Parting brittle hollow extrusions by snapping off at a notch uses a notch that penetrates to less than half the extrusion wall thickness

摘要

A hollow extrusion of a brittle plastic is cut to length by snapping it at a V-notch cut in at least one of the walls, using a device described in DE-U 9110857.8. The device includes guide rails, an adjustable notching device, suction to remove swarf, and a three-point bending arrangement. The claimed improvement is to limit the depth of the notch to less than half, but at least 5%, the wall thickness, e.g. 10 to 40%. An Independent claim is also included for a process using this arrangement to produce sharp-edged cuts. Cutting can be in-line with extrusion, with the cutting arrangement moving with the extrusion at extrusion speed. Two notches on opposite walls of the extrusion can be used.