NEMA 17 0.9 or 1.8 degree ?

[Adalbert]

Hello everybody,

Does anybody know which step-motors are the best for our rails?

Recently I made a new rail and first installed an old motor.
viewtopic.php?f=25&t=44225

Now I want to replace the old one with a new, good, and precise one.
Which motors are the best for our purposes those with 0.9 degrees or with 1.8 degrees?

Do they have to be the high-torque motors?
I use a TMC5130, which according to the description can handle a maximum of 2A.

Best, ADi

[Macro_Cosmos]

I can't exactly elaborate on the best one due to lack of actual experience, but I've had success with both types of motors, and basically jerryrigging them onto Wemacro/Stackshot controllers.

[ray_parkhurst]

I can say from experience that 0.9deg motors make smaller steps easier, and are thus better for higher magnifications. Also in general, 0.9deg motors are designed with lower holding torque, so tend to microstep better than 1.8deg, but this is not universally true, and if you are looking for accurate microstepping it's best to get a motor specifically designed for that purpose. There are many more 0.9deg motors designed for microstepping than 1.8deg.

Regarding torque, it is surprising how little is actually needed for our systems. Almost any NEMA17 motor you can buy has sufficient torque for most any system we'd build. Most difficult to drive from torque perspective are vertical systems with coarse-pitch rails, but seems most folks here do horizontal systems, and all of us choose fine-pitch rails, so for our purposes not much torque is needed.

Edited to add: The biggest disadvantage to 0.9deg vs 1.8deg is they will run at half the speed, given same controller.

[Adalbert]

Hi guys,

I have one with 0.9 degrees from Wantai and one with 1.8 degrees from Stepperonline.
I have already tried to compare their precision but have not found any difference.
I have measured the step-size of the rails driven by the motors.
So, I am not sure if the motors with 0.9 degrees are really more precise.

Best, ADi

[ray_parkhurst]

Hi guys,

I have one with 0.9 degrees from Wantai and one with 1.8 degrees from Stepperonline.
I have already tried to compare their precision but have not found any difference.
I have measured the step-size of the rails driven by the motors.
So, I am not sure if the motors with 0.9 degrees are really more precise.

Best, ADi

Like I said, it is not universally true that 0.9deg motors can be microstepped better than 1.8deg.

@ADi, I'm curious what you mean by "precision". Is this the ability to microstep linearly? Or are you talking about full step resolution? You say you measured the step-size. You did find a difference in full-step size, right?

[Adalbert]

The most important thing for me is the stability of the rail and the invariability of the step size.
The configured step should always have the same size.

[ray_parkhurst]

The most important thing for me is the stability of the rail and the invariability of the step size.
The configured step should always have the same size.

Motors designed specifically for microstepping are best for such goals. They usually have very low (or even zero) detent torque. A more sophisticated controller (like @mawyatt's designs) can partially compensate regular motors but best to start with an appropriate motor.

[Adalbert]

best to start with an appropriate motor.

yes, but now I’m looking for the best one :-)
BTW, I have been using the same TMC controller for a long time, like Mike

[ray_parkhurst]

best to start with an appropriate motor.

yes, but now I’m looking for the best one :-)
BTW, I have been using the same TMC controller for a long time, like Mike

I have been recommending the Vexta PK243 series, as it is usually available on eBay or directly from Oriental, but it might not be the "best" motor. A more accurate motor would be a Lin 416 series. I'd recommend the lowest torque model you can find, with of course appropriate voltage/current for your controller.

edited to add: The Lin 417 series is also a high accuracy motor, and available in more variants. A 417-09-03 would probably be best of the series for you.

https://www.linengineering.com/products ... 417-series

2nd edit: I see there is a 417-11-03 for sale on eBay. It is a "medium" size/torque motor. May be a good choice.

3rd edit: That auction is not properly titled. It's actually a 417-11-40-03, where the 40 indicates a high voltage (24V I believe), so you'll need to ensure compatibility with your controller

[Adalbert]

Many thanks for the hints & links!
As far as I can see, they are available only in the USA.

[physicsmajor]

Digikey does carry the Lin Engineering 417 series, pricing between $40 and $60 per motor brand new - better than a number of eBay listings and you get to pick the exact spec instead of some weird custom job taken from an unknown industrial machine.

[Adalbert]

Many thanks for the hint!

So, I have searched for a good one but I have found only this “funny” one
with 2A and 24V and very low holding torque.
https://www.digikey.de/de/products/deta ... gAyAJKlhUA
https://lin-docs.s3-us-west-2.amazonaws ... -15-08.pdf

These with normal parameters are unfortunately not available

[chris_ma]

So, I have searched for a good one but I have found only this “funny” one
with 2A and 24V and very low holding torque.

not sure what's funny about it?
if you need lower current, the WO-417-15-12 runs at 600aA:
https://www.digikey.de/de/products/deta ... 2/11564388

for higher holding torque, the WO-4209L-01S gives you twice that:
https://www.digikey.de/de/products/deta ... S/11564507

[ray_parkhurst]

At 30oz-in, that motor is actually a medium torque motor. Low torque would be 3-15oz-in.

The motor you linked to is similar to the PK243M I like so much, but in 24V. Can your controller do 24V? One thing I like about the PK243M is it operates around 6V, so there is headroom enough to use a 12V controller.

Here is the PK243M-01BA, with dual shaft, for spec comparison:

https://catalog.orientalmotor.com/item/ ... k243m-01ba

[Adalbert]

Can your controller do 24V?

I use a common power supply 12V for Arduino and motor, therefore I would need a motor with 12V.