Laser automates mould polishing

Researchers at the Fraunhofer Institute for Laser Technology (ILT) in Aachen have developed a way of automating the polishing of injection moulds by using lasers.

Polishing injection moulds is time consuming and monotonous but requires high levels of concentration as any blemish in the mould can render it useless.

A skilled worker may often need a whole week to polish a single metal mould and up until now it has not been possible to use machines for the work because they could not polish the curved parts of the mould.

Describing the new technique, Dr Edgar Willenborg, group leader at the ILT, said: ’The laser beam melts the surface to a depth of about 50 to 100um. Surface tension ensures that the liquid metal flows evenly and solidifies smoothly.’

As in conventional grinding and polishing, the process is repeated with increasing degrees of fineness. In the first stage, the researchers melt the surface to a depth of about 100um, in further steps they gradually reduce the depth.