Abstract: An apparatus for substrate treatment by means of laser radiation includes a rotating polygonal mirror by which at least one incident laser beam is reflected and is pivotable across an arrangement of converging lenses which lie next to one another and which are arranged at a spacing from the substrate corresponding precisely or approximately to their focal lengths. The rotating polygonal mirror is divided into at least two regions having a different number of facets and is adjustable such that different regions can be introduced into the beam path of the laser radiation and accordingly different sweep angles or fan angles of the laser beam reflected by the rotating polygonal mirror can be set.

Abstract: An apparatus for substrate treatment by means of laser radiation includes a rotating polygonal mirror by which at least one incident laser beam is reflected and is pivotable across an arrangement of converging lenses which lie next to one another and which are arranged at a spacing from the substrate corresponding precisely or approximately to their focal lengths. The rotating polygonal mirror is divided into at least two regions having a different number of facets and is adjustable such that different regions can be introduced into the beam path of the laser radiation and accordingly different sweep angles or fan angles of the laser beam reflected by the rotating polygonal mirror can be set.

Abstract: A device for treating a substrate with laser radiation is described. The device has a rotating polygon mirror with N reflecting surfaces which are used to direct a laser beam via a system of converting focusing lenses, whereby the focal planes of the lenses are located on a surface of the substrate. Active reflecting surfaces direct the laser beam onto the converging lens system, and subsequently on the substrate, while inactive reflecting surfaces have a different inclination to the active reflecting surfaces in relation to the converging lens system. The laser beam from the surfaces is directed onto an absorber. The large number of inactive reflecting surface helps to reduce serial hole density. When the laser is switched on and off while the inactive reflecting surfaces are being scanned, further reduction of serial hole density can be achieved.

Abstract: A device for treating a substrate with laser radiation is described. The device has a rotating polygon mirror with N reflecting surface which are used to direct a laser beam via a system of converting focusing lenses, whereby the focal planes of the lenses are located on a surface of the substrate. Active reflecting surfaces direct the laser beam onto the converging lens system, and subsequently on the substrate, while inactive reflecting surfaces have a different inclination to the active reflecting surfaces in relation to the converging lens system. The laser beam from the surfaces is directed onto an absorber. The large number of inactive reflecting surface helps to reduce serial hole density. When the laser is switched on an off while the inactive reflecting surfaces are being scanned, further reduction of serial hole density can be achieved.

Abstract: A process is described for curing sand moldings, in particular casting cores, by the cold box process. In this process a catalyst containing gas mixture escaping from the mold is passed over a mixture feed side of a semipermeable membrane while a pressure is maintained on the permeate side of the membrane which is less than the pressure on the mixture feed side, whereby the catalyst vapors preferentially permeate through the membrane, and a permeate carrier gas stream which is, in particular, 50 to 300 liters greater than the permeate stream passing through the membrane per m.sup.2 and per hour is passed over the permeate side of the membrane. The catalyst, in particular a tertiary amine, is greatly concentrated in the permeate carrier gas stream and can simply and inexpensively be removed from the latter by condensation. Inexpensive, virtually complete recovery of the expensive catalyst is possible using the process.

Abstract: To extrude, for pneumatic tires, uncured tread strips composed of three different rubber or synthetic material mixtures, three extruders are used which feed to a common extruder head and are connected with the latter. The present invention utilizes the favorable flow conditions resulting from the known Y-arrangement of three extruders within the extruder head, while at the same time avoiding the previously unavoidable complex and expensive specialized construction of the extruder head. Inventively, the third extruder, which opposes the two first extruders in the withdrawal direction, is not screwed or clamped to the extruder head which is common to all three of the extruders. Rather, the third extruder is easily detachably connected via a direct metal-to-metal contact with the extruder head only by a frictional connection in a longitudinally movable arrangement.