JPH05269585A - Laser beam machining method and machine - Google Patents

Abstract

PURPOSE:To provide the laser beam machining method and machine capable of meeting both of oxidation prevention and oxidation acceleration on the irradiation surface in laser beam machining to plot various patterns on the metal surface. CONSTITUTION:A metallic material 4 to be machined having an external form of a body of rotation is mounted on a rotary table 3, an opening edge 7a of a gas blowing pipe 7 of a scanning head 2 is brought close to the surface thereof and inert gas or gaseous oxygen or gas 19 having high oxygen concentration is blown against the whole of the scanning area of the surface of the material 4 to be machined through the scanning head 2 from the gas blowing pipe 7. The rotary table 3 is then driven to rotate continuously or intermittently and the metal surface is irradiated with a laser beam 9 to carry out plotting by an irradiation locus while the scanning surface is renewed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method and apparatus for drawing various patterns on the surface of a metal workpiece having an outer shape of a rotating body by irradiation with laser light. The pattern, pattern, mark, character, etc. is composed of a pattern consisting of lines and dots, and the so-called iridescent coloring process in which the shade of the reflective gloss of the pattern itself changes in a rainbow-like manner depending on the angle of incident light and the viewing direction. It is preferably used when applying.

[0002]

2. Description of the Related Art As a means for drawing patterns, patterns, marks, characters, etc. on the surface of metal or the like, drawing of a required pattern is performed by irradiating a laser beam with thin grooves or concave points formed on an irradiation track. The method of applying is widely used. Further, in recent years, interference fringes are generated on the laser light irradiation surface, and fine irregularities corresponding to the interference fringes of the laser light are formed on the metal surface, so that the drawing pattern itself reflects the hue of the gloss of the incident light. There is also proposed an iridescent color processing technique that varies in a rainbow-like manner depending on the viewing direction (for example, Japanese Patent Laid-Open No. 2-263589).

However, when the surface of the work piece is a metal such as stainless steel, the surface irradiated with laser light is easily oxidized by high heat, and the drawing pattern is visually recognized by being colored with an oxide layer having a different shade from that of the metal base. Therefore, the above-mentioned coloring may become a problem depending on the type and application of the work piece, and it is desired to prevent this oxidation. In particular, in iridescent color processing, there is a problem in that the hue of reflective gloss is affected by the above-mentioned oxidation coloring, leading to a reduction in decorative value in terms of sharpness and saturation.

On the other hand, when a quenching mark or the like is formed on the metal surface, it is preferable that the metal surface has a strong oxidizing property from the viewpoints of processing efficiency and finish, and there are also processing for the purpose of the above-mentioned oxidative coloring. On the contrary, it is desired to promote the oxidation.

In view of the above circumstances, it is an object of the present invention to provide a laser processing method and apparatus which can sufficiently meet the contradictory demands of preventing oxidation and promoting oxidation on the irradiation surface of laser light.

[0006]

In order to achieve the above object, the first laser processing method according to the present invention is capable of displacing the optical axis direction on the surface of a metal workpiece having an outer shape of a rotating body. In a laser processing method of irradiating a laser beam from a scan head and drawing on the surface according to an irradiation locus, the workpiece is placed on a rotary table so that its axis coincides with the axis of rotation. From the side, the gas is blown to the entire scan range of the surface of the workpiece, and the drawing is performed by irradiating a laser beam while continuously or intermittently rotating the rotary table to update the scan surface. The configuration adopted is as follows.

A second method of laser processing according to the present invention
In the first processing method, an inert gas is used as the blowing gas, and in the third method, an oxygen gas or a gas having a high oxygen concentration is used as the blowing gas.

On the other hand, for the same purpose, a laser processing apparatus according to the present invention comprises a rotary table on which a metal workpiece having an outer shape of a rotary body is placed and which is continuously or intermittently driven to rotate, and a laser resonator. A scan head for irradiating the surface of the workpiece with a laser beam emitted from the resonator, and a laser beam direction displacement means installed in the scan head, wherein the scan head is provided in the scan head. A gas flow path having a laser beam irradiation port as a gas discharge port is provided, and a peripheral edge of the opening is formed outside the laser beam irradiation port of the scan head so as to be close to the surface of the workpiece and surround the scan range. It employs a configuration characterized by mounting a gas blowing cylinder.

