Glass beads slash weight of cast metal parts

German scientists have used the tiny hollow beads to reduce the density of the components

Microscopic glass beads have helped German scientists to halve the weight of cast metal parts. A team from Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research (IFAM) have added the beads – which are no bigger than 60 microns – to metals during casting. The technique has been used on both zinc and aluminium. It reduced the density of aluminium from 2.7 to 1.2g/cubic centimetre, and zinc from 7 to 3.1g/cubic centimetre. The trick, according to Joerg Weise of the foundry technology working group at IFAM, is to get an even distribution of beads. “If they are evenly distributed, we get a smooth surface – like metal,” he says. “If the glass content is uneven, the materials gets a new appearance, full of streaks.” The technique recently won first place in the International Forum Design.