Extruder motor problem?  

Re: Extruder motor problem?

Just raise the temp..

Re: Extruder motor problem?

Hello.
What kind of filament did you use before we started jogging our extruders?
When the ABS or PETG? Has to be warmed up to 260 degrees and 500 mm of pla filament to clean the nozzle.

Re: Extruder motor problem?

Yes i raised the temperature for print ABS (255°C).
When the nozzle was clogged i cleaned it extruding PLA at 275°C i think nearly 30-40 cm, then i tried a Cold pull.
The video was taken after disassembled completely the extruder, check everything inside, clean the nozze untill inside was free of fusion plastic.
The video show the filament extruding well before start printing, no clogged at that time. Belive m,the nozzle was really cleaned.

Re: Extruder motor problem?

I recently had this problem on my MK2S I do not have MK3. So I'm going to help solve the problems. I apologize for my English from Slovakia. I had a problem with a threaded tube above the nozzle, a small Teflon tube OD3 mm ID2 mm L 8 mm from the bottom. Figure 2 is a thread. You can use a printing works but you have to get the temperature at the nozzle +10 degrees or more. I do not know either or MK3 has the same hotend.

Re: Extruder motor problem?

I'm seeing the same thing on my MK3 after my filament sensor overheated which caused PLA filament to jam in the PTFE tube below the extruder gears and deformed the ABS extruder housing around the sensor. That noise was actually what caused me to discover the meltdown, but now it's still occurring after I pulled the sensor out. While observing it looks like the extruder gears jump whenever the noise occurs, which makes me think the extruder stepper gears might be damaged from the jam or overheat.

I might try reprinting an extruder housing to see if maybe it was more deformed from the overheat than I thought, but it does seem like a stepper motor issue... I wonder if maybe the dual gear Bondtech requires a beefier stepper motor?

Re: Extruder motor problem?

I am having the same problem. My first 3 days of printing were flawless. Best prints ive seen compared to mk2s. Then all of a sudden, clicking sound from bondtech gear. Its skipping all over the place and under extruding. Ive tried everything i could think of to correct the alignment and gear contact but nothing works. Has anyone solved this problem?

Re: Extruder motor problem?

After had first jam and the filament of ABS runs out completely (like TPU filament...) i touched the extruder motor and i really burned my finger. Can try your solution to reprint all extruder base and cover. In effect also the nozzle shroud is a little bit melted. Very strange because i use the silicon sock...

Re: Extruder motor problem?

i have only printed with PLA at normal temperatures ie 210F. what caused gears to misalign?

Re: Extruder motor problem?

Still no answer from Prusa customer service........

Re: Extruder motor problem?

Same happened to me when the filament sensor was overheating and making the filament go soft before the extruder, just before it died in a puff of smoke.

I'm hoping the motor itself is fine when I get the replacement parts from the sensor death.

Re: Extruder motor problem?

Same happened to me when the filament sensor was overheating and making the filament go soft before the extruder, just before it died in a puff of smoke.

I'm hoping the motor itself is fine when I get the replacement parts from the sensor death.

Yes you are right, my bsensor is really too hot!!!! i never touched it before!!! I'm still waiting the answer from the customer service.... by chat they are fast but when they ask you to send the video by email (link to youtube or something else) no answer for 2-3 days..
My opinion or it's a problem from the einsy board or from filament sensor or from the extruder motor....

Re: Extruder motor problem?

Same happened to me when the filament sensor was overheating and making the filament go soft before the extruder, just before it died in a puff of smoke.

I'm hoping the motor itself is fine when I get the replacement parts from the sensor death.

Yes you are right, my bsensor is really too hot!!!! i never touched it before!!! I'm still waiting the answer from the customer service.... by chat they are fast but when they ask you to send the video by email (link to youtube or something else) no answer for 2-3 days..
My opinion or it's a problem from the einsy board or from filament sensor or from the extruder motor....

