Servo - May 2015

(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 Figure 16.

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