In the highly competitive automotive market, effective use of materials is important to engineers in developing parts and components, as manufacturers strive to achieve increased performance and fuel efficiency standards. That means they need superior materials. Join us for a ride through some interesting goings-on in automotive’s “material world.”

The Exterior
As the fuel consumption of the annual 60 million new vehicles increases at a relative rate, there is an ever-growing demand for lightweight components made of high-performance plastics. Significant weight reduction is accepted rationale for designing a component, as reducing the weight of current automobiles offers greater fuel conservation and reduced environmental-pollutant emissions.

Lightweight plastic add-on body parts play a key role in terms of cutting down vehicle weight, of course. Yet nowadays, functionality on its own is not enough: cost-effectiveness of polymer applications, attractiveness and comfort (not to mention environmental compatibility) are also becoming more important to consumers. As such, manufacturers are looking for coating technologies that fully comply with such demands.

One example is Bayer MaterialScience AG, a prominent provider of polymers and plastics. As JobWerx pointed out just last week, the company is now working on “innovative coating systems and application processes for the automotive industry.”

For instance, there is the new in-mold coating (IMC) process that Bayer MaterialScience is currently developing. While the application of a coating to an injection molded plastic part is still a time-consuming and cost-intensive procedure, Bayer MaterialScience’s special variant combines injection molding with reaction injection molding. Trials with prototypes and a number of development projects with cooperation partners have already produced promising results, according to New Materials International.

The company also recently developed dual-cure coatings applying a base coat and a clear coat to films that initially are cured only partially. As a result, the film remains flexible enough to be thermoformed during the next step, and the finish stays smooth and crack-free. Only then is the coating cured by UV radiation. This key technology is called “reverse coating.”

By 2014, the demand for coated plastic parts for automotive applications is likely to nearly double.

The Interior
Automakers have used plastics in the interior of vehicles for many years, as InformationWeek recently noted, “but lighter, more cost-effective materials in a vehicle’s engine area, for instance, could help make that megaton SUV more fuel efficient and therefore more attractive to cost-conscious consumers.”

Those new materials also could prove to have fewer failures in the field than traditional steel parts, lowering warranty costs as well, said Don Schomer, chairman of the American Plastics Council automotive group.

As such, chemical companies are collaborating to develop computer modeling and visualization techniques for predicting the performance of new polymer materials in autos. The use of next-generation tools for developing polymer products employing “long fiber” or “reinforced thermal” plastic materials for automotive parts is one of the hottest areas in the industry, according to Guan Chow, senior manager of engineering for Magna Steyr, formerly Porsche Engineering Services.

Six or seven years ago, you’d have needed a supercomputer to run such tests, like fluid analysis in a mold, said Scott Burr, Dow Automotive‘s engineering material science leader. Now most of these programs run on PCs.

Chemical companies also tap the computational resources and expertise of government research labs such as Argonne National Labs. Over the next four years, Argonne is building a center for massively parallel supercomputing, funded by the Department of Transportation, to perform extremely complex calculations related to fluid dynamic analysis, crash-simulation analysis and visualization, and traffic analysis.

Argonne’s Technology Transfer program provides research findings to companies in the automotive industry from the lab’s analysis using its massive computing power. These companies can incorporate into their computational tools “energy analysis codes” developed by Argonne — software programs that perform complex calculations that, for example, analyze airflow around a vehicle, said David Weber, research program director of Argonne’s energy systems division.

Eventually, Argonne’s new computing center might help chemical companies analyze the finer details, such as the performance of polymer-based auto parts in crashes.

The Below
With the enactment of Federal Motor Vehicle Safety Standard 138, beginning in model year 2007, all new passenger cars and trucks under 10,000 lb. (4535 kg) Gross Vehicle Weight Rating must be equipped with a tire pressure monitoring system (TPMS) to warn drivers when tires become under-inflated.

Two predominant types of systems have emerged: direct and indirect. Direct systems attach a pressure sensor and transmitter to the wheel inside the tire’s air chamber. An in-vehicle receiver warns the driver immediately if the pressure in any tire falls below a predetermined level. Indirect systems use the vehicle’s antilock brake system (ABS) wheel speed sensors to compare the rotational speed of one tire against the others.

Both systems have advantages and drawbacks, but they both also share a particular common element: the need for advanced materials.

A TPMS places significant strains on the electronic components required for their reliable function. Temperatures can range from -40 to +125°C (-40 to +257°F) in a harsh environment of moisture, abrasive dust and potentially corrosive chemicals. Acceleration forces of 1000 g are possible at high speeds, while shock and vibration are virtually constant.

According to Automotive Engineering International magazine:

Silicones have been field-proven to deliver a combination of properties that make them well suited to TPMS applications, helping manufacturers achieve critical device reliability and longevity.

Because of their elastomeric nature, silicone gels help absorb shock and vibration that can damage electronic components and reduce device life in the demanding service environment of TPMS. This same flexibility also helps absorb stresses from thermal movement during repeated temperature cycling, contributing to greater reliability and longevity.

Silicone is also a fitting choice of base polymer for TPMS applications because of its low surface energy. And unlike resins that cure to a very rigid solid, low-modulus silicone materials can absorb stress between substrates having different coefficients of thermal expansion, thereby improving device reliability and service life, according to AEI. With an inert structure and a wide-range service temperature, silicone is one of the few material chemistries capable of withstanding drastic temperature swings and the harsh service environment of TPMS over their projected life span.

In the highly competitive automotive market, effective use of materials is important to engineers in development of parts and components, as manufacturers must continually improve their products. That means they need superior materials and improved materials-performance techniques — inside and out.

Sources

New technologies in coatings for automotive makers
Jobwerx, Oct. 31, 2006

Better Chemistry Through Software
by Marianne Kolbasuk McGee
InformationWeek, Oct. 30, 2006

Silicones suit TPMS electronics
by Jon Nelson
Automotive Engineering International, September 2006