Servo Drive For a lathe Compound

[lkrestorer]

Thank you 'rodw'. And, of course, all you other fine folks. I'm really getting a lot of good usable information from all of this. The "Arduino Rotary Table For Dummies" post is also getting my finger prints all over the pages. I have been spending my time this afternoon searching and sorting. I don't believe this will be a high priced project because Ebay can be a friend.

I'm changing my plans from a double shaft motor to a single shaft and will be trying to set the table up with powered-only operation as per the other posts. My 'itch to build' is getting stronger as I go.

I believe I'm getting a better understanding of how this works and I see it as a three part learning experience. There is the mechanical modification of the device to be controlled, the design and build of the electrical interface and the programming (and understanding) of the Arduino equipment. Then there is the gathering (and understanding) of the necessary materials to accomplish the task.

You will see the word 'understanding' three times in that last paragraph. That describes what I'm working on now - and I appreciate all the help. When I make my purchases (soon!) I'll follow up with a list of them in this post.

 

[Herbiev]

The stepper controller postage at $21 seems a bit steep. This mob has free postage
https://m.banggood.com/DM542-Leadsh...er-for-3D-Printer-p-1397322.html?rmmds=search
Very impressive project tho.

 

[lkrestorer]

Herbiev,

I took that DM542 info and plugged it into Ebay and came up with this:

http://rover.ebay.com/rover/1/711-5...0001&campid=5338413729&icep_item=372500492944

The prices are all over the map. I'm looking at the controllers that will accept up to 50 volts like the one that rodw suggested. I'm not familiar with 'Banggood' so I might stay with the proven world of Ebay.

 

[rodw]

Banggood is OK. A friend of mine has used it a lot. ebay in Australia Sucks. Its flooded with stuff from China that ships from Australia in the description but is sent in bulk to us from China and then posted by a logistics company. Very annoying as it takes a lot more time to arrive.

Just note that I linked to a DM542A, not a DM542. I think there is a difference. I can vouch for the Longs Motor one and am uncertain about Leadshine but they do make some good stuff. Just avoid the ones with a TB6560 ot TB6600 as they have a very poor reputation.

The other one that is popular with the Arduino set is the Pololu A4988 but its limited to 2 amps, 35 volts and does not have the more advanced features in the microstepping the others have. https://www.pololu.com/product/1182 It will get you going but torque will be limited....

 

[ignator]

The prices are all over the map.

I typically do a generic search on eBay, "Stepper motor driver". This brought up over 4000 hits. I sort on price + shipping lowest first.
I found this;
http://rover.ebay.com/rover/1/711-5...0001&campid=5338413729&icep_item=283348655741
@$18 plus sales tax. But you need to know what motor your going to use first. The minimum current setting on this item is 1.4amps. Hence what motor are you wanting to drive.
This search also brought up motor driver packages, which may be of interest.

 

[tjwal]

For those in the US, circuit specialists out of Phoenix has a good price. I don’t know their shipping though. I picked up a few of these on one of my snowbird vacations.
https://www.circuitspecialists.com/nema_23_stepping_motor_57bygh405a-d.html

 

[ninefinger]

You can skip the arduino if all you want to do is drive the stepper forward or backward at a fixed or variable speed. https://www.amazon.com/dp/B077SFDMFJ/?tag=skimlinks_replacement-20
Its a stepper pulse and direction generator. The link is amazon but available from many sources.
Mike

 

[rodw]

For those in the US, circuit specialists out of Phoenix has a good price. I don’t know their shipping though. I picked up a few of these on one of my snowbird vacations.
https://www.circuitspecialists.com/nema_23_stepping_motor_57bygh405a-d.html

These are really designed for NEMA 34's which are too large for whatt is required where the small NEMA 23 is a much better option

 

[rodw]

You can skip the arduino if all you want to do is drive the stepper forward or backward at a fixed or variable speed. https://www.amazon.com/dp/B077SFDMFJ/?tag=skimlinks_replacement-20
Its a stepper pulse and direction generator. The link is amazon but available from many sources.
Mike

Personally , I think the Arduino gives much more flexibility so you can program in other features like length of cut or peck drilling.

