Laser Triangulation Makes 3D Printer Pressure Advance Tuning Easier

On its face, 3D printing is pretty simple — it’s basically just something to melt plastic while being accurately positioned in three dimensions. The devil is in details. There are a lot of factors and parameters that can affect the quality of the print.

One such parameter that had escaped our attention is “pressure advance,” at least until we ran into [Mike Abbott]’s work on automating pressure advance calibration on the fly. His explanation is that the pressure in the 3D printer extruder builds up and releases slowly, resulting in artifacts printed when the printhead slows down or speeds up. Pressure advance is designed to reduce the artifacts caused by changing filament feed speed prior to the print head changing speed.

The amount of pressure to advance is usually determined by empirical means, but [Mike]’s system, which he calls Rubedo, can do it automatically. Rubedo uses an extruder mounted camera and a laser line generation to perform laser triangulation. Rubedo scans through a test-print with a bunch a lines printed using different advance pressure values, using OpenCV in order to look for bulges caused by the printer changing its speed during printing.

The video below gives a lot of detail on Rubedo’s design, some shots of it in action, and a lot of data on how it performs. Kudos to [Mike] Thank you for your thorough analysis and excellent explanation of the issue, as well as what appears to be a very workable solution.

Many thanks [Keith Olson] For the tip.