Extruder motor clicking after changing to direct drive extruder

I changed my extruder from the printed gear type from Think3Dprint3D to a direct drive all aluminium one. I changed the "DEFAULT_AXIS_STEPS_PER_UNIT" to {80, 80, 80, 87} for it to extrude the same amount of filament as before, and then my problems started.

The extruder motor starts clicking under almost no load at all. just extruding at 200mm/min in open air is too tough.

I read several places that I would need to up the amps on the extruder motor, but not so much that it starts making terrible noises or simply stops. Only problem is that my extruder starts making these terrible noises not even a quarter turn on the pot screw, and if I continue it stops completely

What does this tell me? Is my extruder motor too weak? I've seen several kossels running a direct drive extruder?

Are there any settings I've "forgotten", maybe in Marlin, that could help me out of this?

Last and not least; if I need a hardware upgrade to make this work: Where can I buy it?

Thanks,
Eddy

You have discovered why most people use geared extruders. To get enough force from a direct drive extruder using a Nema 17 motor, you need to run the motor close to its rated current. Even then, a short motor won't produce enough torque for some types of filament, and you may need to use a longer motor.

I suggest you look up the specifications of your motor, then adjust the driver pot to run the motor at 80 to 85% of its rated current. If that current is too high for the driver not to overheat, then you will need additional cooling or a better driver - although if you have the Ice Blue ones from T3P3, they are already about as good as plug-in drivers get. Drivers integrated on the electronics board can generally handle higher currents because they are cooled better.

My Kossel used to have the 5:1 geared extruder from my T3P3 Mini Kossel kit, but I found it was over-geared for the long (48mm) motor they supplied. It now uses a 3:1 Ormerod geared extruder.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks dc42. My extruder motor is also the one from t3dp3d, meaning I already have a long nema17? Is this the torquiest nema17 out there?
I really hated that geared extruder and I don't want to go back. Changing filament and retracting full "bowden tube lengths" after skippings/grindings was a pain. Also the 2-screw pressure adjuster was simply a shot in the dark to try and adjust.


I really want to be able to use this nice aluminium extruder. Are there gearboxes to be bought for nema17's that I can mount my new extruder on top of?


Thanks,
Edward

You can get Nema 17 motors with 5:1 planetary gearboxes built in. If you go that route then I suggest you choose a short motor, otherwise you will get either too much torque or too little acceleration, depending on how you set the motor current.

I like the look of this extruder [www.thingiverse.com], which is designed for such a motor.

Edited 2 time(s). Last edit at 09/01/2015 04:39AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
Eddy
Only problem is that my extruder starts making these terrible noises not even a quarter turn on the pot screw, and if I continue it stops completely
Thanks,
Eddy

A quarter turn on the vref pot on the driver can mean a HUGE increase in current.

You need to use a voltmeter to set the vref correctly and what it should be set to depends on what drivers you are using see this: [reprap.org]

If you have a long nema 17 it ought to be sufficient to run a direct drive extruder.

Okey, I hope I didn't break anything will fiddling around, then, since I was turning 1/4 turn at a time...

Still, the problem persists. I will tune the driver properly to double check I'm not missing a "point" where the motor is both strong enough while not getting too hot.

Koenig: is my 58mm Nema17 a "long" Nema17?

I have an additional question; How can one get too much torque? I mean, if the filament gets really hard to push through the hot end and the extruder starts grinding the filament, then surely I have a bigger problem than a too powerful motor?

Quote
Eddy
Okey, I hope I didn't break anything will fiddling around, then, since I was turning 1/4 turn at a time...

Still, the problem persists. I will tune the driver properly to double check I'm not missing a "point" where the motor is both strong enough while not getting too hot.

Koenig: is my 58mm Nema17 a "long" Nema17?

I have an additional question; How can one get too much torque? I mean, if the filament gets really hard to push through the hot end and the extruder starts grinding the filament, then surely I have a bigger problem than a too powerful motor?

A 58mm long Nema17 should be able to provide enough torque for a direct drive extruder, if you can drive it close to its rated current. What is the rated current of the motor?

If you have too much motor torque, then when the nozzle becomes temporarily obstructed, the extruder will grind a notch into the filament, and because of this extrusion won't restart when the obstruction is removed. So you want the motor to skip steps when extrusion is obstructed.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Very well explained, thank you!

Here are my extruder motor specs, given they haven't changed the motor since I bought my printer last year: I see it's listed as 40mm long now, so it might be that I have an even stronger one at 58mm?

Frame size 42 x 42mm - Nema17
1.8 degree step angle
Length 40mm
Holding torque 45Ncm (4.5kgcm, 64 oz-in)
Voltage 2.2v
Current/Phase 2.00A
Resistance/Phase 1.1ohm
Inductance/Phase 2.6mH
Inertia 54g.cm
Bipolar, 4-wire
Weight without cable 281g, with 1m cable 298g
Step Angle Accuracy ±5%（full step,no load)
Resistance Accuracy ±10%
Inductance Accuracy ±20%
Temperature Rise 80℃Max.(rated current,2 phase on)
Ambient Temperature -10℃-+50℃
Insulation Resistance 100MΩMin. 500VDC
Dielectric Strength 500VAC for one minute
Shaft Radial Play 0.02Max.(450 g-load)
Shaft Axial Play 0.08Max.(450 g-load)

Edited 1 time(s). Last edit at 09/01/2015 07:25AM by Eddy.

