Nozzle droping - Not a heat problem!
That the left-hand part of the air-nozzle collapses is a problem when printing high-temperature material.
A simulation of the air flow through the extruder shows that a small amount of air is forced down through slots on the fan's pressure side and hits the left arm of the nozzle.
On its way, the air flow hits the hot parts of the extruder and the heated air then hits the nozzle's left arm which softens and collapses.
There is currently nothing that keeps the extuder body and extruder cover together to prevent this air leakage. On my extruder, this gap is 0.3 mm wide, but there are printers with both larger or smaller slots.
The problem could easily be remedied by screwing the two details together via brackets placed under the Noctua fan.
Also the gap around "heat-sink" should be sealed with some form of seal, for example a lamella seal.
Bear MK3 with Bondtech extruder
Re: Nozzle droping - Not a heat problem!
Nice find AND teasing a bear version of your nozzle! Hooray:-)
Re: Nozzle droping - Not a heat problem!
Hi RHDream box, I confirm that it is an issue and it has been fixed on the Bear extruder since a long time now. The cover is not closing correctly because of the way it is assembled. However, I would not recommend to add a screw under the Noctua because it will block air around the heatbreak and it will not be able to cool down (this is already an issue without the screw).
Re: Nozzle droping - Not a heat problem!
Maybe directing the air from the gap towards the heatbreak could be a solution