Extrusion failure / clogged nozzle since Upgrade to MK2.5  

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Hey, Ive been having this problem for the last 6 months and havent had much luck. Some prints are good but the problem always comes back. Ive tried pretty much everything in this thread and even bought a brand new E3D V6. Re-printed the R3 parts 2x. If I remember correctly this started after switching to the new R3 parts.

@pekka.p One thing I havent tried using M907 E750 which Im doing as we speak and printing a Cali Cat. One thing I wanted to know is does the command auto save and anytime I use the printer it will have that setting? also incase I need to revert what is the stock current?

Other thing I noticed is the fan is pushing air OUT of the heatsink which from what Ive read is whats most agreed on instead of pushing air through the extruder. I feel its the Noctua fan causing all these issues. Before this upgrade included the Noctua fan ppl were upgrading there fan to the Noctua as did I wanting a quieter printer but found I started getting clogging issues so reverted back to the stock fan.

I have tried eeeeverything and it just seems there isnt enough airflow to cool down the heatsink and Noctua just isnt doing the job. I think I might have the stock fan so if M907 E750 doesnt work I will try the stock fan and report back.

Edit: Cali Cat printed! So prior to changing to M907 E750, I was having issues printing Cali Cat on first layer started clicking. While clicking I loosened the idler screws and pulled filament out a bit then let it flow. Printed Cali Cat the current changed and it printed perfect. The print is only 1hr long so the real test will be tonight when I can start a longer overnight print. Will update.

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

@vladimir.h3: M907 command does not save the settings so when the printer is restarted it will reset to default, which is around 500mA I think...

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

I am having the same problems after upgrading to the MK2.5
Strangly enough, i printed 3DBenchy perfectly on the first day, but since then, after some time the extruder motor starts clicking and skips step - nothing is extruded.

Some observations:
- It seems to happen later on lower temperatures (only one test print so not enough data)
- Cold pull seems normal, no hints of a clogged extruder as with the next point
- After unloading the fillament (there is a bit of force required) i can directly load the filament again (cut the tip) and it comes out normally
- One time i had the motor clicking after unloading, so it blocked *without filament*

With point 4 I thought it could be the ptfe tube that seemed a bit to high possibly touching the gears, i shortened it but still the same problems. (I can rotate the extruder motor without problems)

Printing https://www.thingiverse.com/thing:2823006 (hollow) with default settings MK2.5 0.2 Linear Advance, Prusament PLA (using the blue one) fails about 30 minutes in.

I don't really know what could be the cause any more, i can think of:
- Somehow after some time my extruder motor moves a bit hitting the enclosure parts?
- The fan is no powerful enough and the motor cannot handle the heated pla (prusaments can get really gooey)

... any suggestions welcome

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Update: I just finished the print successfully.

Parameters changed:
- Switched from Prusament Azure Blue to Pursa PLA White
- Changed slic3r profile accordingly
- Lowered ambient temperature (Opened the window next to the printer from time to time, it is freaking cold outside :))

I am not sure if it skipped steps, i do not see any indication on the print but thought i heard a click once in a while (or it was just in my head, i was few meters away from the printer). Forgot to mention that both the last failed print and this one were in silent mode as it is late here and i don't want to disturb my neighbors :)) The failed prints before were in power mode.

A bit of hope, but more testing required

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Lowering the ambient temp does seem to help somewhat, but with prints that have lots of retractions, even that has proven inadequate.
I found one setting in KISSlicer that seems to reduce the jamming and that's the Destring (retract) trigger value; I had it at 1 mm which means that it was always doing destring when moving more that 1mm. However, KISS is intelligent enough that when moving to/over perimeters, it does retract anyways so there's no need to have the trigger value that low. Upped it to 10mm and now there's lot less retracts going on when printing infill and supports -> less jams. Sadly there doesn't seem to be similar option in Slic3r PE, or is there?

Also one thing I gave a shot since my other, a 4-material Prometheus based printer, had even more problems with particular cheap black PLA: filament oiling. And lo and behold, a 2-color 12h print was a success. Before, the jamming started to produce visible quality problems after first 30min and results were quite horrible. Successful result: ?dl=0.
One thing to note is that the red PLA was fine, even though the black was constantly struggling to extrude properly. So filament brand does matter.

I used this for the oiling: https://www.thingiverse.com/thing:1657311 . For oil, some olive oil I use for cooking. I did have some misgivings about the print suffering from reduced layer adhesion, but this video shows that at least with PLA that it might even be the opposite: .
I plan to try this with my MK2.5 too, but It's actually been running quite fine for a while now, probably due to lower ambient temp due to winter. I bet that during summer the problems reappear...

