'Unique internal geometry splits the filament into 4 channels', but how to clean that?
Just wondering about these new high-flow nozzles. The product page talks about: Unique internal geometry splits the filament into 4 channels.
Apparently the filament is heated to a level where it can be 'cut' in 4 strings that each individually are heated to extrusion temperature and then merged again before the nozzle. That's all fine but what if one of these 4 channels gets blocked?
A traditional (pre-Nextruder) nozzle can be taken off to take rubbish out or swap the relatively cheap end bit. Nextruder nozzles come as one piece, but you can still do a cold-pull, use a needle, or use cleaning filament. In these high flow nozzles it is unlikely a cold pull will succeed. It would require the material in the mixing room before the actual nozzle aperture is split into four streams that then flow through the heating channels and, without breaking meet in the preheat zone to travel back up. I would not bet on this. A needle will not pass into the channels, and cleaning filament will flow through and clean the non-blocked channels and bypass the blocked one.
Only solution left I see is to buy a new high flow nozzle.
RE: 'Unique internal geometry splits the filament into 4 channels', but how to clean that?
You're spot on. Manufacturers make a big marketing fuss of high flow nozzles, stressing their supposed assets, but avoiding carefully to mention the question of clogs and cleaning.
Besides, the flow capacity of a hotend is mainly dictated by the power of the heater element. There's only so much filament you can extrude with a 40W heater. HF nozzles give only a marginal gain over ordinary nozzles.
RE:
I just ran into a review of 3dkitchen about these nozzles. The blocking issue is mentioned near the end of the article:
And talking about particles. One thing where I’m a bit concerned about is how easily you can clean this nozzle when it’s clogged. Cold Pulling is straightforward on a regular nozzle and with some practice also doable on Bondtechs CHT nozzle. Yet, so far I was only able to Cold Pull a Revo High Flow once and I’d call my self quite skilled in Cold Pulling. E3D also says it’s possible but be prepared for some headaches when you get something stuck in your precious nozzle.
RE: 'Unique internal geometry splits the filament into 4 channels', but how to clean that?
you guys are wrong, cold pulls definitely work on nextruder HF nozzles:
RE: 'Unique internal geometry splits the filament into 4 channels', but how to clean that?
Yeah - a cold pull itself is working but the result is misleading. You see three strands but what if the obstruction is beyond the end of the strands were they unite? Currently got into this problem and am throwing away the hf nozzle.
RE: 'Unique internal geometry splits the filament into 4 channels', but how to clean that?
Indeed. If one channel is obstructed the material will not really enter there because the other (open) channels will shortcut it. Therefore the obstructing particle will not be 'embedded' sufficiently to pull it out.
Also the 'peel' effect will be less effective. When you pull out the filament at a cold pull you see the half-molten filament is strained and contracted. In the contraction it peels any debris from the walls. In a standard nozzle with simple inside geometry that works well, but quickly gets less effective for complex geometries.
RE:
On a good cold pull you see clearly the internal conical shape of the nozzle and a tiny cylinder at the end, corresponding to the diameter of the orifice (0.4mm in this case ).