JPH04309478A - Laser beam machine - Google Patents

Abstract

PURPOSE:To protect the laser oscillating means, etc., by executing the stop control of laser oscillation, based on a detection value of a reflected light from an object to be worked at the time of working by the laser beam machine. CONSTITUTION:The laser beam machine is provided with a reflected light detecting means for detecting a reflected light from an object to be worked, generated at the time of working by a laser light, and a stop control means for controlling a stop of laser oscillation, based on a detection value from the reflected light detecting means in accordance with an operating state of a laser oscillating means. In such a way, even in the case of working a material whose reflectance is high such as aluminum, copper, etc., and even in the case the reflected light from the object to be worked returns to the laser oscillating means, an interlock is operated effectively, and the laser oscillating means, etc., can be protected.

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 materials with relatively high reflectivity, such as aluminum and copper, using laser light.

0002

2. Description of the Related Art FIG. 3 shows an example of a conventionally used laser processing apparatus.

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 perform laser processing such as cutting. will be carried out.

However, when cutting materials with high reflectivity such as aluminum or copper, if a processing defect occurs at the start of cutting or due to a defect in the cutting conditions, the laser beam 2 is completely focused on the workpiece 5. The state is close to reflection, and the laser beam 2
A phenomenon occurs in which the laser beam returns to the laser oscillator 1 through the bender mirror 3. These reflected lights 6 may burn, for example, an O-ring (not shown) around the output mirror of the laser oscillator 1 or airtight parts (not shown), and the reflected lights 6 may burn the condenser lens 4. This may cause damage to the bender mirror 3 or the output mirror (not shown) of the laser oscillator 1, which is located on the way.

Therefore, in the conventional laser processing apparatus, when the reflected light 6 returns to the laser oscillator 1, the laser output monitor detects that the laser output increases due to the reflected light 6, as shown in FIG. Then, the laser output comparator 8 is used to compare whether the output of the laser output monitor 7 has reached a constant value Pe as shown in FIG.
It has been attempted to emit a signal to stop laser oscillation.

[0006]

[Problem to be solved by the invention] However, pulse operation,
Especially during high peak pulse operation, the average laser output is smaller than during continuous operation (CW operation) depending on the pulse ON/OFF ratio, but the peak output is high enough to damage parts such as the laser oscillator 1. Figure 5
In the method of stopping the laser oscillator 1 at a constant output value as shown in FIG. That was impossible.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a laser processing apparatus that can control the stop of laser oscillation based on the reflected light from the workpiece, taking into consideration the operating state of the laser oscillation procedure. purpose. [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 emitting laser light by exciting a laser medium, and a setting for setting the operating state of the laser oscillation means. In the laser processing apparatus, the laser processing apparatus includes a means for reflecting the laser light emitted by the laser oscillation means and guiding it to the workpiece, and a condensing means for condensing the laser light. Based on the detected value from the reflected light detection means according to the operating state of the reflected light detection means for detecting the reflected light from the workpiece and the laser oscillation means set and operated by the setting means. A laser processing apparatus is provided that includes a stop control means for controlling the stop of laser oscillation.

[0009]

[Operation] In the laser processing apparatus of the present invention configured as described above, by optimizing the reference value for determining the stop of laser oscillation according to the operating state of the laser oscillation means,
Damage to the device due to reflected light from the workpiece can be prevented.

0010

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

As shown in FIG. 1, the laser processing apparatus of this embodiment uses an output monitor 7 to detect that when the reflected light 6 returns to the laser oscillator 1, the laser output is amplified by the reflected light 6. , turn on the pulse from the power control panel 9
Using the time t1, the pulse OFF time t2, and the above-mentioned output upper limit Pe, the output calculator 10 calculates the output upper limit Pe', which is set low at a rate commensurate with the pulse ON/OFF ratio, and the output Monitor 7 output value P0
are compared using an output comparator 8, and if P0≧Pe', a signal is sent to the power supply and control panel 9 to stop laser oscillation.

FIG. 2 shows the calculation pattern of this embodiment by the output calculation unit 10. In Fig. 2(a), considering that the average laser output during pulse operation is a value multiplied by the pulse ON/OFF ratio, the output upper limit Pe is used, and the output upper limit Pe' during pulse operation is set as Pe'= This shows the case where the calculation is Pe×t1/(t1+t2).

Furthermore, FIG. 2(b) shows a calculation pattern taking into consideration that even a high peak pulse will not damage the laser oscillator when the average laser output is at a low level. According to this embodiment, in the case of pulse operation with a peak output high enough to damage the laser oscillator 1, the average laser output is caused by the pulse ON/OFF ratio.
Even if the pulse becomes smaller than during W operation, the pulse turns ON,
Since the value of the output upper limit Pe is changed at a rate commensurate with the OFF ratio, the laser oscillator 1 can be effectively protected.

Further, in this embodiment, an example was explained in which the output upper limit value Pe is changed by the pulse ON/OFF ratio, but conversely, the output value of the laser output monitor 7 is changed by pulses while keeping the output upper limit value Pe constant. It may be increased at a rate commensurate with the ON/OFF ratio.

[0015]

[Effects of the Invention] As described above, according to the present invention, even when processing a workpiece made of a material with high reflectance such as aluminum or copper, the operating state of the laser oscillation means is automatically adjusted. The laser oscillation stop control is performed based on the reflected light from the workpiece, so even if the reflected light from the workpiece returns to the laser oscillation means, the interlock is effectively activated and the laser oscillation means etc. can be protected.

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing changes in the laser output upper limit value in the embodiment of the present invention shown in FIG. 1;

FIG. 3 is a schematic configuration diagram showing a conventional laser processing device.

FIG. 4 is a configuration block diagram of a control system showing stop control in the laser processing apparatus shown in FIG. 3;

FIG. 5 is a diagram showing changes in the laser output upper limit value Pe in the laser processing apparatus shown in FIG. 3;

[Explanation of symbols]

1...Laser oscillator 2...Laser beam 3...Bender mirror 4...Condensing lens 5...Workpiece 6...Reflected light 7...Laser output monitor 8...Laser output comparator 9...Power supply/control panel 10...Output calculator

Claims (1)

[Claims] 1. Laser oscillation means for emitting laser light by exciting a laser medium; setting means for setting the operating state of the laser oscillation means; In a laser processing apparatus having a light guiding means for guiding the laser beam to a workpiece, and a condensing means for condensing the laser beam, a reflected light detection means for detecting reflected light from the workpiece generated during processing with the laser beam; A laser processing apparatus comprising: a stop control means for controlling the stop of laser oscillation based on a detection value from the reflected light detection means according to the operating state of the laser oscillation means.