Project 2: Board Game Terrain Piece
For project 2 I created a terrain tile for the game Settlers of Catan. For the final project my plan is create the entire game (with the exception of the cards) using the machines in the maker space; as such, this project was meant as a stepping stone for the final project.
Design
I started this project by designing the base of the terrain tile. I used the same base as a previous tile I had designed for a previous homework. To decide the size of this base I did some research. I found the size of the terrain tiles for a commercially available version of Settlers of Catan and designed my tiles with the same dimensions. These tiles are typically hexagonal and are designed to fit up against each other, over the course of the game "roads" can be placed on the edges of the tile and "settlements" can be placed on the corners of each tile. However, I wanted these roads and settlements to also fit snugly in the board, so I created circular spaces for the settlements in each corner (20mm in diameter). These spaces were offset from each corner by 2.5mm, creating the spaces for the roads (which will be 5mm in width when designed and made).
Next, I designed the top of the terrain piece. This particular piece was meant to represent fields of wheat, so I made a series of rows to represent fields. Since I had limited space on the tile and needed to represent fields by placing grooves in the top of the tile, I knew I needed to use 1/8" CNC bit (as opposed to a 1/4" bit, which would have been too large). To add a little more detail I added a house and hay piles to the top. Finally, I added another circular slot to the top of the terrain. This slot is meant for the tokens which go on top of each module as part of the game (these tokens have numbers on them and are referred to each time the dice are rolled).
With the design set, I moved on to setting up the CNC cuts. My plan was to cut the piece from a 3.5"x 3.5" piece of stock. I set up the cuts on the bottom and used a 1/4" flat bit for each cut, which included the holes for the dowels, the perimeter cut and the cut for the pockets. On the top cuts I used a 1/4" ball bit to shave the part down to top of the "fields". I then did the next cut with a 1/4" flat bit, which cut the larger areas and flattened out the tops of the fields. Finally, I used an 1/8" flat bit for the cuts between the fields. I did my best to minimize the amounts of cuts done with the 1/8" bit, since this would decrease the possibility of a broken bit and speed up the machine time. I knew I eventually wanted to cut the piece out of wood so I also made sure to set up the cuts to remove material so a bit did not run into it later.
Manufacturing
I first cut the piece out of foam. The bottom cuts were done first, followed by the dowel holes in the base of the CNC. To insert the dowel rods in the holes I had made I first inserted a long piece of 5/16" diameter dowel rod and used the oscillatory cutter to cut it to the correct length.
As it turns out, it was fairly easy to mount the foam using double sides tape and the dowel rods as a guide. Cutting the top part of the piece went fairly well, at least until the part neared its finish. At this point, I noticed the part had actually become unaligned. I had incorrectly set the xy origin on the X carver when I transitioned to the carves in the top. After restarting, I was able to align the part correctly and carve the part as I had intended.
The end product was very close to what I had wanted. As can be seen in the figure directly below, the holes for the dowels were drilled to deep and the little bit of foam that was left was pulled up when the top of the terrain piece was being carved, leaving two holes in the piece. Another thing I noticed while the part was being carved was the "waves" which the ball bit left as it carved. I had originally planned to use a flat bit to make the top of the fields completely flat; however, I thought the waves were a cool feature that could better represent a field of wheat, so I kept this in mind as I started a new piece from wood.
Switching over to carving wood required a few changes. Based on my experience with the foam, I made the dowel holes in the game piece more shallow. I also changed the manufacturing settings so that the X-carve would leave the waves from the 1/4 ball bit on the top of the piece. I also changed the tooling for the pockets from 1/4" flat to 1/8" flat, since this allowed better pockets to be crafted. Finally, I changed the stock size so that I was cutting from a 0.85" thick piece. This dimension matched some blocks of cherry wood that Ryan had in the storage room and I really liked the prospect of using that wood for this piece. After a failed start, I made one successful attempt at cutting out the bottom of the game piece. Unfortunately I had performed the main cut first, which caused the piece to start to move around as the CNC worked on the pockets around the perimeter. To hold it in place, I cut some 0.25" pieces from scrap wood to hold the core in place. While this kept it in place, it also ended up breaking a 1/8" bit when one of these scrap wood pieces came loose and the bit ran into it. After a reset, I finished up the cut and moved on to carving the top part of the piece. I cut the dowel holes directly in the base of the CNC and used a combination of tape and dowel rods to keep the part in place. Despite the low amount of surface area available for adhesion, the part did a remarkable job of staying put.
Carving the top of the piece went really well up until the very end. Before the end, the cuts with 1/4" ball bit were done successfully and I was really glad with the quality and detail produced by the CNC. However, when I was the bit to the 1/4" flat bit (the second to last bit) I moved the head of the CNC. This caused the next cut to be non properly aligned, which failed the entire print. I tried again with another piece of cherry wood, making sure not to move the head of the CNC as I changed the tool out.
The second attempt at carving the piece out of wood went much better. I did not break any bits and the head did not move out of alignment at any point. The effect I was going for with the "waves" in the top of the fields turned out really well and the smaller details on the piece, like the house and hay pile also turned out well. Overall I was happy with the results. As a final touch, and to protect the wood better, I added a coat of wood seal over the entirety of the piece.
Conclusion
Overall, I'm really happy with the quality of this piece. Both the foam and wood piece came out reasonably well, though the wood is definitely superior. I would during this process I have learned the importance of cut order and making sure small bits are not allowed to remove a significant amount of wood (to prevent them breaking). I look forward to designing and manufacturing the remaining terrain tiles. I do think that for the final project I will not do cuts in the bottom of the tile. While it would be nice to have pockets in the bottom for more secure tiles, the additional planning and manufacturing time it fairly significant and may be impossible given the time I am given (though I will have to see). If you want to cut out your own tile like this, the design file for foam can be found here and the design file for the wooden piece can be found here. The designs in both cases are basically the same, though the manufacturing tooling and paths are slightly different between the two. I leave it to the maker to set up the g-code, since this will change depending on the machine.
-Nathan Richter
Pricing
This project included two prototypes: one from foam and one from wood.
Prototypes:
Design Time: 4hr @ $10/hr: $40
Material: 4" x 4" block of foam @$0, 4" x 4" block of cherry @ $40/1"x4"x96": $2.86
Manufacturing Time: 6hr @ $20/hr: $120
Total (prototype): $162.86
Final:
Material: 4" x 4" block of cherry @ $40/1"x4"x96": $2.86
Manufacturing Time: 1.5hr @ $20/hr: $30
Total (per game piece): $32.86
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