How To Fix Pro PCTG Filament Buildup On Your Nozzle

One of the biggest settings you should change to reduce the buildup you're experiencing is to drop your acceleration rates in your Process settings under the Speed tab. (in Bambu Studio or Orcaslicer, for reference)

Bambu Studio defaults to 10,000 mm/s^2. I recommend dropping that to 500 or 1000 mm/s^2.

The reason this makes a difference is due to the fact that the toolhead does not have balanced mass above and below the gantry and when it makes a dramatic direction change with fast acceleration rates, it causes the toolhead to tip ever so slightly. 

Because Pro PCTG is a viscous material, it stays where you place it. This means that the previous layer of the print can have a "crown" to the extruded material, and the tipping of the toolhead causes the very top of that crown to be scraped and then built up on the nozzle.

We really need to address this via a Process profile for Pro PCTG, as this setting is not a part of our Pro PCTG Filament profile.

I hope that this feedback helps you to be more successful in printing Pro PCTG.