PiP Telescoping D20 Fidget

Summary (continued)

This 22x20x1.5cm print-in-place fidget toy is designed to look like a D20 so you can show off your nerdiness while occupying your hands! This fidget was made in collaboration with @WadeM_3775879.

Lesson Plan

Create a themed telescoping fidget toy that is identical to your partner’s using sketch offsets and drafted extrusions and cuts. Troubleshoot as needed to ensure the design is sturdy and satisfying.

Design Process

We decided on what shape we wanted our fidget toy to be. After searching the internet for inspiration, we settled on a D20, using this picture as our guide.

We created a constraint box in SolidWorks, imported the image, and resized it to fit inside the constraint box.

We sketched the shape by tracing the image, using some relations to make sure it was a perfect hexagon.

We offset each triangle inside the shape, alternating between 0.08cm and 0.24cm.

We made our first extrusion, extruding the outermost outline in the center triangle. The extrude was 0.75cm high with a draft angle of 32.37°.

We made our first extruded cut, cutting the second outline in the center triangle. The cut used “up to surface” to make sure it fully cut the extrusion, and had the same draft angle of 32.37°.

We repeated the extrusions and cuts in the center triangle. We skipped the final extruded cut because we wanted to engrave a “20” into the center of it, so it needed to be solid.

We repeated the process on the top triangle. We removed the last extrusion and cut because there wasn’t enough room for them.

We repeated the process on the other three inner triangles.

We realized that the imperfections in our sketch, which came from trying to trace over our guide image, would become much more obvious once we extruded the outer triangles. So, we decided to start over and design the sketch mathematically, rather than by tracing. We looked up the dimensions of a flat D20 drawing and used those to create a new sketch.

We offset each triangle in the new sketch. We used the same alternating measurements of 0.08cm and 0.24cm, and tried to match the sizes of the inner triangles to those of our original sketch.

We extruded and cut the inner four triangles, using the same measurements and angles as our original design.

We realized that there wasn’t enough space for the last extrude and cut of the outer triangles, so we removed them.

We finished all of the extrudes and cuts on the triangles.

We sketched the outline structure that held all the pieces together. We made sure the outline went through the first extrude on each triangle by offsetting by 0.08cm so that it would hold them together well.

We extruded the outline structure and mirrored the whole print around it to make it double-sided and to make the inner pieces stay trapped inside.

We engraved a 20 on one side and a 1 on the other side in the center triangle to make the fidget look more like a D20. We did this by drawing the numbers in a sketch using the text tool, then using a 0.12cm extruded cut with the sketch, and finally extruding the sketch by 0.12cm without merging the result so that it could be printed in a different color.

We printed our first attempt. We noticed that some of the outer triangles didn’t print well because they were too small, but the other triangles came out great. So, we increased the size of the initial sketch so that the outer triangles could still have multiple offsets without being too small.

We added a couple more offsets on all of the triangles because the design was bigger.

We extruded all of the new offsets.

We added fillets between each triangle to make it easier for the printer to print.

We noticed that the fillet didn’t reach the edge of the print, so we removed the outer offset of the outline by setting it to 0, letting the fillet go all the way to the edge of the print.

We then mirrored the model again and engraved a 20 and a 1 in the centers of each side.

We adjusted the draft angle of the extrusions from 32.37° to 28° to allow the pieces more room to move.

We realized after printing our model again that the new draft angle was a bit too steep and allowed the pieces to fall out. To fix that, we tried mirroring the model in the other direction, so that it would be concave instead of convex, which would trap the pieces better as well as being structurally stronger.

We attempted to slice and print our new design, but it didn’t quite work. We think it was an issue with the extra overhangs introduced in this iteration, but we didn’t have time to fix it.