Group Assignment Individual Assignment 3D Design CAM Machining Casting Design Files
Week 13

Molding and Casting

This week focused on learning different molding and casting processes, the materials involved, and safety considerations. The goal was to design a mold, machine it, and cast a part using appropriate materials while ensuring good surface finish and mold behavior.

Hero Shot

Learning Objectives

  • Design appropriate objects within the limitations of your process
  • Demonstrate workflows used in mold design, construction and casting
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    Assignments

    Group Assignments

  • Review the safety data sheets for each of your molding and casting materials
  • Make and compare test casts with each of them
  • Compare printing vs milling molds

    Individual Assignments
  • Design a mold around the process you'll be using, produce it with a smooth surface finish that does not show the production process, and use it to cast parts.
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    Group Assignment

    Group Assignment

    Learning Section

    Individual Assignment

    Design Process - Creating the F-22 Mold in Fusion 360

    Form Modelling
    F22 3D Model
    Mold Render

    CAM - Toolpath Generation in Fusion 360

    Setup Workflow

    Setup Window
    Stock Box Mode
    Stock Setup
    Stock Setup

    Tool Library

    Tool Library
    Tool Library Window

    Importing Tools

    Import Tool Library

    Adaptive Toolpath

    Adaptive: Tool Selection
    Adaptive: Geometry
    Adaptive Heights
    Adaptive: Passes
    Adaptive: Linking
    Adaptive Clearing Toolpath

    Pocket Toolpath

    Pocket Parameters
    Pocket Toolpath

    Flat Toolpath

    Flat Parameters: Geometry
    Flat Parameters: Passes
    Flat Parameters: Linking
    Flat Toolpath

    Scallop Toolpath

    Scallop parameters
    Scallop Parameters
    Scallop Toolpath

    CAM

    Toolpath
    Simulation

    Post Processing

    Post Process in Fusion 360
    Selecting Post Processor
    Selecting Machine
    Selecting necessary operations

    Machining - Milling the Wax Mold

    Wax Mold
    Parallels
    Parallels Setup
    Wax Setup
    Attaching Tool to the MAchine
    Edge Finder Tool
    Tool with Tool Holder
    After Roughing Operation
    Final Wax Mold

    Adding Rudder 3D Prints

    Rudders in Slicer
    3D Printed Rudders
    Rudders attached to Wax Mold

    Molding - Using Silicone Rubber

    Aditya Silicone Rubber RTV - 1010

    I used the Aditya Silicone Rubber RTV - 1010 for casting the negative mould of the F22. ADITYA SILICONE RUBBER RTV - 1010 is a Tin cure Silicone Rubber. It comes in 2 parts. One is Silicone Rubber and second is Curing Agent. Curing Agent is mixed into Silicone Rubber in a given ratio. It cures at room temperature. Plaster, Resin, Epoxy Resin, Polyurethane, Wax and other resins can be casted into the cured silicone mould.

    The above video shows me stiring and mixing the silicone rubber with curing agent using a ice cream stick in a plastic cup after mixing correct ratio of the silicone rubber and the curing agent.

    Pouring Silicon in Wax Mold

    My initial mold did not set even after giving enough time, the mixture ratio was not correct supposedely. That's why I had to redo the whole process of mixing the silicon mixture and pouring it in the mold. The second time, the output was perfect and this is how the Silicone mold looks like.

    F22 Silicon Mold

    Casting

    I used two different materials for casting:

    Cerrotru

    Cerrotru is a low-temperature, lead-free metal alloy containing 42% Tin and 58% Bismuth that melts at just 281F. Cerrotru has only slight expansion during solidification

    Cerrotru Alloy
    Cerrotru

    Cerrotru is a fusible alloy that is used for casting and molding applications. It is known for its low melting point, which allows it to be melted and poured into molds without the need for high temperatures. This makes it suitable for creating intricate shapes and designs with minimal risk of damaging the mold or the part being cast.

    The material is heated in a furnace powered by a 110V power supply.

    I am using a pair of heat resistant gloves and tongs to hold the melting pot.

    After pouring the molten Cerrotru into the Silicon mold, I used a heat gun to remove any air bubbles and used the tongs to tap on the silicon mold to release th air bubbles as many as possible.

    I let the casting rest for about an hour

    Cerrotru in Silicon Mold

    The final output after removing the silicon mold is shown below. The surface finish is not that good as you can see the air bubbles are still visible in the final output but still it looks good. There's a golden hue to the final output which is due to the Bismuth content in the alloy. The final output is very light and can be easily handled. I really liked this casting process and material.

    Final Output
    Final

    PU Cast Resin

    ADitya PU Cast Resin

    I used the Aditya PU 3 Minutes Cast Resin Milky - 555 for casting this time. The mixing ratio is 1:1 ratio of compound A and compound B. I mixed the compounds for 1 minute and added a tint of black colour. Initially the resin was transparent, adding black colour made it blackish but after a few minutes it became gray. The setting time was really less for this

    Plastic Cast

    Design Files

    You can download my design files from below

    • Mold Fusion File

    • Fusion File
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