For the creation of the chess pieces we first had to create two positives of the chess piece. One of the positives would be created out of a 3D-printed half. The other positive would be CNC routed out of a block of wood. The first step of the project was to download the STL file from Thingiverse and 3D print the chess piece to get a visual representation of it. However, the triangular legs at the bottom of the chess piece would prove to be a problem for the CNC mill, so we cut it at an angle in meshmixer after checking for the number of triangles and making sure it had less than 10000. The cut wouldn’t work in Solidworks and couldn’t properly mate to the premade bases for us, so we decided to create the piece ourselves in Solidworks.

Figure 1: 3D printed chess piece

From there we put it back into meshmixer checked the number of triangles and then proceeded to make a cut down the middle vertically, so it could properly mate to the base. We decided to 3D print the positive of the face of the chess piece since it is more detailed and would be more likely to fail on the CNC mill. For the CNC routed positive we printed the back half of the chess piece, since it was much simpler and easier.

Figure 2: 3D printed positive

Figure 3: CNC routed positive

From there we created molds of the two positives one for the 3D print and another for the CNC-routed wood.

Figure 4: Two molds from positives

Once the molds were created we used rubber bands to put them together and keep them in place to prevent shifting during the pouring process and the wait for the castable resin. After the two pieces were secured we poured castable resin part A and part B into separate cups using a 1:1 ratio then added food coloring into part A and mixed. Once the food coloring and part A were mixed both part A and part B into a cup quickly mixing them together, before it started hardening and then we poured it slowly into the mold to prevent air bubbles. The curing and hardening process of the chess piece was fairly quick and produced a lot of heat in the reaction and would be done within a few minutes, in which we would remove the rubber bands and remove the chess piece from the mold.

Figure 5: Complete mold

The chest pieces weren’t perfectly aligned when we put the molds together, so some sanding of the edges was needed. For the sanding, we used 100 and 220 grit sandpaper to get a fine finish on the chess pieces, so that it would be smooth to the touch. After the sanding was completed we used a clear coat on it to protect it from the elements and help keep it color longer without fading in the future.

Figure 6: Chess Piece before sanding

Figure 7: Chess Piece after sanding.

Figure 8: All chess pieces after sanding

Figure 9: All chess pieces after clear coat

After the clear coat everything for the chess pieces was done, so we worked on cleaning up our work station and leaving it better than how we found it.

Figure 10: Clean Workspace

Cost:

Materials: Provided free by OEDK

Labor: $15/hour for 20 hours is $300.