Jeremy Fu

Magic School Bus

Capturing the magic and delight in a child’s sketch and bringing it to reality in a manufacturable toy that can be repeated at scale.

  • Human-Centered Design
  • Injection Molding
  • CNC Machining
  • Initial Concept Sketch 
  • 3D CAD and CAD Mold 
  • Injection Molding


My team was given the challenge of transforming local 4th graders drawing into a physical toy, utilizing their drawings as inspiration. Within the stack of 2 dimensional drawings we were given we dew out the most delightful features, meshing them into one final 3 dimensional toy.

My team outlined two key goals for our toy:

  1. How might we keep and even elevate the magic embodied in the original sketch, remaining faithful in our design.
  2. How might we use this experience to learn more about CNC machining and injection molding, taking these learnings and applying them to future projects.

To bring their imagination to life, we first had to take their 2D sketch and reimagine it as a 3D object.

The inspiration

Initial concept sketch

1st Round Computer Aided Design

There are a couple design issues in this initial design that will make injection molding difficult.

1. Tiny features

2. Non-filleted edges

3. Impossible undercuts

4. Deep pockets

2nd Round Computer Aided Design

In the second round of design, we fixed some key issues.

1. Filleted edges

2. Added a claw mount

3. Removed deep pockets and undercuts

One Last Challenge
  • Potential for cold weld lines and extra flash surrounding the claw mount
  • Burden of manufacturing third mold and using small injection molding machine
  • Determined that the production schedule didn’t allow enough time
Final CAD Design

This final design integrates all the design changes made above. The bus will be split in half lengthwise, with each half becoming a set of molds. 

Molds &
Computer Aided Machining 

Right core mold tool path with runner and sprue to deliver hot plastic. 

Right cavity mold tool path


Molds for the right half of the bus. These two molds will mate together in the injection molding machine.

Right core mold machined

Final Toy

Assembly of right (blue) and left (white) halves

Right half showing internal mating pins and attached runner & sprue

We made a bunch of different colors!

The team: Andrew, Zack, Hok, and Jeremy


Developed experience into the considerations that need to be taken in developing a successful injection molded part, from CNC machining to part assembly to operating the injection molder.

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