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August 13, 2000

8 Min Read
Q&A:  Bringing plastics to concept cars

It’s nearly 2001, and automakers have yet to embrace plastic body panels in a big way. Puzzled? In addition to technical challenges to be overcome, there is still another factor many overlook. Most automotive stylists were never given the opportunity to explore polymers as an exterior material during their college years.

To remedy the situation, the American Plastics Council (APC) and Society of Plastics Engineers (SPE) went straight to the mecca for automotive design students—the Center for Creative Studies’ College of Art & Design (CCS). This Detroit-based institution has graduated 65 percent of North America’s auto designers in recent years. 

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Inspired by forms of muscle cars from the late 60s and early 70s, Patrick Quinn's Chevy Octane SS was designed to help domestic automakers recapture the pocket rocket market. Using plastics helped to lighten the overall weight of the vehicle, according to Quinn, enabling a smaller engine package.

APC and SPE sponsored the senior thesis projects of 16 CCS students by affording them several learning opportunities. In January, the seniors attended an all-day briefing on polymer properties and benefits at APC’s Automotive Learning Center in Detroit. Later, the students took field trips to DuPont’s Engineering Materials Customer Service Center and Huntsman’s Polyurethanes Regional Development Center. There, they viewed the injection molding process in action. 

IMM spoke with some of those involved in the project to get a better picture of its impact: Don Schomer, APC student project committee member; Carl Olsen, CCS Transportation Design section chair; Patrick Quinn, CCS senior student; and Bruce Cundiff, APC director of automotive. Here’s what they had to report. 

IMM: Exactly what kind of information on plastics did the students receive as a result of this project? 

Schomer: The project enabled future automotive designer/ stylists to create a plastics-intensive concept car. Students at CCS receive a course or two in materials as part of the curriculum. To supplement this, our program offered both theory in the form of presentations from SPE and real-world experience during visits to DuPont and Huntsman. 

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Christopher Hillman designed a Saturn Dione, inspired by athletic footwear and the Honda Civic. Hillman specified several materials: a rough matte finish polyethylene, ABS, and clear PC. To give the vehicle a "wow" factor, he incorporated two-shot molding into the design.

We wanted to help educate new designers coming into the marketplace by conveying four major points: a better understanding of the unique properties of plastics; how to use them when starting with a clean sheet of paper rather than simply substituting them for metals; the life cycle benefits in terms of fuel savings and recycling; and finally, how plastics lend themselves to part consolidation and modularization as well as interior and exterior surface design possibilities, such as molded-in color and inmold decoration. 

With the visits to the two material supplier facilities, we were able to impart some hands-on experience, show how materials are molded, and explain attributes of the materials themselves. The program went from formal textbook information to physical parts so that students could see how it all comes together to make an exterior body panel. 

Cundiff: Most plastics companies interface with engineering designers and product designers at the OEM levels. Many times the design or style is already set by that time. This offered a great opportunity to start at the concept phase. We focused on basic overviews, the differences between thermoplastics and thermosets, and the differences between processes. Also, in the presentation, we brought in the chief engineer for the Pontiac Fiero, who discussed what you have to go through to get the design from paper to reality. 

IMM: This is the first time that CCS students have worked with polymers. What differences did you find in the concept vehicles they produced? 

Olsen: To give a philosophical overview of the project, I’ve coined the phrase, ‘liberating constraints.’ If you give designers carte blanche and ask them to design a new widget, they will likely come out with clichés of the styles of the moment. If you point out the inherent constraints of using any material, you can often get a better solution from the designer, one that is more original. 

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The Pontiac Concept F2 from Robert Burns was based on both LeMans prototype race cars and the original Pontiac Fiero. According to Burns, plastics help reduce weight and cost. He also specified molded-in-color body panels to eliminate painting.

Plastic body panels today are constrained by their load-bearing capabilities, so that most designers use them in conjunction with a steel frame. This gives rise to the problem of different thermal coefficients, which presents further complications in plastic-bodied vehicles that have been designed to look like steel cars, especially in the area of shut lines [gaps between panels]. Because plastics tend to expand more than metals as temperatures rise, the panels require larger shut lines. 

One of the things we tried to encourage the students to do was to look at ways to overcome this constraint of having plastic panels on a steel frame, because when you overcome the liberating constraints, you’ll get a fresh aesthetic solution. You can see that in the concept cars themselves, and it varied from student to student. 

Some of the students designed their vehicle shut lines in a bold way, and made a feature of them rather than trying to disguise them. Closer shut lines give the impression of quality, as the Japanese standard of 3 mm shows. But if you can solve the shut line issue in an aesthetic way, you not only get newer designs, but overcome this inherent problem of plastic panels over metal frames. 

Another example of overcoming constraints can be found on Pat Quinn’s car. He wanted to do a polycarbonate windshield and roof. You have the advantage over glass of being able to put some style shape in the roof, which could stiffen up the structure. So in the roof there is a raised center section—it stiffens the panel and gives more head room where you need it. By using the properties of plastics, which you couldn’t do with glass, it looks fresher and has two additional benefits. 

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An amusing proposal from Brian Thompson, the Nissan Sun Super-D, is described as a modular leisure-utilitarian vehicle designed for disassembly. Plastic body panels that make up the vehicle itself are also used in the trailer towed behind it.

Pat’s model was also very sculptural, like muscle cars of the 60s and 70s when heavier gauge steel was used and you could draw the metal deeper. Now, you can’t use heavy gauge metal because automakers are trying to take weight out for fuel savings. You’re not able to do these wildly sculptural forms in steel, yet they are a natural for plastics. 

IMM: Patrick Quinn mentioned in his thesis that the rationale for using plastics on his Chevy Octane SS stems from a need for a lighter weight vehicle. Other than light weight, what benefits did the use of plastics bring to the design? 

Quinn: The style of my vehicle was mostly sculptural. By utilizing plastics technology, I saw that you could bring back the sculpturing in car forms that has been lost because of the cost of tooling these parts in metal. My vehicle has a fast roof line like a Corvette, and the big gripe with these types of vehicles is that there is a low amount of visibility. My design attempted to solve this by carrying the windscreen back for better visibility. This also opened up the idea of sun visors embedded in the plastic roof that could be switched on or off electronically. 

Most of the cars we see today have form that seems to be dictated by the edge design that’s popular—in other words, hard breaks in the form. Introducing the use of plastics on exteriors allows for more sculptural forms. 

A good example would be the Porsche Boxster. Its design is more ergonomic—it has more S curves. Plastics also open up the possibility for changing the exteriors more frequently, as in the glory days of automobiles, and for offering customers a choice of textured materials. 

'By utilizing plastics technology, I saw that you could bring back sculpturing in car forms . . .'

IMM: How much real-world advice on the manufacturability of plastics did the students receive when creating their cars? 

Cundiff: In addition to the first couple of sessions, each student made presentations every four weeks showing how their concepts were progressing. At this point, they would get answers to their questions about the feasibility of an idea, either technically or economically. In some cases, the queries centered around how to accomplish specific design objectives using plastics. 

Quinn: From this project, I realized that if I came upon a design or form that I wanted to do, I could work with engineers and materials people who could tell me if this would be too costly or impossible to mold. 

On the other hand, when a design was feasible, I began to see how molded-in-color panels could bring down cost with one set of tooling vs. five sets of tooling for metal panels, giving me greater design freedom. I also got a sense of life cycle costing vs. part costing. 

Contact information
American Plastics Council
Arlington, VA
Cathy Norris
Phone: (703) 253-0619
Fax: (703) 253-0701
Web: www.plastics.org
          www.plastics-car.com

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