We were prompted to create an injection molded toy based on the ideas and drawings of a class of 5th graders.

Mechanical Engineering Capstone
  • Product Design
  • Mold Design
  • 3D CAD Modeling
  • Machining
  • CNCing
  • Injection Molding

  • Inspiration

    After careful evaluation of all the options, we chose a young artist, Johnny, to inspire our product. Below are his illustrations.

    Design Phase

    Part Design

    First Iteration Issues

    • The thickness variety across the product would require very calculated runner placement.b
    • The sharp angles and small corners in the app designs would cause difficult machiening.

    Second Iteration Issues

    • Based on the tools in our machine shop there were a number of details for our app designs that would not allow for efficient machining.
    • The neck connecting the body and the head could create risk in uneven plastic hardening during injection molding.
    Final Design

    Manufacturing Phase

    Mold Design

    Attempted Interference Fits

    • 4 corners of the iPhone
    • Center of robot's face
    • Runner design to ensure a clean injection molding process.
    • Designing the gate thickness to ensure no short shot during the injection process.

    Important Considerations to the Mold Design

    We then CNCed the mold for over 10 hours

    Injection Molding

    During the injection molidng phase we went through many iterations to best identify what combination of pressure and temperature would be most successful for our toy design.

    Next steps...

    • Increase wall thickness
    • Change gate placement to avoid weld lines
    • Change interference fit locations to create a flush alignment
    • Decrease base plate temperature to reduce warping