JPH0716779A - Focusing device for laser beam machine - Google Patents

Abstract

PURPOSE:To provide the focusing device for a laser beam machine in order to automatically focus a laser beam at the time of laser beam processing. CONSTITUTION:This focusing device consists of a laser oscillator 1, an axis controller 5 for moving a lens 4 for condensing a laser beam 2, an optical sensor 8 for indirectly reading the energy density of the laser beam when the laser is impulsively outputted to a work 9, a storage section 7 for simultaneously reading and storing the data from the optical sensor 8 and the coordinates of this time and an arithmetic section 10 for computing the distribution of the data from the sensor indicating the energy density of the laser beam. The lens 4 is moved and the energy density data of the laser beam for the coordinates of this time are successively stored into the storage section 7 and the relation between the max. point of the density of the laser beam and the laser position is determined from this distribution, by which the laser beam is automatically focused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus adjusting device for a laser processing machine for automatically adjusting the focus of laser light when performing laser processing.

[0002]

2. Description of the Related Art Conventionally, when performing laser processing, not only when a lens having a different focal length is replaced, but also when a lens having the same focal length is replaced, a laser beam defocus occurs. Further, when the lens is removed and the lens is cleaned, defocusing of the laser light occurs depending on the mounting method, even though the same lens is reattached. Therefore, it is necessary to focus the laser beam every time the above-mentioned work is performed, and the adjustment is performed manually by the intuition and experience of a skilled person.

A conventional method of manually adjusting the focus with a blue frame will be described below. First, the thickness is 2-3 so that the laser light is vertically irradiated.
Install mm mm stainless steel.

The laser oscillator is set to the pulse oscillation mode, and the laser oscillation conditions are set so that the ON time of one pulse is short and the energy density is high. Nitrogen gas is selected as an assist gas so that the stainless steel does not cause an oxidation reaction during laser irradiation for focus adjustment.

The laser oscillator is oscillated to open the shutter. The axis for moving the lens is moved in the direction in which the lens approaches the stainless steel by moving the handle or the like.

At this time, the color of piercing is observed. Stop the movement of the handle when the color of the spark changes from yellow to blue and read the coordinates at that time. Repeat the above procedure several times to obtain the average value of the coordinates.

Next, bring the lens close to stainless steel,
Handle moves the lens away from stainless steel. Again, when the color of the piercing spark changes from yellow to blue, the handle movement is stopped and the coordinates are stored.

The work of (1) is repeated several times to obtain the average value of the coordinates, and the intermediate point between the result obtained in and the average coordinate value is obtained and the coordinates are set as the laser focus position (coordinates).

[0009]

As described above, in the conventional focus adjustment, when the laser beam is focused by a laser, a skilled worker manually focuses the laser beam. Since the speed at which the handle is moved and the criteria for determining the change in the color of light differ depending on the worker, it is difficult to finely adjust the focus, and even a beginner cannot focus immediately.

The present invention solves the above-mentioned conventional problems and provides a focus adjustment device for a laser processing machine for automating focusing of laser light so that anyone can easily perform laser processing. The purpose is to do.

[0011]

In order to achieve the above object, a focus adjusting device for a laser beam machine according to the present invention comprises a laser oscillator having a function of outputting a pulse of laser light and a lens for condensing the laser light. An axis controller that moves, a sensor that indirectly reads the energy density of the laser light when the laser outputs a pulse to the workpiece, a storage unit that stores the data from the sensor and the coordinates at that time, and stores the data simultaneously. The calculation unit calculates the distribution of data from the sensor that represents the energy density of the laser light, moves the lens, and sequentially stores the energy density data of the laser light in the storage unit with respect to the coordinates at that time. A structure is provided which has means for automatically adjusting the focus of the laser light by obtaining the relationship between the maximum point of the density of the laser light and the lens position from the distribution.

[0012]

In the above structure of the present invention, the relationship data of the lens position and the light spectrum distribution, the piercing sound distribution, or the vibration distribution is collected, and the focus position of the laser light is obtained based on the data. .

[0013]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram of a focus adjusting device for a laser processing machine according to an embodiment of the present invention. As shown, the laser beam 2 output from the laser oscillator 1 is guided to the laser torch 3 and focused on the work 9 by the condenser lens 4. The laser light 2 output from the laser oscillator 1 is almost parallel light, and the focus of the laser light 2 can be adjusted by moving the laser torch 3 up and down. The movement of the laser torch 3 is controlled by the lens movement axis controller 5. Specifically, the lens movement axis controller 5
Is for rotating a motor 6 for moving the laser torch 2 up and down, and outputs coordinate position data uniquely determined by the rotation of the motor 6 to the storage unit 7. Optical sensor 8
Detects the light condition of piercing when the laser beam 2 is applied to the work 9. Here, the intensity of light energy is read in terms of wavelength. The shorter the wavelength, the higher the energy density. The output from the optical sensor 8 is input to and stored in the storage unit 7 together with the coordinate position at that time.

