Temperature dependent Z hight change issue fix
 
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hans.p
(@hans-p)
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Temperature dependent Z hight change issue fix

Since I got my MK2S printer two months ago I had issues with Z height. I do lot of swapping between ABS and PLA. In order to get around this problem I changed my start gcode and I thought I would share it since I know lot of people have this issue and cant wait till new upgrades get shipped in November.

Issue:
My MK2S changes the z height depending on the temperature of the surrounding environment. Specially while auto bed leveling is running close to the bed. This causes bed to get skewed in software since probe gets hot as it get to the last few calibration points.

Solution:
Have predefined temperature/routine for all types of filament and have the part cooling fan running while probing.

Disadvantages of the solution:
Bed changes the physical characteristics as it get hot and probe will not measure that but this is minimal comparing to grand scheme of things.

Slic3r start gcode:
M115 U3.0.12 ; tell printer latest fw version
M83 ; extruder relative mode
G28 W ; home all without mesh bed level

M106 S255; start cooling the probe
G0 X60 Y-3 Z80; move extruder above bed to keep PINDA cool keep extruder in front for cleaning
M104 S200 ; set extruder temp to do mesh bed leveling
M140 S50 ; set bed temp to do mesh bed leveling
M190 S50 ; wait for bed temp to do mesh bed leveling
M109 S200 ; wait for extruder temp to do mesh bed leveling
G80 ; mesh bed leveling to do mesh bed leveling
M106 S0; Stop cooling the probe since we are done with the mesh bed leveling
G0 Y-3 Z80; move extruder above

M104 S[first_layer_temperature] ; set extruder temp
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Y-3.0 Z0.4 F1000.0 ; go outside pritn area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

I set the bed to 50c and nozzle to 200 for every single mesh bed level.

Cura start gcode:
G21 ; set units to millimeters
G90 ; use absolute positioning
M82 ; absolute extrusion mode
G28 W ; home all without mesh bed level

M106 S255; start cooling the probe
G0 X60 Y-3 Z80; move extruder above bed to keep PINDA cool keep extruder in front for cleaning
M104 S200 ; set extruder temp to do mesh bed leveling
M140 S50 ; set bed temp to do mesh bed leveling
M190 S50 ; wait for bed temp to do mesh bed leveling
M109 S200 ; wait for extruder temp to do mesh bed leveling
G80 ; mesh bed leveling to do mesh bed leveling
M106 S0; Stop cooling the probe since we are done with the mesh bed leveling
G0 Y-3 Z80; move extruder above

M104 S{material_print_temperature} ; set extruder temp
M140 S{material_bed_temperature} ; set bed temp
M190 S{material_bed_temperature} ; wait for bed temp
M109 S{material_print_temperature} ; wait for extruder temp
G1 Y-3.0 Z0.4 F1000.0 ; go outside print area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E21.5 F1000.0 ; intro line
G92 E0.0 ; reset extruder distance position

Disclaimer:
I have tested this for about a month now and I haven't touch the z height config. Use this at your own risk and any feedback is welcomed. :geek:

Napsal : 03/10/2017 6:44 pm
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