By Dr. Cameron Chai
Bayer MaterialScience is presenting an innovative sandwich material, apt for diesel engine enclosures based on the Baypreg polyurethane spray system. The completed component is 30% lighter and 30% less costly when compared to its aluminum and steel counterparts. The 2012 JEC Innovation Award has been presented honoring this novel product.
The component designed from this composite material has the following salient features:
- As the enclosure is arranged above the tracks and below the train’s passenger compartment, the engine needs to be protected from rock impacts and the component ensures that the enclosure can bear high mechanical loads.
- The component designed from this composite can prevent the leakage of oil into the track bed.
- The component complies with stringent fire protection demands as defined in the European standard CEN/TS 45545.
These innovative components are directly manufactured in their complex, three-dimensional shape using a spray/press process. It is possible to design components with a maximum area up to 4 sq. m. Even though the part dimensions are large, the superior dimensional stability possible by the process allows the components to be installed accurately in the final assembly. It is possible to conveniently integrate additional elements and functions, considerably bringing down the number of components in each assembly.
The sandwich structure comprises a honeycomb core with upper and lower glass fiber mats. The Baypreg system comprising optionally cut glass fibers and flame retardant is sprayed on either side. The composite is then mounted in a mold and subjected to pressing at a temperature of 130°C. Reaction and foaming of the polyurethane system takes place causing the components to bind together permanently and firmly. After around two minutes, the part is taken out from the mold, deburred and then coated.