Minimum first layer height?
I'm testing the texture produced with various first layer offsets. (The surface is optimal with Z=-0.798, but I'm testing Z=-0.775 and Z=-0.750 to intentionally create grooves on the bottom print surface.)
Does the mk3s firmware force the minimum first layer height to 0.15mm?
Is there a way to use lower first layer heights?
When I create a thin layer model (0.1mm thick, 50 mm x 50 mm square) the printer prints at Z=0.15 mm for the first layer. (I have set the first layer height to 0.10mm in PrusaSlicer). It appears that when the first layer Z is set to 0.10 mm, the printer still prints at 0.15mm first layer thickness.
RE: Minimum first layer height?
[...] Does the mk3s firmware force the minimum first layer height to 0.15mm?
Yes. If you monitor the printer via a serial terminal, you may see a message about software endstops when it hits 0.15mm.
Is there a way to use lower first layer heights?
In general, you don't want to as the bed isn't perfectly flat and if the nozzle is too close, you'll start to get extruder skips and under extrusion. I've tried a couple of gcode tricks with G92 to fake it out, but the printer detects the 0.15mm level and stops Z there.
When I create a thin layer model (0.1mm thick, 50 mm x 50 mm square) the printer prints at Z=0.15 mm for the first layer. (I have set the first layer height to 0.10mm in PrusaSlicer). It appears that when the first layer Z is set to 0.10 mm, the printer still prints at 0.15mm first layer thickness.
This is by design. That is essentially what happens.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: Minimum first layer height?
@bobstro
Thanks!
It's not the behavior I would have expected... my bed happens to be incredibly level, and I'm using a textured sheet, so there's still fair adhesion even with very thin layers (because some of the divots are still deeper).
Do you happen to know if the printer adjusts the extrusion rate for the thickness that it actually prints at? (eg. is it laying down volume for 0.1mm with a 0.15mm layer? Or does it actually bump the extruded volume up to 0.15mm thick layers?)