It’s past time for a 3D printing update so here it goes:
Though I’ve used a few different apps to model printable objects and control the printer, my go-to pipeline has been: model to scale in Blender > export STL > use Repetier Host/Slicr for layout, slicing, and printer control. I supported a Kickstarter campaign for AstroPrint and have used it once since it shipped, but at the time I did not like the lack of slicing control. I can control whether the object should be hollow or filled (and how much infill), as well as how many layers I want on the walls, bottom, and top of the printed object using Slicr, whereas AstroPrint had presets for quality and that’s it – it’s probably changed by now, but I haven’t looked yet. If I change anything in my pipeline I might layout and slice the model using Repetier Host/Slicr and then upload the gcode to AstroPrint to control the printer. BTW, AstroPrint runs on the Raspberry Pi and can provide updates and some control via a web browser and iPad/iPhone app so there is good reason to consider it.
Blender is great for modeling and even does a good job at modeling to scale. The biggest issue I ran across was getting Blender’s scale to match real scale. It hasn’t been a problem in the past with Sketchup models in Blender (1 foot in Sketchup was 1 foot in Blender), but exported STL’s were 1000 times smaller than they were supposed to be. I learned that I needed to change the world scale to .001 instead of the default 1.0 and all was well. Whenever I need to model something to print, I open up a template blend file I saved and it is ready to go for printable sizes. Until I learned about changing the world scale I was scaling the models in Repetier Host 1000x.
So far I’ve only printed with PLA plastic. I’ve got at least one project I need to do ASAP that I think will work better with ABS.
The first big project for the MakerGear M2 was phallus costume pieces for UCA Theatre’s production of Lysistrata. I helped design and printed three different looks for the phalluses. They were modeled in Blender, exported as STL files, and then printed. They were larger than the M2’s print volume so I designed them in two pieces with flanges that were big enough to hold some epoxy to adhere them. Theatre students then filled them with polyurethane foam, sanded them, and painted them. We then adhered metal strips and magnets to them so they would stay on the actors, but the actors could take them off on-stage.
I had only one issue printing the phalluses. On two print runs, a phallus top section was loosened from the print bed and did not finish printing. Luckily it was only the last 1/8 to 1/4 inch so we just filled them. I believe they lost adhesion with the bed because the extruder (“print head”) was moving rapidly between pieces, which made them shake just enough for the extruder to knock a piece over rather than aligning properly to extrude the next layer of plastic. I lowered the speed the extruder travels when not printing and did not have anymore issues.
One character had a unique phallus that was larger than the other men’s and was lighted from within. It was printed in four sections so I could have access to the interior. The idea was that the phallus could change color and/or intensity during his scene. Not having much time or experience with LEDs, we purchased a strip of remote controlled LEDs. The expectation was that it would not need any programming or special wiring. It was already battery powered and remotely controlled with control over color, blinking, intensity, etc.
I cut the LED strip into sections that would fit in the phallus and soldered them together with short wires. Once soldered, I taped them together and fit them into the phallus halves. Then epoxied the whole assembly together. “In the lab” it was working well. On stage, however, it wasn’t going to work. The remote control was infrared, which requires line-of-sight to control the LEDs. It was impossible to control the LEDs from off-stage so we scrapped the idea. I learned a lot about LEDs though and am glad I went through the process even though they were not used on-stage.
I also designed and printed a few badges for the play’s police characters.
Ghost of Christmas Past
A few weeks later I had another 3D printing and LED challenge. I made a necklace for the ghost of Christmas Past for A Christmas Carol, produced and directed by Jim Harris for the University of Arkansas Community College in Morrilton (UACCM). Jim and I decided to model the look off of a Swarovski Christmas ornament and install an array of LEDs in the necklace. The actor would need to turn on the LEDs at a certain moment. I modeled the necklace in Blender in two pieces (front and back). Modeling and printing the necklace was easy at this point. I did print a low-resolution version to make sure the LEDs would fit. Otherwise, no printing issues.
Having learned lessons in LEDs from the phallus, I grabbed some programmable LEDs and a wearable controller so I could control the whole assembly and programming. The LEDs were Neopixels and the controller was a GEMMA, both from Adafruit. I also got a power supply and switch from Adafruit. The first miracle was getting the LEDs wired. After reading a couple of tutorials on Adafruit’s site, I hooked up the LEDs with some solid-core wire. The solid-core wire was great since it can be bent and shaped as needed and it will keep its shape. The next miracle was programming the GEMMA. It is a simple form of an Arduino and Adafruit has some tutorials to help get one going. I finally got it to light up in a pattern, and then lightly pulse randomly. There is one glitch that I did not have time to fix, but I doubt anyone noticed…
I’m proud of the necklace. My original plan was to disassemble the wiring and re-use the LEDs for another project, however, I love the look of the wiring so I’m working on using it as-is.