JPH02280987A - Method for controlling focus to variation of laser beam scanning length - Google Patents

Abstract

PURPOSE:To execute laser beam machining having good accuracy by shifting a laser light condenser lens while calculating variation of a focus due to variation of scanning distance and controlling the focus of the laser light. CONSTITUTION:In the laser beam machine, by shifting a laser beam irradiating device 2 to X-axis or Y-axis or both axes, the laser beam machining is executed to a material 4 to be machined. Then, while calculating the variation of the focus caused by variation of the scanning distance according to shift of the laser beam irradiating device 2 with a CPU, the laser light condenser lens arranged in the laser beam irradiating device 2 is shifted. By this shift, the focus of the laser light is controlled. By this method, the material to be machined, having large cutting area or long scanning distance, can be machined.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a focus control method for changing the scanning length of a laser beam in a laser processing device.

<Prior art> This kind of conventional laser processing equipment is shown in Figs. 4 to 6.
There were three types of devices as shown in the figure. Among them, the laser processing apparatus shown in FIG. 4 irradiates a workpiece 4 placed on a processing table 3 with a laser beam emitted from a laser beam oscillator 1 through a laser beam irradiation device 2 to process the workpiece. When laser processing the material 4, the processing table 3 is aligned with the X-axis and Y-axis as shown in the figure.
It was carried out by moving it to the axis.

Therefore, in this case, since the laser beam irradiation device N2 was fixed, the focus of the laser beam was always constant, and it was possible to obtain a correct focus with extremely high precision.

Next, the laser processing device shown in FIG. 5 moves the processing table 3 only in the Y-axis direction, and moves the laser beam irradiation device 2 to the frame 5 in the
It is configured to move along the Also the 6th
The laser processing device shown in the figure fixes the processing table 3, moves the laser beam irradiation device 2 along the frame 5 in the X-axis direction, and then moves the frame 5 in the Y-axis direction along the rail 6, and then 3 is configured to process a workpiece 4 placed on top of the workpiece 3.

<Problem to be solved by the invention> However, in the laser processing apparatus shown in FIG. 4 mentioned above, since the laser beam irradiation device 2 is fixed, the focus of the laser beam is kept constant and high accuracy is always achieved. Although a focal point can be obtained, in this case, it is difficult to process a workpiece 4 with a large cutting area or a workpiece 4 with a long scanning distance. Furthermore, since the laser processing apparatuses shown in FIGS. 5 and 6 each move the laser beam irradiation device 2, the focus of the laser beam cannot always be kept correctly and constant, and each time the laser beam irradiation device 2 is moved, There are problems in that the focus gradually shifts, which changes the cutting ability and makes it difficult to perform accurate cutting.

In other words, the laser beam oscillated by the laser beam oscillator 1 causes a diffraction phenomenon of several milliradians due to diffraction, and the irradiated laser beam is actually not parallel but spread out, so the scanning distance in the scanning system is The focal point also changes due to the change in the angle, making it difficult to keep the focal point constant.

The present invention relates to a completely new technique developed in view of these conventional problems.

Means for Solving the Problem> A first method of the present invention is a laser processing device that moves a laser beam irradiation device to the X axis or the Y axis or both to laser process a workpiece. The central processing unit (CPU) calculates the amount of change in the focal point due to the change in scanning distance due to the movement of the laser beam irradiation device, and moves the laser beam condensing lens installed in the laser beam irradiation device. This is a focus control method for variations in the scanning length of a laser beam, characterized by controlling the focus of the laser beam.

The second method of the present invention is to use a laser processing device that moves a laser beam irradiation device in the X axis or Y axis or both to laser process a workpiece, and scans as the laser beam irradiation device moves. A laser characterized in that the focal point of the laser beam is controlled by moving a collimator provided in the laser beam irradiation device while calculating the amount of change in the focal point depending on the change in distance by a central processing unit (CPU). This is a focus control method for variations in the scanning length of light.

Effect> As described above, the first method of the present invention is to use the laser beam provided in the laser beam irradiation device while the CPU calculates the amount of change in the focal point due to the change in the scanning distance due to the movement of the laser beam irradiation device. Since the focus of the laser beam is controlled by moving the condensing lens, the amount of movement of the laser beam irradiation device is always reflected in the movement of the laser beam condensing lens, and the focus of the laser beam can always be kept in the correct state. .

As described above, the second method of the present invention is to move the laser beam irradiation device to the X axis or Y axis or both to move the laser beam irradiation device to laser process the workpiece. By adjusting the lens distance of the collimator installed in the laser beam irradiation device while calculating the amount of change in the focal point due to the change in scanning distance due to movement by the central processing unit (CPU), the incident light that enters the collimator is adjusted. By changing the angle of incidence between the beam and the beam emitted from the collimator, the focus of the laser beam can always be kept in the correct state.

