Abstract: An optical system suitable for use in machining plastics sheet material using a laser, brings a beam radiant energy in to a line focus on the work piece. The work piece is moving, and the line focus is perpendicular to the direction of such movement. The focused beam is scanned across the work piece in a direction having a component in the direction of motion of the workpiece so that the line focus traverses the work piece in the direction of the line focus. A cylindrical element may be used to form the line focus and a rotating polygonal mirror may perform the scanning.

Abstract: A machine for making bags out of thermoplastics material including a rotating drum having pockets, a feed station including means for feeding material into the pockets at a predetermined rate to form loops, the rate of feed being linked to the rotational speed of the drum by a feed-back control means to ensure that the loops are of a predetermined size. The loops are welded and cut by a laser to form bags.