China Tongcheng Tianbai Plastic Co.,Ltd.

Researchers at the Fraunhofer Institute for Laser Technology are promoting an advance in laser welding to fuse together transparent plastic components.

Until now, according to the Aachen-based group, one plastic part had to be transparent to permit the laser to shine through, while the other part absorbed the radiation. This usually meant soot particles had to be blended into the plastic.

“Up until now, you usually had to choose a single plastic combination: transparent and black. There are lots of applications -- in medical technology, for instance -- where what’s needed is a combination of two transparent plastics,” said project manager Alexander Olowinsky, in a news release.

Fraunhofer researchers studied the absorption spectra of various transparent polymers to determine the wavelength ranges within which they absorb laser radiation. Then the team developed laser systems to match those wavelengths, as well as special lenses to focus the beam for precise welds.

Researchers are continuing work on the European Commission-sponsored PolyBright project, to create the combination of the right absorption bands with the matching light sources.