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Hi there,

I recently purchased a CTC prusa i3 kit from ebay (£150) and it had been printing ok for about a month or so. But about a few days ago it started producing really nasty prints and I’ve completely rebuilt the whole thing once and the extruder assembly at least 5 times now (I know how to do it).

I’ve found that the problem is with the stepper motor on the extruder. What happens is as follows:

-I turn on the printer

-I set the printer to heat the bed and nozzle to the preset PLA values (180 for the nozzle, 70 for the bed)

-I can extrude plastic fine when manually controlling the stepper

-as soon as I start a print job, the extruder can extrude plastic perfectly fine for the nozzle clearing procedure at the start of a job

-As soon as the print starts, the motor begins clicking and it seems as if the motor is stalling but I completely removed the motor so it had no load on it and it still clicks.

-When I turn the printer on and off again, the motor is fine until it starts printing again.

Please, if anybody knows what on earth is going on then I’d be delighted if you could shed some light onto my problem.

Thanks, James

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If it clicks with no load on it, it may be a bad motor, bad wiring, bad stepper driver or bad solder joints. You can try swapping out the stepper driver with one from another axis if the control board permits. You can also swap the motor with another axis, same thing with the wiring.

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Thanks!

I will do that. I didn’t think about that before

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Pause the print when it clicks, try to put a paper under the nozzle and see if the distance of the nozzle is good enough from the bed, it shouldn’t be too loose nor too tight. Then stop the print, unload your filament, cut the unloaded filament diagonally and rub 5~10cm of it with olive oil, then put the filament back into the extruder and start printing. Make sure the load spring is pushing the filament against the feeder hard enough if you have any.

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The motor clicking usually is caused by either the motor cannot pull anymore into the extruder or it cannot push any more filament out of the nozzle, but if the motor is clicking when under no load I suggest perhaps checking the motor is wired correctly and each pair of coils are wired up properly. Also when the motor isn’t under load, does the shaft rotate even though it clicks?

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I believe you have a E3D v5 or v6 replica hot end. If so, just increase the temp to 210c-220c and turn the layer fan off, if you have one. If that stops the sound then it has nothing to do with the motor or the driver.

Now, you need to check the filament pressure. If you have a bowden tube, just looking at the moving tube you can tell. But, if you have a direct extruder, you need to do it by holding the filament release lever with one hand and pushing filament through with the other. It should be easy to feed at 210c-220c. If not, then you have issue in the hot end. But if it goes easy, then your filament needs high temp to work with. Start printing at {(the temp it stops clicking)+5c}.

I have found, after many many hours of cleaning the hot end, that just putting in new Teflon tube (if you have any) and new nozzle is the most stress free and economical solution. Nozzle can be “burned”, but if the Teflon tube is constricted, you have to put in new one.

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Hi everyone, Thanks so much for all the help. Last night I swapped the stepper motors from the x axis and extruder around but to no gain so I have ruled out a bad motor. I also swapped the stepper drivers but that had no effect so I now know that the problem is mechanical. I then decided to take the extruder apart and take a closer look at the hotend. I did notice that the throat (I think that’s what it’s called) didn’t come out even when I took the grub screw out completely. Is this normal?

In any case I think it would be a good idea to get some more Teflon tubing and more nozzles (combo pack with a 0.2, 0.3, 0.4 and 0.5mm).

I have what looks to be a mk7 extruder, direct drive.

Thanks again, James

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If it extrudes manually then there is nothing wrong with the motor/driver or electronics. Two most likely things:

1. Your slicer settings (which are different then the setting being used for the manual control) are wrong. Look at extrusion rate, extrusion acceleration, etc (depending on your slicer)
2. Your nozzle is calibrated too close to the build plate and there is no place for the material to go that you are trying to push through the extruder.
-Jesse