Phaetus rapido heatbreak clogging
Hey all have a standard kit vcore 3 400 with a Pheatus hortend and lgx lite setup . Not even using the uhf part as I use the standard cooling fan duct .
The printer is supposed to function 24/7 printing pla. However slowly but surely the heatbreak of the hotend is causing friction and therefore fillament flow is impacted. This is the worst because all seems to function but during the faster print part there is under extrusion.
Cleaning the heatbreak helps but after a while prints start getting underextrusion again an while batches get lost. Cold pulls help to clean the nozzle but do not help with the heatbreak issues.
I use the default ratrig retraction settings 0,5 mm and 120mm/s retraction speed.
Also how can I properly clean my heatbreak. The rapido is not the most serviceable for this. So far is use a 1,5 mm allen key to push the fillament through the heated hotend with nozzle removed!
Thanks all
Cleaning the heatbreak helps but after a while prints start getting underextrusion again an while batches get lost. Cold pulls help to clean the nozzle but do not help with the heatbreak issues.
I use the default ratrig retraction settings 0,5 mm and 120mm/s retraction speed.
Also how can I properly clean my heatbreak. The rapido is not the most serviceable for this. So far is use a 1,5 mm allen key to push the fillament through the heated hotend with nozzle removed!
Thanks all
23 Replies
protestant-coral•2y ago
I was in a similar situation. One thing that helped me was making sure the three screws on the bottom aren't too tight. However, I ended up replacing that thing with a CHC Pro and am happy with it.
xenial-black•2y ago
Will defiantly try to loosen the screws. I admit I did tighten the screws a few weeks ago when cleaning the heatbreak and never got the same flow.
Really hope to get the Rapido stable as I’m currently building 2 vcore 3.1 with this hotend. I have lost multiple kg of pla and many days of printing already.
Is your printer enclosed?
xenial-black•2y ago
Nope open. Only use it for pla.
Try lowering your extruder stepper voltage to 0.65 I found the stock 0.707 runs the stepper a bit hot. After a long print it could make your filament a bit soft.
Or just run an 60min print and feel how hot the extruder stepper it. If it is to hot too touch that could be your issue
xenial-black•2y ago
Hey, I'm sure the extruder is not the problem. Just disassembled the hot end once more and inserting an 1,5mm alan key in the heatbreak you can feel friction. When doing the same in one of the new Rapido hot ends the alan key has free play.
The friction starts where the ceramic heater part starts. I have no clue how to clean the heat break. Any tips?
Heat it up till 260 and then push pla through it with some force manualy that works for me most of the time. Otherwise an atomic pull.
xenial-black•2y ago
I just cleaned the heatbreak with the backend of a drill. Did not like doing that and hope I did not scratch the heatbreak but it did the job. No friction and could extrude to 7mm/s without skipping . Anyway is printing now will know tomorrow if OK. Thanks for the tip though will try your method next time. Need to Google atomic pull. Will do so
rising-crimson•2y ago
Just coming along to second this. Once you get it flowing again, pull a decent amount of new filament through and turn the temps down to normal printing temperature, and keep pulling it through.
I even went slightly cold and pulled some more through just to try and pull any residual old material off the heartbreak and through.
Weirdly, when I switched to UHF with volcano nozzle I’ve not had it since.
a bigger fan usually helps with heat creap
i had some issues with my dragon, then i upgraded to a 4020, and i never had anymore clogs
xenial-black•2y ago
The prints last night where success. I did change the filament spool and the heartbreak is still friction less so far. I do intend to speed up prints once stable and use uhf. Not sure if heat creep is the problem. There is a slow build up in the heartbreak. I guess I’ll start use the 260 heat up on a regular base in order to regularly do maintenance hope that prevents the same issue in the future
I tried cleaning my Radpido UHF by cold pulling with cleaning filament. However, once the printhead cools down to 100, I am not able to pull the filament out. It moves quite freely for a few mm, but will not come out. Should it? Sounds like I might be suffering from a congested heatbreak as well..
1. I run a 1.9 mm drill throughthe heat break on all my Rapidos.
2. The three screws do need to be nipped up to prevent the heater block rotating (which can cause other failures) when doing one handed nozzle changes.
3. I used dragon style stand off tubes on the three screws to give them something to nip up against and this make this connection more rigid. Which has a couple of other benefits
4. Make sure not to overtighten the heat brake clamping set screw (grub screw) in the heat sink as you can slightly crush the heat break tube.
5. I have opened up the hex holes in the face plate to allow the cooling air to escape more freely and I also use a Slice Engineering style 2510 fan which is smaller and lighter and seems to have more pressure (at the cost of more noise).
I haven't experience heat creep, heat break clogs, heat break or heater block failures. Been doing these mods for about 9 months now and I most of my printing is PLA for prototypes and ePA-CF for production items.
Nice! I’ll need to order a 1.9mm bit, the local HW store does not seem to carry them :). Sounds like the stand-offs need to be pretty accurate length-wise, so as not to leave a gap between the heatbreak and the heatsink? I’ll also be trying my luck by using thermal paste between the heatbreak tube and the heatsink, let’s see how it works.
The standoffs for my ones needed to be exactly 2.3 mm long. But be careful a different batch of Rapidos might be slightly different. Normally you need to get odd size drill bits from engineering specialist shops. Also double check the drill bit diameter with verniers. The 1.8 mm I ordered turned put to be 1.9 and the 1.9mm one ended up being 2mm.
fascinating-indigo•2y ago
Do you mean short standoffs between the heat block and the heat sync, the space between those two where the heat break tube is? Where did you find / get the stand off tubes?
Yes exactly. I used trimmed down ones from a Dragon hot end. But you can buy appropriate diameter surgical stainless steel tubing from Aliexpress.
constant-blue•2y ago
I think I will implement your Rapido modifications today mate. I assume I got heat creep again 
Shame the quality was stunning
Shame the quality was stunning
constant-blue•2y ago
left a gap in the chamber temps peaked at 32c with the top slightly open
What filament?
constant-blue•2y ago
eSun PLA+ fresh out the packet.
For PLA I still remove the door and lid. The door on my Rat Rig OneBox is magnetically attached, so very quick and convenient to do.
I switched over to a chc pro and never looked back. For me the rapido was also to finiky.