model remain firmly attached to the bed rather than
skittering about into a wild rat’s nest of melted filament
(see Figure 7).
Would You Like a PC with
that Printer?
Two common-place features found on most sub-
$1,000 3D printers are obviously missing from the LulzBot
Mini: an LCD printer information screen and an SD card
interface. Most of these lesser printers would love to tout
these absences as deficiencies, but, in the case of the
LulzBot Mini, not having these fixtures is a real benefit
rather than a curse. Please let me explain.
While the inclusion of an LCD screen is proclaimed as
a valuable resource for monitoring the status of a printer,
it can also be an annoying piece of “eye candy” that
unnecessarily increases the overall cost of the printer at
the expense of adding very little useful information in light
of such a modest amount of screen real estate.
No, “less is not more” here; when it comes to 3D
printing, the more information that you can have at your
fingertips during a print, the greater the guarantee that
your final models will be of higher quality and with more
consistent repeatable results. In other words, when
printing robot parts, you want the first print to be identical
to the eleventh print.
As for the lack of an SD card interface, again, this is a
marketing “bell and whistle” that rings hollow. By using a
tethered PC with the LulzBot Mini, you have complete
control over the current state of your print that is fully
illustrative of all read errors, random G-Code glitches, and
print bed surprises. By using a connected PC with the
LulzBot Mini running Cura software, you have total control
of what your model will look like, as well as how it will be
printed.
There are homebrew options for adding Raspberry Pi
interfaces to 3D printers that are complete with LCD
screens, SD card interfaces, and remotely monitored
cameras, as well as operating with a Linux version of the
Cura software. The expense and programming overhead
for these options might not sit well with some robot
builders, however. This is the second caveat for creating
your own instant robot parts. Use a dedicated PC that is
permanently attached to the LulzBot Mini for your
complete control interface.
Don’t have a spare PC laying around the lab? No
problem! There is a new breed of small 11 inch display
screen PCs that have modest solid-state drives sporting the
latest Microsoft Windows OS (e.g., 8.1 or 10) that are
extremely adept at running the LulzBot Mini.
In fact, these small PCs can rest directly on the flat
upper surface of the printer’s aluminum frame (except
when the printer is cooling down during the end of a print;
whereupon the extruder tool head is raised to the top of
the Z axis and can bump into the controlling PC).
Just plug in the USB cable and your PC-equipped
LulzBot Mini is ready to print all of your required robot
parts with Cura’s extensive print information screen
sprawled out across a spacious 11 inch screen.
Just remember to keep it simple. Load only Cura and
the open source 3D model editing program, FreeCAD
( freecabweb.org; for converting STEP files to printable
Standard Tessellation Language or STL format files) on your
diminutive PC. This PC is the driver for your 3D printed
robot parts factory and not a family gaming console.
As for a PC recommendation that works elegantly with
the LulzBot Mini in this driver capacity, the ASUS X205TA is
a good solution: a six to eight hour battery, cool, fan-less
operation, and two USB ports located on the PC’s right-hand side. Typically sale priced at $150, this is a great
bargain for this control role.
Figure 7. An Actobotics channel model being printed in low
quality "draft" mode.
Figure 6. One of the electrically-conductive washers used for
automatic bed leveling.
SERVO 01.2016 47
