Question: Best settings for maximum torque of stepper motor

wieman01

Hello,

I am running a clay printer with a Duet 2 Wifi and occasionally, my extruder motor would miss a few (micro-)steps because the extruder screw has to push high-viscosity material through the nozzle and work under high pressure.

What are your thoughts on getting the maximum torque out of my extruder motor?

Of course the torque curve (torque/speed) is what matters most, also the motor current. But are there any other settings I should be aware of?

I have also experimented with different micro-stepping settings, and it appears E16 would give me the best results so far.

Any thoughts will be appreciated. Thank you.

M92 X100.00 Y100.00 Z1600.00 E100:5000.00			; set steps per mm
M350 X16 Y16 Z16 E16:16 I1			                ; configure microstepping with interpolation
M566 X500.00 Y500.00 Z20.00 E1000.00:500.00			; set maximum instantaneous speed changes (mm/min)
M203 X5000.00 Y5000.00 Z1000.00 E6000.00:400.00			; set maximum speeds (mm/min)
M201 X300.00 Y300.00 Z500.00 E250.00:500.00			; set accelerations (mm/s^2)

M906 X1200 Y1200 Z1000 E2750:2000 I30  	       			; set motor currents (mA) and motor idle factor in per cent
M84 S30                                            		; set idle timeout

o_lampe

@wieman01 Using the highes possible motor voltage helps. I'd also avoid stealthChop, (bad experience with earlier drivers on a different controller)
High Torque steppers usually have a higher inductance. Picking the right stepper can make a huge difference.

wieman01

@o_lampe said in Question: Best settings for maximum torque of stepper motor:

stealthChop

Thank you.

I did not mention I am using a Duet 2 with a TMC2660 driver, so Stealthchop is not supported anyway.

As for the stepper, yes, I will try another geared stepper, but was wondering if anything can be done here with a little tweaking.

jay_s_uk

@wieman01 have you looked at the EMF calculator? https://www.reprapfirmware.org/emf.html

wieman01

@jay_s_uk said in Question: Best settings for maximum torque of stepper motor:

@wieman01 have you looked at the EMF calculator? https://www.reprapfirmware.org/emf.html

Yes, I have seen it, but I think the graph I have attached shows the same thing. The supplier provides it and I have taken the relevant range (up to 200 RPM) into account.

dc42

@wieman01 the graph you posted should be for a particular driver voltage. What voltage was quoted?

wieman01

@dc42 said in Question: Best settings for maximum torque of stepper motor:

@wieman01 the graph you posted should be for a particular driver voltage. What voltage was quoted?
Yes, this is for 24v. I am using a 24v PSU in combination with a Duet 2.

wieman01

@dc42 said in Question: Best settings for maximum torque of stepper motor:

@wieman01 the graph you posted should be for a particular driver voltage. What voltage was quoted?

Oh, I see my error now I think. The Duet pins I am connecting this stepper to only supply 5v. You're right.

Would it work if I connected the phase to the 24v VIN instead? Hope this is making sense.

The graph is for 24v.

dc42

@wieman01 said in Question: Best settings for maximum torque of stepper motor:

Oh, I see my error now I think. The Duet pins I am connecting this stepper to only supply 5v.

The stepper motor outputs provide up to almost VIN voltage, so 24V if you are providing 24V VIN.

wieman01

@dc42 said in Question: Best settings for maximum torque of stepper motor:

@wieman01 said in Question: Best settings for maximum torque of stepper motor:

Oh, I see my error now I think. The Duet pins I am connecting this stepper to only supply 5v.

The stepper motor outputs provide up to almost VIN voltage, so 24V if you are providing 24V VIN.

Thank you, yes, I see that now. Also it would not make much sense if they did not.

If nothing else works, I will try another (geared) stepper for that purpose.

dc42

@wieman01 what's the rated current of the stepper motor, and what motor current have you set?

wieman01

@dc42 said in Question: Best settings for maximum torque of stepper motor:

@wieman01 what's the rated current of the stepper motor, and what motor current have you set?

I am currently running it at 2.5A. The rated current is 3.0A per phase.

zapta

@wieman01, can you improve the properties of the clay? E.g add water?

wieman01

@zapta said in Question: Best settings for maximum torque of stepper motor:

@wieman01, can you improve the properties of the clay? E.g add water?
Yes, you're right, in principle that is an option, however, in our case the viscosity of the material we are using cannot be changed for various reasons I won't bother you with.

I have order a geared stepper, let's see if that works out for us.