Installed granite base (02/08/2017)
Dimension of the granite plate: 400x400x30 mm
Weight: 13 kg (2.75 g/cm^3)
PINDA probe, live Z calibration, Z-offset and temperature
So I got thinking on that and figured out that it’s not bed warping, nor the nozzle size change (both factors to consider, but definitely not ‘worth’ 0.3mm), but the temperature sensitivity pf the PINDA probe. The original initialization code heats up the bed first and then homes the axes and does the mesh init. Depending on how far the PINDA probe is from the bed, and what temperature the bed is set to, PINDA probe gets more or less hot.
So, I adjusted the init code as follows:
M115 U3.0.8 ; tell printer latest fw version ; M301 P22.1 I1.80 D68 ; set PID for nozzle - set proper values for your printer and uncomment the line, else just ignore it M83 ; extruder relative mode G28 W ; home all without mesh bed level G0 Z80 Y-3 ; get head above bed to keep it cool, move the nozzle up front to make cleaning easier M140 S[first_layer_bed_temperature] ; set bed temp M104 S150 ; set extruder temp to 150C, cold enopugh to avoid ooze, but get some temp on it M190 S[first_layer_bed_temperature] ; wait for bed temp M104 S[first_layer_temperature] ; set extruder temp M109 S[first_layer_temperature] ; wait for extruder temp ; G28 W ; home all without mesh bed level - rehome Y axis to accommodate for thermal expansion -> not necessary, mesh leveling does it too G80 ; mesh bed leveling G1 Y-3.0 F1000.0 ; go outside pritn area G1 X60.0 E9.0 F1000.0 ; intro line G1 X100.0 E12.5 F1000.0 ; intro line
So, in short: home axes, move Z to 80mm above the bed, heat up everything, only after the temperatures stabilize do a mesh leveling.
Result: instead of having to adjust offset of -0.272mm (good for PLA) to -0.550 (so ∆=280µm) for ABS now I have to adjust it only by about 50µm (to -0.300..320), which is by all means something thermal expansion can be responsible for.
The plastic spool holder does nasty thing if you don’t watch it carefully.
I got to guide the filament through a ziptie to prevent the filament getting off the spool holder. The spool actually fell into backside of the print bed during a print when the filament tangled.
I installed the anti-vibration feets. Well it introduces more shakes to the printer frame.
The Z height value for PLA was -0.800 mm. When I tried to print ABS filament, the Z height was way off. I had to set new Z height using Live Z function on the LCD menu after few hours of multiple printing failures and troubleshooting.
I suspected 100 degrees Celsius might change flatness of the PCB bed and later on the Prusa Research’s technician confirmed it. Mesh bed leveling can’t fix the deformation caused by 50 degrees Celsius.
I will keep two set of Z height, PLA and ABS-like filament.
I started applying one layer of glue stick over PEI when I print models in ABS filament.
Prusa Research does provide unfriendly service to Linux users. Why? I don’t know. To download Slic3r configuration files, a Linux user need to download Mac OSX’s Slic3r package, decompress it, then copy 30 KB of ini file.
I complained about it once but the drivers’ page hasn’t showed the link of Slic3r configuration file.
However I got to say this 3D Printer delivers decent quality of printing. I’ve printed ABS parts using the Prusa Research’s Slic3r configuration – layer height 0.25 mm. My printed parts looks better than the kit parts. ^^
ABS printed parts for RepRap Fisher 1 3D Printer