I got a new Biqu H2V2 for my Ender 3 pro , since myold hotend started getting unreliable and that was a great excuse for yet another upgrade.
I wasn't happy with the carriage holder I printed, so I wanted to print a new one. After afew hours of printing, I needed to abandon one part, since it was incredibly messy with blobs of PLA gooped on the print. Since I needed the new carriage mount, I didn't think anything off it and simply abandoned that part and continued the other ones.
Today, I saw that the heating block is completely gooped up with PLA (see pictures). So now, I got two questions:
- How should I remove that gunk? I was thinking o| carefully peeling of everything without the silicone sleeve while the hotend is at a low PLA-bending temp, like 150°C, or 175°C.
- What caused this? Flowrate too high (the prints look the part)? Too fast extrusion? Heatcreep?
Thanks in advance. (:
@Prunebutt @Fenderfreek
Its not about torque only.
If build up correct, the nozzle flange does not touch the aluminium heater block. There must be a gap, can be a tiny gap.
You dont want to screw the nozzle against the block, but you want to screw the nozzle backside face (around the filament bore) against the heatbreak end face. This is the place where you close the oozing hole, the threads are not tight against liquid plastic.
So that means I need to teardown the extruder and check the seal of the heatbreak?
Sort of. As the previous poster pointed out, you need to make sure it’s assembled in a way that the nozzle is seated against the heat break inside the heater block, not against the heater block itself. You’ll have to do a complete disassembly to clean it up properly, and you may need to run a tap through the heater block to clean the threads, but when you assemble it, make sure that you back the nozzle off a turn or so, assemble the hot end so that the heatbreak is bottomed out against the nozzle, then heat it all up and torque the nozzle up snugly to the heatbreak(quarter turn past touching is usually sufficient). There are YouTube vids that will demonstrate hotend assembly better than I can explain it, but solid nozzle to heatbreak seal is critical for preventing this
I've cleaned the outside, but I don't know what you mead by that. Could you explain how I fix the threading?
Most nozzles and heat breaks have M6x1mm threads, so they’re pretty standard (double check yours specifically). Lightly chasing the heater block threads with a tap should clean out any gunk and ensure that your heatbreak and nozzle threads engage properly when you reassemble everything again, and that things get torqued together correctly.
If your heatbreak tube and nozzle don’t have any ptfe liners or anything, using a propane/butane torch to cook the PLA to carbon and wire-brushing it off is a fast way to get those threads clean.
If it’s all super gunked up, and you don’t wanna buy tools, you can generally buy just the heat break, heater block, and nozzle together pretty cheaply for most common hot end designs
Sorry, not an english native speaker, so I didn't know what a tap was. Good thing that context made me not google myself to death with that non-SEO friendly term (it's the drill thing that cuts threads inno holes).
A new heating block is a bit cheaper and I got no use for a tap, so I just ordered a new one. Maybe I give the torching method a try, too before it arrives.
Anywho: I understand the hotend way better now. I guess the 4,50€ for a new heating block is worth it. (:
It's a right of passage, I switched all my hotends to fixed blocks, accidentally loosened the block once on the older style hotend after torquing correctly and enveloped the thing in petg, it kinda vitrified too or something in the heat, was like glass so no getting that off.
Generally, blobs off of your hotend, estop it and take a look, that's a huge tell for a leak.
Worth keeping a few spares around, at least for stuff like nozzles, blocks, heaters and probes.
I see. I probably should have been more specific, sorry. If you do try torching the parts, be very careful with the heater block. They are usually aluminum, and can melt much more easily than the steel and brass parts.
Nah, don't worry about it. You used the correct term, which happens to have an amiguous name (you'd translate the German term to "thread-cutting drill").
Thanks for the heads up. Is it very unadvisable to leave the PLA in the threading if nozzle and heatbreak have proper contact?
I think if you can ensure they all thread together without a problem, it doesn’t need to be perfectly clean, but I suspect that will be difficult if there is melted filament in the threads at all
The new heating block is in transit. I'll do some checks.
@Prunebutt
There is no seal like an o-ring.
It is bare metal to metal surface contact.
If there is a gap between nozzle backside end and heatbreak because the outer hexagonal part of the nozzle hit the heater block first (before the nozzle get tight at the heatbreak), it will leak through the treads and ooze out on the top.
If you can rotate the heaterblock after heating up the nozzle, then there is proof of the inside gap.
On a new hotend i disassemble it before mount it into the printer, screw in the nozzle in first and then turn it back half a turn.
Then screw the heatbreak in until it reaches the nozzle. Install it to the printer, heat to max used temperature, and tighten the nozzle again.
The heater block has bigger thermal expansion, so it tends to get loose by heating up.
If done correct you will never have problems like this, if the mating surfaces are even and not damaged.
That's what I meant with "seal". 😅
Thanks for the advice. Gonna implement it.
@Prunebutt Yw