Abstract: An apparatus for the laser processing of workpieces with shortened processing time. Two laser units that can be simultaneously operated are directed towards each other. Workpieces, for example printed circuit boards, are moved between the two laser units such that the two sides of the workpieces are simultaneously processed. As a result the processing time is considerably shortened.

Abstract: Positioning arms for positioning and assembling systems are subjected to high accelerations and must therefore be made lightweight but nevertheless resistant to bending and twisting. The use of composite materials based on metal or ceramic foams and non-expanded materials for positioning arms in positioning and assembling systems allows these positioning arms to be lightweight and nevertheless to have high rigidity. Semifinished products are arranged in the non-expanded material, since a better connection between the semifinished product and material is ensured there than in the metal or ceramic foam.

Abstract: A carrier medium for recording comprises a ribbon of insulating material and a metal coating deposited thereon in a thickness of at least 250 A which coating is adapted to be electrically seared for producing writing trackings. The coating is predominantly composed of vapor deposited aluminum of which at least 15% by weight is in the form of aluminum oxide, aluminum oxide hydrate or a combination of these two compounds.The content of oxygen-attached aluminum in the metallic coating is determined by first measuring the total aluminum contents per surface unit in a definite size specimen of the coating, then placing the specimen into alkali to evolve hydrogen in an amount equivalent to the metallic aluminum present in the coating, whereupon the amount of hydrogen developed is determined by gas chromatography.