Problems most possibly heat creep while printing
Hello guys,
I was printing fine with my XL and 2 tool heads.
From one day to another I cannot print anymore without filament jams while printing.
The gear is grinding into the filament and the printer continues to print ofc. without extruding on BOTH extruders.
I tried solving it the past couple days and wasted multiple kiloes of filament without any success.
My setup right now:
0.6mm HF Nozzle on Extruder 1
0.4mm Nozzle on Extruder 2
No case.
Room temp around 23°C
Side filament sensor bypassed because it jammed also a lot.
So my tries are:
-New roll of filament (SUNLU PETG and SUNLU PLA) both printed fine until a couple of days ago
-Cold pull on E1 and E2
-Changed nozzle from Prusa Nozzle 0.4mm on E2 to E3D 0.6mm on E2
-Printed PETG with 3mm³ to 30mm³ and 230/240/250/260°C (240 seems to be best...jams later)
-Tried PLA with 3mm³ to 30mm³ and 210...240°C which is fine by the filament
-Complete stock settings for Prusament PETG (240°C and 33m³ limits, which are stock in my prusa-slicer)
-Bed temp usually 80°C which is also stock setting lowered to 70 and 60°C
-Ripped apart both extruders (E1 was a little dirty with 100+h of runtime, E2 was nearly stock clean with about 10h of printing time)
One thing I had in mind is that my heatbreak fan on E1 is damaged since delivery because its not spinning on the correct fax axle and scraping on the plastic shroud but it ran fine for 100+ hours.
But in anyway it seems to have nothing to do with the extruder because both are jamming with all possible settings and nozzles I could try.
Does anyone have any more ideas I could try?
RE: Problems most possibly heat creep while printing
There are updated parts dwarf-cover-connector and dwarf-cover-base. They are suppose to fix loose connections user had experienced. First, try to reseat the connector on one and only one extruder. I wish one could observe the rotation of the extruder motor like in the MK3-series.
Does it happen at first layer or also further up? I guess the latter otherwise you would not have wasted so much filament. On the XL you might observe the nozzle versus heatbreak temperature sensors. Unlike my XL, my MK3S+ showed clicking extruder in summer prior the update to + and a titan heatbreak. Most often during intervals with little extrusion but many retracts. Does a single layer patch look ok? If not z might be off.
Clamping the nozzle tube too tight might compress and ruin it. Clamping it not enough and it might slip downwards and throw mesh bed leveling off. Does the latter work as usual? Does loading and flushing filament work as usual? For a test you can bypass the ptfe tube and put, say, 1m of filament directly into the Nextruder. Try, whether drying the filament helps. The levers carrying the pressure applying rollers on the extruder might have been damaged on both Extruders during your trials. Changing spring load on the Nextruder is worse than on the MK3-series.
Does not hurt to verify the diameter of the filament with a caliper. Do you have some Prusament for comparison?
Btw: Which firmware version do you use?
RE: Problems most possibly heat creep while printing
I haven't replaced the updated parts yet. My connectors are all properly seated and connected.
Btw. I only disconnected E1 and got the same problem with all Extruders.
Also the extruder motors are running fine, because they are grinding away the filament like 1) they can not pull through the ptfe tubes or 2) the force to push the filament through the nozzle is too high.
For 1) I'm using spool holders which are running very very easy. It feels like you could blow onto the spool and it starts moving.
For 2) On E1 is a 0.6mm HF nozzle original prusa which should show very low resistance to allow high flow rates.
On E2 i changed from 0.4mm nextruder nozzle to E3D adapter and used an e3d 0.6mm nozzle which also should result in very low flow resistances.
The prints on both extruders also look totally fine...until the print fails at random points...sometimes after the first layer sometimes after 30 minutes or with 4h prints right at the 2nd last layer. It's totally random.
For the thesis with the pushing force being too high I tried the stock prusa settings with 33mm³ volumetric flow for the filament and 260°C nozzle temp which is the highest specified value for my Sunlu filament...and it works fine...prints for hours and fails to extrude at some point.
Also the filament is newly opened because I wasted 2 full spools until now. Also tried printing directly from a Sunlu dryer box which dried the filament for one whole day at 50°C before I had to open the 2 new spools to waste them.
I think the nozzle tube wasn't tightened too much. It was just tightened enough that it holds but with no excessive force. Also E2 already showed the same behaviour with being in completely original condition and only 10 hours of printing time.
Bed leveling work just fine with both extruders and the first layer is flawless (also the print looks perfectly fine...until it fails to extrude)
Loading and flushing filament also works fine.
Spring loads at the extruder gears was only modified on E1 and not on E2 for testing purposes.
Firmware is the newest available...6.2.5+8912
Last thing I could try is using prusament PLA but my guess it would fail just like the Sunlu PLA which also fails and worked fine for the whole time I got my XL.
RE: Problems most possibly heat creep while printing
Try to print a presliced gcode example from Prusa. Just to rule out the slicer.
If both nozzles are not really clogged and filament running free it sounds like the nozzle temperature is at least temporarily too low or you have indeed a heat creep. Yet with both extruders failing, bad thermistors are unlikely. Unlike on my MK3S with its small extruder gear wheels, on my XL I have not seen filament chopped away by the big gear wheel.
The pcbs at the back are known to become quite hot. Disassemble the cover tor a trial so that the heat is not kept inside.
You can downgrade to a previous firmware version. If that does not help you could try a factory reset. Maybe some internal state got corrupted somehow.
Disconnect the PTFE tube at the toolhead but don't loosen it, maintain the curve then try to pull the filament though by hand - get some idea of the tension at the extruder.
If any of your filaments were in any way dusty or sticky you may find cleaning out the tubes helps. If you have been printing abrasive filament the inside of the tubes may be worn enough to begin gripping ... you can confirm this if you can feed filament directly to the toolhead from above bypassing the tubes; in this case replace them.
As @blauzahn suggests, make certain your filaments are dry, do not assume that new means dry, the manufacturer packed it dry but you have no idea how it was stored and handled in the interim.
Cheerio,