Have you ever wanted to twist the end of a rolling pin to rotate a coaster along an axis, causing a marble to roll across the coaster's two-dimensional track? With Turn-A-Coaster, you can!

Nice to meet you!! Our names are Thomas and Eason and we've been working on a fun project: the TURN-A-COASTER!!! An homage to Taiwan, TAC takes inspiration from Track Dribble, an old yet beloved Taiwanese arcade game. We hope our interpretation of this game brings as much joy to others as it did for us.

Special thanks to Track Dribble for inspiration and Ms. Berbawy for making this possible. This project was made as part of her PLTW Principles of Engineering class.

Supplies

Machinery

Universal VLS3.5 40W (Laser Cutter)
Original Prusa i3 MK3S+ (3D Printer)

Applications

Adobe Illustrator
Fusion360
PrusaSlicer

Materials

Plywood square sheet x4

We used 12 x 12 x 1/2 inch sheets, but some variance is fine. Using thicker sheets may actually be better as our walls weren't entirely stable due to the thinness of the sheets.

Step 1: Preface

So, what even is TAC? Well, it's exactly what it sounds like. We created a 2D coaster and mounted it onto a rolling pin, enabling it to rotate around a fixed axis. This rotation of the track allows the user to move the marble despite it being on a flat surface. The goal of the game is to get the marble from the start of the coaster to the end without it accidentally falling off the track.

Our design of TAC is composed of three major sections: the coaster, supports, and container.

Coaster: A 3D printed track that will sit on top of the rolling pin.

Supports: 3D printed pieces that act as the skeleton of the project, holding together every piece.

Container: Laser cut plywood square sheets that control the direction of the marble after it falls.

Step 2: Designing the Coaster

We began by designing a simple track on Fusion360 that served as our prototype. Using that as reference, we constructed a still simple but more complex design. Keep in mind that TAC, by design, is very difficult due to the precise handling it requires.

In our design, we had trouble creating a track that would be challenging but still enjoyable. For example, our first design had far too difficult start and end points that required the player to roll the marble onto a pad (see Picture 3). We ended up removing it for our final design in place of a simple stopper (see Picture 4).

When designing the track, make sure the path has equal spacing between the contact points for the supports so it sits properly on the holders and is balanced (see Step 3).

Step 3: Designing the Supports

Next, we designed the supports that connect all the pieces together. We also created a replica of our rolling pin in Fusion to make sure everything fit. There are three types of supports in our design.

Stands: The pieces in the shape of a triangular prism. In our design, the base is made to slot seamlessly into our slanted floor (see Step 4). The shape of the stands prevents the marble from getting caught on them.

Holders: The hollow pieces that will sit on top of the stands and hold the rolling pin. From our testing the marble rarely gets caught on the holders, so the design is mostly for aesthetic purposes to match the stands.

Pillars: The cube-like pieces that will be attached on top of the rolling pin and provide a flat surface for the track.

Make sure to size the holders and pillars to fit the rolling pin.

Step 4: Designing the Container

The final section we designed was the box. For our box, we created two walls, a base plate, and a sloped plate. The sloped plate is there to redirect the marble towards the player after it falls.

To allow the box to fit together easily, we laser cut the plywood sheets to create simple wood fingers. While we were at it, we also vector engraved the name of the project and our names on the walls (see Step 6).

Step 5: 3D Printing the Coaster & Supports

After finishing the designs, we moved onto 3D printing. We began by importing our CAD files into PrusaSlicer, and fit the components onto the base plate. Then we exported the G-code and transferred it to the 3D printer and began printing. For our 3D printer, we used an Original Prusa i3 MK3S+, and for filament we used Hatchbox baby blue PLA.

Make sure to do a test print(s) before making your final print. We had to do multiple test prints before our final one as we made many adjustments to our supports.

Step 6: Laser Cutting the Container

To apply our container design on the plywood sheets, we recreated the patterns in Adobe Illustrator. The cuts were all vector cuts, and we vector engraved the names. On Illustrator, we made the cuts RGB red (255, 0, 0) and the vector engraving RGB blue (0, 255, 0) to differentiate the two processes. We made the cuts with a 0.1pt stroke.

We had trouble securing our sheets together because of how thin they were, however we managed to circumvent this in our final design by incorporating Styrofoam to increase structural integrity. This step is not exactly necessary but was how we addressed the issue.

Step 7: Assembling the Parts

Finally, we attached all our pieces using Loctite, applying it between the rolling pin and pillars, base plate and holders, and wood fingers. We had trouble securing the components in place because of the curves, and ended up using clamps to hold it still as it cured (see Picture 3).

Although we used Loctite, any construction or contact adhesive should work fine.

Step 8: Have Fun!

Congratulations, you've completed the project (or at least read to the end of the instructions)! All that's left is to have some fun and maybe add some creative touches of your own. Enjoy! :)