For our final project we were tasked with combining the two manufacturing methods of CNC milling and molding. Our objective was simple; We had to a mill a positive so we could then mold it and then use the mold to create another positive. On paper that is not very complicated. However, in practice it is much more difficult. Our first difficulty was choosing what to mold. To decide, we went on thingiverse and perused our options. After about an hour of searching we came to a decision.

Unfortunately, we could not use this piece because when we tried to convert the file from a .stl to a file that we could edit the file had many issues. Instead, we found a piece on GrabCad that we could edit and used that.

Once we had the file, we imported it into Fusion 360 to develop the g-code. Also we had to edit the piece slightly to make it the way we wanted. The two main changes we made were eliminating one half of the king and adding pegs. Once we completed this, we used the CAM software in Fusion 360 to generate the g-code.

When we first went to cut our king on the CNC, the origin for the piece was at the bottom of the part and off to the side. We managed to fix this by going back into Fusion 360 and changing some of the settings. After that our origin was in the correct location.

When we actually began cutting the pieces was when our greatest difficulties arose. The first cut we attempted we had to stop about twenty minutes in because we realized the tool would hit the wood when it milled the deepest cuts.

To remedy this, we made sure that the origin was set in the exact corner of the block so the edge of the block would not get in the way.

Our next cut went a bit better and lasted about an hour before there was an issue. The drill bit broke but since it was already an hour into the cut I tried to salvage it. Using calipers, I measured how long the original drill bit was and put the new drill bit in to that length. I then made the CNC mill continue milling from where it left off. However, I think my measurements were off because when the CNC started running again the drill bit was above the material.

Our third and fourth tries were our most successful. Both of these tries, however, were broken up into two parts because we were unable to spend two straight hours at the OEDK working on them. In order to be able to continue the cuts later, we paused the cut and did not move anything or change any of the settings so we could resume it from where we left off. This strategy produced two great looking pieces.

Our pieces did not look like this, though, when they first came out of the machine. They actually looked like this.

We first tried to finish them by only sanding them. This technique cleaned them up, but did not remove the ridges which can be seen in this image.

Instead, we used the dremmel to finish them which gave them a smooth surface without ridges. Once we had these we constructed boxes out of Legos to create the molds. Since we had heard from other groups that their pieces floated during this process, we used hot glue to glue our wooden pieces to the Legos. We then poured the Mold Star into the boxes to create the molds. The containers said to let the Mold Star cure for four hours so we let them sit over night before we inspected the molds.

The next day we took of the molds and examined them to ensure they would work.

Upon examination the only error we found was that the holes we had created to line up the molds did not form very well so we used markers to draw lines on the molds so we could arrange them. We also cut a pour hole in the bottom of the mold so we could fill it. Once we filled the mold we let it sit for twenty minutes. After twenty minutes we removed the piece from the mold.

We ended up casting three pieces. The first piece was the white piece so we used the dye to make it white. When it came out it was very rough so we used the dremmel to finish it. Once it was finished it looked grimy so we also spray painted it white. The second piece we cast was slightly misaligned so we tried to cast another piece to see if it would be more aligned. The third piece ended up being more misaligned so we used the dremmel to fix the second piece and make it aligned. We then spray painted the piece black.

Overall, this was a good project because it made me comfortable using the CNC as well as molding and casting. I also enjoyed getting to use multiple manufacturing methods in one project. As a result, I think this project was a perfect way to conclude the class.