University of Rochester

Yo-Yos Help Young Engineers Gain a Can-Do Attitude

April 17, 1997

This spring, the senior class of mechanical engineering students at the University of Rochester will enter the work force with a can-do attitude, thanks to an innovative course that emulates a design team at a real-life manufacturing company. These students are actually building an injection-molding system to turn recycled plastics into mass-produced yo-yos -- allowing the students to enter their first jobs with an engineering success already under their belts.

"The best way to learn is by doing," says Professor David Quesnel, now in his second year of teaching Advanced Mechanical Design (ME 205). Quesnel, an avid fan of water sports, compares the course to waterskiing: "You're not going to learn by watching from the sidelines."

While most colleges and universities require their senior engineering students to take a capstone design course, few of these students ever actually follow through on building the products they design, effectively relegating them to what Quesnel calls "theoretical exercises" where design is never really tested against real-world concerns. Above and beyond questions of design, the 30 Rochester students enrolled in ME 205 are forced to consider the bigger picture surrounding their injection- molding system, just like they'll have to do if they take jobs in industry after graduation. Students find themselves pondering previously foreign topics such as product safety, compliance with government regulations, marketing, aesthetics, noise, costs, service manuals, and even the dynamics of the workplace.

"This is our last chance to show our students how to do their jobs," Quesnel says. "We want to make sure they're as well prepared as they can possibly be for the issues they'll have to face at work."

Although not a real company, it's still very realistic, right down to the performance evaluations that company "managers" complete for their workers. The students are divided into eight teams working on different parts of the injection-molding system, which converts chipped recycled plastic into yo-yos by melting the plastic particles in a compression barrel and then squeezing the molten plastic into a yo-yo-shaped mold. For instance, one group is responsible for devising a way to chop raw recycled plastic into chunks of manageable size, while another has to rinse contaminants from those pieces and then dry them. A third team has to devise a system for accepting the plastic bits, melting them, and then extruding the molten plastic safely into the yo-yo-shaped mold that another group is designing. Yet another group has to create a chilled water system to cool all the other groups' systems.

The intensive design and production experience gives students a big boost in confidence during the pre-graduation scramble for jobs. Quesnel says many of them are keenly aware that the first three years of their undergraduate education has given them skills in theoretical analysis and design rather than in actual hands-on building, but ME 205 reassures them that they possess the tools needed to succeed as engineers. Based on their end-of-course evaluations, the 40 students who took the course last year couldn't agree more.

"This course was the best experience I've had at the University of Rochester," wrote one. "I appreciate the analysis and theory I've picked up over the past four years, but without this course I would feel ... unprepared for my first job."

Another student said the course "truly gave me a secure feeling that the theories I learned can be applied in the real world to construct, design, or analyze." One wrote that ME 205 had given "a sense of self-worth," while another said the course had provided "confidence in my ability to engineer a system -- an affirmation that it was all worthwhile."

Unlike this year's group, last year's ME 205 class split into three competing "companies," all building pneumatic power systems to replace electric motors in factories. Quesnel says the three different designs were all successful, and students' families were impressed by the final products displayed at the mechanical engineering graduation ceremonies. Many of the students told Quesnel that employers were very impressed by their ME 205 experiences, and a few even said that their interviewers lamented not having had such a course themselves.

While building a better yo-yo is the focus of this year's course, Quesnel sprinkles in other exercises to "fill the students' mental toolboxes." Students engage in benchmarking, or reverse engineering, a project in which they fully disassemble products like popcorn poppers, hair dryers, and staplers and report back to the class on exactly how the products work and what considerations underlie their design. There's also the "Break A Chain Project," in which students try to design and build the cheapest yet strongest mechanical joint for linking a chain to an aluminum bar.

In addition, Quesnel holds "Tool Time" before lectures to familiarize students with obscure but useful tools of the trade, such as sine bars, knurling tools, and pipe taps. He also brings in trade journals and product brochures to show the students, and draws on his reservoir of disassembled transmissions, thermostats, electromagnetic motors, and power steering systems for each week's installment of "Gallery of Mechanisms." Field trips to local factories such as Amplico Plastics -- where the students viewed machinery similar to that which they're now building -- round out the course.