@cosmowave said in 1.8mm Bondtech CHT nozzle print issues:

A Nozzle with closing mechanism is needed...but that's not easy to design. 🤔

Yes, that's something that I've been thinking about for quite some time. Going back to my automotive days, that's how fuel injectors work - it's called a "pintle valve". As well as large nozzles, the other use case would be active mixing hot ends where retracting filament doesn't necessarily result in relieving pressure at the nozzle tip due to the size and design of the mixing chamber.