Duck cast

Setting up the environment Link to heading

For this week’s assignment, the desired way to fashion the mold was by using a CNC machine. However, the wealth of possibilities of subtractive manufacturing is a tradeoff for a lack of widespread software support. Thus, I was restricted to only use Fusion which only functions on Windows.

Fortunately, after setting up a virtual machine and enabling various 3d optimizations, I had a working environment. One thing that I only learned later is that in the EDS shop there is also a machine with all tools set up especially for situations like this. (Rotch library also has powerful PC’s with CAD-ing tools, but their schedule is quite restrictive)

3d Design Link to heading

I decided to look for a 3d model that would be compatible with my fabrication process. I decided to go with a duck 3d model since it had nice properties such as its halves being roughly convex and symmetric.

Initially, I accidentally made negative since I forgot that the our object was supposed to be made out of hydrostone which unfortunately sticks to many materials. If we fabricated our objects directly out of silicone mold, this would have worked great since that does not stick(and as a bonus the duck would’ve been actually rubbery)

So I also created the positive of it:

Actual manufacturing Link to heading

In order to save time, I decided to 3d print my cast instead of using a CNC machine. This unfortunately, meant that I would have to do the postprocessing myself instead of letting the machine do it:

The layer lines are visible in the picture above both because I set the layer height a bit higher than usual in order to get my print faster and also because it is a picture taken before postprocessing. In this case, postprocessing takes the form of applying a layer of hot was on top of the object in order to smoothen out the layer differences.

After the waxing, I had to pour the OOMOO over my mold and wait. This wait was longer than usual even with a lamp to speed up the process because my object was a bit bigger than average and thus the heat had difficulty reaching the bottom layer. (I tried flipping the object, but the bottom 3d printed material also started deforming under the heat so I flipped it back)

After obtaining a proper OOMOO mold I stuck the two pieces together using rubber bands, cut a hole and poured the drystone mix in. After letting it dry for a day, I opened it up to examine it:

The parting line is still visible in this picture since the object required additional post processing to file away all of the extraneous parts.

How this relates to my final project Link to heading

The hydrostone seems to be a bit of a hassle and quite limited, however I could create silicone molds in order to fashion special button covers for my project. This is more difficult than a duck because the button’s shape would require additional ventilation holes and also some alignment markers.

Cad files Link to heading

The cads are uploaded on the fusion team since I could not upload it here.