No-stick switching from LNP

LNP says its Lubriloy alloy prevents the pushbutton of this minivan switch from sticking to the base.

LNP Engineering Plastics' Lubriloy alloy is being used to eliminate a sticking problem that beset a switch application on hundreds of thousands of minivans.

Many of the automotive industry's switch bases use glass-filled nylon 6/6. The problem in the minivan application was that the polycarbonate button could wear through the base's outer layer of resin, causing the button to stick. In addition to a non-stick property, LNP's injection-molded, internally lubricated, glass-filled nylon 6/6 alloy solution possesses greater pliancy and elongation properties than regular nylon 6/6.

Pliancy is important, LNP says, because the switch base has an integrally molded snap clip for mounting on the B-pillar. "The switch itself just snaps into place on the pillar," said LNP's Rob Russell. "So, it's important that the switch base retain its strength, yet have enough flexibility to snap in without breaking."

Regular nylon 6/6 switch bases also tend to embrittle in cold weather and often fail when snapped into the pillar. The Lubriloy product's better elongation eliminates that problem, according to the company. Dimensional stability and moisture resistance also are improved, reducing the potential for warp, Russell said.

- Patrick Ponticel

Bosch researching composites

A magnetic enclosure made of a metal-polymer composite (with an optical photomicrograph of its structure in the background) increases the speed of valve switching in injector systems.

Researchers at Bosch are experimenting with metals, ceramics, and plastics to form composites that reduce weight, lessen wear, reduce cost, and provide new properties. One area of research is in diesel direct injection using the common-rail principle, for which injection timing is critical.

The heart of each injector is its magnetic enclosure, inside which the coil for raising the injector needle is wound. If the enclosure were composed of solid iron, unwanted eddies would arise in the material and delay the switching process. The solution, Bosch found, is embedding fine particles of iron in plastic. This is done by pressing plastic-covered powdered iron and subsequently cross-linking the polymers in the component. The plastic matrix insulates the iron particles from one another and prevents eddy currents. The large quantity of iron ensures the necessary magnetization and rapid transfer of force to the injector needles. The trick, Bosch says, is finding the optimum combination of the materials' properties.

In another area of research, the company is developing composite materials with a metallic matrix for components that are subject to wear from friction. A ceramic component in the material makes it hard and wear-resistant while the metallic matrix conducts the frictional heat away. To make the material, powdered-ceramic material is pressed to form a substance with open pores, and impregnated with molten aluminum. The resulting material is tailored just for the components, which are much lighter than those made with conventional materials such as steel or cast iron.

- Patrick Ponticel