I was printing a big model that has heavy support. It had a lot of retraction and during the printing, the nozzle hit a piece, dislocated, then spewing filament in the air. Two hours and 46 minutes of work wasted.
I’m seriously thinking about exclusively running Prusa i3 MK2 or other Carteisan 3D Printer for printing big models that do not have floating Z axis problem.
Anyway there was strings, blobs all over the model. I decided to do retraction calibration.
After printing 22 calibration objects, I managed to find the best setting of retraction. The average printing time of the test object was nine minutes.
Extruder drive: B’struder
Kysan Nema 17 5.18:1 geared stepper motor, 2.4 V, 1.0 A
M201 X4000 Y4000 Z4000 E3000 ; Accelerations (mm/s^2)
M203 X15000 Y15000 Z15000 E15000 ; Maximum speeds (mm/min)
M906 X800 Y800 Z800 E800 ; Set motor currents (mA)
Retraction setting in Slic3r 1.2.9:
Length: 3.4 mm
Z Lift: 0.4 mm
Speed: 15 mm/s (10 mm/s and 20 mm/s give similar result.)
Retraction after layer change: on
Wipe on retraction: on
Calibration model: http://www.thingiverse.com/thing:909901
I followed Ultimaker’s retraction guide that suggests:
Temperature of PLA: 180 C
Printing speed: 20 mm/s
Travel speed: 200 mm/s
PLA filament temperature: 190 C
All speeds of print moves: 30 mm/s (set the speed factor of DWC at 70%, which makes 21 mm/s.)
Travel speed: 250 mm/s