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Extruder motor issues  

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laura.m2
(@laura-m2)
Active Member
Extruder motor issues

Hi everyone!

I'm facing a major problem on my MK2S and I'm out of solutions 🙁

The problem is :
About a month ago, my printer starts failing prints and no filament was extruded during the print. So upon advices from other makers, I thought it was clogging and I checked several things :
- Humidity level, which is ok
- I cleaned the nozzle, the pulley and the extruder, everything is Ok too.
- Tension screws, I checked that the tension was correct and run several test based on the useful thread found on this forum. (it was ok too)

After all that, my prints keep failing and I started to noticed other issues:
- Its not always at the same Z value, it could be on the first layer or in the middle on the print or at the end.
- When a print fails, the extruder motor doesn't push the filament anymore it just steps back and make a clicking sound (see the video, sorry for the poor quality)
- after a failed print, when I reload the filament, the plastic came out nicely no problem.

So I'm assuming that the extruder motor is the problem, but how can I be sure?
What should I do next ?

Thanks,

Veröffentlicht : 04/07/2018 5:37 pm
Knickohr
(@knickohr)
Mitglied Moderator
Re: Extruder motor issues

Check if you have a cable braek of the extruder motor cables.

Sometime it is located at the bending edges of the x-carriage.

Thomas

Veröffentlicht : 05/07/2018 9:11 am
laura.m2
(@laura-m2)
Active Member
Themenstarter answered:
Re: Extruder motor issues

Hi Thomas !!

thanks for your advice, How should I test it? Should I move the extruder from an edge to the other while the motor is working (maybe with the command in the settings ?)

Veröffentlicht : 05/07/2018 2:19 pm
BillC
(@billc)
Reputable Member
Re: Extruder motor issues

Heat the nozzle and unload filament, you don't need it for the test.

With the nozzle still at temperature, use Settings | move axis | Extruder to dial in a move of maybe 200mm
While the motor is running to do that, wiggle the cable bundle gently left and right, up and down and see if the motor cuts out and restarts as the wires move.

If it does, you will need to unwrap the cables and feel along the length to see if you can find the break.

Remember to reset the temperature on the settings menu when you finish the test.

Bill
Tagaytay City, Philippines
Founder member of Philippines Prusa Printer Owners FB Group
Sponsor Pillars of God Academy in Bacoor

Veröffentlicht : 05/07/2018 6:02 pm
Knickohr
(@knickohr)
Mitglied Moderator
Re: Extruder motor issues

Yes, correct.

As Bill describes, extrude some cm of filament, dial the knob very fast !

Another Test :
- mark filament 20cm above hotend
- extrude exact 10cm of filament
- don't touch extruder or move it while extruding
- measure the mark (x) at the end of the extrusion : calculate 20-x
- do the test again while whiggling heavy on the cables and moving the extruder
- is the measurement still the same as the last ?

Thomas

Veröffentlicht : 06/07/2018 8:54 am
laura.m2
(@laura-m2)
Active Member
Themenstarter answered:
Re: Extruder motor issues

Hi bill, thanks for the tutorial!

I'll try out this weekend and let you know!!

Edit : I did see your message soon enough, Thanks Thomas for the tips!

Veröffentlicht : 06/07/2018 9:19 am
laura.m2
(@laura-m2)
Active Member
Themenstarter answered:
Re: Extruder motor issues

Ok Guys!!! Here's the update!

I followed your steps to check if the cable is damaged, result: it seems not. I made the extruder turn for a while and moved the cable in all the directions, the motor keeps turning as expected. I also tried to move the entire block along the axis, nothing wrong the motor keeps turning.

BUT, I got trouble to unload the filament, the pulley was ripping on the filament. So I tried to load the filament and it loads just fine. Then I try again to unload the filament, it get out properly 😕
I don't understand what could be the problem..

Then I reload some filament and tried again a test print (always the leapfrog from prusa), I printed it with Filament-PM PLA @ 218°C/55°C. (I raised to 218 on prupose, to test if it could change something)
After a few minutes, no filament were extruded on the print but the nozzle get messy and full of melted PLA! (see the attached picture)

I was wondering:
- Maybe it could be a partial clog (not full I guess because some filament came out) ?
- Maybe the temperature raise is causing this ?
- can it be a damaged nozzle ?

I thinking about disassemble the entire block and see what is going on in there.


Veröffentlicht : 06/07/2018 11:12 pm
BillC
(@billc)
Reputable Member
Re: Extruder motor issues

If there is any old filament stuck on the nozzle/block then it melts as you print. When it reaches the tip the new filament catches it and starts to blob instead of 'falling' to the print object.

Use the Settings | Temperature on the LCD to heat to print temperature and clean off all the filament on the outside of the nozzle and block. Reset temperature to 0 and let it completely cool down then check again to make sure the block/nozzle are still clean.

Print a temperature tower for the filament you are using - it's a good idea to do this for every roll of filament - and that will guide you to the correct nozzle temperature to use in your prints. First layer 5 degrees hotter and at 40% of the speed. If you start with a clean nozzle and use the right temperatures then this should stop happening.

Bill
Tagaytay City, Philippines
Founder member of Philippines Prusa Printer Owners FB Group
Sponsor Pillars of God Academy in Bacoor

Veröffentlicht : 07/07/2018 3:58 am
Knickohr
(@knickohr)
Mitglied Moderator
Re: Extruder motor issues

Try some atomic pulls and clean your nozzle :

https://toms3d.org/2017/01/09/basics-cleaning-clogged-nozzle/

Thomas

Veröffentlicht : 09/07/2018 10:44 am
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