JPH05245676A - Laser beam machine - Google Patents

Abstract

PURPOSE:To improve the accuracy of laser beam machining by always fixing the diameter of a spot of laser beam with which a work is irradiated irrespective of change of an optical path by the movement of a laser beam machining head. CONSTITUTION:This is a laser beam machine provided with a laser beam machining head 1 which can move freely at least in one axial direction, a lens 23 which can adjust the diameter of the laser beam LB is provided so that it can move in the direction of the optical axis in an optical path of the laser beam LB from a laser beam oscillator to a laser beam machining head 1, and a lens position controller 37 is provided to control the position of at least one of the lens 23 or a condenser lens 7 built in the laser beam machining head 1 corresponding to the optical path length so that the spot diameter of the laser beam LB with which the work W is irradiated is always nearly fixed irrespective of change of the optical path length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus in which a laser processing head can move in at least one axis direction, and more specifically, there are cases where the optical path length of a laser beam changes due to the movement of the laser processing head. In particular, the present invention relates to a laser processing apparatus capable of keeping the spot diameter of laser light applied to a work almost always constant.

[0002]

2. Description of the Related Art In a laser processing apparatus in which a laser processing head moves, the distance from a laser oscillator to a condenser lens installed in the laser processing head changes greatly, so that the divergence angle of laser light causes It is known that the diameter of laser light changes significantly at the position of the condenser lens. The focus position changes due to the change in the diameter of the laser light, and the spot diameter of the laser light irradiated to a predetermined position on the work changes, which affects the processing accuracy.

Therefore, conventionally, for example, Japanese Patent Publication No. 1-550
As disclosed in Japanese Patent Publication No. 76-76, a special mechanism may be adopted so that the optical path length from the laser oscillator to the laser processing head is always constant even when the laser processing head moves. ..

[0004]

In a structure in which the optical path length is always kept substantially constant irrespective of the moving position of the laser processing head, a reversing device for reversing and bending the laser beam is specially provided. The invertor needs to be moved relative to the movement of the laser processing head.

Therefore, the size of the structure is increased due to the provision of the reversing device, and a mechanism or a control device for performing the related movement is required, which causes a problem that the overall structure is complicated.

[0006]

In view of the above-mentioned problems, the present invention provides a laser processing apparatus provided with a laser processing head movably in at least one axial direction, and the laser processing head is changed from the laser oscillator to the laser processing head. A lens capable of adjusting the diameter of the laser beam is provided movably in the optical path of the laser beam to reach, and the spot diameter of the laser beam irradiated to the work is always almost constant regardless of the change of the optical path length. Therefore, a lens position control device for controlling the position of at least one of the lens and the condenser lens installed in the laser processing head according to the optical path length is provided.

[0007]

With the above structure, the diameter of the laser beam at the position of the condenser lens installed in the laser processing head is always kept substantially constant by, for example, adjusting the position of the lens provided in the optical path of the laser beam in the optical axis direction. Therefore, the spot diameter of the laser beam applied to the work can be kept substantially constant.

[0008]

EXAMPLE A laser processing apparatus has a laser processing head X
A type in which the work table is movable in the Y-axis direction and a type in which the laser processing head is movable in the X-axis and Y-axis directions, and a laser processing head is X, Y, Z. There is a type such that it can be moved in the three axial directions, and the apparatus according to the embodiments described below can be used in any of the above types. Since the configuration for moving the laser processing head in the X-, Y-, and Z-axis directions is well known,
In the following description, the structure for moving the laser processing head is omitted.

Now, referring to FIG. 1, a nozzle 5 for ejecting an assist gas to a work W is provided below the processing head body 3 of the laser processing head 1 which is movable in at least one axis direction. A lens holder 9 provided with a condenser lens 7 is provided in the processing head body 3, and the lens holder 9 is a lower end of an up-down adjustment cylinder 11 supported by the processing head body 3 so as to be vertically adjustable. It is properly attached to the section.

A nut member 1 rotatably supported by the processing head body 3 is provided on the upper and lower adjusting cylinders 11.
A worm 17 rotatably supported by the machining head main body 3 meshes with a worm gear 15 that is integrally provided on the outer peripheral surface of the nut member 13 and is screwed so as to be vertically movable. There is. And the worm 17
Are connected to the servomotor M1 as appropriate.

Therefore, the worm gear 15 can be rotated via the worm 17 by appropriately controlling the rotation of the servo motor M1, and the vertical adjustment cylinder 11 and the condenser lens 7 can be rotated.
Can be adjusted up and down.

At a position above the laser processing head 1,
Laser light LB emitted from a laser oscillator (not shown)
A mirror device 21 having a bend mirror 19 for reflecting the light toward the condenser lens 7 is arranged.