[0009]

[Function] During drawing, while blowing an inert gas from the scan head side over the entire scan range of the surface of the workpiece,
If a laser beam is radiated through this gas, the air near the scan range on the surface of the workpiece is eliminated by this gas flow, and the oxygen that is the source of oxidation does not exist. No layering occurs.
Therefore, when the coloring of the drawing pattern due to oxidation is disliked in the ordinary decoration processing or iridescent coloring processing, an inert gas may be used as the gas blown onto the surface of the workpiece in the present invention.

On the other hand, when an oxygen gas or a gas having a high oxygen concentration is used as the gas blown onto the surface of the work piece, oxidation occurs on the surface of the work piece irradiated with laser light as compared with the case of laser processing in normal air. It will be easier. Therefore, it is suitable for the case of providing a quenching mark or the like on the metal surface, or for decoration processing in which the coloring due to the oxidation of the drawing pattern is positively used.

It should be noted that, regardless of which of the above-mentioned inert gas and oxygen gas or gas with a high oxygen concentration is used as the blowing gas, the metal vapor generated on the irradiation surface of the laser beam is rapidly removed by the blowing gas flow. Since the processing efficiency is improved and the irradiation surface is cooled, the same action as that of the gas jet used in the conventional laser cutting or the like can be obtained.

[0012] Therefore, a workpiece having the outer shape of a rotating body such as a vase or a vase is held on a rotary table, and the rotary table is continuously or intermittently rotated with its central axis aligned with the rotational axis. For driving, it is possible to perform processing under the above-mentioned gas blowing while updating the scan surface by rotating the rotary table in a state where the scan head side that irradiates the laser beam is set at a fixed position. Therefore, it is necessary to position the focal point of the converging lens for processing on the irradiation surface of the work piece in ordinary decoration processing, and in iridescent coloring processing, in order to generate interference fringes on the irradiation surface, It is necessary to position the irradiation surface at a fixed position shifted in one direction in depth and depth, but as described above, the scan surface can be held in a fixed position even though the workpiece has a three-dimensional surface with the outer shape of the rotating body. The control of the optical system for adjusting the depth of focus of the laser beam in drawing becomes very easy.

[0013]

FIG. 1 shows a laser beam machine according to an embodiment of the present invention. In the figure, 1 is a processing machine main body having a drawing operation panel 1a on the right front surface and a laser operation panel 1b on the left front surface, 2 is a scan head arranged in a protruding shape on the central front side of the upper portion of the main body 1, and 3 is The rotary table 5 is placed on the rear side of the main body 1 for placing the workpiece 4, 5 is an image display device for observing the machined surface, which is installed in the upper left part of the main body 1, and 5a is its imaging camera.
Reference numeral 5b is a light projector for illuminating the surface to be processed, 6 is a shield plate surrounding the left and right and the rear of the workpiece 4, and a gas blowing cylinder 7 is attached to the laser beam irradiation side of the scan head 3.

FIG. 2 shows the configuration of an optical system in the laser processing machine. Reference numeral 8 in the figure is a laser resonator such as a YAG laser, and a laser beam 9 emitted from this resonator is
The beam is expanded by a beam expander 11 having a built-in magnifying lens to change the direction of 90 ° by a reflecting mirror 10 and passes through a movable lens 12a of a Z scanner (Dynamic Focus) 12 and a condensing lens (Imaging Obj).
and the beam direction is controlled by the rotary reflecting mirrors 14a and 15a of the X scanner 14 and the Y scanner 15, and the surface of the workpiece 4 is irradiated.

Here, the Z scanner 12 converts the focus position by the condenser lens 13 into the beam angle and the curved surface shape data of the workpiece 4 which is measured in advance within a predetermined scanning range by the X and Y scanners 14 and 15. Accordingly, set the fixed position on the machined surface. That is, the fixed position of this focal point is a position displaced to the upper or lower side with respect to the surface of the workpiece 4 in the ordinary decoration processing and the surface in the iridescent coloring processing.

