JPH0292485A - Laser beam machine and method for adjusting beam axis thereof - Google Patents

Abstract

PURPOSE:To obtain the laser beam machine having good cutting accuracy by providing a mirror tilting mechanism to the final-stage mirror of the light guide tube in the laser beam machine provided with the rotary multijoint type light guide device. CONSTITUTION:A laser beam is shot from a nozzle 9 through the light guide tube 2. The beam axis thereof is aligned to the nozzle axis by changing the angle of a mirror by the mirror tilting mechanism 20 if the beam axis has the misalignment of a permissible value or above from the nozzle axis. The mirror 13 is tilted along a spherical body 13a by the cooperative movement of pulling means 22, 23 of the mirror tilting mechanism. Since the mirror is connected by the pulling means 22a, 23a, the three-dimensional displacement of the mirror is free and since the backlash is removed by energizing means 24, 25, the mirror 13 does not clatter. The change rate of the adjustment of the pulling means 22, 23 is measured by a rotary encoder 22f and is memorized in a memory means as the correction value at a point P1. The laser beam machine having good cutting accuracy is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a beam angle adjustment device for a rotary articulated light guide tube in a laser processing machine.

(Prior Art) A laser processing device that performs cutting and welding by three-dimensionally controlling the position of a nozzle of the laser processing device using an articulated industrial robot has been put into practical use.

An example of this laser processing apparatus will be explained based on FIG. 4.

An articulated robot 101 is arranged beside a workpiece mounting table 100 on which a workpiece W is placed.
0 and the robot 101 on the foundation.
02 is erected.

A laser beam transmitter 103 is placed on this pedestal 102, and a light guide tube 104 that guides the laser beam from this laser beam transmitter branches, and its tip is connected to the robot 101.
Laser nozzle 105 attached to the tip of arm 101a of
Connect to.

Since this nozzle 105 is displaced three-dimensionally by the action of the robot 101, the light guide tube 104 is of a multi-joint type in order to follow the displacement.

That is, the light guide tube 104 has a straight tube section 104a and a bend section 104.
b, to freely rotate between the bent part 104b and the straight pipe part 104a, and
Each of the beams is equipped with a mirror that reflects the beam.

The laser beam reaches the nozzle 105 after being sequentially reversed by a plurality of mirrors.

(Problem N to be solved by the invention) In FIG. 4, the nozzle 105 is
When the laser beam moves from point P1 to point P2, the laser beam axis after being repeatedly reflected is biased with respect to the nozzle axis.

The reason for this is that the light guide tube 104 changes its shape into a plurality of shapes while rotating at the bend portion xo4b, and the straight tube portion
The reason is that the amount of deflection of 4a changes.

In particular, the straight pipe portions 104a... are slightly bent, and the amount of deflection increases as the straight pipe portions 104a... approach the horizontal position. The deflection of the straight pipe section 104a affects the adjacent bend section,
The mirror fixed to the bend section is also slightly displaced.

If an attempt is made to increase the bending rigidity of the light guide tube 104 in order to eliminate this displacement, its own weight will increase and the burden on the robot will increase.

Therefore, in conventional laser processing devices, the laser beam axis is shifted or tilted with respect to the nozzle axis, and as a result, it is difficult to improve cutting accuracy.

(Means for Solving the Problems) In order to solve the above problems, the present invention attaches a mirror tilting mechanism to the final mirror of a rotary articulated light guide tube of a laser processing device.

(Operation) The present invention aligns the beam axis with the nozzle axis by tilting the final mirror of the light guide tube.

The above-mentioned tilting movement is characterized in that it is performed for each teaching point.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 shows a laser processing apparatus according to the present invention, FIG. 2 is a sectional view of a mirror tilting mechanism according to the present invention, and FIG. 3 is a view taken along the line A--A in FIG. 2.

As shown in FIG. 1, the light guide tube 2 of the laser processing apparatus 1 according to the present invention includes a straight tube section 3, bend sections 4 and 5 degrees 6, a housing 8 that accommodates a lens 7 for narrowing down the laser beam, and a tapered conical shape. It consists of a shaped nozzle 9.

In this embodiment, the housing 8 is the arm 101 of the robot.
The position of the nozzle 9 is controlled via the housing 8.

Mirrors 11 to 13 are installed in the bend parts 4 to 6, respectively.
The laser beam is sequentially reflected by these mirrors 11 to 13 and guided to the nozzle 9.

Among the mirrors 11 to 13, the mirror 13 closest to the nozzle 9 (hereinafter referred to as the final stage mirror) is provided with a mirror tilting mechanism which will be described in detail below.

