JPH0577073A - Device for observing state of laser beam machining - Google Patents

Abstract

PURPOSE:To improve the precision of an observation of laser beam machining by restricting the influence of a noise except a working sound in the device for observeing the state of laser beam machining which judges the quality of the state of laser beam machining by detecting the working sound generating in the time when the laser beam irradiates on the material to be worked. CONSTITUTION:A light receiving element 16 as the light emitting detecting means detects a light emittion 9 generating in a laser beam machining part 8, outputs a signal to a controlling part 18. This controlling part 18 detects the deviation of the center axial line 15 of a microphone 15 which is the working noise detecting means by utilizing this signal, and makes this microphone 15 to follow so as to eliminate this deviation. Therefore, the microphone 15 becomes always itself toward the direction of the working part 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing state monitoring device for judging whether or not a processing state of an object to be processed by laser processing is good and monitoring whether or not the processing state is a predetermined value. is there.

[0002]

2. Description of the Related Art Conventionally, a method disclosed in Japanese Patent Laid-Open No. 62-114786 has been proposed as an example of a laser processing state monitoring method.

In this method, as shown in FIG. 5, a processing sound 53 generated when a workpiece 51 is irradiated with a laser beam 52 is collected by a microphone 54 and amplified by an amplifier 55. Further, the quality determination value setting unit 57 of the processing state monitoring device 56 holds an analysis and quantitative value of the processing sound generated when the workpiece 51 is processed properly as a reference value.

The reference value and the processed sound collected and amplified by the microphone 54 are compared by the comparator 58, and the result of the judgment of the quality of the processed state is displayed on the display unit 59 each time.
Display by.

As a result, without a destructive test or the like,
It is possible to display the quality judgment of all the workpieces in real time.

[0006]

However, the conventional laser processing state monitoring method described above has the following problems.

That is, during the laser processing, the XY table 60 is moved and the processing gas 61 is injected. X like this
Noise 62 caused by movement of the Y table 60 and injection of the processing gas 61 is generated at the same time as the processing sound 53 during laser processing.
The generated noise 62 is detected by the microphone 54 like the processed sound 53.

The processed sound 53 and the noise 62 detected by the microphone 54 are not clearly distinguished. Therefore, when the processing state monitoring device 56 determines the quality of the processing state, the magnitude of the noise 62 may affect the accuracy of the quality determination of the processing state.

Conventionally, the microphone 54 has been arranged so that the direction of the microphone 54 and the processed portion coincide with each other. However, when the position of the processed portion is intentionally moved as shown in FIG. 6 or the position of the processed portion is moved by an accidental factor, there is a problem that it is particularly susceptible to noise. ..

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a laser processing state monitoring device capable of accurately monitoring the laser processing state.

[0011]

In order to achieve this object, a laser processing state monitoring device of the present invention includes a processing sound detecting means for detecting a processing sound generated from a processing portion during laser processing, and a processing sound detecting means. A machining state monitoring means for monitoring the machining state by comparing the machining sound detected by the means with the machining sound stored in advance during normal machining; and a light emission detecting means for detecting light emission generated in the machining part, And a control means for causing the processing sound detection means to follow the direction of the processing portion based on the signal from the light emission detection means.

The processing sound detecting means has unidirectionality or superdirectivity in which its detection sensitivity is strong directivity with respect to one specific direction.

[0013]

According to the laser processing condition monitoring device of the present invention having the above-mentioned structure, the light emission detecting means detects the light emission generated in the laser processing portion and sends a signal to the control means. The control means uses this signal to detect the deviation between the axis of the processing sound detecting means and the processing part, and causes the processing sound detecting means to follow so as to eliminate the deviation.

As a result, the processing sound detecting means always faces the processing section.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to FIGS. A specific example of laser processing will be described with reference to welding processing.

The laser processing machine comprises a CO ₂ laser oscillator 1 and a laser processing head 2, and a laser beam 3 oscillated from the CO ₂ laser oscillator 1 is reflected by a reflecting mirror 4 toward the laser processing head 2. Is condensed by the condenser lens 5 in the laser processing head 2 and is irradiated onto the workpiece 6. The wavelength of the laser light 3 is specifically 10.6 μm (micrometer).

The workpiece 6 is arranged on a movable XY table 7 and moves while irradiating the laser beam 3 to form a processed portion 8. At this time, the processing section 8 emits light 9, and further the processing sound 10 is generated from the processing section 8.

Further, a processing nozzle 11 is arranged at the tip of the laser processing head 2 and an injection hole 12 at the tip thereof.
From the laser light 3 condensed by the condenser lens 5
Is ejected. Further, the processing nozzle 11 is provided with a supply port 14 for a shield gas 13 mainly composed of argon, and the shield gas 13 is supplied from the supply port 14. Thereby, the injection hole 12 of the processing nozzle 11
The shield gas 13 is jetted coaxially with the laser light 3 to shield the processing portion 8.

The microphone 15 as the processing sound detecting means and the light receiving element 16 as the light emission detecting means are arranged in the block 17, and the microphone 15 and the light receiving element 16 are provided.
The central axes of the two intersect with each other on the laser beam 3. The microphone 15 is a unidirectional microphone whose detection sensitivity is strong on the central axis and in one direction on the front surface, and the light-receiving element 16 has a spectral sensitivity wavelength range of ultraviolet rays. It is a light-receiving element that is in the visible region from the region.

