JP3418462B2 - Laser processing torch - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to laser processing of a laser processing machine for facilitating passage of laser light condensed by a condensing lens through a processing nozzle. It is about the torch. 2. Description of the Related Art A conventional laser processing machine will be described below with reference to FIGS. (Description of FIG. 1) FIG. 1 is a block diagram of a laser beam machine.
In the figure, 1 is a laser oscillator. 2 is a laser oscillator 1
It is the laser beam output from. Reference numeral 3 denotes a bend mirror that reflects the laser beam 2 and causes the laser beam 2 to enter a condenser lens 6 to be described later. Reference numeral 4 denotes a central axis of a laser light guide tube 5 and a laser processing torch 9 which will be described later. Reference numeral 5 denotes a laser light guide tube for protecting the optical path of the laser light 2, and reference numeral 6 denotes a condenser lens for condensing the laser light 2. Reference numeral 7 denotes a laser beam condensed by the condenser lens 6, 8 denotes a machining nozzle, and 9 denotes a laser machining torch including the condenser lens 6 and the machining nozzle 8 described above. Further, the workpiece 20 is mounted on a machining table 22 and is NC (Numerical Co).
ntrol) and PLC (Programmable Logic Controller) or the like, controlled and moved by a control device 21 to perform laser processing. The laser light 2 is provided in a laser oscillator 1 (not shown) so as to pass through the center of the laser light guide tube 5 along the central axis 4, be reflected by the bend mirror 3, and pass through the center of the laser processing torch 9. The optical axis is adjusted by the adjusted screw. The laser beam 2 is collected by the condenser lens 6 and passes through the center of the hole bored by the laser beam itself of the processing nozzle 8 and is irradiated onto the workpiece 20. (Explanation of FIG. 2) FIG. 2 is a sectional view of the conventional laser processing torch 9 of FIG. In the figure, the laser beam 2 bent by the bend mirror 3 is guided to a laser processing torch 9 attached to a laser beam guide tube 5. The laser processing torch 9 includes a lens holder 16 to which the condenser lens 6 is attached, a holder 12 that supports the lens holder 16, a processing nozzle 8, and a set screw 1 for the processing nozzle 8.
5 and a height adjusting spacer 17 of the processing nozzle 8. The machining nozzle 8 moves along the nozzle holder 11 about the central axis 4. The set screw 15 sets and fixes the positions of the nozzle holder 11 and the processing nozzle 8. The height adjusting spacer 17 is an adjusting jig for changing the position of the processing nozzle 8 by a certain amount in a direction parallel to the central axis 4. Reference numeral 40 denotes an inlet for supplying assist gas from a gas supply source (not shown). (Explanation of FIG. 3) FIG. 3 is an enlarged cross-sectional view of a conventional machining nozzle 8. In the figure, the thickness 24 of the bottom 24 of the processing nozzle 8 is 1 mm or less, and has a flat bottom 19 perpendicular to the central axis 4. The bottom portion 19 is irradiated with the condensed laser beam 7, and a nozzle hole serving as a laser beam passage opening is opened. (Description of FIG. 4) FIG. 4 is a diagram showing the relationship between the focused laser beam 7 and the nozzle hole 10 formed in the bottom 19 of the processing nozzle 8. As shown in FIG. In the figure, a mode cross section 7A before the focused laser beam 7 passes through the nozzle hole 10 and a mode cross section 7B after the passage are shown. The mode cross section 7A before passing through the nozzle hole 10 has a shape that maintains the mode cross section irradiated from the laser oscillator, and the mode cross section 7B after passing through the nozzle hole 10 has a focused laser beam 7 and nozzle. The interference phenomenon of light appears by the edge of the hole 10. The cause of the light interference phenomenon is that the shape of the bottom of the mode cross section of the laser light is not a mechanically sharp boundary, but an asymptotic shape that gradually and gradually expands. This is because when the hole is opened at 7, the size of the hole and the diameter of the laser beam passing through the hole are substantially equal, and the end of the laser beam causes a diffraction phenomenon at the end of the hole. Therefore, the condensing property of the laser beam 7 condensed due to the light interference phenomenon is deteriorated, the power density of the laser beam at the focal point is lowered, the power density necessary for the processing cannot be obtained, and the processing failure Cause. Therefore, the nozzle hole 10