As shown in FIG. 2, the mirror tilting mechanism 20 includes a lid body 21 that is bolted to the final stage bend portion 6, and a ball with a ball that passes through the approximate center of this lid body 21 and is fastened and fixed with a nut 21a. A bolt 21b and a spherical seat 13a drilled in the center of the back of the mirror 13 to fit into the ball of the bolt.
, two sets of tensioning means 22.23 that engage with the back surface of the mirror at a distance from this spherical seat 13a, and biasing means 24.25 that apply a tension force to these tensioning means 22.23.
It consists of

The tensioning means 22 includes a ball joint 22a that enables three-dimensional change, a thrust shaft 22b that engages one end with the ball joint 22a, a gear 22c that is screwed into the thrust shaft 22b, and the gear 22c. A drive gear 22d that meshes with the gear, and a reducer 22e that rotates this gear.
and a housing 22 that supports a motor 22g with a rotary encoder 22f, the gear 22c1 motor 22g, etc.
It consists of h.

With this configuration, the motor 22g rotates the gear 22c via the reduction gear 22e and the drive gear 22d, and the gear 22c raises or lowers the thrust shaft 22b.

Since the gear 22c is positioned by bearings 22i, 22i, it is rotatable but does not move vertically.

The other tensioning means 23 has the same mechanism as the tensioning means 22 described above, and is separated from the tensioning means 23 by 90 degrees as shown in FIG. 3, which is a view taken along arrow A-A in FIG. placed in position.

Further, a biasing means 24, represented by a spring, is provided at a position substantially symmetrical to the tensioning means 22 with the spherical seat 13a as the center, and biases the mirror 13 in a direction toward the lid 21.

Similarly, the other biasing means 25 is arranged symmetrically to the tensioning means 23.

The operation of the mirror tilting mechanism constructed as described above will be described below.

First, the nozzle 9 is placed facing point P1 in FIG.

A laser beam is emitted from the nozzle 9 via the light guide tube 2. If the beam axis deviates from the nozzle axis by more than an allowable value, the mirror tilting mechanism 20 changes the angle of the mirror to change the beam axis. Align it with the nozzle axis.

That is, as shown in FIG.
It can be tilted along a. At this time, the tension means 22.23 and the mirror 13 are connected to the ball joints 22a, 22.
3a, the mirror can be freely displaced in three dimensions, and the tension means 22.
Since a tensile force is constantly applied to the mirror 13 to eliminate so-called backlash, there is no wobbling of the mirror 13.

The amount of adjustment change of the tensioning means 22, 23 carried out in this manner is measured by the rotary encoder 22f23f, respectively, and is stored in the storage device as a correction value at the point P1.

Next, the robot positions the nozzle 9 at point P2 (see FIG. 4), and at this point, the mirror tilting mechanism 20 is operated to again align the beam axis with the nozzle axis, and the result is stored.

In this manner, the present invention obtains a correction value by the mirror tilting mechanism 20 for each teaching point of the robot, stores this value, and automatically corrects each teaching point during laser processing in the next process and subsequent steps.

According to the beam axis adjustment method described above, the accuracy of laser processing is improved because the beam axis is matched with the nozzle axis at the teaching point.

Since the beam axis is adjusted again at the next teaching point, the amount of deviation between the nozzle axis and the beam axis does not accumulate.

Furthermore, since the mirror tilting mechanism is attached only to the final stage mirror, there is no risk that the light guide tube will become complicated or large.

Note that the biasing means 24.25 described in this embodiment may be combined into one unit, and if the backlash of the tensioning means 22.23 is kept to a small amount below an allowable value, the biasing means 24.2 may be combined into one unit.
You can omit 5.

(Effects of the Invention) As described above, the present invention provides a laser processing device with a simple structure and high cutting accuracy.

[Brief explanation of the drawing]

FIG. 1 shows a laser processing device according to the present invention, FIG. 2 is a sectional view of a mirror tilting mechanism according to the present invention, FIG. 3 is a view taken along arrow A-A in FIG. 2, and FIG. 4 is an industrial robot. FIG. 3 is a diagram illustrating a combination of the laser processing device and the laser processing device. 1...Laser processing device 2...Light guide tube 9...Nozzle 13...Final stage mirror 20...Mirror tilting mechanism

Claims (2)

[Claims] (1) A laser processing device equipped with a rotary articulated light guide tube, characterized in that a mirror tilting mechanism is attached to the final stage mirror of the light guide tube. (2) In a beam axis adjustment method of aligning a laser beam guided by a rotary articulated light guide to a nozzle at the tip of the light guide, the beam axis adjustment is performed by tilting a final stage mirror of the light guide. A method for adjusting a beam axis of a laser processing device, characterized in that the tilting is performed at each teaching point of a robot that controls the position of a nozzle.