Compounding-molding technology offers a market edge in automotive front ends

Combining compounding with injection molding helped one high-profile auto manufacturer streamline a well-known front-end system.

Not even thermosets are exempt from the expanding presence of fluid-assisted injection molding. One company discovered how to do it by accident.

In the July 2002 issue of IMM we talked about the market acceptance of integrated compounding and molding systems, specifically the IMC system from Krauss-Maffei. We described the technology and noted that the leading adapter is the French-based global Tier One automotive supplier, Faurecia.

That left a question: Why did Faurecia move as quickly as it has to adopt this technology? So, we went where the first systems were in use, Faurecia’s large (more than 400,000 sq ft) manufacturing campus at Audincourt in eastern France.

Philippe Dumazet, manager of process and material research in Faurecia’s R&D unit, quickly made it clear that Faurecia sees technology development primarily in terms of gaining market advantage through increased customer satisfaction. The primary market in this case is automotive front ends, and the compounded-molded part is the front-end carrier.

Markets Drive Manufacturing
The Faurecia Group’s strategy of concentrating on six automotive modules has resulted in leading market shares (see Table 1). Seats are the largest single component, followed by cockpits, doors, and acoustic packages.

Supplying complete front-end modules (FEMs), as opposed to individual components, is still primarily a European market. (An FEM typically includes bumper, carrier, fan/cooling system, lighting, wiring, electronics, and trim and structural components.) Faurecia supplies both, but given carmakers’ increasing shift to modules, Faurecia sees a worldwide market for FEMs. Over the last 14 years, the company has made FEMs for 10 vehicle platforms. In 2001, Faurecia made more than 1.6 million carriers and 800,000 FEMs.

Using integrated compounding-molding technology to produce the increasingly complex carriers that form the structural base of a front end advances this strategy. As it turns out, it also fits into the in-house development of nonmetal carriers that Faurecia has been advancing since 1989. That year the company began thermoforming carriers using polyester sheet molding compound (SMC). The early 1990s brought a toughening of European Community recycling regulations. In response, Faurecia began production in 1994 of carriers using glass-matrix technology (GMT), thereby moving from thermoset to more recycling-friendly thermoplastic resin.

The company sought new ways to improve manufacturing efficiency, lower costs, and increase design flexibility. The two-step GMT process—make the prepreg, then form it—became a prime target for improvement. A continuous process would not only be faster, it would also eliminate handling and storing the intermediate products.

Internal Process Development
Faurecia developed an inline process called XRE and began using it in 1998. A twin-screw extruder made a GF-reinforced intermediate that was then pressed into the final form inline. However, an intermediate product was still there. So Dumazet’s R&D group devised a system to marry compounding, a continuous process, with injection molding, which is discontinuous. They even built a prototype system to prove its feasibility. The catch, says Dumazet, is that Faurecia’s business is developing and producing automobile modules, not building machines.

While visiting the K 1998 fair in Düsseldorf, Faurecia saw the prototype of Krauss-Maffei’s IMC system, which just so happens to integrate compounding and injection molding. Dumazet says it was instantly clear that Faurecia and Krauss-Maffei had been working along the same technological lines.

Faurecia installed its first IMC System in June 2000 at the Audincourt facility and standardized the process it calls XRI (the “I” stands for injection). The IMC system uses a twin-screw extruder to compound the polymer, reinforcements, and additives. It feeds a shot-pot that serves as a buffer between the continuous compounding process and the injection molding cycles.

Using the XRI process on the IMC system, Faurecia has been making more than 2000 carriers/day for the front end of the Peugeot 307 since March 2001. This model includes overmolding metal inserts and two gates positioned to optimize glass fiber orientation relative to part geometry. Dumazet says that the orientation of fibers during injection is often seen as a problem. However, it also presents the opportunity to use the orientation to advantage, as is done with the Peugeot carrier. Faurecia has both the part and tooling design expertise to make this work for them.

Beyond Process Integration
Although eliminating intermediate steps in GMT and SMT production chains was a primary motivation for Faurecia undertaking inline compounding-molding, the IMC system yields a stack of other benefits. For instance, the controlled variability of both the reinforcement quantity and orientation with the IMC system produces front-end carriers with impact strength near those made with GMT.

The system’s ability to use virtually the full range of reinforcement types, including natural fibers, means Faurecia offers its clients a broad range of possibilities. Further, reinforcement types can be in a variety of form factors. Fiber length can be adjusted precisely to achieve specific performance parameters. Various nontraditional materials are being considered by Faurecia, as are a variety of reinforcements and filler combinations, all with the aim of increasing the application specificity. This wider range of reinforcements means Faurecia purchasing agents can more easily seize market opportunities and gain negotiating leverage with suppliers.

The integrated IMC process permits closed loop recycling with virtually no scrap, which supports Faurecia’s objective of “green” factories and helps meet EU criteria for easier recycling. Hybrid technology presents problems in this area. It is easier to separate metal from PP than PA. PP’s softening and melting points are relatively far apart, while those of PA are fairly close.

An IMC system might seem large compared with a normal injection machine. However, compared with Faurecia’s injection-compression systems, it is positively compact in both footprint and overall volume. Beyond saving floor space and offering greater flexibility, the IMC has a better investment cost. Faurecia’s newest and largest IMC costs more than 20 percent less than an injection-compression system, and needs half the operating manpower.

Although Faurecia continues to use hybrid, conventional injection molding, injection-compression, and its XRE process, the trend is toward the XRI process using IMC. Besides the benefits just mentioned, the process offers an advantage in the combined costs of materials, tooling, and processing. The first IMC application took shape more than two years ago in the front end of the award-winning Peugeot 307. In all, more than 10 vehicle platforms have been designed around IMC technology, a number of which will be seen in cars to be introduced soon. More than 2 million front-end carriers in all have been made using IMC and the production level soon will be rising.

Faurecia recently received Krauss-Maffei IMC system number three, its largest at 2000 metric tons. A further two systems will be in production by the middle of 2003, one of them at Audincourt.