JP2002035972A - Laser beam cutting machine for extra-thin metal plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam cutting machine for an extra-thin metal plate which suppresses positional fluctuation of a convergence point by assist gas with simple structure. SOLUTION: In this device where an extra-thin metal plate processing object W is cut and processed by irradiating a laser beam thereon from a nozzle 6 of a machining head 3 having a condenser lens 4 and injecting assist gas AG, a pushing device 7 having a shape cut out flat at the upper part of a sphere and a cavity inside thereof is fixedly arranged right under the nozzle 6. A wavy state at the time of cutting and processing is eliminated by partially pressing and contacting the periphery of a convergence point A from the back surface of the processing object W with the pushing device 7, thereby, distance from the condenser lens 4 to a surface of the processing object can be fixed at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser cutting process, and more particularly to an apparatus for performing a fine cutting process on an ultra-thin metal plate using a laser.

[0002]

2. Description of the Related Art For example, in processing a metal mask used for manufacturing a mounting board, an extremely thin metal plate (0.1 to 0.5 m) is used.
m) is required to be finely cut with high precision and high quality by a laser. In such processing, it is necessary to condense the laser beam as small as possible so that the focal position does not fluctuate, and to inject the assist gas to the processing portion effectively.

However, cutting by laser light is performed by instantaneously and locally inputting heat to a workpiece and melting it, and removing it by an assist gas pressure injected from the laser beam coaxial. In addition, there is a problem that local bending (referred to as a waving phenomenon) occurs in the processing portion due to the injection pressure of the assist gas, and the focal point of the laser beam fluctuates.

Conventionally, as a solution to this problem, there is, for example, Japanese Patent Application Laid-Open No. 10-328867. This is shown in FIG.
As shown in FIG. 2, the workpiece W is tensioned and held on the workpiece base 24, a bellows is provided between the processing head 25 and the nozzle 6, and an upper pressing member 20 integrated with the nozzle 6,
The work W is sandwiched from above and below by the high lubrication plate 22 of the lower fixed surface plate 21 fixedly arranged at the lower part of the work,
The workpiece W is constrained in a narrow area near the laser focus point A.

[0005] For the purpose of focusing the laser beam, contact type displacement meters 32 are provided on both left and right sides of the processing head 25, and these are connected by a connecting plate 31. The upper holding member 20 is fixed to the connection plate 31. In FIG. 3, 4
Is a condenser lens, 27 is an X-axis drive axis, 28 is a Y-axis drive axis, 26 stores detection information of the contact type displacement meter 32, and operates the X-axis drive axis 27 and the Y-axis drive axis 28 This is the NC control device to be operated.

[0006]

In the above-mentioned laser cutting apparatus, the vicinity of the laser beam processing position of the workpiece is sandwiched between the upper holding member 20 and the lower fixed surface plate 21. However, the bending of the workpiece due to the pressure of the assist gas can be suppressed.

However, in the case of this method, the parallelism of the three elements of the upper holding member 20, the lower fixed platen 21, and the work table 24 attached to the processing head 25 must be high. If the degree of parallelism is poor, the workpiece is forcibly pressed against the lower fixed platen 21, so that the portion is easily deformed locally. In addition, since the workpiece slides between the upper holding member 20 and the lower fixed platen 21, the upper holding member 20 must always be pressed against the lower fixed platen 21 by the same pressure. Must be adjusted by a contact type displacement meter or the like. Therefore, not only is the device complicated and large, but also it takes time to mount a workpiece in the cutting process.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser cutting apparatus for an ultra-thin metal plate, which has a simple configuration and suppresses a change in the position of a focal point due to an assist gas.

[0009]

In order to achieve the above object, the present invention employs the following means. That is, in a laser cutting apparatus for an ultra-thin metal plate that cuts by irradiating a laser beam from a nozzle of a processing head equipped with a condensing lens and injecting an assist gas, the upper part of a sphere is formed in a planar shape immediately below the nozzle. A pressing tool with a hollow inside is fixedly arranged in the shape cut out, and the workpiece is pressed locally from the back surface around the condensing point with the pressing tool, and the condensing lens is moved to the surface of the processing object. The feature is that the distance to is fixed.

According to the present invention, the workpiece is restrained in a narrow range near the focal point by pushing up the periphery of the focal point with a pressing tool having a shape obtained by cutting the upper part of the sphere in a plane from the back surface of the workpiece. Then, the position of the condensing point is kept constant on the workpiece. Here, the meaning of "a shape obtained by cutting the top of the sphere into a plane" does not mean an exact sphere,
This includes those that are curved in the vertical cross section.

In the present invention, the workpiece is pushed up from the back surface by the pressing tool so as to oppose the pressure of the assist gas injected from the nozzle, so that the workpiece undulates around the processing portion, ie, condenses. It acts to suppress the fluctuation of the position of the point. The material of the pressing tool should be slightly softer than the material of the workpiece (for example, aluminum).
It is good not to damage the workpiece.

It is desirable that the workpiece is pulled and gripped. In addition, even if the tensile force is slightly weak and not uniform, when viewed only around the laser processing part, during processing, the periphery of the focal point is pushed up by the pressing tool, which is the same as the case where the uniform tensile force is always applied. State can be maintained.

[0013] The cavity at the center of the pressing tool is preferably connected to a suction device so that the assist gas and the melt can be sucked.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a laser cutting apparatus for an ultra-thin metal plate according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, the processing head 3 is provided with a condensing lens 4 for condensing a laser beam L incident from the laser oscillator 1 via the reflection mirror 2, and a nozzle 6 is provided at a lower end. . Further, a protective glass 5 for protecting the condenser lens 4 from the injection pressure of the assist gas AG is provided below the condenser lens 4.

