Fab Academy 2025

@ Fab Lab Rwanda, Kigali

Output Devices

Output Devices


  • Team Kigali
  • Team Botswana
  • Week 13 - Mold and casting

    Group Assignment

    For our group assignment, we began by reviewing the safety data sheets for each of the molding and casting materials we used. We then made and compared test casts using silicone with its hardener and wax. To create the molds, we used two different methods: 3D printing and CNC milling. This allowed us to compare the outcomes and effectiveness of printing versus milling molds.

    Materials used

    Our final working setup
    Silicon Glue Part A,dawnload data sheets
    dawnload data sheets
    Our final working setup
    Silicon Glue Part A hardener,mix ratio (A100:B3)
    Our final working setup
    Wax
    Our final working setup
    PLA
    Our final working setup
    MDF

    3D printing and silicone casting process

    For the 3D printing and silicone casting process, the plan was to design and print a mold using a 3D printer with PLA filament. Once the mold was ready, we poured silicone mixed with its hardener into the printed mold to create the desired cast. This method allowed us to test the compatibility of 3D printed molds with silicone casting and observe the level of detail achieved in the final product.

    Our final working setup
    3D-printed design
    Our final working setup
    Mixing the Silicone and the hardener on the A100:B3 ratio
    Our final working setup
    we poured silicone mixed with its hardener into the printed mold
    Our final working setup
    Our final working setup
    the Final cast

    CNC milling and wax casting process

    For the CNC milling and wax casting process, the plan was to first create a design and use the CNC machine to mill the mold into MDF material. Once the mold was ready, we heated the wax until it melted and then poured it into the mold to form our cast. This method allowed us to explore the precision of CNC-milled molds and the casting behavior of wax in MDF molds.

    We started off with the design of star shape body

    Mold Design

    Then after, we made solid body around shape.

    Note: This body must be bigger than that volume since we are using the combine tool to make cavity.

    Mold Design

    We then used combine tool (substraction) to form cavity.

    Mold Design

    And then we duplicated the body using SolidWorks mirror pattern.

    The two sides are the same; only is that one is mirror of another.

    Mold Design

    Lastly, we designed holders. These will hold mold parts together.

    Mold Design

    2. Milling mold on CNC

    We exported STL file and then imported in Aspire.

    Mold milling

    We started with 3D roughing

    Mold milling Mold milling

    After 3D roughing, we followed with 3D finishing. This to make mold as smoth as possible.

    Mold milling

    This is a video of CNC machine milling (3D finishing)

    All parts after milling

    Mold milling

    3. Preparing mold parts and heating bee wax

    We made sanding on rough surface and then applied oil. This facilitate mold release afterward.

    Mold preparation

    We then holded all parts together will adapters.

    Mold preparation

    We used bee wax as molding material

    Mold preparation

    We then melted bee wax on flying pan

    We then poulled molten wax into the mold and let it for 2 hours to harden.

    Mold preparation

    Afterwards, we separated the two halves.

    Mold preparation

    The mold and part did not sepate correctly. Part just broke in half. This could be caused by sevearal factors such as applied oil, and mainly we are using hard part and hard mold.

    What we learned

    First, reviewing the safety data sheets helped us understand the proper handling and potential risks of the materials we used. Through the casting tests, we learned how different materials behave—how silicone flows and cures in 3D-printed molds, and how melted wax interacts with CNC-milled MDF molds. We also saw the strengths and limitations of each mold-making method: 3D printing allowed for complex shapes but required more time, while CNC milling was faster for simple designs but had some surface roughness. Overall, we gained hands-on experience in choosing suitable materials and methods for molding and casting based on design needs and available tools.

    Instructor

    Contacts

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