 

[lkrestorer]

1) I can see the flexibility of using the Arduino because it looks like it can be programmed to do both simple traversing and the more complex (in my mind) positioning. Plus it looks like an interesting thing I'd like to try my hand at. I will be going this route.

2) My searches on Ebay do bring up a tremendous number of drivers and motors. I believe I'm understanding that the driver's maximum current output has to be the same or more than the motors maximum to get full range operation.

3) The motor's torque seems to be proportional to the length of the case (more wire inside = more oomph). This brings up the possibility of using a NEMA 34 motor that is much shorter than an (almost) comparable output NEMA 23 to limit overhanging length. I probably don't need a tremendously strong motor to turn an 8" rotary table but less length to get in the way might be nice. Then there is the cost factor. The NEMA 23 equipment is generally cheaper than the NEMA 34 equipment.

4) It was mentioned to stay away from the TB6560 and TB6600 drivers. What is the difference between the DM542, DM542A and the DM542T drivers? These all seem to be sized for NEMA 17 and NEMA 23 motors. The NEMA 34 motors have another bunch of drivers rated for them (higher current output). I realize that the current rating is the deciding factor but is one really better than the other as far as models go? Does the idea that 'you get what you pay for' hold true? China seems to be the only place manufacturing any of this stuff and it's well known that all of their stuff isn't top-of-the-line. (Don't slam me for that. I'm using a Grizzly 12x36 lathe and a Grizzly Bridgeport clone - but I've had to do extensive rewiring of both of them.)

5) And then there is the voltage question. It seems like the more robust setups use 48 volt power supplies. It's probably more efficient getting the higher currents with higher voltages but some of those units get pretty spendy. I'm seeing power supplies with 48 volts and 8.3 amps output for $19.99 and for $173.99.

I've come close to ordering this stuff several times but the more I dig the deeper the hole gets. I don't really want to end up with a pile of parts that doesn't work like it should and then have to start all over again. I can feel my understanding going up but this is a world that I haven't walked through before.

 

[tjwal]

I’m using TB6600 drivers for the steppers I mentioned in message 86. They only go to 42 volts but are significantly less expensive than the higher voltage drives. I’m currently only using a 24V supply anyway. Both the PS and the drivers can be replaced if need be.

 

[rodw]

Forget NEMA 34's for your application. They are too big and bulky and have a torque output way more than you need. Waaayy overkill. Doubling the voltage at least quadruples the torque. At 24 volts on my rotary table I had missing steps because of this. 48 Volts fixed this. TB6XXX drives have a very poor reputation for reliability. That might be whats in a 542 and 542T but I'm not 100% sure. I do know the DM542A was a significant upgrade over the DM542. No-one said this would be cheap! Anyway, you have enough info to make a decision now and remember doing nothing is always an option!

 

[lkrestorer]

Anyway, you have enough info to make a decision now and remember doing nothing is always an option!

Well, thanks. I'm taking that as a kick in the pants. I do have a tendency to over analyze things - especially when I'm diving into uncharted waters.

I've ordered the Arduino board and supplies as was detailed in bmac2's Arduino Rotary Table for Dummies. I also ordered a motor: NEMA 23, 114mm length, 4.2amp, 425 oz/in torque, and has mounted cord, dual shaft & threaded holes on the rear endplate in case I decide to reconnect the handwheel.

And I put in offers on a 48 volt, 4.2 amp power supply and DM542A driver (when somebody says 'best offer' I have to give it a try).

 

[tjwal]

Rod
I don’t understand why you quoted my message when you posted this

These are really designed for NEMA 34's which are too large for whatt is required where the small NEMA 23 is a much better option

??
John

 

[rodw]

Rod
I don’t understand why you quoted my message when you posted this



??
John

I have no idea now either now ...