I recently received my dual extruder upgrade kit and was excited to start printing after all the trouble I had with it initially. Unfortunately the trouble continues.
I tried printing the dual material calibration cube from the Luban library. Black PLA on the left extruder and black TPU on the right.
Part way through the print the left extruder blocked and only the right side finished printing. See the attached image.
I opened the extrusion gears on the left side but I don’t see anything notable. The filament goes in and has some gear marks on it. I tried both advancing and retracting the filament using the touch screen, but it won’t move in either direction (200 degrees).
I’m not sure what you mean… The clips that hold the tubes going in the top are installed. The one on the left is pretty visible, the photo cuts off the one on the right.
The crossed angle of the PTFE tubes is causing the filament to be misguided as it inters the grip of the extruder they shouldn’t crisscross make them as straight as possible even if that means dropping the Z manually to make sure its seated fully
When I experience clogs, one of the things I always do is change the nozzle because it’s hard to tell what might be baked inside. I’m not talking about replacing the entire extruder, just the MK8 nozzle.
I’d perhaps try to exchange the left and the right hot end module. If the left is the one that keeps clogging, the problem is likely not related to the hotend module. If after the swap the right side starts acting up, it may be related to the hotend module. That at least gives a starting point for troubleshooting.
It looks like my problem is too much retraction. I was able to clear the nozzle and found that the filament had bunched up in the extruder gear area. I hadn’t seen that before because it was so dark. I was able to reload the filament and then I transfered a gcode file and tried printing it from the machine interface (not via Luban as before). It gave a warning saying that the retraction setting was too high.
I can’t find the retraction setting in Luban at all. Where do I find that? I was trying to slice with Luban. I guess I should switch to Cura…
EDIT: I’m now not so sure this is the issue. I opened the gcode in a text editor and the comment says the left extruder retraction distance is 1mm which seems OK. The warning was from the right (TPU) extruder which was 5mm. This is probably fine for TPU and it isn’t the one I have trouble with.
I’m on my second dual extruder print head and I have the exact same problem. Left will start printing, but then stops in the middle of the print. I’ve tried higher temperatures, lower temperatures, increasing the pressure on the drive gears by installing the silicone wedges. Adjusting the Zheight, in case, the initial layer was getting blocked and causing the filament to strip out. I’m at a loss…I will say, installing the silicone wedges (in the correct position) made the print head so tight I broke the bottom tab just by squeezing it to open it, so be careful with those.
I have had all sorts of trouble with the dual extruder. What fixed this issue for me was to take the hot end apart and apply new heatsink compound where the heatsink is located. This fixed it for all my hotends (I have 8). The same stuff used for heatsink compound for PC’s
Simply put, the Snapamaker hotends did not have enough heatsink compound. I think some melted plastic formed a plug just above the heating block. Once formed, it is impossible to remove without taking the hotend apart. In my case, I had to drill out the stuck PLA.
Does the heat sink slide off the filament tube? I assume you have to undo the tiny hex head grub screw? After the heat sink is off do you just apply the heat sink compound around the tube so it is in contact with the aluminum heat sink?
Correct @MasterHobbyist, It took me a while to work it out (as our friends at Snapmaker have not provided any documentation), but yes, the grub screw needs to be loosened and the barrel connected to the hotend should slide out of the heatsink. You should be able to see a smudge of paste applied to the outer of the barrel when being manufactured.
I did have one that was jammed in (as if glued) and I snapped the head off when I applied force.
