Molding and Casting

This weeks individual assignment:

• design a mold around the process you'll be using
• produce it with a smooth surface finish that does not show the production process toolpath
• use it to cast parts

• See this weeks Group Assignment

This weeks learnings:

This week I learned that you should always double-check whether the necessary materials are in stock. I also learned that I never want to sand and fill a 3D print eight times again to get a smooth surface finish and that there must be smarter ways than this.

ideation and design

As always: The idea comes first. Things get complicated when things get complicated at this point. Since we're already preparing for the graduation ceremony, and the weather in Germany is already inviting us to cool drinks (I'm not lying), I thought the best way to create an ice cube tray would be to use it. Water has the pleasant side effect of being largely safe to handle, depending on the amount, of course. To offer something as silly as possible to keep up with my recent weeks, I thought you could scare people by pretending there's a shark swimming in their glass. As should be common knowledge from various films, you use the silhouette of a fin gliding through the water. That's exactly what I do.

For this, I downloaded a suitable silhouette of a shark fin as an .svg file and then imported it into Fusion360. I extruded it and added a larger body at the bottom, tapering it to create a larger mass at the bottom. I hope this will allow the shark fin to sit in the drink in a way that will create a sense of fear and terror.
Here is a quick video of my design:

3d-printing and finishing

Then I 3D printed the model using FDM, which looked like this:

The end of the print also marked the beginning of the fun. Sanding, sanding, and sanding this 3D print was a great honor for me. At least I was able to spray it with filler every now and then to gain new substance for sanding. At this point, I warmly recommend just about any other method for producing a smooth positive part. Next time, I would definitely use SLA printing or directly mill a mold.

mold making

For the mold-making process, or rather, the casting of my negative mold from food-safe silicone, I quickly assembled a small box from scrap wood and wood waste from the FabLab. It fits the dimensions I need to safely and comfortably house my shark pack. After sealing the corners, I filled the mold with silicone and let it cure according to the data sheet. The process can be followed in the following slideshow.


Maybe worth a note: I calculated the silicone required to avoid unnecessary waste. The volume of the mold is quickly calculated (just be careful about the actual height!) – I got the volume of my positive part from the slicer.
After removing the gaffer tape, I noticed that the silicone underneath was still slightly damp, so I decided to give my casting a little more time so as not to jeopardize the result. In the end, my casting hardened for about 24 hours before I removed it from the mold.

The result of the process was this beautiful ice cube tray that I can now call my own.

castings

I made my first attempt at casting with water, because, as I said, I'm aiming for ice cubes. To test the material a bit, I then ventured into chocolate. Accordingly, there are now various foods that spread fear, which brings us to this week's hero slide.


To be honest, my Shark Ice Cube pack is relatively lazy; their preferred position is on their sides. Personally, I find that all too human.

Download this weeks files

this weeks Fusion360-File