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Laser Technology
Tuesday | 28 August, 2012 | 4:21 pm

Real-world experience

By Lauren Duensing

United Performance Metals works with university students to laser cut brake parts for a one-of-a-kind race car

August 2012 - For college students, end-of-semester term papers and exams often require burning the midnight oil. In addition to their coursework, the Formula SAE team at California State University, Fullerton, is spending long hours on campus gaining real-world engineering experience by designing and building a unique race car.

Formula SAE is a student design competition organized by Warrendale, Pa.-based SAE International, an association of engineers and related technical experts in the aerospace, automotive and commercial vehicle industries (formerly the Society of Automotive Engineers). More than 140 universities around the world compete to design a scaled-down Formula-style race car.

The competition began in 1979, and, according to SAE International, “the prototype race car is to be evaluated for its potential as a production item. The target marketing group for the race car is the non-professional weekend autocross racer. Each student team designs, builds and tests a prototype based on a series of rules whose purpose is both to ensure onsite event operations and promote clever problem solving.”

The SAE chapter has existed at Cal State Fullerton since the 1970s, but the students first began their journey to compete in the Formula SAE competition in 2007. The chapter worked for three years to get its car running and achieved its first breakthrough in the 2011 competition, successfully designing and fabricating the car and participating in all of the events at the competition.

Engineering goals

To kick off Cal State Fullerton’s 2012 entry, the design team identified its focus for this year’s car. “By analyzing the strengths of last year’s prototype, we were able to determine the areas that could be improved upon,” says Kurosh Jozavi, the team’s lead brake systems design engineer. “Some improvements included integrating components as a means of reducing the car’s weight as well as increasing the manufacturing feasibility and also incorporating designs that utilize geometric advantages to provide better control to the driver.”

He says once the team determined its goals, they began designing and manufacturing the components. In this year’s entry, the team implemented a full-floating rotor for the car’s brake system. This type of rotor can move laterally within the brake caliper, preventing loss of friction and brake failure.

It was Jozavi’s responsibility to ensure the brake system was functional, cost-effective and feasible to machine. “It is very important when designing the brake components to account for all possible failures and take the necessary measures to prevent them from occurring,” he notes.

Jozavi contacted United Performance Metals, Hamilton, Ohio, to find out which alloy might work best for his application, says Scott Fasse, vice president of marketing.

“Our in-house laser capabilities allowed us to not only recommend an alloy but to go a step further and actually cut pieces for them,” Fasse says.

Choosing stainless

United Performance Metals assisted the team with material selection, testing a number of grades of stainless steel to ensure the students were working with an ideal material for their application. Fasse says UPM’s quality manager and laser cell leader were instrumental in the project, contributing their knowledge toward material selection and ensuring the CAD files were properly translated into a finished part.

“Material selection was important for the students at Cal State Fullerton because the component they were designing was destined for a critical system in their vehicle—the braking system,” Fasse says. ‘The vehicle competes in a timed competition where improved braking can deliver a competitive advantage.”

“When considering material selection for the brakes, heat dissipation capabilities, friction coefficients, maximum operating temperatures and torsional rigidity were significant factors,” Jozavi notes. “Cast iron is an ideal choice, but it is very difficult to machine, and thus increases the overall time and cost in manufacturing. Stainless steel became the best option because it would not rust over time and was compatible with the maximum operating temperature range of the brake pad material.”

In the full-floating brake rotor system, “the brake disc is fastened to a mount, and the fasteners or full-floating buttons allow for marginal lateral movement, thus the fastening points and the disc and the mount must have incredibly tight tolerances, otherwise it fails to perform properly,” Jozavi says.

He notes the manufacturing of the parts “proved very difficult with a manual or CNC mill, so we decided that laser and waterjet cutting were the best options for us” because both technologies saved manufacturing time and maintained consistent tight tolerances.

“I spoke with United Performance Metals about assisting us with laser cutting our brake disc components, and they were made exactly as we needed them,” he adds.

UPM’s precise laser cutting capabilities allowed the company to produce the work as specified. UPM cut the parts from 321 annealed stainless with its Mazak 4,000-watt laser equipped with SigmaTek’s SigmaNest software, Fasse says. “UPM’s laser cell also includes a Virtek Laser QC system, which aids in the delivery of parts that are to our customer’s exacting specifications,” he continues. “The system not only speeds the parts verification process but also delivers detailed reporting and can even reverse engineer parts. UPM’s laser cell has been audited and approved by Nadcap and holds special approval by General Electric.”

Working together, solving problems

Fasse says this project was UPM’s first direct involvement with SAE; however, “other O’Neal companies have participated in the past.” In addition, he notes the company also has received small orders that have been used for similar projects.

The company’s interaction with the Cal State Fullerton team mirrors its experience with all customers. “United Performance Metals works hard to be a company that does more than simply deliver metal,” Fasse says. “We are typically involved with our customers in problem solving, which has covered everything from material selection to developing unique sourcing options. As a supplier, our role as a partner in the supply chain continues to evolve. We have worked hard to make sure that we are capable of delivering the services, solutions and expertise that our customers desire.”

For the students, learning more about material grades, alloys and usage will help them as they enter the workplace. Programs like Formula SAE enable them to gain experience solving problems and confronting engineering challenges, ultimately strengthening the U.S. manufacturing base.

“Remaining competitive in today’s global market requires engineers to find ways to do things better, cheaper and faster,” Fasse says. “We see programs like the SAE program as an important part of the education process. It challenges students to be competitive and creative in their approach. It also provides a great opportunity to witness the entire cycle as designs move from the drawing board to production and ultimately into use. In short, it forces that connection between the theoretical and the practical, which is so often the most difficult step between academia and the real world.”

“This project allowed me to better understand the engineering industry in various fields, ranging from the design approach, simulated analysis and testing, implementation, and integration, to the manufacturing and assembly challenges of proper tolerances, feasibility and cost effectiveness,” Jozavi says. “I learned the importance of geometric dimensioning and tolerances, running accurate finite element analysis, various machining processes, identifying key factors in material selection and documenting and presenting the entire process. Coming out of this program, I feel much more versatile and capable in the mechanical engineering industry.”  MM

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