JPH0568871B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a method and apparatus for modulating a laser beam, and more particularly to a method and apparatus for mechanically pulsing a continuous wave laser beam, for example.

b Prior art When performing cutting, drilling, etc. on a suitable workpiece, such as a metal plate, using a laser processing device, it is necessary to avoid thermal effects on the periphery of the processed part or to further improve processing accuracy. For this purpose, a pulsed laser beam is desirable. Particularly in the case of deep hole machining, it is desirable to irradiate the same location with the pulsed laser many times.

In order to meet the above demands, a method and apparatus for mechanically pulsing a continuous wave laser beam are disclosed in Japanese Patent Laid-Open No. 163912/1983.

Conventionally, when performing laser processing by mechanically pulsing a continuous wave laser beam, the duty ratio of the pulsed laser was constant, making it difficult to process smaller holes and narrow cutting widths. .

c Problems to be Solved by the Invention The present invention was invented in view of the above-mentioned problems, and when a continuous wave laser beam is mechanically pulsed, the processing mode of the laser processing, such as simple fusing or fine processing, etc. It is an object of the present invention to provide a laser beam modulation method and apparatus that can appropriately change the duty ratio of a pulsed laser according to the situation.

d Means for solving the problem A plurality of rotary plates each having laser beam transmitting parts formed at appropriate intervals near the outer periphery are placed at positions that cross the path of the laser beam emitted from the laser oscillator, and An auxiliary rotary plate arranged coaxially with several rotary plates is rotatably and fixedly provided, and the number of laser beam transmitting parts formed on each auxiliary rotary plate is different from the number of transmitting parts of the coaxial rotary plate. It becomes.

e Effect When multiple rotary plates rotate at a constant speed and each auxiliary plate is stopped or rotates together with each rotary plate, the transmission part of each rotary plate and each auxiliary rotary plate is on the path of the laser beam. Only when there is a match, the laser beam is allowed to pass; otherwise the laser beam is blocked. In other words, the continuous wave laser beam is pulsed.

As described above, the number of times that the transmission portions of the plurality of rotary plates and the auxiliary rotary plate coincide on the path of the laser beam is changed by selecting the auxiliary rotary plate that rotates integrally with the rotary plate. That is, for example, the number of times the laser beam can pass through the transmitting portion per revolution of the rotary plate rotating at a constant speed is changed, and the number of pulses per revolution of the rotary plate is different. Therefore, the duty ratio of the pulsed laser beam will be changed.

f Embodiment Referring to FIG. 1, a laser processing device is generally designated by the reference numeral 1, and the laser processing device 1 is equipped with a laser oscillator 3 such as a carbon dioxide laser oscillator. The laser oscillator 3 is a general type and is configured to oscillate a laser beam LB toward the laser processing device 1. In this embodiment, the laser oscillator 3 is located at the rear side of the laser processing device 1. attached directly. The laser oscillator 3 is preferably of a continuous oscillation type, but may be of a pulse oscillation type.

The laser processing apparatus 1 includes a base 5, a post 7 vertically erected on the base 5, and a beam member 9 horizontally supported above the base 5 in a cantilevered manner via the post 7. A work table 11 is provided on the upper part of the base 5, and the work table 11 is provided with a number of slide balls for supporting a work piece W, such as a sheet metal, placed horizontally to be processed. A processing head 13 is provided at the tip of the beam member 9, and the processing head 13 has a mirror assembly 15 and a focusing lens 17 built therein. The mirror assembly 15 receives the laser beam from the laser oscillator 3.
It is configured to refract and reflect LB toward the workpiece W, and the focusing lens 17 is arranged to focus on the workpiece W. During laser processing, the processing head 13 passes the laser beam LB from the laser oscillator 3 through the mirror assembly 15 and the focusing lens 17 to the workpiece W.
The structure is such that the assist gas is injected into the machining area at the same time as irradiating the machining area.

In order to move and position the workpiece W, the laser processing apparatus 1 includes a first carriage 19 that is horizontally movable, and a second carriage 21 that holds a plurality of work clamps 23 that grip the workpiece W. ing. The first carriage 19 is movably supported by a pair of rails 25 fixed in parallel to each other on both sides of the upper part of the base 5.
It is possible to approach and leave the processing area directly below the processing head 13. The second carriage 21 holding a plurality of work clamps 23 is supported by the first carriage 19 so as to be horizontally movable in a direction perpendicular to the direction of movement of the first carriage 19. Therefore, the workpiece W held by the workpiece clamp 23 is moved between the first and second carriages 1.
By moving the parts 9 and 21, it is possible to transport the work table 11 below the processing head 13.

With the above configuration, the first and second carriages 1
By positioning the workpiece W in the machining area directly under the machining head 13 by 9 and 21,
The workpiece W can be processed by the laser beam LB. The laser beam LB emitted from the laser oscillator 3 is irradiated onto the processing head 13,
It is refracted downwardly by mirror assembly 15. Then, the laser beam LB is transmitted through the focusing lens 1
7 and irradiates the workpiece W, and at the same time assist gas is supplied to the processing section.

In the path of the laser beam LB between the laser oscillator 3 and the processing head 13, there is a modulation device 27 that mechanically pulses the laser beam LB oscillated from the laser oscillator 3 or modulates it as appropriate.
are arranged appropriately.

Referring to FIGS. 2 to 4, the modulation device 27
The base plate 31 includes a cooling chamber 29 for cooling a sleeve, a bearing, a cylinder, etc., which will be described later. More specifically, the base plate 31 and the lid member 3 are separated by the partition member 33.
5 by separating and sealing the cooling chamber 2.
A plurality of elbow joints 37 for supplying and discharging cooling water are connected to the cooling chamber 29. A cylindrical body 39 passing through the cooling chamber 29 is attached to the center of the base plate 31 .
This cylindrical body 39 is connected to a laser conduit LT provided in the laser processing machine 1. Therefore, the laser beam LB oscillated from the laser oscillator 3 is
The light can be transmitted through the modulation device 27 and irradiated onto the laser processing device 1 .

Further, on the base plate 31, a plurality of sleeves 41A to 41D (sleeves 41C and 41D are not shown in the drawing) passing through the cooling chamber 29 are arranged at positions equidistant from the cylindrical body 39. A rotary shaft 43A that passes through the sleeve 41A is rotatably supported by the sleeve 41A via a plurality of bearings 45, and a disk-shaped rotary shaft is attached to the end of the rotary shaft 43A on the one end side where the rotary shaft 43A extends widely. A plate 47A is integrally attached. The rotating plate 47A is the path L of the laser beam LB emitted from the laser oscillator 3.
A plurality of appropriate transmitting portions 49A, such as cutouts or holes, are formed at equal intervals at the positions where the path L is crossed. In this embodiment, as shown in FIG. 4, eight transparent parts 49A are formed, but the number is not limited to eight and may be any number.

With the above configuration, the laser beam LB can be transmitted only when the transmission part 49A is aligned with the path L of the laser beam LB due to the rotation of the rotary plate 47A, and the transmission part 49A is aligned with the path L. When the laser beam LB is not positioned, the laser beam LB
The state is cut off by 7A. Therefore, the laser beam LB irradiated toward the processing head 13 of the laser processing apparatus 1 can be pulsed.

A cylinder 51 is attached to one end of each of the sleeves 41B to 41D other than the sleeve 41A, and each cylinder 51 is integrally equipped with a piston 53 and a cylindrical piston rod passing through the cylinder 51. 55
is provided so that it can only slide freely. In addition, each sleeve 41B to 41D has a
Rotating shafts 43B to 43D passing through 1D and the piston rod 55 are rotatably supported via a plurality of bearings 57, respectively. Each of the rotating shafts 43B to 43D is sequentially shorter than the rotating shaft 43A, and one end of each of the rotating shafts 43B to 43D is provided with a plurality of transparent parts 49B to 49D at equal intervals, similar to the rotating plate 47A. Rotary plates 47B to 47D are respectively attached.

Therefore, the laser beam LB emitted from the laser oscillator 3 is transmitted through the plurality of rotating plates 47A to 47D.
It will be understood that transmission becomes possible only when each of the transmission sections 49A to 49D provided in the above coincides with the path L.

At the tip of each piston rod 55 slidably provided in each cylinder 51 described above, each rotary plate 4 is attached.
Auxiliary rotating plates 59B to 59 corresponding to 7B to 47D
D is rotatably supported. Each of the auxiliary rotating plates 59B to 59D has an appropriate number of transparent parts 61.
B to 61D are formed. Each auxiliary rotating plate 59B
The number of transmitting parts 61B to 61D in ~59D is different, and in this embodiment, the auxiliary rotary plate 59B has four transmitting parts 61B at equal intervals, and the auxiliary rotary plate 59C has two transmitting parts 61B.
C is in a symmetrical position, and furthermore, 1 is on the auxiliary rotary plate 59D.
Two transparent portions 61D are formed.

With the above configuration, each transparent portion 49A to 49D of each rotary plate 47A to 47D and each auxiliary rotary plate 59B
It will be understood that the laser beam LB can be transmitted to the laser processing apparatus 1 side only when the transmission parts 61B to 61D of 59D coincide with the path L of the laser beam LB.