The working head 3 is configured to be movable in the Z-axis direction, and the nozzle 6 is provided with an assist gas AG.
Is set to a diameter (1.0 mm or less) so as to intensively flow into a processing portion of the workpiece W. Also, assist gas A
G is at a higher pressure than in normal laser processing.

The workpiece W is gripped by a gripping device 8 provided on an XY stage 9 movable in the X and Y directions.
The control device 10 is controlled based on cutting data set in advance, and is configured to move according to a predetermined shape. In addition, 12 is an X-axis driving device, 13 is Y
It is a shaft drive.

Immediately below the processing head 3, a pressing tool 7 is fixedly arranged to face the nozzle 6. The holding member 7a is made of an aluminum material and a screw 7f is attached to the fixed receiving member 7b.
It is mounted so that it can be adjusted vertically. And
As shown in FIG. 2, the head of the pressing member 7a has a shape in which a hemispherical upper portion is cut off in a horizontal plane, and the upper surface has a diameter B
The hole is clear. The end 7d of this hole is formed in an arc-shaped cross section.

The inside of the holding member 7a is a cavity 7c, and a hole 7e communicating with the suction device 11 is provided in the lower part. Next, the operation of the laser cutting apparatus for an ultra-thin metal plate configured as described above will be described.

In cutting the workpiece W,
The laser beam L emitted from the laser oscillator 1 is previously focused by the condenser lens 4 via the reflection mirror 2 so that the focal point A comes to the surface of the workpiece W. Then, according to the thickness of the workpiece W, the height of the pressing metal 7a of the pressing tool 7 is adjusted so that the surface of the workpiece W is at the converging point A. Note that the focal point A is set at a position slightly higher than the surface when the workpiece W is gripped by the gripping device 8.

In this adjustment, since the condenser lens 4 and the nozzle 6 are fixedly arranged on the processing head 3, there is no change in the focal point A, and there is no change in the distance between the nozzle and the workpiece.
It only needs to be performed once at the beginning and is unnecessary thereafter. Processing head 3
Is raised, the workpiece W is attached to the gripping device 8 with a slight tension, and the processing head 3 is lowered.

The position for descending and stopping is a position set in advance as described above, and is instructed by the NC control device 10 to stop automatically. At the time of cutting, the workpiece W is locally and instantaneously melted by the heat input of the laser beam, and the workpiece W is controlled by the NC controller 10 based on preset cutting data and moves. At this time, the assist gas AG is jetted at a high pressure from the nozzle 6 arranged coaxially with the laser beam L toward the workpiece W, and the pressing tool that is in a negative pressure state with the molten material. The air is sucked into the suction device 11 from the cavity 7c through the hole 7e.

At this time, the workpiece W is pushed up in an annular shape at the end 7d of the hole, which is the upper end of the holding member 7a of the holding member 7, and in the local region pushed up, an appropriate amount is obtained. Since it is in a state where a tensile force is applied,
The focal point A is always held on the surface of the workpiece W.

Note that, depending on the pressure of the assist gas ejected from the nozzle, the light-converging point A may be slightly displaced. No significant change in the focal point A occurs. Further, since the cross-section of the contact portion of the pressing metal 7a with the workpiece W has an arc shape, the pushed-up portion is not plastically deformed, and the flatness of the product at the time of completion of cutting is not impaired. Furthermore, the knife edge shape of the end portion 7d is also effective in removing dross that tends to adhere to the back surface of the workpiece W.

[0024]

As described above, in the laser cutting apparatus of the present invention, a pressing tool having a hollow inside in a shape obtained by cutting the upper part of a sphere into a flat shape immediately below a nozzle is fixedly arranged. The workpiece is pressed locally from the back side around the focal point with the tool to keep the distance from the condenser lens to the surface of the workpiece constant. Can be kept constant during the cutting process, and as a result, a stable cutting performance without variation in the cutting width can be obtained. In addition, there is no need for conventional adjustment using a contact displacement meter or the like when setting a work piece, and there is an effect that a setup time is not required for a variety of plate thicknesses and the structure is simple, so that it is easy to handle. .

[Brief description of the drawings]

FIG. 1 is a front view showing the overall configuration of an embodiment of a laser cutting machine for ultra-thin metal plates of the present invention.

FIG. 2 is a detailed view of the pressing tool 7;

FIG. 3 is a front view showing the overall configuration of one embodiment of a conventional laser cutting apparatus for an ultrathin metal plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laser oscillator 2 ... Reflection mirror 3 ... Processing head 4 ... Condensing lens 5 ... Protective glass 6 ... Nozzle 7 ... Pressing tool 7a ... Pressing tool 7b ... Receiving 7c ... Cavity 7d ... End 7e ... Hole 7f ... Screw 8 ... Grip device 9 ... XY stage 10 ... NC control device 11 ... Suction device 20 ... Upper holding member 21 ... Lower fixed platen 22 ... High lubricity plate 24 ... Workpiece table 25 ... Working head 26 ... NC control device 27 ... X-axis drive base 28 ... Y-axis drive base 30 ... Bellows L ... Laser light A ... Condensing point W ... Workpiece AG ... Assist gas

Claims (1)

[Claims] 1. A laser cutting apparatus for an ultra-thin metal plate, which irradiates a laser beam from a nozzle of a processing head provided with a condensing lens and injects an assist gas to perform a cutting process. A pressing tool with a cavity inside is cut and fixed in a planar shape, and the workpiece is pressed locally from the back surface around the light collecting point by the pressing tool, so that it is covered from the condensing lens. A laser cutting apparatus for an ultra-thin metal plate, wherein a distance to a workpiece surface is made constant.