Okay… I’m stuck here… I have what I highly suspect as a clogged nozzle. I can get it to extrude “normal” for a millimeter, but then crawls to a slow output after that and then the hobbled bolt starts stripping the filament.
It’s been working fine for about 18 months before this.
My hot end setup:
3mm ABS (suspected clog by eSun ABS)
Makerfarm J-Head IV with 0.35mm output
direct (non bowden) extruder… Wades’s Greg’s Reloaded Geared,hinged, sprung extruder
So I’ve been attempting the “cold pull” (heat and melt then pull at around 120C).
Is there any other way to clear the nozzle?
Couple if things looking at the J head design. If the ptfe tube has moved back up the head it would be quite possible to have a lump of hardened abs above the nozzle orifice. I would remove the nozzle and soak in abs, then by hand run a drill the same diameter as the ptfe tube into the nozzle till it gently seats where the orifice is. Remember this is by hand so you don’t damage the nozzle. You can also remove a piece of wire from a wire brush and carefully poke it back into the nozzle. Then assemble ensuring the ptfe tube is pushed all the way down to the orifice
Hmm ok. I’ll try that out. I was wondering about a possible “crusty” in there. I have another nozzle coming in but I’ll try to clear it that way in the mean time.
Nozzles can be cleaned by holding them with pliers over a flame such as a propane torch or the burner of a gas stove. If you use Mapp gas or acetylene, you could melt or distort the nozzle.
I’m no expert, but if it is just ABS you can just soak the nozzle in acetone for a few minutes. Then make sure it dries all the way before putting it back on (not sure if there is a fire hazard here).
@Whosa_whatsis Yeah, I’ve been trying that at various “cold” temperatures from 110C to 150C, and I can’t get the elusive “nozzle cone” on the tip. Either it’s some really stretched out shape (with the ABS feeling rubbery) or a flat tip.
However, I’ve been removing a lot of cruddy, burnt residue!
If there’s lots of burnt stuff the drill method will work quickest then a soak in acetone. You will not damage anything doing it by hand. this is because the burnt stuff will not melt with heat
@Brad_Smith Most nozzles are made of brass. You WILL damage brass if you try to use a drill bit to clean it.
@Francis_Lee Yeah, it’s tricky with ABS. It works best if you pull it out very slowly at the lowest temperature that will allow it to move. You may find PLA easier, you just need to make sure that you pull slowly enough that the stretched section cools and hardens enough that it doesn’t break. Of course, nylon works best for this purpose.
@Whosa_whatsis I agree with what you are saying but if you are careful and use a sized drill equivalent to the hole there is no problem however this is reliant on the operators skill. The drill in only held in your fingers so pressure is very light. Acetone is always my first choice with a drill only used for extreme circumstances.
@Brad_Smith You’re still rubbing a sharp-pointed piece of hardened steel against a piece of soft brass. The plastic is actually more likely to survive that unscathed than the brass is.
Will it still work after you put a scratch in it with a drill bit? Almost certainly, but it’s definitely going to be a little be harder to clean next time.
Very true and if the interior is honed and polished yes damage could happen. I am yet to try the cold pull method you have listed but will certainly give it a try if I ever get a blockage.
TL;DR: Does teflon tubing harden and shrink after a while?
OKAY… so I took apart my extruder and found some interesting things.
1: Both bearings on the hobbed bolt were seized. Well, they could turn by hand a few degrees, but they’re goners. (I’m guessing the “heat enclosure” is probably causing them to die faster?)
2: I took apart the J-Head and found the teflon tube a little gray (As if burnt/overheated). I tried sliding the filament through it, and it got stuck in the gray section, as if the tube shrunk and hardened.
I tried installing an old nozzle that I had sitting in acetone for several months, and I reamed out the teflon until the filament slid through. I also replaced the bearing with some new ones I had on hand.
Now my extruder motor is skipping… :-/ It’ll run great for about 10mm then the clicking starts to happen. However, if I run in reverse, it spins fine, no skipping at all.
Uh, is that normal for the teflon tube? Does it over time harden and shrink?
(Thankfully Makerfarm is delivering a new nozzle that’s arriving tomorrow!)
