Assignments

Week 13 - Molding and Casting

Group Assignment

  • Review the safety data sheets for each of your molding and casting materials, then make and compare test casts with each of them.
  • Compare mold making processes.

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, and use it to cast parts.
  • Extra credit: use more than two mold parts.
  • Extra credit: make your own materials.

Summary - Group Assignment

In the group assignment, we designed a brain-shaped model to test different molding and casting materials. The objective was to compare how each material behaves during the process.

We worked with two different types of silicone to create molds and then used resin as the casting material. This allowed us to evaluate differences in flexibility, surface detail, curing time, and ease of demolding.

Through these tests, we were able to understand how material selection affects the final result and which combinations are more suitable depending on the application.

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Materials Checklist

Select a material
Selected material

Click one button to see the material image and description.

Molding Tools

Mold Case
Selected tool

Supports the matrix and holds the silicone.

Safety

Gloves
Selected safety item

Used to protect your hands from chemicals.

Individual Assignment

  • Design a mold around the stock and tooling that will be used.
  • Produce the mold and use it to cast parts.

For this individual assignment, I worked on the process of designing and producing a mold to create a final casted piece. The main objective was to understand the complete workflow from digital design to physical fabrication.

Design Process

I started by designing the piece in CAD software. While designing the model, I had to consider the shape of the mold, the available stock material, and the tool that would be used for machining. I also considered the geometry of the piece to make demolding easier.

CAD design for molding and casting

Mold Design

The mold was designed considering the material block and the machining process. I avoided very deep or complex areas because they could be difficult to mill or could create problems when removing the casted piece.

In this stage, I also considered the importance of leaving enough space around the model, so the mold would have proper walls and enough strength during the casting process.

Mold design process

Toolpath Generation

After finishing the design, I prepared the toolpaths for machining. The toolpath defines how the machine will remove material from the stock to create the mold. This step is important because the final quality of the mold depends on the tool size, cutting depth, and machining strategy.

Toolpath generation

Mold Fabrication

The mold was fabricated by machining the stock material. During this process, the machine removed material layer by layer until the desired mold shape was obtained.

I checked the mold after machining to verify the surface finish and to make sure that the design was correctly produced.

Mold machining process

Preparing the Material

Once the mold was ready, I prepared the casting material. The material had to be mixed according to the recommended ratio. This step is important because an incorrect ratio can affect the curing process and the final result.

Preparing casting material

Casting Process

After mixing the material, I poured it slowly into the mold. Pouring slowly helps reduce air bubbles and improves the final surface quality of the piece.

Then, I left the material to cure completely before removing it from the mold.

Casting process

Final Result

After the curing time, I carefully removed the final piece from the mold. This step must be done slowly to avoid damaging either the mold or the casted part.

Final casted piece

Problems I Had

  • Some air bubbles appeared during the casting process.
  • The material had to be mixed carefully to avoid curing problems.
  • Demolding required patience to avoid damaging the final piece.

How I Solved Them

  • I poured the material slowly to reduce air bubbles.
  • I followed the recommended mixing ratio for the material.
  • I removed the final piece carefully after the material was fully cured.