Sunday, February 16, 2025
Create 16 micron points in GCODE directly from PrusaSlicer
First, how does RepRapMicron's current accuracy compare with a commercial resin printer? These have pixel sizes going down to 25μm, however this is not their print resolution. According to this 2023 paper a modified $10,000+SLA resin printer with 37μm pixels can be persuaded to create a solid feature as small as 100μm wide. That's the with of the "m" in the photo below.
To create the model I've written a simple script that is compatible with Prusaslicer that lets you generate GCODE for a RepRapMicron by slicing a model just as you normally would. I run the PrusaSlicer printer configuration on the scale of 1mm = 1 micron and change the bed, extrusion width, and layer size to suit RepRapMicron. I have not played with infill yet. The printer configuration is set to Mach 3/LinuxCNC and the extruder is basically otherwise ignored.
I've put the python filter and simple script (which, yes, is a bit of a hack and should be done in the python code) up on github. The script now trims out all the "M" commands and movement of the A axis from the GCODE, as these confuse GRBL and are unnecessary.
The latest 0.5mm test line looks like this (I've turned the contrast up) which was created by just bashing the probe into a layer of Sharpie marker:
By my reckoning (scaling the image in Inkscape and using the W/H tools) the scale line is about 30μm wide worst case, which is about right for something poked in Sharpie with a hypodermic every 15μm. The drawn "m" is 120μm high and 95μm wide and the three legs of the "m" are clearly separate, so placement looks to be around 10μm but let's carry on. The original SVG file has the width at 108μm and height of 78μm but does not define the line width.
The left pair of legs on the "m" are 50μm edge-to-edge, and the right pair 66μm. So I feel fairly justified in saying I'm positioning within 16μm with this probe on at least one axis, which I'm happy with.
