JPH09248685A - Laser beam machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the diameter of a laser beam corresponding to the change in passage length of the laser beam of being outputted from a laser beam oscillator to being converged with a condensing lens of a laser beam machining head. SOLUTION: This device 1 is composed so that a work W is irradiated and machined with a laser beam after the laser beam LB emitted from a laser beam oscillator is converged with a condensing lens 13 provided inside a laser beam machining head 9 of being moved freely at least to one axial direction. In this case, a diameter controlling means 23 which controls the diameter of beam corresponding to the change in laser beam passage length from a laser beam oscillator 3 to a laser beam machining head 9 following to moving of the laser beam machining head 9 is installed in the laser beam passage of the laser beam LB between the laser beam oscillator 3 and the laser beam machining head 9. The diameter controlling means 23 is composed of, for example, a rotary plate of freely rotating or a moving plate of freely moving, etc., having a diaphragm 23 or plural numbers of apertures of different diameters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the diameter of a laser beam output from a laser oscillator according to a change in the optical path length of the laser beam from the laser oscillator to the laser processing head when performing laser processing on a workpiece. The present invention relates to a laser processing device.

[0002]

2. Description of the Related Art In a laser processing machine, in a type in which an optical axis moves, that is, a type in which a laser processing head moves, an optical path length of a laser beam, which is a distance from an exit of a laser oscillator, varies depending on a processing place. Further, the laser beam output from the laser oscillator is not parallel light but propagates with a divergence angle.

For this reason, the diameter of the laser beam varies depending on the processing location, and during processing, a difference in the focused spot size, a change in the focal position, etc. occur, which may change the processing state. In particular, in a laser processing machine in which the distance (laser optical path length) along which the optical axis moves is long, that state is prominent, and sometimes processing defects occur.

In order to solve this problem, the laser beam output from the laser oscillator is provided with optical parts such as mirrors and lenses in the optical path of the laser beam between the laser oscillator and the laser processing head, and the same at any position. Collimation is performed so that the beam diameter is made.

[0005]

By the way, in the above-mentioned conventional collimation of the beam diameter, since the laser beam output from the laser oscillator is collimated by the external optical component, the output attenuation medium increases. Further, if the number of external optical components increases, the number of maintenance targets increases and the optical alignment adjustment becomes complicated. Further, the collimation device itself may be a source of defects due to dirt on the collimation optical components.

An object of the present invention is to enable a laser beam output from a laser oscillator to be controlled in accordance with a change in optical path length of the laser beam until the laser beam is focused by a focusing lens of a laser processing head. To provide a processing device.

[0007]

In order to achieve the above object, a laser processing apparatus according to a first aspect of the present invention is a laser processing head provided in a laser processing head capable of moving a laser beam output from a laser oscillator in at least one axial direction. A laser processing apparatus for performing laser processing on a work by irradiating the work to be processed after converging with a light lens, wherein the laser is provided in an optical path of a laser beam between the laser oscillator and a laser processing head. It is characterized in that a diameter control means is provided for controlling the beam diameter according to the change in the optical path length of the laser beam from the laser oscillator to the laser processing head accompanying the movement of the processing head.

Therefore, when performing laser processing on the workpiece, after the laser beam output from the laser oscillator is focused by the focusing lens provided in the laser processing head,
A laser beam is irradiated toward the work, and the work is laser-processed.

When the laser processing head is moved in the uniaxial direction, the optical path length of the laser beam from the laser oscillator to the laser processing head changes. According to the change in the optical path length of the laser beam, the beam diameter is controlled by controlling the diameter control means provided in the laser optical path between the laser oscillator and the laser processing head.
Thus, the laser processing is performed on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

A laser processing apparatus according to a second aspect of the present invention is the laser processing apparatus according to the first aspect, wherein the diameter control means comprises a diaphragm mechanism.

Therefore, the aperture of the aperture mechanism is controlled in accordance with the change in the optical path length of the laser beam to control the beam diameter. Thus, the laser processing is performed on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

According to a third aspect of the present invention, there is provided a laser processing apparatus according to the first aspect, wherein the diameter control means is a rotatable rotary plate or a movable movable plate having a plurality of apertures having different diameters. It is characterized by being.

