Week13 | Molding and casting

Overview

This week focuses on understanding the fundamentals of molding and casting as a digital fabrication process. The goal is to explore how to transform a designed geometry into a physical object by creating molds and producing casts using different materials.

Molding and casting is essentially a process where a liquid material is poured into a shaped cavity and allowed to solidify, resulting in a final part that replicates the mold geometry . This week combines material knowledge, machining, and design considerations to achieve accurate and clean results.

Group Assignment

In the group assignment, first we reviewed the safety data sheets for each of your molding and casting materials, then made and compared test casts with each of them, and then compared mold making processes.

Individual assignment

For the individual assignment, I am making a mold that can be used later in our research group. My plan is to design a mold of a human brain and test it using casting.

Design Brain Mold

I got the 3D model from BigBrain Project, which provides a very detailed 3D model of the human brain. Scientists scanned a real brain in very thin slices and reconstructed it digitally, image reference.

I downloaded the brain STL 3D model and inserted both the left and right hemispheres into Fusion 360 as mesh models:

I combined both hemispheres:

After preparing the brain model, and before designing the mold, I checked it with Toni. He mentioned that the many cavities and details could make it difficult to remove the cast cleanly,

So, I decided to slightly modify the model and make it smoother by filling the cavities. Since I have some experience working with mesh models in Blender, I exported the model from Fusion 360 and imported it into Blender.

It is easier to work with mesh models in Blender. I used the Shrinkwrap tool to create a kind of “skin” around the original model.

I applied Shrinkwrap several times until I reached the desired result.

This is the modified brain model:

Then, I exported the new design from Blender and imported it back into Fusion 360 using insert mesh. Since Fusion 360 recommends using mesh models with less than 10k triangles, I reduced the mesh as much as possible without losing too much detail.

Next, I converted the mesh into a solid:

I created a rectangular box that covers the whole model, leaving at least 5 mm extra space on each side. Using the combine feature, I subtracted the brain from the box: