JPS57193289A - Method and device for cutting of tubular body by laser beam - Google Patents

Abstract

PURPOSE:To prevent sticking of the projections of melts on cut parts in the stage of cutting a tubular body by irradiation of a laser beam by irradiating the laser beam of about the energy at which it cannot penetrate through the tubular body in one shot while rotating said body >=2 turns. CONSTITUTION:While a thin-walled metallic pipe 5 is supported and rotated by the rotation of a roller 35 and a holding body 27, the laser beam 12 oscillated by a laser oscillator 41 is focused with a lens 44, and is condensed onto the surface of the rotating body 5, whereby the body 5 is cut. Here, the intensity of the laser beam is set at about the intensity at which it cannot penetrate through the tubular body when irradiated once, and the body 5 is cut by irradiating the beam to its surface >=2 times. Before the completion of the cutting, the greater part of the pipe wall in the cut part evaporates and only the slight parts melt; therefore, projections 3 are less produced in the cut parts. The cutting operation is accomplished by converting the working light generated during cutting to an electric signal with a photoelectric converting body 52, comparing the same with the set value of a setter 57 in a comparator 56, and stopping the irradiation of the laser beam upon completion of the cutting by the operation of a shutter 42 or the oscillator 41 for the leaser beam.