their maximum torque in some cases. You will have to overcome that resistance before you can turn the screw at all manually.
Click to expand...
Only if power is applied. After that it has a lot to do with the coil driver circuit when powered off.

It's an easy experiment that can be done to verify the concept. Take a stepper motor. Make sure the wires aren't connected to anything including each other. With a disk or pulley on the shaft turn the motor shaft. You can feel the detenting but it's not that hard to turn.

Now short out the two windings. In this sketch the windings can be set as parallel or series for each phase.
1725164351346.webp

So wire it up in parallel and then short both pairs to each other. Now try and turn the shaft and you will find a massive resistance to that. The reason is now the voltage generated by the magnets moving through the the coil is shorted out and requires a lot more torque to generate the power.

A lot of motor drivers have diodes for suppressing high voltage back emf. It's those diodes that can make the motor difficult to turn when connected to the driver. It's also why you should never unplug the motor from the driver when powered. Magic smoke is possible.

Therefore if you use a relay to disconnect the windings add an extra pole to not allow the drive to be powered while the windings are disconnected.

BTW, although I've rarely done it I have used the gears to turn my South Bend Heavy 10L lead screw while the stepper motor is still connected. I've also used the Gingery Lathe with Z and X motors connected but my ELS switched off.
 
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stepper motors are a special case of AC synchronous motors. I know of 2 main kinds - those with permanent magnets and those that use induction to produce a so called reluctance reaction.

Even though they are theoretically AC motors, they are powered by DC pulses sent from electronic controllers - those electronics count the 'steps' to make these useful whereas AC sync just controls the speed

The internal geometry matters a lot

but if you just want power feed and not CNC, a treadmill or window motor is a way better choice. The whole point of stepper motors is to be able to count the steps, and if you don't need that, then you don't want one
 
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