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Another ELS build in the works

Marknb

Member
I’ve decided to add an ELS to my CX709 13x24 lathe. I realized it’ll be a while before I can replace it as I’d rather add a mill first. I’ll update the thread as I make progress.

I‘ve ordered one of John‘s (from the forum) kits and now need to decide on electronics. Electronics are completely foreign to me, and after a couple days of reading and watching videos, I’m not much further ahead. I thought I’d ask here for help first before pestering John with emails. I’ve read through the threads here I could find, but ELS is too short to search for, and my other search terms aren’t having much luck. I also joined the io ELS group, but find that difficult to search through.

John suggested a size 34 motor for the lead screw in the 400 to 600 oz-in range and a size 23 for the cross slide in the 270 oz-in range. No problem, found some, but then realized I’m not sure if I want open loop, closed loop, stepper, servo, hybrid. I may very well have read the information I need, but I’m in information overload now, and things are making less sense.

What does everyone prefer? Any preferred retailers? Where do you find the other bits, like gears and belts?

I appreciate your help and input.
 
My ELS journey is posted as “ELS Electronic Lead Screw Concept”

My 10x18 works just fine with a NEMA 23 geared 5:2. I don’t know how much torque you‘ll need but I suspect a NEMA 34 would be just fine.

Straight open loop stepper is all you require, John‘s ELS doesn’t need anything too sophisticated.
 
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In the past I've ordered from:
This motor isn't expensive, has the dual shaft out the back for adding an encoder if you eventually wanted some sort of closed loop control of the motor.
Here's a size 34 with a shaft on the back. With the motors not powered you can install a hand wheel on this or once again an encoder. They don't really cost more than a motor without the shaft so in the long run more useful.
Motor drivers like this will run both motors so you need two.
I prefer to run linear power supplies so I can't really advise too much on which supply to use but one like this would likely work and is cheap.
Since the drivers are good to 50V you can't go above about 48V. Higher voltage ultimately results in better high speed on a stepper motor. You could use a cheaper 36V 9.7A at $40 US and if speed turns out to be an issue upgrade later.
 
Oh and just to add to the general education about stepper motors. The torque curve for the motor shows how higher voltage almost doubles the torque at higher speeds. Another reason to go for more expensive drivers and power supplies. For a lathe it's not such a big deal compared to CNC.

Lots of people rave about Leadshine. I think I bought one of their stepper motor drives once through Amazon. Sold it shortly after at 50% of the original price because I couldn't handle the whine. It may have been an anomaly.

I then ordered two from Bergerda in China since I was already using their AC Servos and I have a good relationship with their sales and engineering people. But They only ship FedEx and although competitive on their parts the shipping is expensive. I was ordering AC Servos at the same time.
They don't sell through AliExpress so you have to get price quotes from Daniel their sales guy. I don't think they are any cheaper than others.

This is my test setup for driving motors from either an ELS or my Raspberry Pi4 LinuxCNC test bench. When I want to play to make a motor turn. The Bergerda stepper drive good to 80V and 6A. A linear power supply that produces 56VDC up to 20A. And behind, although you can't see it very well is an Olympic Ring Light processor board. I use the 70VDC in, 12.6V out 500mA voltage regulator on it to make power for the ELS when I use it for that. I now have some Chinese modules that do that but it's too much work to change it.
1685120416434.webp
 

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Thanks, I probably should’ve just asked you for recommendations.

Any suggestions on a 1ppr sensor. My google search didn’t return much.

Mark
 
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