JPH05305473A - Laser beam machine - Google Patents

Abstract

PURPOSE:To always nearly parallelize a laser beam without originating in the divergence angle of the laser beam emitted from a laser generator and to have this parallelized laser beam taken in a laser beam machining head without reference to the length of a light path. CONSTITUTION:The laser beam machine 1 is provided with the laser machining head 11 which is freely movable at least to one axial direction, and is also provided with a laser beam parallelization processing device 17 near the exit of the laser generator 15 so as to always nearly parallelize the laser beam LB without reference to the variation of the length of the light path in the laser beam LB from the emission out of the laser generator 15 to the laser beam machining head 11. Also, the laser beam parallelization processing device 17 is constituted of a polarizing mirror 21, convex mirror 23 and concave mirror 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus in which a laser processing head is movable in at least one axis direction, and more specifically, even if the optical path length of a laser beam is changed by the movement of the laser processing head, The present invention relates to a laser processing apparatus capable of keeping a diameter of a laser beam taken in by a laser processing head substantially parallel to each other, and keeping a spot diameter and a focal point position of a laser beam applied to a work substantially constant.

[0002]

2. Description of the Related Art In a laser processing apparatus of a type in which a laser processing head moves, the distance from a laser oscillator to a condenser lens inside the laser processing head changes greatly, which is caused by the divergence angle of a laser beam. It is known that the diameter of the laser beam changes significantly at the position of the condenser lens. The focus position changes due to the change in the diameter of the laser beam, and the spot diameter of the laser beam irradiated to a predetermined position on the work changes, which affects the processing accuracy.

Therefore, conventionally, for example, Japanese Patent Publication No. 1-550
As disclosed in Japanese Patent Publication No. 76-76, a special mechanism may be adopted so that the optical path length from the laser oscillator to the laser processing head is always constant even when the laser processing head moves. ..

[0004]

In a structure in which the optical path length is always kept substantially constant regardless of the moving position of the laser processing head, a reversing device for reversing and bending the laser beam is specially provided. The invertor needs to be moved relative to the movement of the laser processing head.

Therefore, the size of the structure is increased due to the provision of the reversing device, and a mechanism or a control device for performing the related movement is required, which causes a problem that the overall structure is complicated.

In order to improve the above problems, an object of the present invention is to make the diameter of a laser beam almost always parallel without causing the divergence angle of a laser beam emitted from a laser oscillator, and to change the optical path length. Regardless of this, the collimated laser beam is taken into the laser processing head so that the spot diameter of the laser beam irradiated to a predetermined position on the workpiece can be held substantially constant and laser processing with good processing accuracy can be performed. The present invention is to provide a laser processing device.

[0007]

In order to achieve the above-mentioned object, the present invention provides a laser processing apparatus having a laser processing head movably in at least one axial direction, and a laser beam oscillated from a laser oscillator. A laser beam collimating device is provided in the vicinity of the exit of the laser oscillator, which enlarges the diameter to a constant magnification and makes the diameter of the laser beam substantially parallel regardless of the change in the optical path length up to the laser processing head. It is characterized by that.

In the laser processing apparatus, the laser beam parallelization processing apparatus is composed of a circular polarization mirror or a plane mirror, a convex mirror and a concave mirror, and the laser processing head is moved to perform laser processing on a work. It is desirable that the concave mirror of the laser beam collimating apparatus is selected and provided so that the beam waist of the expanded laser beam is located in the substantially middle part of the processing range.

[0009]

By adopting the laser processing apparatus of the present invention, the laser beam oscillated from the laser oscillator is passed through a laser beam collimating processing device provided near the exit of the laser oscillator, for example, so that the laser beam is kept constant. It is magnified to a magnification and is almost parallelized, and is taken into the laser processing head. Even if this laser processing head moves and the laser optical path length from the laser oscillator to the laser processing head changes, the laser beam that exits the laser beam collimator will always be almost parallel regardless of the optical path length of the laser beam. Since the laser beam is applied to the work from the laser processing head, the spot diameter and the focal point position of the laser beam are always kept substantially constant for laser processing. Therefore, the work is processed with good processing accuracy.

[0010]

Embodiments of the present invention will be described in detail below with reference to the drawings.

The laser processing apparatus includes a laser processing head movably in the Y-axis direction and a work table movably in the X-axis direction, and a laser processing head movably in the X-axis and Y-axis directions. There are a type provided with the laser processing head and a type provided with a laser processing head movable in three axial directions of X, Y, and Z. In the present embodiment, the laser processing head is Y
An example will be described in which the work table is movably provided in the axial direction and the work table is movably provided in the X-axis direction.

