Daniel Daesoon Kim
Manufacturing and Design Engineer
The imagined injection molded toy
Medimax
The MediMax is a polypropylene injection-molded toy that came from my Northwestern Injection Molding class.
The course utilized CAD modeling, CNC milling, and injection molding to turn the toy ideas of 4th graders into a reality. The project culminated in a fair, where the 4th graders and their family could keep their own toys and learn about the manufacturing process!
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Team Size:
team of 4
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Project Duration:
10 weeks
Concept & Design
Our team was given 4 drawings of different toy ideas made by 4th graders from a local school.
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Combining their ideas for rocket boots, a cancer-fighting nanobot, and a hoverboard, I designed the toy concept: a cancer-fighting hovercraft that used rocket boots to fly!
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For the scale of the molds and timeframe of the class, the design was then simplified for manufacturability.
CAD Models
My Role
As the lead CAD modeler, I created the dimensions, designs, and tolerances for the top of the body, bottom of the body, boots, and chairs.
CAM Models & Operations
My Role
I created accurate and aligned mold halves for 50 mm square aluminum blocks for the Body, Seat, and Boot models.
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I was also responsibly for the creation of the CNC milling operations and the many hours that went into optimizing them as well. I then took these operations and translated them into G-code for the Haas Mini Mill 2.0.
Errors & Insights
The Milling Process
The CNC milling process was lengthy and took over a week of supervised automation. There were times where incorrect G-code, improper calibration, or a hidden chip in a drill bit resulted in a destroyed mold forcing us to start over.
Errors
Once the molds were finished, the injection molding process also proved to have its own difficulties. Our initial pieces were subject to sinking, warp, and flash.
Insights
From my experiences I was able to learn how to account for different thicknesses through CAD geometry or ribs. The importance of using different CAD milling operations for maximum accuracy and reduced operation time.
In the end, we were able to bypass our injection molding issues by increasing runner size, injection pressure, and mold latent heat.