For molding and casting week, I learned how to use CAM to program the large milling machine in EDS, create molds with Oomoo, and cast with hydrostone. During our safety training, Anthony walked us through the different options for creating our oomoo mold (big mill, othermill, 3d printing) and also safety details for the oomoo and stone (no eating). We also looked at past molds and casts from previous years. I decided to make a bookend using a 3D model of a Roman sculpture of Aggrippina. I took the model from online and sliced it at an angle, then modeled the wax around it so that the mill would carve out a positive that we could use to make the negative oomoo mold. Here is the finished product on my bookshelf!
Here is the finished CAD model and the toolpaths for adaptive clearing with the 1/4th in flat end mill and finishing with the 1/8th in ball end mill, respectively. Anthony helped to set the spindle speed and feed rates for the different tools, as well as explained different variables like stepover and retraction. We had 7" x 3" x 1.5" wax blocks, so those are the dimensions of my final CAD.
The milling took about 35 minutes. You can see it here halfway, where the adaptive clearing step happened (and you can see the steps), then also when the finishing path defined the details.
After the wax mold was created, the rest of the process was relatively straightforward-- very arts and crafts-esque. I cast the oommoo mold, which I left to sit overnight, and then mixed hydrostone and left that to cure for around 5 hours. I mixed in too much water with my hydrostone so it was still a little bit soft when I demolded it, but overall it seemed quite happy!
Here is the final stone cast, which I super-glued onto an aluminum sheet I cut with a bandsaw to use as a bookend. You can see a few extra appendages at the base of the statue from bubbles in my oomoo mold, but since the stone was still a bit soft, I easily pried them off with a small flat screwdriver.