Therefore, the rotating plate or the moving plate is rotated or moved according to the change in the optical path length of the laser beam, and one aperture having the optimum diameter is selected from the plurality of apertures having different diameters in the laser optical path. Is controlled. Thus, the laser processing is performed on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

According to a fourth aspect of the present invention, there is provided a laser processing apparatus according to the first aspect, wherein the diameter control means is a rotatable rotary pipe holder having a plurality of pipes having different diameters or is movable. It is a type pipe holder.

Therefore, the rotary pipe holder or the movable pipe holder is rotated or moved according to the change in the optical path length of the laser beam, and the pipe having the optimum diameter is selected from the plurality of pipes having different diameters in the optical path of the laser beam. And the beam diameter is controlled. Thus, the laser processing is performed on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

A laser processing apparatus according to a fifth aspect is the laser processing apparatus according to the first aspect, wherein the diameter control means is provided in an optical axis pipe provided in the optical path of the laser beam and the optical axis pipe. It is characterized by comprising a purge fluid inlet and a fluid flow rate control device for controlling the flow rate of the fluid supplied from the purge fluid inlet into the optical axis pipe.

Therefore, when the gas flow rate control device is operated in accordance with the change in the optical path length of the laser beam, the flow rate of the fluid supplied from the purge fluid inlet to the optical axis pipe is controlled to control the beam diameter. Thus, the laser processing is performed on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of a laser beam in a laser beam machine will be described before describing an example of an embodiment of the present invention. That is, the laser processing machine is provided with a beam guard using a pipe or bellows in the path along which the laser beam propagates. Usually, these beam guards do not interfere with each other.

The shape of the laser beam is normally confirmed by irradiating the acrylic plate with a laser beam, but the burned part of the acrylic plate is where the output distribution in the laser beam is high. The output distribution of the laser beam is high at the beam center and low at the hem portion, as shown in FIG. 10A, for example, and cannot be confirmed by irradiation on the acrylic plate.

The above-mentioned design of the beam guard is performed in such a size that the acrylic plate can be confirmed. When the portion of the laser beam that can be confirmed by the acrylic plate interferes with some obstacle as shown in FIG. 10C from the state shown in FIG. 10B, interference fringes are generated in the laser beam,
Although it has a great influence on the processing characteristics, the skirt (the part that cannot be seen on the acrylic plate) cannot be visually confirmed, and there is no great influence on the processing.

Since the interfering laser beam propagates with a larger divergence angle as compared with the case of not interfering, the laser beam is collimated by interfering the skirt.

An example of an embodiment of the present invention achieved based on the above principle will be described in detail below with reference to the drawings.

Referring to FIG. 1, the laser processing apparatus 1 includes a laser oscillator 3, and the laser beam LB output from the laser oscillator 3 has a plurality of bend mirrors 5, 7.
The laser processing head 9 is movably provided in the Y-axis direction. In the laser processing head 9, the light is focused by the condenser lens 13 via the bend mirror 11.

The laser beam LB condensed by the condenser lens 13 is irradiated toward the work W mounted and fixed on the processing table 15, and the work W is laser-processed.

The laser processing head 9 is screwed into a ball screw 17 extending in the Y-axis direction, and a drive motor 19 is connected to the left end of the ball screw 17 in FIG. The drive motor 19 is provided with, for example, an encoder 21 as a position detecting device.

With the above structure, when the drive motor 19 is driven, the ball screw 17 is rotated to move the laser processing head 9 in the Y-axis direction.

In the middle of the laser beam optical path of the laser beam LB output from the laser oscillator 3 to the bend mirror 5, referring also to FIG.
A diaphragm mechanism 25, which is used in a camera or the like, is provided. A drive motor 27 for adjusting the diaphragm is connected to the diaphragm mechanism 25. The drive motor 27, the drive motor 19 and the encoder 2
1 is connected to the control device 29.

With the above structure, when the drive motor 27 is driven, the diaphragm mechanism 25 operates and the diaphragm is adjusted. For example, as shown in FIG. 3 (A), if the aperture of the aperture mechanism 25 is small, the laser beam L can be seen at a distance.
If the beam diameter of B becomes large, and if the aperture mechanism 25 has a large aperture as shown in FIG. 3B, the beam diameter of the laser beam LB does not become large at a distance. When the laser processing head 9 moves in the Y-axis direction by utilizing this property, the optical path length of the laser beam LB from the laser oscillator 3 to the condenser lens 13 in the laser processing head 9 changes, so that the laser beam LB Encoder 2 for optical path length change
The detected signal is sent to the control device 29. In this control device 29, a command is given to the drive motor 27 according to the change in the optical path length of the laser beam LB to drive it, and the diaphragm of the diaphragm mechanism 25 is adjusted.

Therefore, no matter which position the laser processing head 9 moves in the Y-axis direction, the diameter of the laser beam LB focused on the condenser lens 13 is adjusted by adjusting the aperture of the aperture mechanism 25. Since they can be the same, uniform laser processing can be performed. Therefore, the conventionally used optical component for controlling the beam diameter is not required, which facilitates maintenance and is advantageous in terms of maintenance cost.

An example of another embodiment as the diameter control means 23 is shown in FIGS. For example, in FIG. 4, a rotatable plate 33 having a plurality of apertures 31 having different diameters is provided. The rotary plate 33 is rotated about the rotation center 33C as indicated by an arrow. Therefore, by selecting an appropriate aperture 31 in accordance with the change in the optical path length of the laser beam LB accompanying the movement of the laser processing head 9 in the Y-axis direction, the same beam is always provided regardless of the position of the laser processing head 9. Uniform laser processing can be performed depending on the diameter.

FIG. 5 shows a plurality of apertures 31 having different diameters.
There is provided a movable plate 35 which is movable. This moving plate 35 is moved in the vertical direction as shown by the arrow. Therefore, by selecting an appropriate aperture 31 in accordance with the change in the optical path length of the laser beam LB accompanying the movement of the laser processing head 9 in the Y-axis direction, the same beam is always provided regardless of the position of the laser processing head 9. Uniform laser processing can be performed depending on the diameter.

FIG. 6 shows a plurality of pipes 37A to 37A having different diameters.
37D is rotated about the rotation center 37C as indicated by the arrow. Further, in FIG. 7, a plurality of pipes 37A to 37D having different diameters are moved in the vertical direction as indicated by arrows. Therefore, by selecting an appropriate pipe from the plurality of pipes 37A to 37D according to the change in the optical path length of the laser beam LB accompanying the movement of the laser processing head 9 in the Y-axis direction, the position of the laser processing head 9 can be determined. Even if there is, a uniform laser beam can always be processed with the same beam diameter.

FIG. 8 shows an example of another embodiment in which the diaphragm mechanism 25 is used as the diameter control means 23 in FIG. In FIG. 8, the same parts as those in FIG. 1 are designated by the same reference numerals, and overlapping description will be omitted.

In FIG. 8, an optical axis pipe 39 as a diameter control means 23 is provided in the optical path of the laser beam LB between the laser oscillator 3 and the bend mirror 5. A purge fluid inlet 41 is provided on a part of the outer peripheral surface of the optical axis pipe 39, for example, on the outer peripheral surface of the optical axis pipe 39 substantially at the center in the longitudinal direction. A proportional valve 45 is connected to the purge fluid inlet 41 via a pipe 43. A control device 29 is connected to the proportional valve 45.

With the above structure, when the controller 29 controls the proportional valve 45 and air, for example, air as a fluid is flowed from the fluid source (not shown) through the pipe 43 from the purge fluid inlet 41 into the optical axis pipe 39, The propagation characteristics of the laser beam LB change, and the beam diameter is adjusted.

Between the flow rate of air and the changing beam diameter, for example, as shown in FIG.
It was confirmed by experiments that the beam diameter changes almost proportionally with a certain flow rate as the critical point, although it depends on the shape.
Further, when the critical point is exceeded, the beam diameter saturates. Between this critical point and the critical point, the beam diameter is adjusted by controlling the proportional valve 45 according to the change in the optical path length of the laser beam LB accompanying the movement of the laser processing head 9, so that the laser processing head 9 can be detected. Even at the position, uniform laser processing can always be performed with the same beam diameter.

In the example of the embodiment shown in FIG. 8 described above, the fluid is not limited to air and may be a fluid such as gas, liquid or solid that can control the laser beam LB. Also, as a means for controlling the flow rate of the fluid,
A step-type switching valve, an orifice, or the like may be used instead of the proportional valve. Further, the position of the laser processing head 9 may be detected by a position switch, a limit switch, a laser length measuring device, or the like, in addition to the encoder.

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

[0039]

As can be understood from the above-described examples of the embodiment, according to the invention of claim 1, the laser beam output from the laser oscillator is used as the laser processing head when performing laser processing on the workpiece. After being condensed by a condenser lens provided inside, a laser beam is irradiated toward the work to perform laser processing on the work.

When the laser processing head is moved in the uniaxial direction, the optical path length of the laser beam from the laser oscillator to the laser processing head changes. According to the change in the optical path length, the beam diameter can be controlled by controlling the diameter control means provided in the optical path of the laser beam between the laser oscillator and the laser processing head. Thus, it is possible to perform uniform laser processing on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

According to the second aspect of the present invention, the aperture of the aperture mechanism can be controlled according to the change in the optical path length of the laser beam to control the beam diameter. Thus, it is possible to perform uniform laser processing on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

According to the third aspect of the present invention, the rotating plate or the moving plate is rotated or moved in accordance with the change in the optical path length of the laser beam, and one aperture having the optimum diameter is selected from the plurality of apertures having different diameters. It can be selected inside to control the beam diameter. Thus, it is possible to perform uniform laser processing on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

According to the invention of claim 4, the rotary pipe holder or the blade moving pipe holder is rotated or moved in accordance with the change in the optical path length of the laser beam, and the pipe having the optimum diameter is selected from a plurality of pipes having different diameters. Can be selected in the laser optical path to control the beam diameter. Thus, it is possible to perform uniform laser processing on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

According to the fifth aspect of the present invention, when the gas flow rate control device is operated in accordance with the change in the optical path length of the laser beam, the flow rate of the fluid supplied from the purge fluid inlet to the optical axis pipe is controlled, and the beam diameter is controlled. Can be controlled. Thus, it is possible to perform uniform laser processing on the work with the same beam diameter at any position of the laser processing head according to the change in the optical path length of the laser beam.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a laser processing apparatus according to an embodiment for carrying out the present invention.

FIG. 2 is an enlarged perspective view of a portion indicated by an arrow II in FIG.

FIG. 3 is an explanatory diagram illustrating an operation of a diaphragm mechanism in FIG.

FIG. 4 is a diagram showing another example of the diameter control means.

FIG. 5 is a diagram showing another example of the diameter control means.

FIG. 6 is a diagram showing another example of the diameter control means.

FIG. 7 is a diagram showing another example of the diameter control means.

FIG. 8 is a perspective view showing another example of the diameter control means in place of FIG.

FIG. 9 is a diagram showing a relationship between an air flow rate and a beam diameter.

10A is a diagram showing a relationship between a laser optical path length and an output, and FIGS. 10B and 10C are explanatory diagrams for explaining a state of a laser beam emitted from an oscillator of a laser.

[Explanation of symbols]

 1 Laser Processing Device 3 Laser Oscillator 9 Laser Processing Head 13 Condensing Lens 19 Drive Motor 21 Encoder (Position Detection Device) 23 Diameter Control Means 25 Aperture Mechanism 27 Drive Motor 29 Control Device 31 Aperture 33 Rotating Plate 35 Moving Plates 37A-37D Pipe 39 Optical axis pipe 41 Purge fluid inlet 45 Proportional valve LB Laser beam

Claims (5)

[Claims] 1. A laser beam output from a laser oscillator is converged by a condenser lens provided in a laser processing head that is movable in at least one axis direction, and is then irradiated onto a work to be processed so that the work is laser-irradiated. A laser processing apparatus for performing processing, wherein an optical path length change of a laser beam from a laser oscillator to a laser processing head is accompanied by movement of the laser processing head in an optical path of the laser beam between the laser oscillator and the laser processing head. A laser processing apparatus characterized in that a diameter control means for controlling the beam diameter according to the above is provided. 2. The laser processing apparatus according to claim 1, wherein the diameter control means comprises a diaphragm mechanism. 3. The laser processing apparatus according to claim 1, wherein the diameter control means is a rotatable rotating plate or a movable moving plate having a plurality of apertures having different diameters. 4. The laser processing apparatus according to claim 1, wherein the diameter control means is a rotatable rotary pipe holder having a plurality of pipes having different diameters or a movable movable pipe holder. 5. The diameter control means supplies an optical axis pipe provided in the optical path of the laser beam, a purge fluid inlet provided in the optical axis pipe, and a supply from the purge fluid inlet into the optical axis pipe. 2. A laser processing apparatus according to claim 1, comprising a fluid flow rate control device for controlling the flow rate of the fluid to be generated.