As for the processing state at the irradiation position of the laser beam 9, the spray cylinder 7 is made of a transparent material such as glass or synthetic resin, and the processing surface of the workpiece 4 illuminated by the projector 5b is imaged by the imaging camera 5a. And is displayed on the screen of the image display device 5 for observation. An auxiliary laser 16 made of a He—Ne laser or the like is installed coaxially behind the laser resonator 8 in order to visualize the laser beam 9 and observe the focus position.

As shown in FIG. 3, the scan head 2 includes
The X scanner 14 and the Y scanner 15 are installed in a case 2a having a substantially rectangular parallelepiped shape, a laser beam irradiation port 2b is opened on one side surface of the case 2, and the laser beam irradiation port 2b is concentrically spread outside the irradiation port 2b. A megaphone-shaped gas blowing cylinder 7 is attached. Then, in the state where the tip end side of the gas blowing cylinder 7 is brought close to the workpiece 4 on the rotary table 3, the entire circumference of the opening peripheral edge 7a comes close to the workpiece 4 and is scanned by the laser beam 9. It has a shape capable of enclosing the range.

A pipe 17 is connected to the bottom of the case 2a to cover the optical path of the laser beam 9 from the laser resonator 8 into the scan head 2. A gas inlet 17a is provided in the middle of the pipe 17. A gas 19 introduced from a gas supply pipe 18 connected to the introduction port 17a enters the scan head 2 through the pipe 17, and is processed through the gas blowing cylinder 7 from the laser beam irradiation port 2b. 4 is set to be sprayed on the surface.

Here, as the gas 19, an inert gas is used when the coloring of the drawing pattern due to oxidation is disliked by ordinary decoration processing or iridescent coloring processing, or a quenching mark or the like is applied to the metal surface or the drawing pattern. In the case of the decoration processing in which the coloring due to the oxidation of (1) is positively used, oxygen gas or a gas of high oxygen concentration is used, respectively. Then, the laser beam 9 emitted from the scan head 2 passes through the gas 19 inside the gas blowing cylinder 7 and is applied to the surface of the workpiece 4.

The gas blowing cylinder 7 is replaced with one having an opening peripheral edge 7a corresponding to the outer shape of the rotating body according to the type of the workpiece 4. For example, when the workpiece 4 has a substantially cylindrical shape as shown in FIGS. 4 and 5, gas spraying having an opening peripheral edge 7a whose upper and lower edges are concave arc shapes in plan view along the circumferential surface thereof The cylinder 7 is used.

3 to 5, reference numeral 20 is a receiving seat screwed onto the rotary table 3, and has a recess 20a corresponding to the bottom shape of the workpiece 4 on the upper surface side thereof. The work piece 4 is positioned and held on the work piece 3 in a stable manner. The receiving seat 20 having an upper surface shape corresponding to the shape of the bottom portion of the workpiece 4 is exchanged for use.

Note that vacuum suction may be used as a means for more reliably fixing the workpiece 4 on the rotary table 3. For example, the rotary table 3 shown in FIG.
Is provided with a vacuum suction hole 21 that vertically penetrates along the axis, and the center of the receiving seat 20 also has a through hole 2 that communicates with the suction hole 21.
0b is provided, and the workpiece 4 is configured to be sucked and fixed to the rotary table 27 by vacuum suction. Then, the interface between the rotary table 3 and the receiving seat 20,
In addition, seal rings 22a and 22b are provided at the interface between the receiving seat 20 and the workpiece 4, respectively.

In FIG. 6, the rotary table 3 has its shaft portion 3a rotatably supported by the working table 23 via bearings 24, 24 so as to be rotatable about the vertical axis.
By driving a motor 25 attached to the lower surface side of the shaft 3, a bevel gear 26a fixed to the lower end of the shaft 3a and a bevel gear 26b provided at the shaft center of the motor 25 are rotationally driven. .. The processing table 23 may be set as a so-called XY table that is movable in the front-rear direction and the left-right direction with respect to the scan head 2.
Further, the structure may be tilted back and forth.

