JPH04371380A - Laser beam machine - Google Patents

Abstract

PURPOSE:To prevent damage of optical parts by detecting an oscillated laser beam and a reflected laser beam and controlling a laser beam oscillation means based on detected values. CONSTITUTION:A laser beam 2 emitted from a laser beam oscillator 1 is reflected by a bender mirror 3 of an optical transmission means and led to a workpiece 5. This laser beam 12 is condensed by a condenser lens 4. The laser beam 12 is detected by an incident beam output monitor 13 of the first laser beam detection means. A part of the laser beam 12 is then reflected on between the bender mirror 3 and the condenser lens 4 by a chopper 11 and a reflection plate 10 of a reflection means. A reflected laser beam reflection beam 6 is detected by the second laser beam detection means 14. The laser beam oscillator 1 is controlled by a control means 15 based on the detected values from the first and second laser beam detection means 13 and 14. Consequently, a stable laser beam machine can be furnished.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for processing a workpiece using a laser beam.

0002

2. Description of the Related Art FIG. 2 shows one row of conventional laser processing equipment.

A laser beam 2 emitted from a laser oscillator 1 is guided to a condensing lens 4 by one or more bender mirrors 3 along the way, and is irradiated onto a workpiece 5 together with an assist gas such as oxygen to cut the material. .

However, when cutting a material such as aluminum or copper that has a high reflectance with respect to the carbon dioxide laser, if a processing defect occurs at the start of cutting or due to a defect in the cutting conditions, the laser beam 2 A state close to total reflection occurs above the beam, and a phenomenon occurs in which the beam returns to the laser oscillator 1 through the bender mirror 3. The reflected light 6 may burn, for example, the O-ring (not shown) around the output mirror of the laser oscillator 1, the airtight parts (not shown), etc. The light is condensed by the optical lens 4,
Damage may be caused to the bender mirror 3 in the middle and the output mirror of the laser oscillator 1. Therefore, in the conventional laser processing apparatus, when the reflected light 6 returns to the laser oscillator 1, the oscillator built-in output monitor 7 uses the configuration shown in FIG.
The output of the built-in oscillator output monitor 7 is compared with a certain value using a laser output comparator 8, and a signal is sent to the power control panel 9 to stop the laser oscillation. It's here.

[0005]

[Problem to be Solved by the Invention] However, in the case of such control, a thermocouple type sensor is normally used as the output monitor 7 with a built-in oscillator, and the time constant of this sensor is long and the response is slow. It takes time to detect the reflected light 6 returning to the laser oscillator 1, making it difficult to protect the laser oscillator 1 reliably.

Furthermore, if the distance from the laser oscillator 1 to the processing point is long and there are many bender mirrors 3 along the way, making the optical path complicated, the reflected light 6 from the workpiece 5 will not return to the laser oscillator 1. The bender mirror 3 in the middle may be damaged, making it impossible to provide a stable laser processing system.

In order to solve the above-mentioned problems, the present invention has been developed to enable stable laser processing at all times without being affected by the reflected light generated from the workpiece during laser processing of workpieces such as aluminum and copper. We provide laser processing equipment. [Structure of the invention]

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a laser oscillation means for oscillating laser light;
A laser beam transmission means for reflecting the laser beam emitted from the laser oscillation means and guiding it to the workpiece, a condensing means for condensing the laser beam transmitted by the laser beam transmission means, and oscillation from the laser oscillation means. a first laser beam detection means for detecting the laser beam transmitted by the laser beam; A second laser beam detection means for detecting the reflected laser beam; and a control means for controlling the laser oscillation means based on detection values from the first and second laser beam detection means. Provides a laser processing device characterized by the following.

[0009]

[Operation] The laser processing apparatus of the present invention configured as described above reflects a part of the laser beam between the laser beam transmission means and detects the reflected laser beam and the laser beam oscillated from the laser oscillation means. Since the laser oscillation means is controlled based on each detected value, damage to optical components due to reflected light etc. can be prevented even when the optical path from the laser oscillation means to the processing point is relatively long and complicated. In addition, abnormal conditions in the optical path can be detected, and the laser output at the processing point can be stably controlled.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Note that FIG. 1 shows an example of the configuration of a laser processing apparatus according to an embodiment of the present invention, and the same parts as those in FIG.

