Goal: create 8 identical chess piece

Creation Process

• design — what’s the style?

Picking what kind of chess piece to create was the hardest. Neither Tracy nor I play chess, so we were aiming for a classic style. After some searches, this is the chess piece we would like to make. We first printed a 3D chess and it looks good. Even though the result was bigger than we thought, we both like it because it is really easy to sight it and feels good when holding. So we decided to go with this design.

• design — creating files!

We used Autodesk Fusion and SolidWorks to make our 3D and CNC parts that included a base plate. We also added a part on the bottom for us to pour casting into it and we’ll cut it out from the final result.

    

• 3D & CNC prints

We first printed out the 3D part, which turned out OK.
We were a little concerned about the CNC part since our piece has some delicate parts and it is a relatively big piece. When creating the Vcarve file, we used TA’s mountain file tutorial as a reference. We used bit  #201 for the roughing file and bit #101 for the finishing part. Before printing, we put a safety board underneath to protect the machine board and to make sure our piece really stuck to the machine board. (and on the right was us nervously waiting for the result~)

    

After some nervous waiting. We were able to cut the part out! (–> this is us cleaning up in joy~)

Now we have both pieces we were ready to move on to mold and cast.

• mold and cast

Wow the video is too big on this screen! But this process was much easier than the CNC or 3D prints. Here we used cardboard to cover all edges of the two pieces and seal all edges using hot glue guns so the molding material will not spill.

 

To create the green mold, we mixed 1:1 by weight of the green and yellow liquid (acetate) minus the chess’s volume then mix it together to pour it into both positive and negative pieces. We carefully pour the mixture from a corner and watched it slowly cover the entire piece. After seeing there was no leaking, we decided to come back the next morning to take it out. The mold has no bubbles or breaking parts, so we moved on to casting using liquid polyurethane. We used two scrap wood to secure the mold and used plenty of rubber bands to tie it up. We applied the same volume in our first try but found that it was too much, so we slightly reduced the volume for the other pieces.

We did not do the same color for all pieces, we were playing around with different dyes and wanted to see what it’ll look like. Honestly, the color did not turn out to be what we expected, but it helped us realize that tie dye is not easy. Now it makes more sense how a normal tie dye t-shirt could cost 20 bucks. After we got the pieces, we used a utility knife to clean up pieces and used the bandsaw to cut the pouring part out then lightly sanded each piece for a smoother touch.

However, we noticed that the final piece was not really symmetrical and did not align really well. But we were still quite happy with the result since we had a lot of fun in this process : )

Thank you~~

Cost analysis

Materials:
– Wood block: $3.48 (for 2 in. x 4 in. x 8 ft.) /19 * 2 = ~$0.37

– PLA 3D printer filament: $19.99 / 20 * 4= ~$3.8

– Molding: Platsil kit $180 (for 8lb)/6 = $30

– Casting: 2-Part Polyurethane Casting Resin $80.99 (for 1 gallon kit)/4.7 = ~$17.2

– Polycolor: $12.5 (for 1oz)/5 = $2.5

Labor:
3D printing: 3 hours
CNC machining: 2 hours
Molding and casting: 4 hours
9 hours * $15 (Rice minimum wage per hour) * 2 people= $270

TOTAL COST:  $0.37 + $3.8 + $30 + $17.2 + $2.5 + $270 = $323.87