June 1, 2008 Students learned the principles of engineering and manufacturing when asked to design a toy car for a contest. They used computer design software to shape the car, then created wax and aluminum molds for producing a plastic prototype of their design.
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Think engineering is child's play? Well, for a few months every year in Bethlehem, Pa., it is. Lehigh University mechanical engineering majors and Tyco electronics team up to give middle school students an inside look at the science behind the industry.
"On your marks. Get set. And they're off, Ladies and Gentlemen!" This is no ordinary day at the races. These cars may hit the finish line in a flash, but each one represents months of planning and preparation by 13-year-old budding engineers.
"My favorite part would probably be designing the car and seeing it come to life through injection molding and a rapid prototype," Paul Hess, a Broughal Middle School student in Bethlehem, Pa. told Ivanhoe. Some tricky terms you wouldn't expect to hear from eighth-graders, but that's exactly the point.
Lehigh University mechanical engineering students are "steering" more than 60 middle school students through the manufacturing expo. College students lead dozens of teams through all the steps of building a matchbox car, starting with computer-aided design. "It's a chain chomp and it's modeled after the Mario games. One of his enemies is a chain chomp," student Alex Knowles says about the car he helped design.
Next, wax molds are cut. Then, aluminum molds are made to form the final product. Plastic pellets are melted and injected into the mold to create the car shapes. The students want something that looks great and moves fast. "Aerodynamics is the main thing; how the front of our car is a lot heavier than the rest," student Evan Wescoe says.
Not every design races well, but in the end the students "win" some valuable insight. "We expose the middle school students to this so they understand really what an engineer does and what he has to do in order to be successful," Chuck Smith, Ph.D., a mechanical engineering professor at Lehigh University, told Ivanhoe. And it may put the teens on a career track they hadn't considered before.
The manufacturing expo has become an annual event. The project is also a requirement for mechanical engineers students at Lehigh University taking classes in manufacturing.
WHAT IS INJECTION MOLDING? Injection molding is a process used to shape material into a desired form. This process most often uses plastic, but can use other liquid materials, even molten metals. First, a moldmaker creates a mold of the desired shape from a metal. Then, the liquid material can be forced into that mold, where it cools and solidifies into the end product. This process is used in manufacturing to create an extraordinary variety of items.
ABOUT PLASTICS: Plastics are a type of polymer, a chemical substance made up of many very large, chain-shaped molecules. These molecules in turn form thousands of repeating units, much like the links in a chain. Different plastics are made by linking together different monomers into different length chains. Mixing polymers with various additives gives them many useful properties, which is why plastics are used so often in our everyday lives. Thermoplastics soften with heat and harden when cooled, such as polyvinylchloride (PVC) and Teflon. They are used in food packaging, milk and water bottles, electrical insulation, carpet fibers, and credit cards, among other applications. Thermosetting plastics harden with heat, such as epoxy and polyester. They can be found in mattresses, cushions, varnishes, glues, and coatings on electrical circuits.