I was wondering if anyone would be so kind to help.

3D Printing
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1

I was wondering if anyone would be so kind to help. I’m building a reprap and using Marlin FW. I’ve finally gotten the axes wired correctly & those motors moving pretty well. Except for some endstop issues, most things seem to be functioning okay, other than my extruder motor. The motor doesn’t move on either of the controller set-ups I have tried. I have determined it’s not a problem with the motor, driver or controller. I must have something configured wrong on Marlin because the same problem occurs on both controllers. What setting/settings or configurations might I need to adjust for the extruder (E0) in order for the motor to turn the gear? Or, what might be causing this issue? Any assistance would be greatly appreciated.

2

Extruder will not move at all unless the hot end is up to temperature. That is a safety feature of Marlin, stops cold extrusion. Try putting a low resistor in place of the usual 100k thermister, I think there are tables in Marlin that should give you a guide as to what resistor to use.

3

Yes, I realized that when I received the error message for cold extrusion prevention, so I heated the hot end up to PLA temperatures, but it still wouldn’t move

4

I didn’t receive the error message when I preheated the hotend.

5

I wonder if it has anything to do with the fact I didn’t have my extruder fan running. I didn’t bother to connect it since I was just checking to see if the motor worked.

6

I don’t have a fan at all, so I know you can configure it for no fan to overcome this one.

7

How do you configure it for no fan?

8

On arduino, that is

9

Remove any load (gear) from extruder servo (in case it’s mechanically jammed).
Swap the wires between the extruder and a known good servo. This will prove the servo is ok. Swap wires back after test.
Swap the Pololu drivers between extruder and known good other. This will prove the Pololu. Swap drivers back afterwards.
If it has Pololus, ensure trimmer is on Pololu is not set too low.

10

I’ve already tried that. The motor & driver is fine.

11

You’ve also tried swapping connectors to check the wiring?

12

Is your extruder nozzle hot when you try to move it? Marlin might have a temperature limit enabled that keeps the extruder from turning when it is cold to keep you from grinding out your filament. If you set the min temp limit to below 20C it should turn for you. Just don’t have filament in it and remember to set it back up to something like 190C before you go back to fine tuning your filament feed.

Just saw the other comments that already covered this possibility…

13

Yes, I connected the extruder motor to one of the axis connections and it worked fine.

14

To check endstops: http://marlinfw.org/docs/gcode/M119.html
To check hotend temp: http://marlinfw.org/docs/gcode/M105.html

By default the hotend must be above 170c to extrude. Change temp here:
http://marlinfw.org/docs/gcode/M302.html

15

I’ll recheck, but when I ran that motor by placing it on the x-axis, it ran the filament into the extruder/nozzle. I can lower the min temperature to 20-30, but it usually gives a min temp error if that’s the problem

16

Thanks guys

17

Is the current limit pot set correctly on E0’s driver?

18

My initial thoughts would be wiring. I would bet it’s something simple, but it’s frustrating

19

(Sorry, I deleted my redundant comment above - the thread made more sense with it in retrospect)

20

Actually, there is no pot on the 2nd controller (Rambo), I adjusted the current to above the other drivers on the other controller (MKS GEN v1.4)