Each of the auxiliary rotary plates 59B to 59D is movable in the axial direction integrally with each piston rod 55 of each cylinder 51.
A suitable number of suitable engagement recesses 63 such as holes are formed at appropriate positions where D faces each of the rotary plates 47B to 47D, and the rotary plates 47B to 47D can be freely engaged with and disengaged from the respective engagement recesses 63. An engaging convex portion 65 is provided.
When the engagement protrusion 65 of each rotary plate 47B to 47D and the engagement recess 63 of each auxiliary rotary plate 59B to 59D are engaged, each auxiliary rotary plate 59B to 59D
The transparent parts 61B to 61D and each rotary plate 47B to 47
The transmitting portions 49B to 49D at appropriate positions of D are aligned, and each rotary plate 47B to 47D and each auxiliary rotary plate 59B to 59D rotate integrally.

Further, each of the auxiliary rotary plates 59B to 59D is formed with an engagement hole 69 that can be freely engaged with and disengaged from the tip end portions 67E of the plurality of fixing pins 67 attached to each of the cylinders 51. Engagement hole 69 of each auxiliary rotary plate 59B to 59D
is in the fixed state engaged with the tip 67E of the fixing pin 67, each of the auxiliary rotary plates 59B to 59D
The transmitting portions 61B to 61D at appropriate positions are in a state that corresponds to the path L of the laser beam LB, and the engaging concave portions 63 of each of the auxiliary rotary plates 59B to 59D and the engaging convex portions 65 of each of the rotary plates 47B to 47D. is in a detached state.

As can be understood from the above configuration, by appropriately operating each cylinder 51, appropriate auxiliary rotary plates 59B to 59D are brought to a stopped state individually.
Alternatively, it may be selected to rotate integrally with each rotating plate 47B to 47D.

As best shown in FIG.
In order to synchronously rotate 3A to 43D, each rotating shaft 4
A pulley 71 is provided at each other end of 3A to 43D.
A to 71D are installed, and each pulley 71A to 7
An endless belt 73 is wrapped around 1D. A driven pulley 75 (third
A belt 77 (see figure) is attached, and a belt 77 that is wound around this driven pulley 75 is wound around a driving pulley 81 that is attached to a motor 79. The motor 79 is
It is controlled by an appropriate control device such as a numerical control device, and is supported by the base plate 31 via a bracket 83.

With the above configuration, each rotating shaft 43A to 43D and each rotating plate 47A to 47 are driven by the motor 79.
D will rotate synchronously. Therefore,
A plurality of transmitting portions 49A to 49D formed on each rotary plate 47A to 47D periodically coincide with each other in the path L of the laser beam LB, and the transmitted laser beam
LB will be pulsed. The frequency of this pulse can be changed by appropriately controlling the rotation of the motor 79.

In order to fix the rotating shafts 43A to 43D in a stopped state, the modulation device 27 includes a lock cylinder 85.
is provided. That is, as best shown in FIG. 3, the lock cylinder 85 is disposed coaxially with the rotating shaft 43A, and a bracket 89 is attached to a plurality of columns 87 having one end fixed to the lid member 35. is supported through. A dog pin 93 fitted into a slit 85S formed in the lock cylinder 85 is fixed to a piston rod 91 which is slidably provided on the lock cylinder 85, and its rotation is restricted. A hole 91H is bored in the end of the piston rod 91 in the axial direction into which the other end of the rotating shaft 43A can be inserted. Furthermore, the end surface of the piston rod 91 is formed into a cam surface 91C that is inclined with respect to the axis. On the other hand, at the other end of the rotating shaft 43A, a pin 95 which can be freely engaged with and detached from the cam surface 91C is implanted in a direction perpendicular to the axis.

With the above configuration, the rotation shaft 4 is inserted into the hole 91H of the piston rod 91 by the operation of the lock cylinder 85.
When the other end of 3A is inserted and the pin 95 provided on the rotating shaft 43A is regulated by the cam surface 91C, not only the rotating shaft 43A but also the other rotating shafts 43B to 43D are attached to each pulley. 71A~
It is in a stopped state via 71D and belt 73. When each rotating shaft 43A-43D is in a stopped state in this way, each rotating plate 47A-43D is in a stopped state.
47D as appropriate transmitting portions 49A to 49D and each of the auxiliary rotary plates 59B to 59D as appropriate transmitting portions 61B to 61
D is configured to match the path L of the laser beam LB and allow the laser beam LB to pass therethrough. Therefore, when the laser oscillator 3 continuously oscillates the laser beam LB,
Each rotating shaft 43 is
By holding A to 43D in a stopped state, the continuous wave laser beam LB is irradiated onto the laser processing apparatus 1.

Limit switches LS1 and LS2 are provided near the lock cylinder 85 to detect whether or not each of the rotating shafts 43A to 43D is fixed by the lock cylinder 85. As is clear from FIG. 3, the limit switches LS1 and LS2 are supported by a bracket 97 attached to the base plate 31, and are arranged to be operated by a dog pin 93 at the stroke end of the piston rod 91. . Therefore, limit switches LS1 and LS2
By knowing the operating state of each rotating shaft 43A~
It is possible to know whether 43D is in a stopped state or in a rotatable state.

