(one is fast, the other switch is for slow operation) is
connected to a relay board for electronically “holding” the
switch down during operation of the DUPe1.
A strand of plastic filament has been
inserted into the 3Doodler in Figure 15. The
Z axis trolley is being raised for a print in
10. Electronics Test. You should test
your printer before you print with it. A
simple test of each stepper motor, along
with the relay toggle button for the
3Doodler can be conducted with an Arduino and Arduino
protoshield. Using sample code available at SparkFun
Electronics ( www.sparkfun.com/tutorials/400), each of
the stepper motors can be exercised. Also, the relay printed
circuit board (PCB) can be triggered for holding the
3Doodler in an extended ON state for testing plastic
output. A sample print from DUPe1 is shown in Figure 17.
After all the tests have passed, remove the Arduino
electronics test equipment and replace it with your
preferred 3D printer electronics board and power supply.
Remember, there are no hot end, thermistor, or extruder
connections on DUPe1.
A Work in Progress
Although DUPe1 looks great, there are several
significant flaws in its design which — luckily — can all be
easily worked out. Right off the bat, the stepper motors in
this design are woefully inadequate. Additionally, these
particular stepper mounts have a non-standard mount (e.g.,
1.56” vs. 1.50” diagonal hole center-to-center
measurement) which makes them incompatible with
Actobotics. Switching to NEMA 17 stepper motors would
be a better choice — there might be two NEMA 17 stepper
motors that I can salvage from my failed 3D printer kit.
Additionally, two stepper motors — one on each Z axis
channel — should be used for lowering the Z axis trolley.
Using one Z axis stepper motor can cause the trolley to
stutter during long movements.
Along a similar line, a rigid spacer should be added
between each X and Y axis gear rack to prevent warping
and binding during movement. Furthermore, the Y axis
beams should be replaced with a smarter Actobotics tubing
arrangement. In this case, remove the beams and use four
60 SERVO 05.2015
Figure 15. Place some seam-locking blue painter's tape on the build plate.
1 - Arduino SFE DEV-#12757
1 - Arduino protoshield SFE DEV-#07914
Extruder Parts List
1 - 3Doodler B&H #3DOODV1A1P3U
1 - M3x10 mm bolt
1 - M3x6 mm bolt
1 - Relay control PCB SFE KIT-#11042