Solved Cannot release hotend

Hi all,

so I got myself another clog and wanted to release the hotend to fix it. I've done this a few times in the past and never had much trouble with it. This time I over loosened the screw though, and it came off. Still this wouldn't be a big issue I guess, but now I can't seem to be able to release the hotend for some reason. I have pulled the tab all the way back but still the hotend won't fall-off as usual. I can wiggle it a big a but it just doesn't fall-off.

Is this related to the me over-loosening the screw and letting it fall? How can I fix it?

Thanks in advance

 

no, there's a piece stuck inside (just barely sticking out of the feeder's teeth) which I was unable to remove so far

 

No I didn't. Do those springs keep the hotend in place as well? Looking at https://help.robo3d.com/hc/en-us/articles/115000716831-R1-Plus-Quick-Release I thought it was only the frontal screw and the side tab?

 

that must be it then :\

thanks, I'll try removing the loaded springs to get better access and then trying again to remove the filament

 

yes of course, but I already tried to remove the filament (both through the nozzle or back up) with the hotend at 240ºC and was unable to do so, that's way I want to release the hotend in the first place :\

 

Bad news for my printer I'm afraid

After releasing the hotend, heating the nozzle up to 240ºC and after a looong time to let the head go up I gave up on trying to get filament free by hand (couldn't get it out nor up nor down). So I basically cut the filament just above the heatsink and then tried to push down with the tiny screwdriver Robo provides that fits inside the heatsink. I managed to pull the filament a few cm down, but that was it. Couldn't even get the screwdriver to the end of heatsink.

I never had such a bad clog so I am a bit at a loss on how to proceed. In the meantime I've seen Robo support (https://help.robo3d.com/hc/en-us/sections/115000193252-Troubleshooting) suggests heating the hotend and turning it upside down so any plastic can slowly ooze down. Is that what you'd recommend as well? And what if that fails to fix it?

Thanks in advance

 

I'm getting really desperate here. I set to 230ºC and tried for a long while to push the filament with the screwdriver and also to turn it upside so that something could slip out. I couldn't slip it 90º for fear of breaking the flimsy thermistor cables and it should be around 75-80ºC, still nothing came out. Overall it must have been at 230ºC for almost an hour so I guess the heatbreak should have been pretty hot by then as well, but still I could not push anything out.

Any other suggestions? :\

 

So, I tried something a bit different. I heat the hotend up to 240ºC and took the nozzle out. Then I tried once again (still at 240ºC) to push with the allen wrench, this time from both sides (by inserting the wrench from where the nozzle would fit and pushing upwards). After a very short fight I managed to push a small piece of filament out, so I think I got it unclogged. At least now the wrench when inserted from the top seems to go all the way down as usual.

My question now is, should I just put the nozzle back in, or should I try the clean the nozzle out as well? I tried inserting a 0.3mm driill bit into the nozzle hole (it's a .4mm nozzle) and failed, but I'm not sure if that means it's clogged or if it can be normal. I saw some people use Ethil Acetate as a PLA solvent to clean the nozzle but I don't have it at hand. Should I jjust assemble it again and try to print, or should I do something with the nozzle first? I thought about putting it in the oven at 240º for like 15mins and try the drill bit again, would that be a good idea?

Thanks once again for all the help

 

I will remember that in the future

Unfortunately my saga continues... (please let me know if I should create new threads, since this one seems to derailing way off the original one)

After unclogging the heatskin like I described I also baked the nozzle in the oven to clear it a bit. I re-assembled everything, re-tuned the Z-axis offset and all seemed well. Unfortunately, I've now tried to print twice and both times it has stopped printing after like 30mins. I don't mean it clogs, it actually "aborts" the printing procedure or something. When I reconnect the cable to it (I usually print from SD card to avoid USB problems) I need to power off-and-on the printer to be able to get a connection, but then everything is fine. The only time I've seen print abortion issues in the past was either because the USB cable was connected and causing errors or a bad contact with the thermistor probe. Since I've been messing with the hotend etc... I kinda suspect the latter :\

Do you agree a thermistor probe malfunction is the most probable cause? Is there any way I can know for sure (like if I print with the cable connected, will it say the error causing the abort)? Any other suggestions? :\

Thanks once again

 

I've tried to print again the cable connected and managed to catch the error (see images below). As expected, it seems to be a thermistor failure. I also noticed something weird; after it failed I ordered it to re-heat to 190ºC again so as to be able to free the stuck part from the nozzle; while it was heating I overshoot quite a bit to 200ºC (I wasn't really paying much attention so i don't know the whole temperature trajectory, but when I looked once and it was at 160º and then a few moments later at 200ºC and cooling back to 190ºC). Is this consistent with a bad contact in the thermistor wire?

I was thinking of just raising the extruder as high as the printer lets me, unscrew the thermistor wire, shove it as inside as possible and screw it again, avoiding disassembling the hotend again. Is this the most sensible thing to do at this point?