Great ! 30/35mm³/s is largely enough if it can be kept constant,
In addition to being able to print with a 0.6mm nozzle and 0.3mm layer height, wich is for now useless as it take same time as 0.4 Nozzle with 0.28 layer height, really wonder why Bambulab sell 0.6 & 0.8 nozzles, the big improvment is that it should give a lot more consistent flow & plastic temperature. Did you experiment quality between print with and without this Nozzle ? like filament color/apparence changing between slow and fast move ? did you notice other improvment not related to printing even faster ?
PS: you say you dont want to explain how you did, but as mentioned above there is a kit seled online to use different kind of nozzles , I’ll post feedbacks when I will have tried it.
EDIT :
As can see there is a nozzle height z delta that makes the silicon sock not really hide the end of the CHT nozzle this can be pulled off a bit to hide a bit more a protect it from the nozzle fan air
Which needs a new design because the nozzle is a few MM under the default nozzle which makes the present nozzle fan duct ineffective and actually cool the nozzle end
Fortunately this is probably the easiest silicone sock shape to mold using high temperature silicone
I asked Bambu Lab in a ticket for the PID but got no answer so far…
Yes the RepRap size is the good one, I am using this size and fits perfectly
I did not experiment quality prints between different nozzle or hotend, I just measured the increased flow rate, everything else seems to be on par
Improvements: You can replace the nozzle instead of the whole hotend assembly, you get access to CHT and CHT clones and cheap hardened nozzle, tons of advantages so far
The machining complexity of that would be nearly impossible in bambu’s all in one design. In my testing with 20mm long nozzles, multiple throats creates more drag than it helps flow. I have data to back that up. Long CHT is bad for flow.
Just because the heat block is small, does not mean the output of the heater cartridge is. Its 50watt which is bigger than most basic printers. The small mass means it can transfer the heat more efficiently to the bore where it is needed. IMO its one of the best designs.
The biggest bottleneck on speed is material properties. Many people do not have any clue that every PLA even between colors can have vastly different melt indexes which leads to wildly different rates of success at different speeds.
40W IIRC, but you’re right, I was misremembering specs on others. It’s seemingly still more than most printers, even those pushing out high flow.
This is a little bit like saying, “we could extrude faster if people chose to extrude soup rather than plastic”.
For considering speed bottlenecks it’s best to just consider a pure base resin filament and work from there. Printers fundamentally cannot change the filaments that people are printing with, and there’s always going to be a compromise made with other material properties if more filaments are optimised for high flow printing.
Would you be able to share your test setup and the data you got from it?
This is just not enought to go over 35mm3/s (there is a video of CNC kitchen explaining that, it is not proportional), When I was triying CHT on Bambulab I was stuck at 35mm3/s because the temperature was not able to go over 220°C, setting 230°C it was sticking to 220/221°C when I was printing at 35mm3/s. But anyway it is still more than 50% improvment in speed, wich is already very very good.
I only tryied 0.6 CHT, am gonna order a 0.4 nozzle now
So the ceramic heater is 48W at 24V 12ohm
You’re about right, I’ve hit a bottleneck at around 35mm³/s on with CHT nozzle on the Bambu cloned hotend
As I was printing a speed flow rate tower, the flow kept increasing but around 35 the temperature kept decreasing, after 3minutes of being off the printer gave me a temp runaway error and stopped print, it was almost 20C under set printing temp because the cool filament was flowing too fast and actively cooling the hotend faster than the heater / PID was doing its job.
But some other user mentioned that with this hotend and CHT nozzle he did not have this temperature / heater issue, so I think this need much more tests
So… I’ve wired 2 ceramic heaters in parallel and put the second one on the other flat side of the hotend. This is not recommended at all and it might damage some electrical components, but it works for me, it heats faster and allows to bypass the previously mentioned bottleneck. I have a ticket with Bambu Lab, they do not recommend this but they recognize this might work as well, so do what you want with that
I can now reach above 40mm³/s with PETG
I am also about to design an external electrical circuit to allow 4 ceramic heaters on all sides of the hotend for super fast heating and no more heating issues
@Nairod : I am interrested in adding a second ceramic heater, could you give more information about the component that get hotter, wich one (photo) and how much it get hotter ? Basically I would like to be sure that it is safe for the mother board ?
It is pattented by 3DSolex, there is a CNC Kitchen video & blog post that explain everything about CHT nozzle from design to why it works so well, history etc…
I am also interested in doing such a modification, I’m also curious to know if BBL current limits these components but seeing as how you were able to heat up the hotend faster its probably not the case? Only thing that concerns me is the doubling in current from 2 amps to about 4 amps and how that could affect components of the printer if there is not a current limit in place.
, I’ll post feedbacks when I will have tried it.