The procedure for reading data is shown below. First, make sure that the laser torch 3 gradually approaches the work 9.
The laser torch 3 is moved using the lens movement axis controller 5. The coordinate position from the lens movement axis controller 5 and the data from the optical sensor 8 are stored in the storage unit 7.
The stored data are as shown in Table 1.

[0015]

[Table 1] When this is expressed in a graph, the curve becomes as shown in FIG. 2, and the peak of the mountain is obtained from this value. The coordinate position is defined as the first focus position.

Next, the laser torch 3 is moved so that the laser torch 3 gradually moves away from the position close to the work 9, and the coordinates from the lens controller 5 and the output from the optical sensor 8 are graphed, and the second focal point from the top of the peak. Find the position. The average of the first and second focus positions is calculated and used as the focus position. The calculation unit 10 uses the optical sensor 8 corresponding to the coordinate position.
The calculation of the focal position is performed using the output from the.

The above processing is an automation of the focusing method which has been performed by a person skilled in the art of processing in the completely same procedure. Therefore, the setting of the assist gas and the like are the same as those manually performed.

Although the wavelength of light has been used as the energy density of the laser in the above description, the focal position can be obtained by the intensity of the reflected light in the same device. FIG. 3 shows a second embodiment of the invention, which uses a sound sensor 11 instead of the optical sensor 8. In this configuration, the sound sensor 11 picks up the sound when the light hits the work 9 and instantaneously evaporates the surface of the work 9, and the focus position is obtained from the distribution of the loudness of the sound according to the coordinate position. Table 2 shows the data stored in the storage unit 7, and its graph is as shown in FIG.

[0019]

[Table 2] FIG. 5 shows a third embodiment of the present invention, which uses a vibration sensor 12 instead of an optical sensor. In this configuration, the vibration sensor 12 picks up the vibration when the light hits the work 9 and instantaneously evaporates the surface of the work 9.
The focus position is obtained from the distribution of the magnitude of the vibration depending on the coordinate position. Table 3 shows the data stored in the storage unit 7, and the graph is as shown in FIG.

[0020]

[Table 3]

[0021]

As is apparent from the above description of the embodiments, the present invention is an optical sensor and a sound sensor for reading the energy density of laser light in a laser processing machine equipped with a shaft for moving a lens and capable of pulse oscillation. Or, a vibration sensor is installed and the calculation function of the area and distribution for storing the coordinate data and the data from the sensor at that time is provided, so that the laser light focus adjustment can be automated, and it is not necessary for an operator skilled in laser processing. Both can be easily focused.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a focus adjusting device for a laser processing machine according to a first embodiment of the present invention.

[Fig. 2] Distance in the focus adjusting device for the laser processing machine-
Graph of output data from optical sensor

FIG. 3 is a configuration diagram of a focus adjusting device for a laser processing machine according to a second embodiment of the present invention.

FIG. 4 is a distance in the focus adjusting device for the laser processing machine-
Graph of output data from sound sensor

FIG. 5 is a configuration diagram of a focus adjusting device for a laser processing machine according to a third embodiment of the present invention.

FIG. 6 is a distance in the focus adjusting device for the laser beam machine-
Graph of output data from vibration sensor

[Explanation of symbols]

 1 Laser Oscillator 2 Laser Light 3 Laser Torch 4 Condensing Lens 5 Lens Moving Axis Controller 6 Motor 7 Memory 8 Optical Sensor 9 Work 10 Computing Unit 11 Sound Sensor 12 Vibration Sensor

Claims (4)

[Claims] 1. A laser oscillator having a function of outputting a laser beam as a pulse, an axis controller for moving a lens for focusing the laser beam, and an energy density of the laser beam when the laser is pulsed to a work. A sensor that reads indirectly, a storage unit that stores and simultaneously reads the data from the sensor and the coordinates at that time, and a calculation unit that calculates the distribution of the data from the sensor that represents the energy density of the laser light. Move the laser beam, and store the energy density data of the laser light in the storage unit in sequence with respect to the coordinates at that time.From the distribution, find the relationship between the maximum point of the laser light density and the lens position, and focus the laser light Focus adjusting device for a laser processing machine having means for automatically adjusting. 2. The focus adjusting device for a laser processing machine according to claim 1, wherein an optical sensor is used as a laser beam energy density sensor. 3. The focus adjusting device for a laser processing machine according to claim 1, wherein a sound sensor is used as the energy density sensor of the laser beam. 4. The focus adjusting device for a laser processing machine according to claim 1, wherein a vibration sensor is used as an energy density sensor for the laser beam.