In the above configuration, the piston rod 55 in each cylinder 51 is retracted, and the engagement hole 69 of each auxiliary rotary plate 59B to 59D is engaged with the tip portion 67E of each fixing pin 67, so that each auxiliary rotary plate 59B to 59D is held in a stopped state. Then, when each rotating shaft 43A to 43D is rotated synchronously by the motor 79, each rotating plate 47A to 43D is rotated synchronously by the motor 79.
Each transmission part 49A to 49B of 47D is a laser beam.
Laser beam only when matching path L of LB
LB transmission is allowed. Therefore, even if the laser beam LB emitted from the laser oscillator 3 is a continuous wave, the laser beam LB can be mechanically pulsed. In this embodiment, each rotary plate 47A to 47D has eight transparent parts 49A to 47D.
49D is provided for each, so the laser beam
LB is 8 pulses per rotation of each rotating plate 47A to 47D. Note that by appropriately controlling the rotation speed of the motor 79, the frequency of the pulsed laser beam LB can be changed.

Next, the piston rod 55 in the appropriate cylinder 51 is operated to extend, thereby making the appropriate auxiliary rotary plate rotatable integrally with the rotary plate. For example, only the auxiliary rotary plate 59B can be rotated integrally with the rotary plate 47B, and the other auxiliary rotary plates 59C and 59D are held in a stopped state, and each rotary plate 47A is controlled by the motor 79.
47D are rotated synchronously, the auxiliary rotary plate 59B is provided with only four transmitting portions 61B in this embodiment, and the laser beam LB is transmitted 4 times per rotation of each of the rotary plates 47A to 47D. Modulated into pulses.

Furthermore, when only the auxiliary rotary plate 59C or the auxiliary rotary plates 59B and 59C are integrated with the respective rotary plates 47B and 47C by the operation of each cylinder 51, the number of transparent parts 61C provided on the auxiliary rotary plate 59C is reduced to two in this embodiment. Therefore, the laser beam LB is modulated into two pulses per rotation of each rotating plate 47A to 47D. Furthermore, when the auxiliary rotary plate 59D is integrated with the rotary plate 47D, the laser beam LB is transmitted to each rotary plate 47A.
It is modulated to one pulse per rotation of ~47D.

That is, by holding all of the plurality of auxiliary rotary plates 59B to 59D in a stopped state, or by rotating an appropriate auxiliary rotary plate integrally with the rotary plate, the laser beam LB irradiated and transmitted from the laser oscillator 3 can be controlled. , it can be modulated into a pulsed laser with appropriate pulses per rotation of the rotary plates 47A to 47D. In other words, the duty ratio of the pulsed laser can be adjusted by changing the number of pulses per rotation of the rotating plates 47A to 47D.

g Effects of the Invention As understood from the description of the embodiments above, according to the present invention, even when the laser oscillator continuously oscillates a laser beam, the laser oscillator can be operated without any adverse effect on the laser oscillator. , it can be mechanically modulated into a pulsed laser, and the duty ratio of the pulsed laser can be changed. Therefore,
When laser processing a workpiece in a laser processing device, the laser processing of the workpiece can be performed by modulating the continuous wave laser or the pulsed laser with a different duty ratio depending on the processing mode, such as simple fusing processing or micromachining. becomes. Therefore, it is possible to improve machining efficiency and machining accuracy.

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

[Brief explanation of drawings]

Fig. 1 is a front view of a laser processing device implementing the device according to the present invention, and Fig. 2 is a -
FIG. 3 is an enlarged sectional view taken along the line - in FIG. 2, and FIG. 4 is an enlarged view taken along the line - in FIG. 1. LB...Laser beam, 47A-47D...Rotating plate, 49A-49B...Transmission part, 59B-59
D...Auxiliary rotating plate.

Claims (1)

[Claims] 1. A laser beam oscillated from a laser oscillator is intermittently interrupted by a plurality of rotary plates in which laser beam transmission parts are formed at appropriate intervals, and the laser beam is pulsed and rotated at each rotation. A laser beam modulation method characterized by changing the duty ratio of a pulsed laser beam by changing the number of transparent parts of a plate. 2 A plurality of rotating plates each having laser beam transmitting parts formed at appropriate intervals near the outer periphery are provided at positions that can freely cross the path of the laser beam emitted from the laser oscillator, and an appropriate number of rotating plates are provided. An auxiliary rotary plate arranged coaxially with the rotary plate is rotatably and fixedly provided, and the number of laser beam transmitting parts formed on each auxiliary rotary plate is different from the number of transmitting parts of the coaxial rotary plate. Characteristic laser beam modulation device. 3. The laser beam modulation device according to claim 2, wherein the number of laser beam transmission parts on each auxiliary rotating plate is different.