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? ...

Making reliable measurements of the extrusion system requires a controllable and repeatable system. Ideally, to measure the width of extruded filament we would print a long straight continuous line over a perfectly flat surface. This ideal, however, is impossible with the constraints of a standard 3D printer. At some point you need to stop or change direction, and doing this affects the processes that determine the output of the printer. The kinds of effect that pressure advance corrects for take place over a period of seconds or tens of seconds, making the bed size a problematic constraint! ...

A widespread innovation in FDM printing is the Bowden type extruder, where instead of mounting the motor that drives extrusion directly on the print head the motor is attached at a fixed location away from the print head and the filament is fed through a long flexible tube into the extruder. Bowden type extruders help to decrease the mass of the print head, which in turn allows for an increase in acceleration and/or decrease in mechanical vibrations from the printer motion system. ...

Following on from the previous post, in this post we will be outlining our initial work on using cameras and machine vision to quantify print performance – measuring the width of printed tracks in different conditions. Future blogs will discuss how we are applying this to various problems. ...

The latest generation of Duet3D control boards: the Duet3 family, come with single board computer integration – they can be attached to a Raspberry Pi (or your preferred SBC). Much of the Duet 3 controller’s functioning can be controlled and monitored from the SBC through an API (C#, Python, Go), making it relatively easy to integrate Duet 3 controllers with other applications and peripherals on the SBC. One such possibility is interfacing with a camera. There are lots of uses for this configuration, from gathering data that can be used to improve tuning and procedures, to producing timelapses for YouTube videos. ...

Welcome to the Duet3D blog. Here we will be highlighting our research and development, new features, and other aspects of the work we are doing. ...