JPH0810465Y2 - Laser processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a laser processing apparatus, and more specifically,
The present invention relates to a laser processing apparatus in which a sensor detects return light that is reflected and returned by a laser beam applied to a work, and when the return light enters a certain range, the laser beam is blocked.

(Prior Art) Conventionally, a laser beam oscillated from a laser oscillator is focused by a condenser lens through an appropriate number of bend mirrors. The laser beam condensed by the condenser lens is applied to a work provided below the condenser lens to perform desired laser processing.

(Problems to be solved by the invention) By the way, when a desired laser processing is performed by irradiating a work with a laser beam by the above-described conventional laser processing apparatus,
Part of the laser beam is reflected by the work. The reflected return light is returned to the laser oscillator via the bend mirror. When the work is made of iron or the like, the returned light is not so much and the output of the laser beam is not hindered.

However, when the work is made of a highly reflective material such as aluminum, copper, or brass, the returned light is large, and when returned to the laser oscillator, the laser power is disturbed and the output of the laser beam is disturbed, and the mirror beam is disturbed. There are problems such as damage and adverse effects on the oscillator.

The purpose of this invention is to improve the above-mentioned problems by irradiating a laser beam to a work and performing laser processing, and detecting the return light of the laser beam reflected from the work with a sensor, It is an object of the present invention to provide a laser processing apparatus capable of interrupting a laser beam when an integrated value obtained by integrating a sensor voltage at a certain time exceeds or falls below a preset reference integrated value.

[Structure of the Invention] (Means for Solving the Problems) In view of the conventional problems as described above, the present invention contemplates that a laser beam oscillated from a laser oscillator is condensed by a condenser lens and is irradiated onto a work. Based on the detection of the return light, a return light capturing device that captures only the return light of the laser beam from the workpiece, a sensor that detects the return light captured by the return light capturing device, and a laser processing device that performs processing. An integrating circuit for integrating the sensor voltage of the sensor,
A comparison arithmetic processing device for comparing an integrated value integrated by the integrating circuit with a preset reference integrated value, and a return light blocking device capable of blocking return light from returning to the laser oscillator. The comparison arithmetic processing device outputs a shutoff signal to the return light shutoff device when the cutting of the workpiece is in an abnormal state or a defective state as a result of the comparison between the integrated value and the reference integrated value. It will be as.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a laser processing apparatus 1 is provided with a laser oscillator 3 for oscillating a laser beam LB and a laser processing body 5. A bend mirror 7 for changing the optical path of the laser beam LB oscillated by the laser oscillator 3 is arranged in front of the laser oscillator 3 in the laser processing body 5. A condenser lens 9 for condensing the laser beam LB reflected by the bend mirror 5 is arranged below the bend mirror 7.

A work table 11 is provided below the condenser lens 9, and a work W made of a highly reflective material such as aluminum, copper, or brass is placed on the work table 11.

With the above configuration, the laser beam LB oscillated by the laser oscillator 3 is focused on the condenser lens 9 via the bend mirror 7. Furthermore, the laser beam condensed by the condenser lens 9
The work W placed on the work table 11 is irradiated with the LB, and a desired cutting process is performed.

For example, a return light catching device 13 for catching the return light BL reflected from the work W is provided between the laser oscillator 3 and the bend mirror 7. The return light catching device 13 is composed of a rotatable member 15 having a semicircular cross section and made of, for example, a molybdenum rod, and a rotatable member 15.
And a drive motor 21 for rotating the support disk 17 via a shaft 19 on the support disk 17.

With the above configuration, when the drive motor 21 is driven, the support disk 17 is rotated via the shaft 19. The rotation of the support disk 17 causes the rotation member 15 to rotate at a desired rotation speed. By rotating the rotating member 15, only the return light BL reflected from the work W is chopped and captured by the rotating member 15.

