JPH0114670Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention relates to a laser processing apparatus having a laser beam cutting device that cuts both ends of a laser beam that is swung to scan a workpiece by a scanning optical system. .

[Technical background of the invention and its problems]

As an example of surface hardening or alloying using a laser beam, as shown in FIG. There is a method in which the workpiece W is swung in a direction perpendicular to the moving direction of the workpiece W, and the surface of the workpiece W is scanned in a zigzag pattern as shown by the broken line 2 by the relative movement thereof. In this case, the power density and spot diameter of the laser beam are adjusted so that a hardened layer or alloyed layer of the required depth can be obtained, and the workpiece W
In order to improve absorption of laser light, a laser light absorbing material is sometimes coated on the surface of the material.

By the way, when the required portions of the workpiece W are hardened (or alloyed) using the above method, overlapping parts of the laser beams are created at both ends in the scanning direction of the laser beams, and when the scanning of the laser beams is performed using a swinging reflector or the like. Since the scanning speed of the laser beam is slower at both ends than at the center of the scanning area, the depth of the hardened layer (or alloyed layer) 3 at both ends is lower than that at the center, as shown in Figure 6. It's deeper than that. Therefore, there is a conventional method of uniformly hardening or alloying the required portions by emitting excessive laser light and shielding both ends of the laser beam.

For example, JP-A-54-118848 discloses that a light shielding plate made of a metal with good thermal conductivity is disposed between the workpiece and the laser beam scanning device to shield both ends of the deflected laser light. It is shown. Furthermore, as shown in FIG. 7, Utility Model Application No. 1800 discloses that a heat dissipation section 5 is provided between the workpiece W and the laser beam scanning optical system 4 to dissipate heat generated due to light shielding. It is shown that a light shielding plate 6 is provided.

However, with such a light-shielding plate, the laser beam that has been swung by the scanning optical system and focused to obtain a predetermined spot diameter on the workpiece is incident at an acute angle close to a right angle, so it is easily overheated, especially when the power Cannot withstand high-density, high-power laser light.

[Purpose of invention]

The purpose of this invention is to construct a laser processing apparatus having a laser beam cutting device that has sufficient intensity for incident laser beams and can withstand laser beams with high power density.

[Summary of the idea]

This idea is based on a laser processing device that cuts both ends of a laser beam that is swung to scan a workpiece by a scanning optical system. a pair of light shielding parts having a convex curved surface that reflects the reflected laser light, and a pair of laser light absorption parts having a concave curved surface that absorbs the reflected laser light;
The distance between the pair of light shielding parts can be changed arbitrarily to withstand laser light with high power density, and the scanning area can be easily adjusted.

[Example of idea]

Hereinafter, this invention will be explained based on examples with reference to the drawings.

FIG. 1 shows a laser beam cutting device which is an embodiment of this invention, and FIG. 4 shows its arrangement. This laser beam cutting device 10 includes a workpiece W and a scanning optical system that swings as shown by an arrow 11 and swings a laser beam L emitted from a laser oscillator 12 so as to scan the workpiece W. placed between 4 and
A pair of light shielding parts 14 that shield both ends in the scanning direction of the laser light deflected by the scanning optical system 4; a pair of laser light absorption parts 15 that absorb the laser light reflected by the light shielding parts 14; Support body 16 that supports the light shielding part 14 and the laser light absorption part 15
and an adjustment mechanism 17 that changes the distance between the pair of light shielding parts.
It is composed of.

Each of the pair of light shielding bodies 14 includes a base body 19 and a convex curved surface portion 20 that is integral with the base body 19 and protrudes from one end thereof in the four directions of the scanning optical system, and is made of oxygen-free copper. . The convex curved surface portion 20 is
One side of the convex curved surface 21 is formed, and the back surface 22 is an inclined surface that intersects the convex curved surface 21 at an acute angle.
is facing outward in the scanning direction of the laser beam, and the rear surface 22
are arranged so as to face each other.

The convex curved surface 21 of the convex curved surface portion 20 has a mirror surface so as to reflect a part of the deflected laser light, that is, the laser light at both ends in the scanning direction, and as shown in FIG. It is composed of a cylindrical surface 23 having a predetermined radius r and whose center is on an extension of the upper surface, and the base 19 side thereof (from the point where the radius r of the cylindrical surface makes an angle α with the upper surface of the base 19 to the base 19 is a plane including the tangent 24 thereof). It reflects the incident laser beam in a diverging manner as shown by the broken line 25.
2 is inclined along the deflected laser beam, and the inclination extends to one end surface of the base 19, so that even if the deflected laser beam is incident on this surface, only a small amount will be incident thereon.

Further, each of the pair of laser light absorbing sections 15 is formed in an L-shaped block shape having the same width as the convex curved surface section 20 of the light shielding section 14, and the concave curved surface 27 formed inside the L-shaped block has the same width as the convex curved surface section 20 of the above-mentioned light shielding section 14. It is integrally attached to the base body 19 of the light shielding body 14 so as to face the convex curved surface 21 . End face distance D between the upper ends of the pair of laser light absorbers 15 attached to this base 19
is wider (D
>d), and its end face is inclined at approximately the same angle as the back surface 22 of the convex curved surface portion 20 so as not to obstruct the incidence of the deflected laser light.