Your problem is that the rated current of the motor is 2A, so to get close to maximum torque while not overheating it, you need to run it at about 1.6 to 1.8A. This is more than normal stepstick-type drivers can manage without overheating and going into thermal shutdown mode.

Your best bet is to get another motor with a rated current in the range 1.3 to 1.6A. However, if you are using a cheap A4988 driver module, you could try a better one. Think3DPrint3D makes an Ice Blue stepstick with A4982 driver and a 4-layer PCB that provides better cooling that the standard stepsticks. DRV8825-based drivers are also supposed to be able to handle a bit more current.

In the meantime, try setting the pot to give about 1A (use a multimeter to set the correct Vref). That may give you enough force to extrude PLA without overheating the driver.

btw if you ever decide to upgrade to 32-bit electronics (which is recommended for driving a delta), be sure to get a board with software control of stepper motor currents, which makes adjusting the motor currents much easier. I upgraded my T3P3 Mini Kossel to Duet electronics - see my blog for details.

Edited 2 time(s). Last edit at 09/01/2015 08:26AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I appreciate your thorough answers, dc42, it really helps me understand my problems myself.

So to conclude on the matter I do have a strong enough motor, but before reaching its optimal current ratings I've already maxed out the drivers current ratings. To tackle this the best thing to do is get a driver that handles more current, so my motor can perform its best...?

My second option is to find a gear for the Nema 17 that I can fit my direct drive extruder on top of.

Quote
Eddy
So to conclude on the matter I do have a strong enough motor, but before reaching its optimal current ratings I've already maxed out the drivers current ratings.

Yes.

Quote
Eddy
To tackle this the best thing to do is get a driver that handles more current, so my motor can perform its best...?

No, because I don't think you will find a plug-in driver that will handle anything like 1.7A without overheating. Plug-in drivers just don't have enough PCB area to cool the chip properly. However, if you find that by setting your existing driver to about 0.8A or 1A you can get reliable extrusion most of the time, then upgrading the driver will let you increase the current by 20% or so to give you some extra margin.

Edited 1 time(s). Last edit at 09/01/2015 01:01PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

hello
I have some printers where usually I use geared extruders upon which I never had problems
Lately I have built this [reprap.org], based on ultimaker2
This printer use a direct drive extruder with a bowden to an e3d and 1.75 mm filament!
works great and at speeds comparable to its original version!!!! there is a drv8825 on ramps 1.4 with 1.2V Vref on the extruder !

now I'm testing an aluminium direct drive with same caracteristics for electronics but with 3mm filament

at this point I have the same issue due to clicking!! torque is not enough to push filament, print go for example in good condition for an hour and then I go to underextrusion!!
therefore it is seen that in the case of the filament about 1.75mm I say that this system worked I'll try in this way !!
But my final question is :
why original Ultimaker2 that use a direct drive bowden system and 3mm filament works fine????
It use a simple nema 17 and not a geared motor!!

Edited 2 time(s). Last edit at 09/22/2015 03:04AM by mdcompositi.

Quote
dc42
You have discovered why most people use geared extruders. To get enough force from a direct drive extruder using a Nema 17 motor, you need to run the motor close to its rated current. Even then, a short motor won't produce enough torque for some types of filament, and you may need to use a longer motor.

I suggest you look up the specifications of your motor, then adjust the driver pot to run the motor at 80 to 85% of its rated current. If that current is too high for the driver not to overheat, then you will need additional cooling or a better driver - although if you have the Ice Blue ones from T3P3, they are already about as good as plug-in drivers get. Drivers integrated on the electronics board can generally handle higher currents because they are cooled better.

My Kossel used to have the 5:1 geared extruder from my T3P3 Mini Kossel kit, but I found it was over-geared for the long (48mm) motor they supplied. It now uses a 3:1 Ormerod geared extruder.

hello
I have some printers where usually I use geared extruders upon which I never had problems
Lately I have built this [reprap.org], based on ultimaker2
This printer use a direct drive extruder with a bowden to an e3d and 1.75 mm filament!
works great and at speeds comparable to its original version!!!! there is a drv8825 on ramps 1.4 with 1.2V Vref on the extruder !


now I'm testing an aluminium direct drive with same caracteristics for electronics but with 3mm filament


at this point I have the same issue due to clicking!! torque is not enough to push filament, print go for example in good condition for an hour and then I go to underextrusion!!
therefore it is seen that in the case of the filament about 1.75mm I say that this system worked I'll try in this way !!
But my final question is :
why original Ultimaker2 that use a direct drive bowden system and 3mm filament works fine????
It use a simple nema 17 and not a geared motor!!

Edited 1 time(s). Last edit at 09/24/2015 11:42AM by mdcompositi.