In this embodiment, a lens 23 (convex lens in this embodiment) capable of adjusting the diameter of the laser beam LB is axially movable along the optical path from the laser oscillator to the mirror device 21. It is provided. More specifically, the lens holding member 29 holding the lens 23 is provided in the middle of the protection tube 27 that protects the optical path of the laser beam LB.
Are provided so as to be movable in the optical axis direction. Then, in order to automatically adjust the position of the lens holding member 29 in the optical axis direction, a servo motor M2 for rotationally driving a ball screw 33 screwed with a nut member 31 integrally provided on the lens holding member 29 is provided. It is provided.

Therefore, the position of the lens holding member 29 can be adjusted in the optical axis direction by appropriately controlling and driving the servo motor M2. Therefore, the laser light LB is generated by the lens 23 held by the lens holding member 29.
The diameter of the laser beam LB at the position of the condenser lens 7 can be constantly controlled to be constant.

A control device 35 is provided to control the servomotors M1 and M2, and the control device 3 is provided.
5 is provided with a lens position control device 37 and an optical path length correction value data table 39.

The optical path length correction value data table 39 is
The relationship between the change in the distance (optical path length) from the laser oscillator to the condenser lens 7 in the laser processing head 1 and the correction value due to the change in the focus position is stored in advance as data.

The lens position control device 37 calculates the optical path length from the laser oscillator to the condenser lens 7 based on the axial movement data from the NC device 41 which controls the laser processing device, and based on this calculation result. An appropriate correction value is retrieved from the optical path length correction value data table 39, and the servomotors M1 and M2 are appropriately controlled based on this correction value.

In the above construction, the laser processing head 1 in the laser processing apparatus is moved in at least one of the X, Y and Z axes to move the work W on the work table.
When laser processing is performed on, the optical path length from the laser oscillator to the condenser lens 7 provided in the laser processing head 1 changes. This change in the optical path length can be calculated based on a detection value by a position detector (not shown) provided on the X, Y, and Z axes, but in the present embodiment, the X, Y, and Z axes are calculated. The axial movement data corresponding to the position control data pulse-distributed to each servo motor (not shown) is input from the NC device 41 to the lens position control device 37, and the optical path length is calculated based on this axial movement data.

Then, an appropriate correction value corresponding to the optical path length calculated by the lens position control device 37 is retrieved from the optical path length correction value data table 39, and the servo motor M is searched.
At least one of 1 and M2 is controlled.

When the servomotor M1 is controlled, the condenser lens 7 is moved up and down to adjust the focus position. Further, when the servomotor M2 is controlled, the diameter of the laser light LB from the laser oscillator to the condenser lens 7 is adjusted, and the diameter of the laser light LB at the position of the condenser lens 7 is always substantially constant. Controlled to be.

It is also possible to control the servomotors M1 and M2 at the same time. In this case, compared with the case where only one servomotor is controlled, each servomotor M is controlled.
The control amount of 1 and M2 is reduced.

As will be understood, in this embodiment, the condenser lens 7 provided in the laser processing head 1 or the lens provided in the optical path from the laser oscillator to the condenser lens 7 of the laser processing head 1 is used. Since the position of at least one of the lenses 23 is adjusted in the optical axis direction, when adjusting the positions of both the condenser lens 7 and the lens 23, the position adjustment amount of both lenses 7 and 23 may be small.
This makes it possible to quickly respond to changes in the optical path length of the laser light LB.

When only the lens 23 provided in the optical path is positionally adjusted in the optical axis direction, the position adjustment of the condenser lens 7 provided in the laser processing head 1 is unnecessary. You can In this case, it can be easily implemented in a laser processing apparatus including a conventional general laser processing head.

[0024]

As will be understood from the above description of the embodiments, according to the present invention, the light focusing provided in the laser processing head 1 corresponding to the change of the optical path length due to the movement of the laser processing head 1. The position of the lens 7 is adjusted to adjust the focal position, or the position of the lens 23 provided in the optical path is adjusted in response to the change in the optical path length, and the diameter of the laser beam at the position of the condenser lens 7 is adjusted. Can be adjusted almost constantly.

That is, according to the present invention, the spot diameter of the laser beam applied to the workpiece can be kept substantially constant regardless of the change in the optical path length due to the movement of the laser processing head, and the laser processing can be performed with a relatively simple structure. The accuracy can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Laser Processing Head LB Laser Light 23 Lens 7 Condenser Lens 37 Lens Position Control Device

Claims (1)

[Claims] 1. A laser processing apparatus comprising a laser processing head movably in at least one axis direction, and the diameter of the laser beam can be adjusted in the optical path of the laser beam from the laser oscillator to the laser processing head. A lens is provided so as to be movable in the optical axis direction, and a condenser lens installed in the lens or the laser processing head so that the spot diameter of the laser beam irradiated to the work is always almost constant regardless of the change of the optical path length. A laser processing apparatus comprising: a lens position control device that controls the position of at least one of the lenses according to the optical path length.