Abstract: In a laser beam relay unit for shifting the direction of a laser beam, two reflecting mirrors (31, 37) are placed in parallel to each other and at a predetermined angle relative to incident light, and are fixed to rotatable light guide members (33, 36), respectively. Reflecting-mirror holders (10, 20) are provided in the backs thereof with inlets for cooling air, air retaining sections, and outlets for discharging air. The reflecting mirrors are air-cooled and can be satisfactorily cooled due to the provision of the air retaining sections.

Abstract: Galvanized steel sheets or a galvanized steel sheet and a sheet of another metal are welded to each other by a laser beam. An intermediate layer for suppressing evaporation of zinc is formed between the galvanized steel sheets (1, 4) or the galvanized steel sheet (1) and the sheet of another metal. A laser beam (8) is applied to the galvanized steel sheet (1) or the sheet of another metal, thereby welding the sheets with the laser beam. As a result, porosity is prevented from being formed in a weld bead (9), and the weld bead (9) has a constant width.

Abstract: A laser processing apparatus including a laser oscillator, a beam expander, and a light converging system. An output-end-side optical component formed by the beam expander and the light converging system includes one light converging system having composite characteristics of the optical component and the light converging system. Accordingly, the number of lenses used is reduced, the absorption loss of the laser output is lowered, and the number of parts used is reduced. Also disclosed is a laser processing apparatus in which an optical component forming a beam expander is formed partially of an output coupling mirror of the laser oscillator, whereby the number of lenses used is reduced.

Abstract: A laser beam bender for changing the direction of a laser beam which includes a mirror holder having a spherical sliding surface having the reflection center of a reflection mirror as the center of curvature thereof is fixed on an L-shaped light guide member for guiding the laser beam. A mirror holding member holds the reflection mirror and has a sliding surface which slides on the sliding surface of the mirror holder. A micrometer moves the mirror holder in a lateral direction and causes the mirror holding member to slide. The reflection center of the reflection mirror remains stationary when the mirror holding member is slidably moved by the micrometer to adjust the reflection angle of the reflection mirror.

Abstract: A power control method in a CNC (computerized numerical control) laser machining system including a CNC apparatus and a laser machining apparatus. The CNC apparatus (10) lowers a laser output by reducing both a pulse duty ratio and a pulse frequency in accordance with the lowering of a machining velocity when machining a corner portion. According to this method, a machining accuracy in the corner portion is improved, thermally influenced regions on the workpiece are reduced, and a surface roughness of the machined engraved surface is improved.

Abstract: A beam bender for changing the direction of a laser-beam in a laser-beam machining apparatus which comprises a base (1), a flange (2), a light-guide member (5), and a mirror holder (6) housing a bender mirror (7). Depending on the direction from which the laser beam is applied to the beam bender, the flange (2) may be removed and moved to another side of the base and the light-guide member (5) rotated to orient the bender mirror (7) in the direction from which the laser beam is applied.

Abstract: An assist gas control method is provided for a CNC laser machining device including a combination of a laser beam machine and a numerical control apparatus (CNC). The kind, mixing ratio, pressure, and flow rate of a assist gas are controlled by instructions from a machining program, and a numerical control apparatus (10) controls the kind, mixing ratio, pressure and flow rate of the assist gas by controlling a flow rate control valve (32), a pressure control valve (33), and other components, to perform laser machining. Since the kind, mixing ratio, pressure, and flow rate of the assist gas are controlled by the instructions from the machining program and are controlled automatically, an operator is not required to select, set or adjust the assist gas, whereby the preparation time for machining is shortened and laser machining can be carried out with a satisfactory precision.

Abstract: A beam bender for varying the direction of a laser beam in a laser-beam machine apparatus which comprises a mirror holder (6) having therein a mirror holder member (10) fitted in an inner bearing race (14) having an outer spherical surface. The inner bearing race (14) is coupled to an outer bearing race (16) either through balls 15a, 15b or directly, the outer bearing race (16) having an inner spherical surface. The inner bearing race (14) is spherically rotatable with respect to the outer bearing race (16). The angle of inclination of a bender mirror (7) held by the mirror holder member (10) can be adjusted without moving the center of the reflecting surface of the bender mirror (7).