<Example> A laser processing device for implementing the focus control method according to the present invention will be explained with reference to the drawings. In FIGS. 1 and 2, 1 is a laser beam oscillator, which is A device 2 is installed in series, and this laser beam irradiation device 2 is configured to be movable along a frame 5 in the X-axis direction. Further, the frame 5 is configured to be movable along the rail 6 in the Y-axis direction.

A collimator 7 is provided within the laser beam irradiation device 2, which can obtain a parallel beam of light from the laser beam oscillated by the laser beam oscillation device 1 using a plurality of lenses.

As is particularly clear in FIG. 2, a condensing lens 8 is provided within the laser beam irradiation device z, and this condensing lens 8 is movable in the Z-axis direction, that is, in the direction perpendicular to the material 4 to be cut. It is configured. 9 is a hide sensor that detects the height between the tip of the laser beam irradiation device 2 and the material to be cut 4;
Next, 10 is a condensing lens control device, which moves the laser beam condensing lens 8 in the Z-axis direction while the CPU calculates the amount of change in the focal point due to the change in scanning distance due to the movement of the laser beam irradiation device 2. The structure is such that a constant focus can be always obtained on the workpiece 4.

As described above, the first method according to the present invention is configured such that the laser beam condensing lens 8 of the laser beam irradiation device 2 can be moved in the Z-axis direction, so that the laser beam irradiation device 2 in the X-axis or Y-axis direction via the frame 5, the amount of change in focus caused by the movement of the laser beam irradiation device 2 is calculated by the CPU,
Condensing lens control device 10. The laser focusing lens 8 is moved and adjusted in a direction perpendicular to the workpiece 4 via a pulse oscillator (PG) and a motor (M), thereby making it possible to always obtain a constant and good focus.

In the above embodiment, a constant good focus was always obtained by moving the laser beam condensing lens 8, but as shown in FIGS. 1 and 3, this laser beam condensing lens 8 Keep it fixed.

Alternatively, a good focus can be obtained by moving the collimator 7.

That is, in the second method according to the present invention, when the laser beam irradiation device 2 is moved in the X-axis or Y-axis direction via the frame 5 during laser processing, the laser beam irradiation device 2 is moved in the X-axis or Y-axis direction. ! While the CPU calculates the amount of change in the focal point caused by the movement of the collimator 7, the lens of the collimator 7 is moved via the collimator control device 11, the pulse oscillator, and the motor to change and adjust the angle of incidence. By changing the direction of the bundle, it is possible to always obtain a constant good focus on the workpiece 4.

<Effects of the Invention> As described above, the first and second methods according to the present invention emit a laser beam while constantly calculating, via the CPU, the amount of change in the focal point due to the change in scanning distance caused by the movement of the laser beam irradiation device. By moving the laser beam condensing lens or collimator installed in the irradiation device, the focus of the laser beam can always be kept in the correct state, making it possible to perform extremely precise laser processing on the workpiece. Furthermore, in the method of the present invention, the laser beam irradiation device can be moved widely, so it is possible to process workpieces with large cutting areas or long scanning distances, and the overall operation is simple. It has the characteristics of being simple.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a device for carrying out the method according to the present invention, FIGS. 2 and 3 are circuit diagrams for controlling the device, and FIGS. 4 to 6 are conventional examples, respectively. FIG. 1 is a laser beam oscillator, and 2 is a laser beam irradiation device. 3 is a processing table, 4 is a workpiece, 5 is a bridge, 6 is a rail, 7
8 is a collimator, 8 is a laser beam condensing lens, 9 is a hide sensor, 10 is a condensing lens control device, and 11 is a collimator control device. Patent applicant Koike Sanso Kogyo Co., Ltd. Representative Patent attorney Shukichi Nakagawa Figure 1 Figure 6 Figure 4 Figure 5

Claims (2)

[Claims] (1) In a laser processing device that moves the laser beam irradiation device in the X-axis, Y-axis, or both to laser-process the workpiece, the focus changes due to a change in the scanning distance due to the movement of the laser beam irradiation device. The scanning length of the laser beam is controlled by moving a laser beam condensing lens provided in the laser beam irradiation device while calculating the amount by a central processing unit (CPU). Focus control method for fluctuations. (2) In a laser processing device that moves the laser beam irradiation device in the X-axis, Y-axis, or both to laser-process the workpiece, the focus changes due to a change in the scanning distance due to the movement of the laser beam irradiation device. Focus control for fluctuations in the scanning length of a laser beam, characterized in that the focus of the laser beam is controlled by moving a collimator provided in a laser beam irradiation device while calculating the amount by a central processing unit (CPU). Method.