​R.E.D. Design Fellowship Print

In early June of 2019, I had the pleasure of consulting with the R.E.D. Design Fellowship team at NC A&T. Their goal was to create a "party golf game" that utilized a Texas Instruments Robotics System Learning Kit (TI-RSLK). Ideally, the device would have an integrated golf ball hole with some way to track how many times during a game the user would score a point. In this case they used an Adafruit Round Force-Sensitive Resistor (FSR) and some 7 segment displays on top for counting the score.

I was brought in on the project for the purpose of designing and fabricating a "shell" of sorts that would integrate those features in a slim and effective way. Of course I turned to Fusion 360 (as shown below) and 3d printing utilizing NC A&T's large form factor Fusion3 410 3d printer. Below you will also find a gallery of images and videos showing the process from sketch and design, to prep and print. Enjoy, and feel free to download the images at austinge.com/golfpics!
From start to finish, the design process took about 10 hours and was mainly done utilizing a pair of calipers and Fusion 360's calibrated canvas abilities. This "calibrated canvas" technique is basically taking a picture or scan of an object and correctly applying the dimensions to the photo, then working from those images for sketches and reference when a 3 dimensional model is not available for the main body of an assembly.

Notable features include:
  • Cutout on top for 7 segment display
  • Ramp with guide rails to golf ball inset
  • Divot for pressure sensor at bottom of golf ball inset
  • Cutout for pressure sensor cable to pass cleanly through to internals
  • Simple finger hole for power on and reset switch
  • Mounting notches lined up to TI Robot base holes
As you can see below, I chose to print the "RoboDome", as I'm calling it, on its side. I did this so that as the strands of filament were laid down, they would create strong, reinforced fibers that would keep the ramp incredibly fused with the rest of the dome, as well as keep the mounting notches fused with the rest of the piece. If I had printed it in the normal, standing orientation, the dome would be quite full of support material, and the mounting notches would also be limited in strength to only the layer adhesion of the 3d printed filament.

The software shown in the three images below is Simplify3d. In order to 3d print something you first need a file, typically a .obj or .stl file that is comprised of thousands of triangles that make up your model. Second, you need a "slicer" software that will use the model file and export machine code to your 3d printer. This is typically a .gcode file but some manufactures have specific proprietary file types that their given program may export. This machine code is what tells the 3d printer to heat up the extruder, move the x, y, and z axis in order to make your part. This is also where you specify print settings such as temperatures, speeds, retraction (pulls filament back into extruder when moving to a different spot so to decrease "stringing" and "oozing", and support/scaffolding material among other settings.
In the video below you can observe me applying "Kapton tape" to the heated bed of the Fusion3 410 3d printer. I am doing this because I decided to utilize ABS plastic filament for this print and ABS adheres quite well to Kapton tape. I went with Hatchbox's black ABS filament for this 3d print because of my prior experience with their filament and because of their high quality control and +/- .03mm diameter tolerances.

In oder to apply the Kapton tape, I suggest heating the bed up to about 110C and using a squeegee to slowly spread it over the surface, starting from the middle and moving outward. 

In Summary...

So in summary, this was a very enjoyable project and I'm excited to see how the R.E.D. Design Fellowship team will complete the rest of their goal. A couple things I would change and improve for next time include increasing retraction distances within Simplify3d so that there would be less "oozing"/"stinging" between areas of the part caused from the print nozzle moving while there is still filament coming out of it. This imperfection in the retraction settings also made support material more difficult to remove than I am typically comfortable with since I needed to apply a great deal of force that could have damaged the end use part. All in all, a success in my books!