As shown in FIG. 1, the laser processing apparatus of this embodiment has a chopper 11 that rotates a reflector 10, such as a needle or a thin plate, of a laser output monitor unit 9 emitted from a laser oscillator 1. Before the incident light 12 reaches the processing point, a part of it is reflected and reflected to the incident light output monitor 13, so that the laser output near the processing point can be monitored.

Furthermore, when processing highly reflective materials such as aluminum and copper, if reflected light 6 occurs on the surface of the workpiece 5, such as when starting cutting or when cutting is defective, the laser output monitor unit 9 Since a part of the reflected light 6 is reflected by the back surface of the chopper 11, the presence or absence of the reflected light 6 and its size are monitored by the reflected light output monitor 14.

In the laser processing apparatus of this embodiment which performs such an operation, if a high-speed response type laser output sensor such as a pyroelectric element is used for the reflected light output monitor 14, the reflected light 6 can be processed in a short time. The detection control unit 15 monitors the voltage output of the reflected light output monitor 14, and if it is determined that the reflected light 6 is large, an interlock is provided to stop the laser oscillator 1. This can prevent damage to the optical components of the laser oscillator 1 and the bender mirror 3 in the middle.

Furthermore, since the laser output near the processing point is also monitored by the incident light output monitor 13, the output control unit 15 compares the laser output value on the output monitor 7 with built-in oscillator and the laser output value near the processing point. This may cause dirt on the bender mirror 3 and reflected light 6.
By also determining the attenuation of the laser output due to damage to the bender mirror 3, etc., abnormalities in the laser optical path can be detected. Furthermore, in this case, the reflected light output monitor 1
3, and the output control unit 15 issues an output increase signal to the laser oscillator 1 to compensate for the decrease in output at the processing point, thereby keeping the laser output at the processing point constant. With these, a stable processing system can be provided.

Furthermore, in this embodiment, since such a laser output monitor unit 9 is provided between the final bender mirror 3 and the condenser lens 4, the optical path length from the laser oscillator 1 to the processing point is long. Since the reflected light 6 can be reliably monitored even when the number of bender mirrors 3 is large and complicated, the optical parts of the laser oscillator 1 and the bender mirror 3 can be
etc. can be reliably protected and stable machining conditions can be maintained. Note that in this embodiment, the output control unit 15 is
Although it is provided outside the laser oscillator 1, the laser oscillator 1
It may be built in.

[0016]

[Effects of the Invention] As described above, according to the present invention, reflected light can be reliably detected even when the optical path from the laser oscillation means to the processing point is long and complicated, thereby preventing damage to optical components. This can be prevented.

Furthermore, since the laser output near the processing point can be detected at the same time, abnormalities in the optical path can be detected.
Since the laser output at the processing point can be controlled to be constant, a more stable laser processing apparatus can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a conventional laser processing device.

FIG. 3 is a block diagram showing a control system of a conventional laser processing device.

[Explanation of symbols]

1...Laser oscillator,
2...Laser beam, 3...Bender mirror, 4...Condensing lens, 5...Workpiece,
6...Reflected light, 9...Laser output monitor unit, 13...Output monitor for incident light, 14...Output monitor for reflected light, 15...Output control unit

Claims (1)

[Claims] 1. A laser oscillation means for oscillating a laser beam, a laser beam transmission means for reflecting the laser beam emitted from the laser oscillation means and guiding it to a workpiece, and a laser beam transmitted by the laser beam transmission means. In the laser processing apparatus, the laser beam transmitting means is arranged between the laser beam transmitting means and the focusing means, and the laser beam detecting means detects the laser beam emitted from the laser oscillating means. A reflecting means for reflecting a part of the light, a second laser light detecting means for detecting the laser light reflected by the reflecting means, and based on detected values from the first and second laser light detecting means. , A laser processing apparatus comprising: a control means for controlling the laser oscillation means.