Nozzle Back-Pressure, Speed and Pressure Advance
Written by: Lucas Wilkins & Tony Lock Posted on: 2023-04-18
The standard approach to pressure advance assumes that the rate at which filament exits the nozzle is determined by the force provided by the extruder motor, and that other forces are negligible or constant. One of the forces assumed to be constant is the “back pressure” - the reactive force caused by trying to squeeze plastic through the gap below the nozzle. Although this is mostly constant during straight lines at constant speed it changes during turns and as a function of layer thickness, extrusion width, and speed. Most of these things are constant during a given print run, but will potentially change between them. The question is then, what is the effect of back pressure on the relationship between extruder force and print width? ...