In the laser processing machine having the above-mentioned structure, the opening edge 7a of the gas blowing cylinder 7 of the scan head 2 is brought close to the surface of the workpiece 4 held on the rotary table 3, and the rotary table 3 is continuous or intermittent. The laser beam 9 is radiated to the surface of the workpiece 4 from the scan head 2 side while the laser beam 9 is radiated to perform the required drawing. At this time, when the coloring of the drawing pattern due to oxidation is disliked by the usual decoration processing or iridescent coloring processing, an inert gas may be used as the blowing gas. In addition, when applying a quenching mark or the like to the metal surface or performing decorative processing that positively utilizes coloring by oxidation of the drawing pattern,
An oxygen gas or a gas having a high oxygen concentration may be used as the blowing gas.

[0025]

According to the laser processing method and the laser processing apparatus of the present invention, a gas is blown over the entire scan range of the surface of a metal workpiece having an outer shape of a rotary body placed on a rotary table, and the scan is performed. Since it is possible to irradiate a range with a laser beam and perform drawing with the irradiation trajectory, if you dislike coloring of the drawing pattern due to oxidation coloring in ordinary decoration processing or iridescent coloring processing, use an inert gas as the above gas. In addition to being able to prevent the above-mentioned oxidation by using, when performing a decoration process that makes a quenching mark or the like or positively utilizes coloring due to the oxidation of the drawing pattern, the oxidation is performed by using an oxygen gas or a gas with a high oxygen concentration as the gas. It is possible to promote high-quality laser processing in any case, and by rotating the rotary table, the laser beam Morphism position can the update while scanning surface is kept constant, the control of an optical system for adjusting the depth of focus of the laser beam in the drawing there is an advantage that becomes very easy.

[Brief description of drawings]

FIG. 1 is a perspective view of an entire laser processing machine according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a configuration of an optical system in the laser processing machine.

FIG. 3 is a schematic vertical sectional side view of a main part of a laser processing section of the laser processing machine.

FIG. 4 is a side view of a main part in another example of the laser processing part.

FIG. 5 is a partially cutaway plan view of the same main portion as in FIG.

FIG. 6 is a vertical cross-sectional side view of the laser processing section on the side of a workpiece.

[Explanation of symbols]

 1 ... Laser processing machine main body 2 ... Scan head 2b ... Laser beam irradiation port 3 ... Rotating table 4 ... Workpiece 7 ... Gas blowing cylinder 7a ... Opening edge 8 ... Laser resonator 9 ... Laser beam 14 ... X scanner (laser beam) Direction displacement means) 15 ... Y scanner (laser beam direction displacement means)

Continuation of front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical display location H01S 3/00 B 8934-4M (72) Inventor Yoshikazu Okano 1-9-1, Jokoji Amakosaki, Hyogo Prefecture Osaka Fuji Industry Co., Ltd.

Claims (4)

[Claims] 1. A laser processing method for irradiating a surface of a metal workpiece having an outer shape of a rotating body with a laser beam from a scan head capable of displacing an optical axis direction, and drawing on the surface according to an irradiation locus, The workpiece is placed on a rotary table so that its axis coincides with the axis of rotation, and gas is blown from the scan head side over the entire scan range of the surface of the workpiece, and the rotary table is continuously or A laser processing method characterized by performing the above-mentioned drawing by irradiating a laser beam while intermittently rotating and updating the scan surface. 2. The laser processing method according to claim 1, wherein the replacement gas is an inert gas. 3. The laser processing method according to claim 1, wherein the replacement gas is oxygen gas or a gas having a high oxygen concentration. 4. A rotary table, on which a metal workpiece having an outer shape of a rotary body is mounted and which is rotationally driven continuously or intermittently, a laser resonator, and laser light emitted from the resonator. In a laser processing apparatus comprising a scan head for irradiating the surface of a workpiece and a laser beam direction displacement means provided in the scan head, a gas having the laser beam irradiation port as a gas emission port in the scan head. A flow path is provided, and a gas blowing cylinder having a shape whose opening peripheral edge is close to the surface of the workpiece and can surround the scan range is mounted outside the laser beam irradiation port of the scan head. Laser processing equipment.