If I were you I would immediately disconnect the filament sensor. As far as I can tell, there is nothing in place to cut power in the event of a short on the sensor board and it seems to be able to draw a lot of ampage from the controller board in order to reach ABS-melting temperatures. I'd get back on chat and stay on chat, the support guy I got last night was very helpful.

I suspect the following happened to me (based on what I could see in the aftermath):
1: All was working.
2: It looks like part of the printed housing for the sensor board got damaged and broke off. This is below the sensor cover, though, so you won't see it happen!. I would guess that the "blob" at the end of an unload would be the culprit.
3: Continued printing moved the broken part around and destroyed the sensor
4: Sensor goes open circuit (short) and will draw all the amps the power supply will give it.
5: Einsy pumps lots of amps to the sensor so it can melt ABS(!). The sensor should never need this much, surely - Einsy should run a fuse or limit ampage or detect short and cut power.
6: Heat builds, catastrophic failure with lots of heat and smoke. Nice.

So (and I am speculating):
1: Design flaw in the sensor housing area, where part of the printed part can break off with odd-shaped filament or brittle filament can end up loose in this area after a load/unload.
2: No protection of the sensor in the event of a foreign object being present in the housing whilst filament is constantly moving through it or being pushed around during a load/unload. I'd say bits of filament ending up in here is almost an inevitability from unloading. The sensor might need to be better protected by the housing design or board design to leave it less exposed to damage.
3: Einsy offers no protection from the sensor going open circuit. It does know that there's a problem with the sensor, but will continue to supply power enough to melt ABS.

Re: Extruder motor problem?

So finally i spoke with a very good person at prusa chat, he watched my video and after explain other things he also suspect the problem come from the filament sensor. He suggest to try print without the sensor ( take off the plug) and magically my MK3 start print good again!!
He also said me they are working to better power control from Einsy board.
Now i can print but i'm waiting for the new sensor.

Re: Extruder motor problem?

i think the problem is that the idler pulley shaft is too short so even if you center it perfectly, it ends up sliding towards the motor side leaving the gear side to have some play and therefore click as it skips because of loss of contact with the motor pulley. This play will likely damage your bearings. Mine are grinding as it turns and mk3 is underextruding significantly. Waiting for some replacement parts to repair this. I will update when I receive parts and replace.
(obviously there is more than 1 problem occuring and being discussed in this thread) It appears that they are busy at prusa, but customer support has been great on chat window.

Re: Extruder motor problem?

My extruder stepper motor gets stinking hot.. I'm going to check the sensor.... 🤔

Re: Extruder motor problem?

If there are no changes prior to getting my unit I think I might pull back the extruder motor from the extruder housing by 1mm and insert four flat washers as spacers. This will reduce the heat from the stepper motor from going into the housing. The Bondtech gear will need to be repositioned on the shaft. I may also design in heat vent channels in the top sensor cover for better ventilation.

Re: Extruder motor problem?

If there are no changes prior to getting my unit I think I might pull back the extruder motor from the extruder housing by 1mm and insert four flat washers as spacers. This will reduce the heat from the stepper motor from going into the housing. The Bondtech gear will need to be repositioned on the shaft. I may also drill 5mm heat vent holes in the top sensor cover for better ventilation.

Careful with those holes... If light gets through and hits the sensor you will have false readings.

Re: Extruder motor problem?

Thanks Leonardo,

I changed the concept for possible sensor cooling while you were posting your reply.

Might even give this extra 20mm to 30mm QUIET fan a try.

20mm Fan:
https://www.jameco.com/z/AD2012LB-K70-ADDA-Corporation-12-VDC-0-6-CFM-DC-Fan-with-5-5-Inch-Leads-20x20x6-mm_2134299.html

30mm Fan:
https://www.digikey.com/product-detail/en/sunon-fans/HA30101V3-000U-A99/259-1615-ND/3694182

Re: Extruder motor problem?

I am considering an insulating gasket between the motor and the mounting (where an air gap is suggested above).