Abstract: A package of bags of plastics film material, e.g. for storing food, comprises a wallet of plastics film containing a stack of bags. Each bag in the stack is individually folded in half with separate folds. A removable panel allows the bags to be removed from the wallet. The bags can be taken out one-by-one leaving the remainder neatly in the pack.

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: An apparatus for thermally machining thermoplastics sheet, i.e. cutting and/or welding the sheet, uses a laser. The sheet is tensioned over a backing member of a suitable refractory material such as fused silica. The laser beam is focussed on the sheet over the backing member and the laser energy passing through the sheet is absorbed in the surface layers of the backing member which is highly absorbing at the laser output wavelength. The material of the backing material also has a low thermal diffusivity so that a hot spot is formed at the point where the focussed laser beam is incident. Because the sheet is held in intimate contact with the backing member, heat from the hot spot passed back into the sheet to aid machining.