Referring to FIG. 1, the laser processing apparatus 1 has an X
A processing table 3 is provided which is movable in the axial direction (left and right direction in FIG. 1). The processing table 3 is movable in the X-axis direction by, for example, an X-axis servomotor, a ball screw, etc., which are not shown. Moreover, the work W to be machined is placed on the machining table 3,
Further, it is clamped and fixed by a work clamp (not shown).

A gate-shaped frame 5 is erected on the processing table 3. The frame 5 is provided with a Y-axis carriage 7 which is movable in the Y-axis direction (vertical direction in FIG. 1). Moreover, this Y-axis carriage 7
Is movable in the Y-axis direction by a Y-axis servomotor, a ball screw, etc., which are not shown.
A bend mirror 9 is attached to the upper end of the Y-axis carriage 7.

Below the Y-axis carriage 7, there is provided a laser processing head 11 which is movable in the Z-axis direction (direction orthogonal to the paper surface in FIG. 1). The laser processing head 11 is, for example, a Z-axis servomotor (not shown),
It is movable in the Z-axis direction by a worm, a worm gear, etc. Moreover, the laser processing head 11 is provided with a condenser lens for condensing the laser beam LB, and the laser beam LB condensed by the condenser lens is applied to a desired position of the work W. A laser nozzle for ejecting the assist gas to a desired position on the work W is provided at the lower end of the laser processing head 11.

A bend mirror 13 is provided at one end of the upper portion of the frame 5, for example, at the lower end of FIG. 1, and a laser oscillator 15 is arranged separately on the right side of the frame 5 in FIG. A laser beam parallelizing device 17 is provided near the exit of the laser oscillator 15, for example, on the lower side in FIG.

With the above construction, the processing table 3 on which the work W is placed is moved in the X-axis direction, and the laser processing head 11 is moved in the Y-axis direction so that the laser processing head 11 is positioned above the desired position of the work W. Positioned.
Next, the laser beam L oscillated by the laser oscillator 15
B is magnified to a certain magnification by the laser beam collimating device 17, and after collimated, the bend mirrors 13 and 9 are used.
Then, the light is focused on the focusing lens of the laser processing head 11. The laser beam focused on the focusing lens is irradiated from the laser nozzle toward the work W, and the work W is laser-processed.

As an example of the laser beam collimation processing device 17, as shown in FIG. 2, it is arranged near the exit of the laser oscillator 15 and a circular polarization mirror 21, a convex mirror 23, and a convex mirror 23 are provided in the case 19. A concave mirror 25 is provided. Holes 27 and 29 for passing the laser beam LB are formed in the front wall and the side wall of the case 19.

A hole 31 for passing the laser beam LB is formed on the exit wall of the laser oscillator 15, and an output mirror 33 is provided in the exit portion of the laser oscillator 15. In this embodiment, the laser beam LB _A linearly polarized by 45 degrees from the laser oscillator 15 is used.
Is an example in which the circularly polarized laser beam LB _B is circularly polarized by the circularly polarized light mirror 21.

With the above configuration, the 45-degree linearly polarized laser beam LB _A oscillated by the laser oscillator 15 is output from the output mirror 33.
It is sent to the laser beam collimation processing device 17 through the hole 31. In the laser beam collimation processing device 17, the circular polarization mirror 21 reaches the circular polarization mirror 21 through the hole 29 of the case 19, and the 45-degree linearly polarized laser beam LB _A is circularly polarized laser beam LB _B.
The light is circularly polarized and is incident on the convex mirror 23. This convex mirror 2
At 3, the diameter of the circularly polarized laser beam LB _B is expanded to the preset beam diameter D ₀ . The collimated circularly polarized laser beam LB _B is output from the hole 27 through the concave mirror 25. Diameter of the circular laser beam LB _B to be output is expanded to a constant magnification by the convex mirror 23. Diameter D ₀ of this is enlarged to a predetermined magnification and collimated circularly polarized laser beam LB _B, the optical path length and the laser processing head 11 of the laser beam by the laser machining head 11 has the maximum movement in the Y-axis direction Z-axis direction The diameter D _{1 of} the circularly polarized laser beam LB _B that has reached the condenser lens of the laser processing head 11 when the optical path length has moved to the maximum downward direction is within a margin of error (D ₀ ≈D ₁ ). ..