The control unit 18, which is a control means for controlling the direction of the microphone 15, has a moving mechanism 19 of the microphone 13 as shown in FIG. 1 and a moving mechanism 19 for operating the moving mechanism 19 as shown in FIG. And a computer 20.

The moving mechanism 19 of the microphone 15 includes a drive motor 22 vertically connected to the side surface of the laser processing head 2 via an arm 21 and a feed screw connected to the lower end of the output end of the drive motor 22. 23 and the feed screw 23
And a guide plate 24 fixed to the arm 21 for guiding the block 17.

According to the moving mechanism 19 configured as described above, the microphone 15 always maintains a constant posture with respect to the light receiving element 16, and when the drive motor 22 further rotates, the central axis of the laser beam 3 is rotated. It will be moved in parallel with respect to.

The computer 20 includes a CPU 25 and a ROM
26, a RAM 27 and an input / output port 28. Based on a signal from the light receiving element 16, an operation as shown in FIG. 4 is performed to output to the drive motor 22 and the microphone 15 to the processing section 8. It is always aimed at.

Next, the operation of the laser processing state monitoring apparatus of the present invention will be described with reference to the flowchart of FIG.

First, it is judged whether or not the laser processing is completed (S1), and if it is not completed, the intensity of the light emission 9 in the vicinity of the processed portion 8 is measured by the light receiving element 16, and P1 is measured.
(S2). Then, the drive motor 22 is driven to rotate the feed screw 23 in the forward direction (S3). As a result, the block 17 moves in the + Z direction in FIG.
With the movement of the block 17, the microphone 15 and the light receiving element 16 arranged on the block 17 simultaneously move in the + Z direction.

When the block 17 has moved by a predetermined amount, the intensity of the light emission 9 near the processed portion 8 is measured again, and this is taken in as P2 (S4). P1 and P2 are compared, and if P2 is stronger, the feed screw 23 is rotated further in the forward direction, and if P1 is stronger, the next judgment is made (S5).

If the previous measured value P1 is larger, it is judged whether or not the laser processing has been completed (S6). The measurement is performed and this is taken in as P3 (S7). Then, the drive motor 22 is driven in the reverse direction to rotate the feed screw 23 in the negative direction (S8). As a result, the block 17 moves in the -Z direction in FIG. With the movement of the block 17, the microphone 15 and the light receiving element 16 arranged therein move at the same time in the −Z direction.

When the block 17 has moved by a predetermined amount, the intensity of the light emission 9 near the processing portion 8 is measured again, and this is taken in as P4 (S9). P3 and P4 are compared. If P4 is stronger, the feed screw 23 is further rotated in the negative direction. Conversely, if P3 is stronger, the process returns to the start and the same operation as above is repeated. (S10). In this way, the central axis of the microphone 15 always faces the processed portion 8 where the intensity of the light emission 9 is maximum.

The processed sound 10 detected by the microphone 15 is amplified by the amplifier 29 as in the conventional case. Further, a processing state monitoring device 3 which is a processing state monitoring means.
In the pass / fail judgment value setting unit 31 of 0, the analysis and quantitative values of the processing sound generated when the workpiece 6 is processed favorably are held as reference values. This reference value and the microphone 15
The processed sound 10 collected and amplified by the comparator 3
The comparison result in 2 is displayed, and the determination result of the quality of the processed state is displayed on the display unit 33 each time.

The present invention is not limited to the embodiments described in detail above, and various modifications can be made without departing from the spirit of the invention.

For example, in addition to welding, it can be applied to drilling, cutting, etc., and the light receiving element as the light emission detecting means for detecting the light emission of the processed portion is the type of processing or the object to be processed. It may be appropriately selected according to the type.

Regarding the type of the microphone as the processing sound detecting means, the effect of the present invention is greater when the directivity of the detection sensitivity is stronger in one direction, but in other microphones as well, the relative position of the microphone with respect to the processing portion is changed. Since it can be controlled, the processed sound can be detected more accurately than before.

[0033]

As is apparent from the above description, according to the laser processing state monitoring apparatus of the present invention, the processing sound detecting means in laser processing can always follow the processing portion. As a result, by suppressing the influence of noise other than the processing noise such as the movement noise of the XY table and the jetting noise of the processing gas, it is possible to improve the accuracy of the laser processing state monitoring by the laser processing noise, which is a remarkable industrial effect. Play.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment embodying the present invention.

FIG. 2 is a detailed view of an embodiment embodying the present invention.

FIG. 3 is a block diagram of a computer portion showing an example of control means in the present invention.

FIG. 4 is a flowchart showing an example of operation of the control means in the present invention.

FIG. 5 is a diagram showing an example of a conventional laser processing state monitoring method.

FIG. 6 is a diagram showing an example of processing in a conventional laser processing state monitoring method.

[Explanation of symbols]

 1 Laser Oscillator 2 Laser Processing Head 3 Laser Light 5 Condensing Lens 6 Workpiece 8 Processing Part 9 Light Emission 10 Processing Sound 15 Microphone 16 Light-Receiving Element 18 Control Section 19 Moving Mechanism 30 Processing Condition Monitoring Device

Claims (1)

[Claims] 1. Processing sound detection means for detecting a processing sound generated from a processing portion during laser processing, and processing sound detected by the processing sound detection means and processing previously stored during normal processing. Processing state monitoring means for monitoring a processing state by comparing sound, light emission detection means for detecting light emission generated in the processing portion, and the processing sound detection means based on a signal from the light emission detection means for the processing portion. A laser processing state monitoring device, characterized in that the laser processing state monitoring device is provided with: