A tale of two applications. (WIP).

Driven by automakers looking for lower-weight, higher-capability materials, suppliers are pushing new polymer formulations into areas that have been traditionally dominated by metals and thermoset plastics. Take AMODEL polyphtalamide [PPA] made by Solvay Advanced Polymers [Alpharetta, GA]. The 45% glass-reinforced PPA reduced both the weight [by 60%] and the wall thickness of the "power piston" of Delphi's new vacuum brake boosters when compared to traditional thermosets. The thinner walls allow for larger air passages, better pedal feel and quicker feedback. Delphi senior project engineer Michel Vermoesen says, "This gives us much greater control over the dimensions and geometric location of the critical features on the part, which greatly reduces variation within the system, and improves its function, reliability and durability."

DaimlerChrysler chose a grade of the same material to replace a cast aluminum thermostat housing on the 2.4-liter Jeep Liberty engine where it is exposed to a hot stream of long-life coolant. Engineers at DaimlerChrysler say the material was chosen mainly for its resistance to wear, and its ability to handle the required 225[degrees]F normal maximum operating temperature. But it has also yielded benefits in manufacturing since the housing now can be injection molded as a net shape, eliminating the machining operations necessary for the previous aluminum part.