A sensor 23 such as a pyroelectric infrared sensor is provided in the vicinity of when the rotating member 15 rotates and is positioned on the path of the laser beam LB. A control device 27 is connected to the sensor 23 via an amplifier 25. Controller 25
Relay contact 29 is connected to the relay contact 29.
Is a laser beam LB on the front side of the laser oscillator 3.
A return light blocking device 31 such as a return light shutter provided in the middle of the path is connected. For example, a rotary lamp 33 is connected in the middle of the relay contact 29 and the return light blocking device 31, and a buzzer 35 is connected to the rotary lamp 33.

As shown in FIG. 2, the control device 27 integrates the sensor voltage V amplified by the amplifier 25 with the passage of time to obtain an actual integrated value V, and a reference integrated value V in advance. A reference integral value database 27B that stores ₀ ,
It is composed of a comparison calculation processing device 27C for comparing the actual integration value V obtained by the integration circuit 27A with the reference integration value V ₀ stored in the reference integration value database 27B.

The reference integrated value database 27B shows, for example, a curve of the sensor voltage v with time as shown in FIG. 3 (A). Then, the reference integral value V _0, which is the area of the sensor voltage v at a certain time, is precalculated and stored. This reference integral value V ₀ is determined by the material of the work W, the plate thickness, etc. and is set with a certain width. The reference integrated value V ₀ is obtained by cutting the work W made of a highly reflective material such as aluminum, brass, or copper in a normal state.

The curve of the sensor voltage v according to the time detected by the integrating circuit 27A is the curve shown in FIG. 3 (B) and FIG. 3 (C), and is obtained from the actual integrated value V at a certain time from this curve. To be The curve shown in FIG. 3 (B) is a state in which the work W made of a highly reflective material is cut and the spatter is scattered on the surface of the work W (referred to as a gouging state).
It is smaller than the return light when cutting normally, and shows an abnormal state in cutting processing.

The curve shown in FIG. 3 (C) shows a state in which the laser beam LB is almost reflected by the work W and returned as return light in a defective cutting state in which the cutting process is not performed at all.

With the above configuration, the return light BL is captured and reflected by the circumferential portion of the semicircular cross section of the rotating member 15 and is captured by the sensor 23. Although the laser beam LB oscillated by the laser oscillator 3 is captured in the plane portion of the semicircular cross section of the rotating member 15, the reflected light is reflected so as not to be captured by the sensor 23.

Therefore, only the return light BL captured by the rotating member 15 is taken into the sensor 23.

The return light BL taken into the sensor 23 is amplified by the amplifier 25 and taken into the controller 27. In the control device, processing is performed based on the flowchart shown in FIG. In FIG. 4, the sensor voltage v is amplified by the amplifier 25 in step S1. The sensor voltage v amplified by the amplifier 25 is the step S2.
Is integrated in the to time taken in by the integrating circuit 27A at.
In step S3, the actual integration value V integrated by the integration circuit 27A and the reference integration value V ₀ previously stored in the reference integration value database 27B are fetched by the comparison processing unit 27C.

Furthermore, in step S4, V = V in the comparison arithmetic processing unit 27C.
A determination is made as to whether it is _zero . If V = V ₀ ,
For example, in the state shown in FIG. 3A, and since the normal cutting process is performed, the process returns to the step before step S1 and the sensor 23 detects the return light again. If it is determined that V = V ₀ is not satisfied, then in step S5 it is determined whether V <V ₀ or V> V ₀ . If V <V ₀ , it is the state shown in FIG. 3B, for example, and it is in the gouging state, indicating defective cutting, and if V> V ₀ , it is the state shown in FIG. 3C, for example. It means that the cutting is not performed at all.

In such a state, the output signal is sent to the return light blocking device 31 via the relay contact 29 in step S6 to operate, the laser beam LB is blocked, the work W is stopped, and the rotation is performed in step S7. Light 31 is turned on or buzzer 35 is sounded to notify the operator that the cutting is abnormal.

