During the initial startup of the software, you must pick
your printer (e.g., LulzBot Mini), as well as install drivers for
Windows installations. Then, just plug the included USB
cable into your computer, attach the included power cord
into a three-prong outlet (I used an IsoBar isolated, surge
suppressor, multi-connector power strip), flick the power
switch ON, then launch Cura. Within a few moments, the
rocktopus 3D model will automatically load into Cura.
There is a dead-simple six-step procedure in the
LulzBot Mini Quick Start guide that will lead you through
the removal of the leftover HIPS filament (that’s the
filament used by Aleph Objects for printing the test
octopus for your printer), the insertion of the one meter
test filament, and the printing of the rocktopus 3D model.
During the start of the printing process for every 3D
model, the LulzBot Mini performs a regiment of tests,
checks, and controls that will quickly inspire you with the
incredible amount of mechanical precision and
engineering robustness that has been designed into this
First of all, the extruder tool head assembly is raised to
the maximum height of the Z axis (see Figure 4) for
preliminary heating. At this same time, the bed is
withdrawn to the furthest back extent of the Y axis.
Once the hot end reaches approximately 160 degrees
Celsius (that is about 80 degrees shy of the final printing
temperature of 240 degrees Celsius for HIPS), the extruder
retracts the filament from the hot end and the entire tool
head assembly is lowered to the back area of the bed
where a dedicated “wiping pad” is installed as shown in
This thick heat-resistant user-replaceable material is
actually deeply gouged with the nozzle for clearing all
filament residue from the hot end. It’s a simple and
effective process that is supported with six extra pads that
are included with the printer.
Why is so much effort expended for cleaning the
nozzle before every print? Because the next step in the
The Mini’s technique is an impressive
technological wonder featuring a gentle double kiss
of large electrically-conductive washers fixed to the
four corners of the print bed (see Figure 6).
Now that the printer has been tested and we’ve
checked its electrical and mechanical operation, one
final print control is performed. Having precisely
established the actual print bed height, the extruder
tool head heats up to printing temperature, lowers
to the print bed, begins to draw filament into the
hot end, and establishes a simple outline skirt
around the upcoming print.
This final control element does two things right:
It ensures that the filament is extruding consistently
from the nozzle, and it creates a simple moat or
boundary around the print that helps the upcoming
Figure 4. Twin Z axis stepper motors with lead screws
connected by flexible couplers.
Figure 5. The hot end nozzle wiping pad.
Figure 3. The LulzBot Mini Edition Cura software opening
46 SERVO 01.2016