X-axis power feed recommendations

[rodm1]

This is one of those projects that would be well liked. I would like one for the Z to.

 

[Tomzo]

I am in the design stages to develop one that use a high torque NEMA23 stepper, a compatible stepper driver board, and an Arduino for controls. I plan to use a two position momentary joystick switch to send a signal to enable the stepper (which locks it up) and drive it in the direction desired. Speed control will be with a rotary potentiometer for the joystick switches but I am thinking of another smaller momentary toggle that will drive each direction at whatever I feel the right max speed is. If I get fancy, I will add an LCD screen where, once I figure out all the math involved, will display the feed rate when driving the stepper. Of course, some limit switches will be involved. I working out the right ratios of pulley sizes now to ensure I can get to the speed/torque sweet spot.

I have a rotary table coming next week so I plan to machine an adapter that mirrors the engagement system that the handwheel uses so I can attach that to a stepper pulley. I may even work out a way to reconnect the handwheel so I can use that side when the stepper is disabled. That is TBD. A good deal of this idea is still roaming around in my head although I may get it all into Fusion 360 before I get through to the final design.

I have done a number of simple arduino projects and use open source code from Github on a regular basis, so I will certainly rest on the shoulders of others as I go down this path. I have seen a number of YouTube videos and other forum posts on the topic so I am pretty confident it will all work out. I think that parts will run under $150 for the whole thing. I can afford to buy one commercially, but the challenge and fun of designing and making it myself is a form of entertainment for me!

Any advice or guidance is appreciated!

Tom

 

[rodm1]

Please keep use posted on your progress.

 

[RJSakowski]

Another possible for a DIY motor is a cordless drill driver. The battery is usually the first thing to go and replavcements are almost the cost of a new drilldriver so they are just chicked out. Typical speeds will drive the lead screw at better than 100 ipm. You have variable speed forward and reverse electronics built in. All you need to do is supply d.c. power and replace the trigger and reversing switch with a remote setup.

 

[Tomzo]

Another possible for a DIY motor is a cordless drill driver. The battery is usually the first thing to go and replavcements are almost the cost of a new drilldriver so they are just chicked out. Typical speeds will drive the lead screw at better than 100 ipm. You have variable speed forward and reverse electronics built in. All you need to do is supply d.c. power and replace the trigger and reversing switch with a remote setup.

I have considered other motors that I have (although a cordless drill has not among them so far) but the idea here is to have the precision of the stepper that can be controlled through code that can give a readout of the feed rate on the LCD. Yes - for a small hobby shop like mine doing it by feel works just fine and I could certainly make something like that work, but a big stepper is less than $40 so the investment is not too high. This is about 70% a fun academic exercise and 30% need for the shop. Truth be told, most of the time that applies to whatever I am doing out there!

 

[RJSakowski]

My Tormach has a NEMA 34 stepper, 500 oz-in. of torque, driving a 5mm pitch ball screw. Maximum rate is 100 ipm or 2500mm/min equivalent to 500 rpm. Ball screws are considerably more efficient the an Acme lead screw in transmitting power which must be taken into consideration. The stepper on my lathe ELS is a NEMA 24 600 oz-in. of torque driving a 12 tpi lead screw. It struggled driving the lead screw so I used the gear box for 2x torque multiplication. Were I using a stepper for power feed on a mill, I wouldn't consider less than 600 oz-in holding torque.

 

[Tomzo]

Thanks RJ - that is helpful information. The model I am looking at is rated at 425 oz-in (3Nm) and I planned to use a belt/pulley system to drive the leadscrew. Depending on the sizes of the pulleys (TBD) I should be able to double that torque. I have some additional testing to do to measure what is needed on the mill. With that said - I might just find something with overkill on the torque side.

 

[RJSakowski]

I made a simple device to measure torque consisting of a disk of known diameter wound with a cord. A scale attached to the cord measured the force required to rotate the lead screw against a load and the force x the radius of the disk is the torque. I would set a cutting scenario representative of the maximum load that you will want to use and measure the torque. The Tormach mill uses angular contact ball bearings for thrust bearings and the use of a ball screw and nut greatly reduces friction.

 

[Eddyde]

I just installed a Vevor power feed on my mill, last week, I was initially impressed with the apparent quality for only $129.00 But Yikes! Sorry to hear yours crapped out so soon, I was hoping to get at least 10 years out of it.
One thing I remember from the sparse instructions, It said if it "overloads" to cycle the on off switch to reset it. Don't know if you tried that but it might work.

 

[ARC-170]

I just installed a Vevor power feed on my mill, last week, I was initially impressed with the apparent quality for only $129.00 But Yikes! Sorry to hear yours crapped out so soon, I was hoping to get at least 10 years out of it.
One thing I remember from the sparse instructions, It said if it "overloads" to cycle the on off switch to reset it. Don't know if you tried that but it might work.

I was able to fix it. There was a cracked soldering joint. I've documented this in another thread.