In this way, the return light BL is captured by the rotating member 15, the captured return light BL is reflected and detected by the sensor 23, and when returned to the laser oscillator 3, the laser power is disturbed and the output reduction is eliminated. Therefore, if the preset reference integration value V ₀ is not set (V> V ₀ ), the return light blocking device 31 operates to block the laser beam LB. As a result, the disturbance of the laser power of the laser beam is prevented and the mirror is not damaged or the oscillator is not adversely affected.

The present invention is not limited to the above-described embodiments, but can be implemented in other modes by making appropriate changes. Although the return light catching device 13 and the sensor 23 are provided between the laser oscillating device 3 and the bend mirror 7 in this embodiment, they may be provided between the bend mirror 7 and the condenser lens 9. It is possible.

[Effects of the Invention] As can be understood from the above description of the embodiments, in short, the present invention focuses the laser beam LB oscillated from the laser oscillator 3 by the condenser lens 9 and irradiates the work W with the laser beam LB. As a laser processing device for processing, a return light capturing device 13 for capturing only the return light of the laser beam LB from the work W, a sensor 23 for detecting the light captured by the return light capturing device 13, and the return light An integration circuit 27A for integrating the sensor voltage of the sensor 23 based on the detection of the above, and a comparison calculation processing device 27C for comparing the integration value V integrated by the integration circuit 27A with a preset reference integration value V _0. A return light blocking device 31 capable of blocking the return light from returning to the laser oscillator 3;
27C is the result of comparison between the integrated value V and the reference integrated value V ₀ ,
When the cutting work of the work W is in an abnormal state or a defective state, a blocking signal is output to the return light blocking device 31.

As is apparent from the above configuration, in the present invention, since the return light catching device 13 only catches the return light (reflected light) of the laser beam LB from the work W, the detection value of the sensor 23 is only the return light. This is a detection value obtained by detecting (1), and it is possible to accurately detect variations in the return light.

Then, the comparison calculation processing device compares the integral value V of the sensor voltage detected by the sensor 23 with a preset reference integral value V _0.
27C, and as a result of the comparison, when the cutting processing of the work W is in an abnormal state or a defective state, the return light blocking device 31 is operated to block return light from returning to the laser oscillator 3. .

That is, according to the present invention, only the return light (reflected light) from the work W is detected to judge whether the working state of the work W is normal or not, and when it is not normal, the return light is blocked. Of course, it is possible to prevent the return light from adversely affecting the laser oscillator 3, and even if the output of the laser oscillator 3 changes due to a change in the input power to the laser oscillator 3, for example, the work W
If the cutting process is normal, the laser process can be continued without detecting the output fluctuation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment for carrying out the present invention, FIG. 2 is a configuration block diagram of a control device in FIG. 1, and FIG.
(A), (B), (C) are state diagrams of the sensor voltage at the time based on the return light detected by the sensor, and FIG. 4 is a flow chart showing the operation of the control device. DESCRIPTION OF SYMBOLS 1 ... Laser processing device, 3 ... Laser oscillator 5 ... Laser processing main body, 7 ... Bend mirror 9 ... Condensing lens, 13 ... Return light catching device 23 ... Sensor, 27 ... Control device 31 ... Return light blocking device

Claims (1)

[Scope of utility model registration request] 1. A laser processing apparatus for performing laser processing by converging a laser beam (LB) oscillated from a laser oscillator (3) with a condenser lens (9) and irradiating the workpiece (W) with the laser beam (LB). (W) Return light catching device (13) for catching only the return light of the laser beam (LB), and sensor (23) for detecting the light caught by this return light catching device (13)
An integrating circuit (27A) for integrating the sensor voltage of the sensor (23) based on the detection of the return light, and the integrating circuit (27A).
A comparison processing unit (27C) for comparing the integrated value (V) integrated in A) with a preset reference integrated value (V ₀ ).
And a return light blocking device (31) capable of blocking the return light from returning to the laser oscillator (3), and the comparison operation processing device (27C) includes the integrated value (V). As a result of comparison with the reference integrated value (V ₀ ), when the cutting work of the work (W) is in an abnormal state or a defective state, a cutoff signal is output to the return light cutoff device (31). Characteristic laser processing equipment.