Therefore, even if the optical path length from the laser oscillator 15 to the laser processing head 11 changes from the minimum to the maximum, the circularly polarized laser beam LB _B is expanded by the laser beam parallelization processing device 17 to a certain magnification and parallelized. Due to this, the beam diameter of the collimated circularly polarized laser beam LB _B is always kept substantially constant. Then, the circularly polarized laser beam LB _B condensed by the condenser lens is irradiated from the laser nozzle toward the work W. That is, the circularly polarized laser beam L irradiated onto the work W from the laser nozzle
Since the spot diameter of B _B and the focal point position can always be kept substantially constant, laser processing with good processing accuracy can be performed.

FIG. 3 shows a laser beam collimation processing device 17
Another embodiment of is shown. 2 in FIG.
The same parts as the parts in FIG. That is, in the embodiment of FIG. 3, the difference from FIG. 2 is that the plane mirror 35 is used instead of the circular polarization mirror 21, and the linear laser beam LB _C oscillated from the laser oscillator 15 is used.
Is incident on the plane mirror 35, and the plane laser 35 causes the linear laser beam LB _{C to} be a 45 ° linearly polarized laser beam LB _D.
Is polarized to. In this case, for example, a circularly polarized mirror is used as the bend mirror 9 immediately before the condenser lens, and the circularly polarized circularly polarized laser beam LB _B is incident on the condenser lens. Thus, the same operation and effect as those of the embodiment shown in FIG. 2 are achieved.

The laser processing head 1 passes from the concave mirror 25 of the laser beam collimator 17 through the bend mirror 9.
Circularly polarized laser beam LB _B incident on the condenser lens 1
The diameter of the beam is enlarged by the convex mirror 23 to a constant magnification and is made substantially parallel to be incident as the beam diameter D ₁ . However, as shown in FIG. 4, the beam diameter D ₁ has a beam waist portion due to the nature of the mirror at a distance L ₀ from the position of the concave mirror 25, for example. The beam diameter of the beam waist portion is smaller than the beam diameter D ₁ by 2ΔD. Considering that the beam waist portion is generated, when the maximum processing range in which the laser processing head 11 is moved in the Y-axis direction is set to 2L ₁ , the center of the processing range is adjusted to the position L ₀ of the beam waist portion. If you keep it, (D _1-2 Δ
Laser processing in the maximum processing range can be performed uniformly with the collimated circularly polarized laser beam LB _B having a beam diameter of D) to D ₁ . Moreover, ΔD is a very small value close to zero. Therefore, it is possible to perform laser processing with better processing accuracy than laser processing that does not consider the beam waist. That is, so that the center of the maximum processing range is located at the beam waist,
By selectively providing the concave mirror 25, it is possible to perform laser processing with high accuracy. Moreover, if the maximum processing range is within about 3 m, for example, it is not necessary to select and provide the concave mirror 25 once to change the concave mirror 25 according to the change in the maximum processing range. When the maximum processing range is, for example, about 3 m or more, the concave mirror 25 may be replaced with a concave mirror 25 so that the processing accuracy is not affected.

The present invention is not limited to the above-described embodiments, but can be implemented in other modes by making appropriate changes.

[0024]

As can be understood from the above description of the embodiments, according to the present invention, the laser beam oscillated by the laser oscillator has the structure as described in the claims. The beam is collimated by the beam collimator. Therefore, even if the laser processing head moves and the optical path length from the laser oscillator to the laser processing head changes, the laser processing head is always provided with a parallelized laser with a substantially constant diameter regardless of the change in the optical path length. The beam is captured. Thus, since the spot diameter of the laser beam applied to the work from the laser processing head can be kept substantially constant at all times, laser processing with good processing accuracy can be performed.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a laser processing apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a laser beam parallelization processing device in FIG.

FIG. 3 is a perspective view of another laser beam collimation processing device that replaces FIG.

FIG. 4 is an explanatory diagram of a laser beam processed by a laser beam parallelization processing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser processing device 11 Laser processing head 15 Laser oscillator 17 Laser beam parallelization processing device 21 Circular polarization mirror 23 Convex mirror 25 Concave mirror LB Laser beam W work

Claims (3)

[Claims] 1. A laser processing apparatus comprising a laser processing head movably in at least one axis direction, the diameter of a laser beam oscillated from a laser oscillator is expanded to a constant magnification, and the laser processing head is reached. A laser beam collimating device for making the diameter of the laser beam substantially parallel regardless of a change in the optical path length of the laser processing device. 2. The laser processing apparatus according to claim 1, wherein the laser beam collimation processing device is constituted by a circular polarization mirror or a plane mirror, a convex mirror and a concave mirror. 3. The concave mirror of the laser beam collimation processing device is arranged so that the beam waist of the expanded laser beam is positioned substantially in the center of the processing range where the laser processing head moves to perform laser processing on a work. The laser processing apparatus according to claim 2, wherein the laser processing apparatus is selectively provided.