Extruder Motor Issue!

MindFuLL · 2016-09-28T17:52:53.000Z

Unless you have a multi-meter to check the Vref pin, the best metric is to monitor the heat. If the motor and/or driver is running very hot to the touch(warm is okay) then you want to turn it down.
-Jesse

Derek_Tolliver · 2016-09-29T09:49:31.000Z

What kind of printer is it? Are the two wheels that push the material clean? They can get gummed up and no longer grip the material. Are the two wheels under tension? When the material is pushed through the wheels, the material should have little dimples in it where the wheels grip tight.

DreamSpace · 2016-09-29T10:20:21.000Z

I have had the same problem countless times and the main causes that I have found on my printer is that when the extruder gets too hot the heat creeps up the barrel and melts some of the plastic inside it, making it harder to get filament through. If I were you I would replace the barrel and maybe the nozzle. Also check the vref of the extruder motor and look up what it is supposed to be. I believe it’s somewhere around. 6 vref. I have noticed it helps to turn the extruder one up a bit to give it a little more current and power to turn the motor. I personally never liked the little peice of tubing in the barrel no matter what material it’s made of… I usually take that out

martin_p · 2016-09-29T11:16:02.000Z

What if you try to push manually the filament through the extruder? Does the material come out? It shall come out very easily. I had also an issue with the extruder and in the end it was the toothed sprocket misaligned with the wire because the PLA extruder body was deformed. It was very small offset but was enough to prevent filament to be pushed out.

ProtoPlastik · 2016-09-29T12:44:41.000Z

What hot end are you using? In my experience, poor feed is the result of the following:

- low temperature

- on e3D hot ends, check the PTFE tube. They should be replaced occasionally. If you’re not sure, replace it anyway.

- also on e3D, make sure the heater block, nozzle, and barrel are all tight

- drive gear alignment with the tension bearing

- drive gear clogged

- drive gear slipping

Run the stepper without it being installed. Check to make sure motion is smooth. Bad cable is a possibility. Also check the header on the board. If you replaced the motor with similar results, it’s not likely the motor. Could be current, low current will cause the motor to “clutch” and that produces an audible clicking sound.

Ronca · 2016-09-29T12:49:09.000Z

Hi there

In your shoes I wolud check and/or rise the Vref value of the pololu of the referred extruder motor.

I rised up the Vref over the suggested value. The motor is a little bit warm during the whole (long) printing, but it works just fine.

Ciao

CollectorCNC · 2016-09-29T13:20:23.000Z

Try lubricating your filament. Do one drop of canola oil on the end of your filament then feed it in. Also you can take a paper towel and a binder clip to make an oiler that lubes the filament before it enters your ptfe tubing. I find that especially with PLA, this really helps on both my direct drive and Bowden printers.

ABigBirch · 2016-09-29T13:44:53.000Z

I do this almost every time I reload the filament, it doesn’t seem to do much for ABS or PLA. Thanks for the help though.

ABigBirch · 2016-09-29T13:48:32.000Z

How would I go about changing this? I have tried to adjust the current, but it didn’t seem to do anything. I just need a bit more detail, this is my first printer I have owned.

christiangentry · 2016-09-29T14:26:17.000Z

There’s rarely an issue with the stepper motors. I’ve had feeding trouble, also, and it’s always been a mechanical issue such as the tension spring had too much or too little tension.

One other factor you may not be thinking about is thermal issues. If the ambient temperature in your printing area is too cold, you will have trouble with feeding.

Can you respond with specific details about what you’re seeing? For instance, when you preheat the hotend, then extrude do you see the hob rotate and chew up the filament? Does the hob NOT move? I think if you can paint a clearer picture for us we could help more.

ABigBirch · 2016-09-29T14:37:30.000Z

The stepper motor does not run smoothly, it will rotate on its own when it is not installed, but it has a very jerky motion. It’s a new motor, and the old motor does the same thing when connected to that cable.

ABigBirch · 2016-09-29T14:43:51.000Z

The filament does not get chewed up and the and there hasn’t been anything wrong with the temperatures. (I installed my hot end on another printer, and it worked fine) The motor doesn’t seem to have enough strength to push the filament through, it is unable to strip the plastic off the filament. It twitches back and forth when it hits any resistance. The hot end is also completely clear of all plastic debris.

christiangentry · 2016-09-29T14:44:17.000Z

If the same behavior is occurring with different motors, then the issue is likely not the motors. It could be a physical issue with your controller board such as power delivery or firmware. Also, wiring is always a possibility. “Jerky” sounds like a bad connection, so that may be a good place to start.

ABigBirch · 2016-09-29T14:47:52.000Z

It is a modified Prusa i3 printer, the whole extruder assembly is completely clean and free of debris. The two wheels are under the correct tension. The plastic does have the small dimples. When the filament does not extrude, it is not being stripped either, the motor simply twitches back and forth, like it’s too weak to do the job.

ABigBirch · 2016-09-29T14:49:43.000Z

Thanks for the reply, I’ve ordered new wiring. I’m not sure it’s the control board, because every other motor works perfectly, and it’s a new board that I had replaced rather recently.

ABigBirch · 2016-09-29T14:51:52.000Z

When the motor is not installed, I can easily push the filament through. Even when the motor is installed, if I help push the filament, the motor will extrude it, on its own it is unable to.

ABigBirch · 2016-09-29T14:55:16.000Z

I now know it’s not the hot end, I’ve installed it on another printer and it worked printed fine. I checked the vref, and it seems to be sitting at 0.2. How much would I have to turn the trim pot on the stepper driver to increase this? Or is that just for increasing the current?

ABigBirch · 2016-09-29T14:56:41.000Z

My vref is at 0.2, what would be the best way to increase this?

ProtoPlastik · 2016-09-29T15:44:43.000Z

Is it a RAMPS board? If so, check to make sure you have all the jumpers in place. Got tripped up by that one more than once. Try swapping out drivers.

christiangentry · 2016-09-29T15:56:14.000Z

The following possible causes come to mind

a) physical connectivity: polarity reversed?

b) firmware needs reflashed

c) hotend temp lying! Thermistor issue? (it it doesn’t extrude, maybe its not hot enough)

Please use the “divide and conquer” technique for troubleshooting

Isolate the faulty / problematic variable. Do this by testing the integrity of each component SEPARATELY. This will include running the stepper motor by itself from a static power source, or plug it into a different port then manually control it to determine if its faulty or healthy. Also, you’ll need to test the port on the controller board with a different motor. When testing it don’t have the motor installed on your extruder. Divide and conquer.

“Twitching” instinctively seems like a physical connectivity issue. A shorting wire that is exposed or something else that is affecting the continuity of the circuit.

EDIT: not enough power to extrude the filament could be just that: a power issue. You need to use a multimeter to check the appropriate power is being delivered all the way from the PSU to the stepper motor’s port.