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

I thought I could force a quicker fail by using a Lattice Cube with lots of retractions ( https://www.thingiverse.com/thing:1856832 ) but it printed normally (of course it did). So right after that, a new try with the Spinner ( https://www.thingiverse.com/thing:2823006 ) and it failed (of course it did)

All with Slic3r (default settings) 0,2 mm, LA, Prusamant, power mode.

Spinner: As soon as the extruder started clicking ...
- i could pause the print, wait a bit, and resume the print for a while
- at least most of the time, i played the game 5 times than it did not work anymore
- unloading and reloading made it print again. (about 30 min from the end)
- print finished after that but i still wouldn't call that a successful print by any stretch

I used an ir thermometer in the hopes i could measure a noticeable temp change somewhere but nothing conclusive happened.

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Hi there,

i am experiencing simmilar issues with my Mk2.5 (in spannerhands enclosure).

Did anyone of you try to go back to the old Hotend-Fan instead of the noctua?

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Thanks @pekka.p for the reply about the M907 command. I had a good run for awhile but issue had come back. I took a long break as this has been frustrating but hopefully may have found a solution. As we speak I have tried a different extruder assembly slightly changed from the R3 parts. This: https://www.myminifactory.com/object/3d-print-81846

Now these parts may not even be needed. While changing the parts I tried spinning the extruder motor from the bondtech gear with minimal force until I noticed it would feel like it got stuck and needed way more force to continue spinning. My thoughts are it should just keep moving without changing the amount of effort. It reminds me of the times it would start clicking and sometimes I would need to nudge the bondtech gear with my hex driver to keep it moving and would continue on.

Sooo I took the extruder motor apart and with machine oil I lightly coated the bearings (there's 2) and put it back together. In doing this I tried again and now with continuous minimal effort it kept spinning without interruption. Makes me wonder if this had added to the issues but still worth mentioning.

In any case Im printing a cali cat to see how it goes!

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

@vladimir.h3: disassembling the motor might not be a good idea, apparently they might demagnetize and lose torque: https://reprap.org/forum/read.php?1,194350

Still, if the motor is already behaving badly and might need replacing, doesn't hurt to try...

Re: Extrusion failure / clogged nozzle since Upgrade to MK2.5

@vladimir.h3: disassembling the motor might not be a good idea, apparently they might demagnetize and lose torque: https://reprap.org/forum/read.php?1,194350

Still, if the motor is already behaving badly and might need replacing, doesn't hurt to try...

Thanks for the heads up! will definitely keep that in mind before even thinking of doing it again. Its been printing great so far, knock on wood.

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

I have the same problem on my prusa since the 2.5s upgrade. I had no problem with my mk2 prior to the upgrade... I tried several different setup, ordered new hotend, reassembled the whole extruder following the instructions carefully, but no luck so far. I'm still having this issue sporadically. The printer is now almost not usable... Wasting almost 1 print out of 2... Not reliable enough for my needs...very dissapointed about this upgrade so far...

I think the bondtech extruder is part of the problem... too much debris and too much friction added to the system.

Is there anyone been able to get rid of this issue?

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Maybe a combination of two different things: noctua fan not powerfull/not cooling enough & bontech gear that make dent in the filament...

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Hi @kevin-dionne

i made my upgrade last week from mk2s to mk2.5s and i had a lot of issues from there 😐

clogged nozzle at first print, lot of noise in the extruder ( clicking ) and no filament rolling 😐 try to reassembly everything in the extruder, no more stranges sounds so far, but i never finish a simple print...

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

@bruno-s5

Hi, 

I have been able to solve the clog problem I think... I added some thermal paste to the heatbreak threads on the cold sise. Now the heat goes away faster and the filament does not get soft before entering the heatbreak hot side... I don't know why prusa is not recommanding this on the assembly instructions. I found this info on E3d forums...

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

@kevin-dionne

thanks for the quick reply, can you share more info about this changes? thanks!

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

Is this http://wiki.e3d-online.com/wiki/E3D-v6_Assembly#Thermal_Compound  ?

Thanks

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

I use thermal compound like that.

but don't forget to wipe the excess off after screwing together,

regards Joan

RE: Extrusion failure / clogged nozzle since Upgrade to MK2.5

@bruno-s5

https://www.matterhackers.com/articles/how-to-assemble-an-e3d-v6-all-metal-hotend

Step #15