The diameter of the hole needs to be larger than the diameter of the laser beam passing through the nozzle hole 10. (Explanation of FIG. 5) FIG. 5 is an enlarged sectional view showing nozzle drilling of the conventional processing nozzle 8. As shown in FIG. The difference in the diameter of the nozzle hole 10 opened in the bottom 19 of the processing nozzle 8 is shown by the difference in height between the focused laser beam 7 and the processing nozzle 8. FIG. 5A shows a nozzle hole diameter 10A opened at a machining height 30 (hereinafter referred to as a machining height) in which the distance between the workpiece 20 and the nozzle bottom 19 is optimal when machining. FIG. 5B shows a nozzle hole diameter 10B opened at a position 30A higher than the machining height 30 (hereinafter referred to as a nozzle hole adjustment distance). Also, the size of the nozzle holes having the nozzle hole diameters 10A and 10B is optimal for punching the condensing shape of the condensed laser light 7, for example, the nozzle hole adjusting distance 30A corresponding to the focal length of the condensing lens 6. By selecting and using an appropriate height adjusting spacer 17, the nozzle hole diameters 10A and 10B having different sizes are bored. In order to make the nozzle hole 10 having a diameter larger than the beam diameter at which the focused laser beam 7 passes through the processing nozzle bottom 19 at the bottom of the processing nozzle, the processing is performed. It is necessary to move the position of the nozzle 8 along the central axis 4. For this reason, in the prior art, the position of the processing nozzle 8 is adjusted depending on whether or not the above-described height adjusting spacer 17 is inserted between the processing nozzle 8 and the nozzle holder 11. However, this method has a problem that time is required and work is complicated. Therefore, an object of the present invention is to place the machining nozzle 8 on the bottom 19 of the machining nozzle 8 by the focused laser beam 7 without inserting the height adjusting spacer 17 in the laser machining torch 9. , Processing nozzle bottom 19
It is an object of the present invention to provide a structure of a laser processing torch 9 that makes a nozzle hole 10 larger than the beam diameter of the focused laser beam 7 when passing through the nozzle. The laser processing torch according to the present invention comprises a condensing lens 6 for condensing the laser beam 2 output from the laser oscillator 1 and is condensed by the condensing lens 6. When the laser beam 7 is irradiated onto the workpiece 20, the laser beam is irradiated by the condensed laser beam 7 itself and a passage port through which the assist gas is jetted is bored in the processing nozzle 8 for laser processing. In the laser processing torch 9 to be started, the processing nozzle 8 is a compression molded product obtained by mechanically press-molding the material of the processing nozzle 8 using water pressure, hydraulic pressure, etc., and has a shape that retains elasticity or flexibility. This is applied to the laser processing torch 9 formed into the above. The laser processing torch 9 according to the first aspect is characterized in that the positions of the bottom portions 29 and 29A of the processing nozzles 18 and 18A with respect to the central axis 4 as shown in the sectional views of FIGS. This laser processing torch has a structure having a processing nozzle that is changed by utilizing the elastic force of the processing nozzles 18 and 18A by a nozzle hole adjustment distance 30A having a constant length in the X direction. FIG. 6 is an enlarged sectional view of the machining nozzle 18 showing an embodiment of the first aspect of the present invention. 3A is compared with the cross-sectional view of the conventional processing nozzle 8 of FIG. 3, the periphery of the base portion 29 is bent, and the position of the base portion 29 is located inside the processing nozzle 18 along the central axis 4. The structure is recessed to 50. The processing nozzle 18 is a thin plate compression-molded product and is molded into a shape that retains elasticity or flexibility. For this reason, the shape has a structure that can be deformed within the elasticity range of the material. For example, when the bottom portion 29 is mechanically pressurized from the inner side 50 of the processing nozzle 18 along the central axis 4 or by the pressure of the assist gas, the bottom portion 29 is elastically deformed and protrudes to the outer side 51 of the processing nozzle 18. Deform to shape. FIG. 4B is a sectional view of the deformed processing nozzle 18. Similarly, in the shape of (b), mechanical force is applied from the outer side 51 of the bottom part 29 of the machining nozzle 18 to the central axis 4.
