Anyone have any tips on cleaning out the Hexagon Hotend? I’ve read the tip in the manual for removing the hotend but from other users saying that the threads are near impossible to realign, and with my nozzle being “welded” (not actually) to the hotend, i’m a little leery of taking it off. I attempted to unscrew it with the 18mm holding the hotend and 7mm wrench on the nozzle (after letting it completely cool) but it’s firmly in place.
What brought me to this point is it stopped mid print and I was getting very very fine “clown wig” extrusions, nothing like a normal extrusion. I tried lowering the temp on the hotend just to where the filament will melt a little and tried pulling out the clog from above but no such luck.
Well I do not think you can take it off cold. I usually heat it up to the ‘normal’ temp for the filament I had in it prior, then using the two wrenches try to remove it. But I have never clogged a nozzle yet, but have replaced 6-7 broken off nozzles so far. I have not found it that hard to align the threads on one yet, but I will wait for that one as long as possible.
Have you tried heating the extruder up to around 270, and then slowly dropping the temperature to about 115, and then pulling out the filament? This can sort of weld the stuck filament to the filament you have in the extruder and allow you to pull it out. Some of these clogs can be attributed to other things. I had just recently sent my entire extruder back to aleph for them to fix or replace. Patiently waiting for its return.
I had an idea of getting the smallest gauge syringe that i could, and injecting acetone into the nozzle. I think then you may be able to loosen it up and push it out with anything you can get to fit in there. Maybe piano wire. I haven’t tested this, but it sounds logical. Do so at your own risk!
Try a cold pull first. If you absolutely must remove the nozzle to soak in acetone, the heater block needs to be at 165C+ for removal.
To reattach, heat the hotend to 165 and thread the nozzle. Easiest at max z height. Use your fingers to begin the threading. You’ll only have a few seconds before the nozzle heats up… if it gets too hot, just let the nozzle cool for 30-60 seconds and retry. I find it easiest to screw clockwise slowly (as if you’re removing), when the thread lines up, you’ll feel a subtle “click” when the threads align. Practice on a regular but and bolt to get familiar with feeling the click.
Once the nozzle is threaded use the 18 & 7mm wrench to tighten. Make sure to retighten at 240-250C.
Awesome, thx for the tips, i’ll heat it up and give it a try. The small wire sounds like a good idea, just need to find such wire, i’ll just try the removal first. Thx.
Just an update, I heated the hotend up to ABS temp and using the 18mm and 7mm wrench it came off without a problem, just be careful the wrench and tip will be very hot. The threads are just like any other screw or bolt nothing to worry about at all, I was expecting very small hair sized threads, but it’s not. After unscrewing and letting it cool, i bathed it in acetone for about 2 hours. The acetone loosened some of the clog, but I found that some of the abs had become carbonized with burnt black granules stuck in the tip…so using a pair of vice grips and a propane torch I gently heated the tip and removed the remaining clog with very small tweezers (different that the lulzbot toolkit). I also used a .3mm micro drill bit which can be bought at harbor freight http://www.harborfreight.com/20-pc-carbide-rotary-micro-bit-assorted-set-62379.html for $8.00, to carefully and gently push through the hole of the tip to clear it out, be warned you can very very easily snap the micro drill bit off in the tip, so be prepared for that. This heating and tweezing was much quicker than the pure acetone bath.
I heated the tip back up to about 185 C and quickly screwed in back in without issues.
I’ve been using only the esun abs filaments at 240-250, so I don’t know what could have caused the abs to burn and turn to carbon in the tip. Could of just been that particular roll of filament.
Nice! I forgot to mention to plan for the hot nozzle. Put a silicone pad over the print bed for protection and some large forceps or vise grips to grab the nozzle. I suppose we could design a basket for the 7mm wrench also… @160C the ABS should be fine.
“Flossing” the nozzle opening with wire is a good thing too. A stran of wire from stranded 22AWG works well. I was thinking one of those twist ties (sans the paper) would work well too.