3D Printed Dice Tower

For my final project for MAT 238 at UCSB, I decided to design my own dice tower, dice tray, and storage unit for Dungeons and Dragons dice. This project was inspired by https://www.thingiverse.com/thing:2511974, where the designer created a two part dice tower that was connected with magnets and collapsed nicely to fit inside the top of the dice tray. I wanted to experiment with something similar, using magnets to connect my pieces, but instead of a dice tower with a few slants, I wanted to create a sort of spiral staircase.

Printer: Creality Ender 3 Pro

Filament: Overture White Filament, Hatchbox Light Rainbow Filament

CAD Software: Fusion 360

Extras: 32 8x2mm magnets

Following a Fusion 360 tutorial on Youtube (https://www.youtube.com/watch?v=C46jVq7g6bk), I was able to create a spiral staircase. The biggest problem was that following the tutorial, the units of the staircase became much larger than I needed. The staircase in the tutorial also only has one spiral, but I wanted to create a little ramp for the dice entry and exit points. After changing the start/end points of the spiral, I was able to create this effect, but the parts were disconnected from the main staircase pillar, which I fixed by adding extrusions to connect the piece.

I designed two alternatives to my youtube staircase, because I wanted to experiment with different shapes and see if I liked the effects. The first alternative was more of a ramp design where the steps were connected to each other, and the second alternative was just the basic staircase, except that the steps had slants built into them, and the extra stair steps were removed so that the spiral staircase included just the original parts attached to the pole. After printing out both versions, I decided to go with the steeper variant because I reasoned that it would probably cause the dice to roll out faster (and not be stuck at the base of the tower).

This first print of the dice tower took around 3 hours of printing time. Since I wanted to test just the spiral, I elected to use an empty water bottle as the casing for the staircase. The objective was simply to test how fast the dice rolled out of the spiral. There were some observations that I noticed with this first prototype. First, since the staircase was detached from the walls (water bottle), the dice falling through made the spiral spin backwards from the rolling force. Second, my initial opening was too small for the dice to roll through, which meant that I needed to give the dice ample space to clear the exit if I wanted it to come out as fast as possible. Lastly, the aligning the staircase to the water bottle hole was a little awkward because of the angle that the staircase met with the wall, so I adjusted the hole to become even wider. I came to the conclusion that I wanted the staircase to be joined with the wall of the dice tower, and that I wanted about a fourth of the circular wall to be missing so that the dice would have more than enough clearance to be able to roll out smoothly.

I first decided to create a brick texture for my tower so that it would look nice and thematic! To accomplish this, I found a video tutorial for it on Youtube (https://www.youtube.com/watch?v=FG5WGxxUMrw). The tutorial left me with a cylinder with a brick texture, so I added a few touches. First, I added extrusions which mimicked the top of a castle tower. Then, I carved out the middle section to make space for the staircase, and created a hole for the dice to come out. In another iteration, I made the hole much larger and made the pole of the staircase much smaller to allow for more space for the dice to come out. I did this change because after printing a smaller version, not all of the dice could fit through the opening because of the pole. Following a tutorial from https://www.instructables.com/How-to-Make-Your-3D-Printed-Projects-Magnetic/, I created cuts in the walls for the magnets. I originally had the middle pole be 10mm in diameter, but this didn't allow enough space for the dice to pass through, so I opted for just 3 cuts in the walls instead. For the magnets, I made a 8.4 x 5mm space for two 8 x 2mm magnets to fit in, which 1mm of solid on either side. The magnets would stick to the printer fan otherwise if there was not enough distance. Finally, I added in the staircase and cut the staircase with the tower first to make sure that the steps didn't extend past the walls. Then I combined the two bodies to create just one object.

With this final design, I printed out three sizes of dice towers. The smallest took around 5 hours, and I was able to roll the magnets from the tower. The next size (75% of original) took 16 hours and the larger dice (d12 and d20) could not fit, but the other sized dice could roll. This was more original intended size, and this size also housed 6 magnets in the 3 spaces. I then decided that I would just print the full size of the tower, which took around 30 hours of print time. This size was larger enough for all the dice to roll out smoothly! This meant that I just needed to design the rest of the project, which was a dice tray and dice storage.

In my first attempt at creating a dice tray, I had the idea of adding magnets so that the tower would snap to one of the corners for easy assembly. Upon actually printing the tray (25~ hours) and testing it, I came across two main problems. First, when the dice were rolling too fast out of the tower, there was a chance that the dice would jump over the dice tray wall. Second, because of the angle of the magnets and the tower, most of the dice rolling out would go towards one of the walls, and not the opposite corner as I would have liked.

In this second iteration, I increased the height of the walls from 13mm to 30mm, and I also rotated the magnet placement by 35 degrees so that the dice would be more aligned with the corner. This next print took 30 hours on the Ender 3 Pro.

When I first designed the tray bottom, I originally planned to use magnets to keep the drawer closed when in a resting position. For this, I wanted to put the magnets along the back wall of the tray, but I realized that it would be hard to 3d print using the embedded magnet technique from above. To address this, I added the holes to the bottom face of the tray, with 5mm for the two magnets and 1mm extra on both sides of the cavity. This meant that the bottom floor was 7mm thick. Since I wanted the walls to be sturdy and balanced with the floor, I made all of the walls 7mm thick, with the total length of the bottom 200mm x 200mm. 200mm x 200mm was the biggest area I felt comfortable with printing on the Ender 3 Pro. Lastly, I printed a test corner to see if it would fit.

After printing out the tray bottom, I came across a problem. Since the walls were only 7mm thick, I created pegs that were 3mm in diameter. This made the pegs a lot weaker than I initially anticipated, and most of them snapped off when I tried connecting it with the tray top. As a workaround, I decided to just join the tray top and tray bottom by using epoxy instead.

For the dice storage, I wanted it to have 7 trays for the 7 types of dice. I originally started with 20mm wide holes with 5mm walls in between. After a test print, I realized that the d20 wouldn't fit in 20mm, so I increased the gap to 23mm, and shrank the walls to be 3mm. I spaced the magnet holes to be the exact same as the tray bottom, but shrank each of the sides to allow for 0.5mm of tolerance. This print took around 35 hours.

This is what all the components together looked like in Fusion 360! However, I found that when I printed the dice storage with only 1mm of tolerance between the storage and tray bottom, the storage wasn't able to fit inside the tray bottom. After some sanding, I was able to almost press fit the storage into the tray bottom, but decided that I would like more room to allow for a sliding storage unit. I changed the overall tolerance from 1mm to 5mm, and made sure to remove the pegs from the tray bottom that I decided on in step 9. With this new design, I attempted to re-print the tray bottom. Quite bizarrely, two of the prints failed when the print bed fell off of the 3D printer. I theorized that it may have been caused by warping (my 3D printer is close to my door), and that the extruder may have caught onto one of the corners and pulled the whole bed off. To amend this, I put my printer in isolation inside a closed closet, and the print succeeded after that.

For this final step, I needed to add epoxy to attach the dice tray to the tray bottom, since the pegs were not rigid enough to keep them together. I had never used epoxy before, but luckily it wasn't too difficult to figure out! After applying the epoxy to the tray bottom, I put two clamps to keep the piece steady while waiting for the epoxy to cure. Between printing test, final, and failed pieces the total print time came out to be well over 100 hours. But I'm quite happy with the final project to close out my class at UCSB :)