, The base 29 is elastically deformed and deformed into a concave shape on the inner side 50 of the processing nozzle 18. (A) is the shape after deformation. In this way, the processing nozzle 18 can change the shape of the above two bottom positions by applying an external force due to the elasticity or flexibility of the material. When actually making a laser light passage hole in the base 29, first, the laser light 7 condensed at the position where the base 29 is close to the condenser lens 6, that is, in the state of FIG.
2, the assist gas is sealed from the assist gas inlet 40 of the laser processing torch 9 shown in FIG. 2, and the gas pressure causes the bottom 29 of the processing nozzle 18 to move along the central axis 4 in the X direction. It is moved to a position far from the condenser lens 6, that is, a position shown in FIG. The processing nozzle 18 is a thin plate compression processed product, and is designed to have a thickness and strength sufficient to deform the shape by the internal gas pressure as described above. FIG. 7 is a sectional view of a machining nozzle 18A showing another embodiment of the first aspect of the present invention. In the figure, the bottom portion 29A is not a flat surface, but has a curved surface structure integrated from its peripheral portion. Similarly to the case of FIG. 6, the bottom side 29 </ b> A has a nozzle hole adjustment distance 3 having a constant length in the direction parallel to the central axis 4.
The position can be changed by 0A. Bottom part 29A
The change in the position is similar to the method of FIG. In the laser processing torch of the present invention, the laser beam 7 focused on the processing nozzle bottom 19 is used to open a nozzle hole 10 larger than the beam diameter passing through the processing nozzle bottom 19. The positions of the bottom portions 29 and 29A of the processing nozzles 18 and 18A are changed by the nozzle hole adjustment distance 30A having a fixed length in the X direction with respect to the central axis 4 by utilizing the elastic force of the processing nozzles 18 and 18A. By adopting a structure that allows the height adjustment spacer 17 to be inserted,
It is not necessary to move the position of the processing nozzle 18 in the X direction along the central axis 4, and the above-described nozzle hole can be opened only by applying a gas pressure, so that the operation is simple and the operation time is shortened. . Further, the structure of the processing nozzle 18 portion of the laser processing torch 9 also eliminates the need for the height adjusting spacer 17,
Simple structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a laser beam machine. FIG. 2 is a cross-sectional view of a conventional laser processing torch. FIG. 3 is an enlarged cross-sectional view of a conventional processing nozzle. FIG. 4 is a relationship diagram between a focused laser beam and a nozzle hole. FIG. 5 is an enlarged sectional view showing nozzle drilling of a conventional processing nozzle. FIG. 6 is an enlarged sectional view of a processing nozzle showing an embodiment of the present invention. FIG. 7 is an enlarged sectional view of a processing nozzle showing another embodiment of the present invention. [Explanation of Symbols] 1 Laser oscillator 2 Laser light 3 Bend mirror 4 Center axis 5 Laser light guide tube 6 Condensing lens 7 Condensed laser light 7A Mode cross section 7B before passing through nozzle hole Mode cross section 8 after passing through nozzle hole (Conventional) machining nozzle 9 Laser machining torch 10 Nozzle hole 10A Nozzle hole 10B drilled at the machining height Nozzle hole 11 drilled at a position higher than the machining height by the nozzle hole adjustment distance 11 Nozzle holder 12 Holder 15 Set screw 16 Lens holder 17 Height adjustment spacer 18 Processing nozzle 18A (invention) Processing nozzle 19 Processing nozzle 19 Processing nozzle bottom 20 Workpiece 21 Control device 22 Processing table 24 Processing nozzle bottom thickness 29 (Invention) Nozzle bottom 29A (of the present invention) Processing nozzle bottom 30 Processing height 30A Nozzle hole adjustment distance 40 Outside the inner 51 processing nozzle of the gas introducing port 50 processing nozzle

Claims (1)

(57) Claims 1. A condensing lens that condenses laser light output from a laser oscillator, and a laser beam condensed by the condensing lens is irradiated onto a workpiece. In addition, after irradiating the processing nozzle with a laser beam by the condensed laser light itself and piercing the passage port for injecting the assist gas,
In a laser processing torch that starts laser processing, the processing nozzle is formed of a compression molded product, and the shape of the bottom portion of the processing nozzle is deformed in the direction of the central axis of the processing nozzle by the pressure of the injection gas or mechanical pressure A laser processing torch having a nozzle.