The concave curved surface 27 is a surface for absorbing the laser beam reflected by the convex curved surface 21 of the convex curved surface portion 20, and is a heat-resistant black surface that is roughened so as to effectively absorb this reflected laser beam. covered with a membrane. Moreover, inside this laser light absorption section 15,
As shown in FIG. 3, hollow portions 29 are provided that communicate with conduits 28 attached to both side surfaces in the width direction of the laser light absorbing portion 15. As shown in FIG. This conduit 28
The hollow portion 29 is a heat exchange portion for dissipating heat generated by absorption of laser light by the concave curved surface 27, and a cooling medium flows therethrough.

The support 16 consists of a bottom plate 32 having an aperture 31 formed in its center, and a pair of end blocks 33 and side blocks 34 mounted on the periphery of the bottom plate 32. Each base 1 of a pair of light shielding parts 14 to which the laser light absorbing part 15 is integrally attached
9 is supported on the bottom plate 32 of this support 16,
and this bottom plate 3 using the side block 34 as a guide.
2 can be moved arbitrarily.

The adjustment mechanism 17 includes the pair of end blocks 33
It has a pair of adjusting screws 36 that rotatably pass through the laser beam absorbing portion 15 and whose distal ends are screwed into the pair of laser light absorbing portions 15, respectively. Each adjusting screw (36) is prevented from moving in the axial direction by a stop ring 37 attached to each adjusting screw 36 with the end block 33 in between, and by rotating the knob 38 at the rear end, a pair of The laser light absorption section 15 and the light shielding section 14 integrated therewith can be made independent, and the distance d between the pair of light shielding sections can be set arbitrarily.
is a screw hole into which the tip of the adjustment screw 36 is screwed.

By the way, when the laser beam cutting device is configured as described above, the pair of opposing light shielding parts 14 allows
The back surface of the convex curved surface portion 20 that reliably blocks both ends of the deflected laser beam in the scanning direction, and is inclined along the deflected laser beam, passes between the pair of light blocking portions 14 to scan the workpiece W. Since the laser light is not obstructed, a sharp scanning area can be obtained. In addition, since the convex curved surface 21 constituting the convex curved surface section 20 of this laser beam cutting device reflects the laser beam incident on this surface in a diverging manner, the concave curved surface 27 of the laser beam absorption section 15 that absorbs the reflected light On the other hand, the local concentration of reflected light is eliminated, and the burden of heating this concave curved surface 27 is reduced. In addition, the reflective surface made of the convex curved surface of the convex curved surface portion 14 increases the spot diameter of the laser beam incident on this surface, and can withstand high power laser beams without being damaged even by laser beams with high power density. Tolerable enough. Further, in this laser beam cutting device, the pair of light shielding parts 14 can be moved independently, and the distance d between the pair of light shielding parts 14 is
can be arbitrarily adjusted, and the scanning area for the workpiece W can be easily adjusted.

[Effect of idea]

The laser beam swung by the scanning optical system to scan the workpiece is reflected by the convex curved surface of the light shielding part so as to diverge outward in the scanning direction, and the reflected light is absorbed by the concave curved surface of the laser light absorption part. In addition, since the back surface of the convex curved surface is tilted along the oscillating laser beam, the laser beam at both ends in the scanning direction can be blocked without being damaged even by laser beams with high power density. , and a sharp scanning area can be formed on the workpiece. Furthermore, since the pair of light shielding parts can be moved arbitrarily, the scanning area can be easily adjusted.

[Brief explanation of the drawing]

Figures 1 to 4 are explanatory diagrams of one embodiment of this invention, Figures 1A and B are a plan view and a partially sectional front view of the laser beam cutting device, respectively, and Figure 2 is its light shielding device. 3A and B are respectively a front view and a partially sectional side view of the laser beam absorbing section, and FIG. 4 is a diagram showing the arrangement of the laser beam cutting device. Fig. 5 is an explanatory diagram of a method of scanning a workpiece with a laser beam, Fig. 6 is a cross-sectional view showing the state of surface hardening by the laser beam, and Fig. 7 is a diagram showing the arrangement and configuration of a conventional light shielding plate. It is. 4... Scanning optical system, 10... Laser beam cutting device, 12... Laser oscillator, 14... Light shielding section, 1
5... Laser light absorption section, 16... Support body, 17...
... Adjustment mechanism, 20 ... Convex curved surface part, 21 ... Convex curved surface, 22 ... Back surface, 27 ... Concave curved surface, 28 ... Conduit, 29 ... Hollow part, 36 ... Adjustment screw, W ...
Workpiece.

Claims (1)

[Claims for Utility Model Registration] A laser oscillator, a scanning optical system that swings a laser beam emitted from the laser oscillator so as to scan a workpiece, and a space between the workpiece and the scanning optical system. and a laser beam cutting device arranged to block both ends of the laser beam swung by the scanning optical system, the laser beam cutting device reflecting the end portions of the laser beam so as to diverge outwardly. a pair of light shielding parts having a convex curved surface made of a mirror surface, the back surface of the convex curved surface being inclined along the laser beam; and a pair of light shielding parts configured to prevent the laser light from passing between the pair of light shielding parts. A heat exchanger having a concave curved surface, at least the surface of which is made of a laser absorbing member, which faces the convex curved surface and absorbs the laser light reflected by the convex curved surface, and which dissipates the heat generated by the absorption of the laser light by the concave curved surface. a pair of laser light absorbing parts integrally provided with a pair of laser light absorbing parts, and an adjustment mechanism that adjusts the spacing between opposing back surfaces of the pair of light shielding parts by integrally displacing each pair of the light shielding part and the laser light absorbing part. A laser processing device characterized in that: