JP2817555B2 - Laser processing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam machine for irradiating a laser beam to a workpiece as a workpiece to perform laser processing such as welding or cutting. Using a laser oscillator.

[0002]

2. Description of the Related Art FIG. 6 is a view showing the relationship between the direction of a laser beam and the processing direction of a work in a conventional laser processing machine of this kind. In the figure, 1 is a CO ₂ laser oscillator,
As shown in FIG. 9, an elliptical laser beam having a major axis length a and a minor axis length b is emitted. Some laser oscillators emit a laser beam whose cross-section is a perfect circle, but in reality, an elliptical cross-section may occur due to various conditions such as the formation of a laser resonator, the output used, and the mode of the laser beam. Many.

Reference numerals 2 to 7 denote optical components constituting an optical system 10 for transmitting a laser beam L emitted from a laser oscillator 1 to a processing position of a work 8; 2 denotes a plane mirror mounted on a fixed portion (not shown); Is a concave mirror for beam diameter correction attached to the fixed part, 4 is a plane mirror attached to the Y-axis direction (welding direction) moving part of space coordinates, 5 is a plane mirror attached to the X-axis direction moving part, 6 is a plane mirror attached to the Z-axis direction moving unit, and 7 is the same Z
The condensing mirror attached to the moving part in the axial direction
Focus on S above.

[0004] 8a, 8b in contact with the workpiece at butt line, at welding mirror 4 to 7 has a structure which moves in the direction of Y-axis direction Y _W → Y _D integrally.

Here, as shown in FIG. 6, when the major axis direction of the laser beam L at the exit of the laser oscillator 1 is in the Z-axis direction, the condensing mirror 7 passes through the optical system 10.
7A, the long axis direction of the laser beam machine formed at the focal point S of the laser beam L is perpendicular to the butting line (corresponding to the welding direction) of the work 8 as shown in FIG. It has a crossing shape.

If the major axis direction of the laser beam L at the exit of the laser oscillator 1 is the X axis direction,
As shown in FIG. 7B, the cross-sectional shape 9 of the laser beam L irradiated onto the work 8 has its major axis direction coincident with the direction of the butt line.

[0007]

As described above, if the relationship between the long axis direction of the sectional shape of the laser beam L and the welding direction is different, the processing characteristics are different as shown in FIG. That is, when the welding speed is kept constant, the penetration depth is more excellent when the longitudinal direction of the beam and the welding direction are matched. Therefore, even if a laser oscillator with the same output is used,
When the longitudinal direction of the beam and the welding direction are orthogonal to each other, as shown in FIG. 7A, there may be a case where an unfused portion occurs during welding and sufficient welding characteristics cannot be obtained. Further, when the major axis direction of the beam changes due to an abnormality of the laser oscillator during welding, the processing characteristics change due to the influence, and the welding finish quality of the work varies.

In order to solve the above-mentioned drawback, for example, Japanese Utility Model Laid-Open No. 4-54582 discloses an apparatus for modifying an elliptical cross-sectional shape of a laser beam into a substantially perfect circular shape. However, in this conventional device, it is necessary to individually select the focal length of the two-dimensional convex lens based on the ratio of the major axis length a to the minor axis length b of the cross section of the laser beam emitted from the laser oscillator. In consideration of the application, the device becomes complicated and impractical. Further, the position to be corrected to a substantially perfect circle is also limited to a certain point shorter than the focal length f of the two-dimensional convex lens. For example, if the a / b ratio is 2 and f = 1000 mm of a two-dimensional convex lens, the perfect circle is l = 500.
mm, and remains elliptical in other positions. Therefore, it is necessary to irradiate the work at a position other than the minimum spot position, and it can be used for heat treatment such as surface treatment. However, it is difficult to use it for laser processing that requires high-density energy such as welding.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been made in consideration of the length of the cross section of a beam applied to a workpiece regardless of the longitudinal direction of the beam cross section at the exit of a laser oscillator. It is an object of the present invention to obtain a laser beam machine in which the directional relationship between the axial direction and the machining direction is constant.

[0010]

According to a first aspect of the present invention, there is provided a laser processing machine comprising: a movable mirror capable of converting an incident angle into an optical system for transmitting a laser beam from a laser oscillator to a work;
And the long axis direction of the cross section of the incident laser beam.
A long axis direction changing mechanism for changing the length of the laser beam at the emission exit of the laser oscillator, regardless of the long axis direction of the cross section of the laser beam, and processing the work and This is to match the direction.

According to a second aspect of the present invention, there is provided a laser beam machine including a plurality of laser beam detecting elements configured to be able to advance and retreat from the optical axis at predetermined intervals in a circumferential direction surrounding the optical axis of the laser beam. The major axis direction of the cross section of the laser beam is detected from the forward and backward beam detection end positions of the respective laser beam detecting elements, and the major axis direction coincides with the processing direction of the workpiece.
This is to control the long axis direction changing mechanism so as to match .

[0012]

According to the present invention, the optical system has a long axis direction change.
Provide a mechanism and drive the movable mirror to adjust the angle of incidence
By this means, for example,
And correcting the inclination, always match the machining direction of the long axis and the workpiece of the beam.

Further, when a predetermined laser beam detecting element is provided, its output is sent to a long axis direction changing mechanism so that the long axis direction of the beam section always coincides with the processing direction of the workpiece.
You .

[0014]

[Embodiment 1] FIG. 1 is a configuration diagram showing a laser processing machine according to Embodiment 1 of the present invention. In the drawings, the same or corresponding parts as those in the related art are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 11 denotes a direction changing unit newly added in this embodiment, which is composed of three plane mirrors 11a, a plane mirror 11b as a direction changing mirror, and a plane mirror 11c, and is attached to a fixed portion (not shown).

Of these, the plane mirror 11a is arranged so that its reflection surface is parallel to the Z axis, and therefore parallel to the long axis direction of the beam. The optical axis of the laser beam L reflected by the plane mirror 11a is Y. It changes from the axial direction to the X-axis direction,
The major axis direction of the beam maintains the Z axis direction. Next, the plane mirror 11b is arranged such that its reflection surface is inclined by 45 ° with respect to the Z axis, and therefore also inclined by 45 ° with the major axis direction of the beam. The optical axis of the laser beam L reflected by this plane mirror 11b is X While changing from the axial direction to the Z-axis direction, the major axis direction of the beam is converted from the Z-axis direction to the X-axis direction. The plane mirror 11c is arranged so that its reflection surface is parallel to the X axis, and thus parallel to the long axis direction of the beam. The optical axis of the laser beam L reflected by the plane mirror 21c is again changed from the Z axis direction. Returning to the Y-axis direction, the long-axis direction of the beam maintains the X-axis direction.

After all, the direction conversion unit 11 has a function of converting the long axis direction of the laser beam L emitted from the laser oscillator 1 from the Z axis direction to the X axis direction without changing the optical axis direction. That is the reason. Then, as a result of newly inserting the direction changing unit 11 on the optical path of the optical system 10, as shown in FIG. 1, the major axis direction of the beam at the emission exit of the laser oscillator 1 is the same as that of the related art. However, the work 8 finally passes through the optical system 10.
The long axis direction of the beam irradiated to the weld is the welding direction (butt line)
And high-quality welding characteristics with high-density energy can be obtained.

In FIG. 1, if the major axis of the beam at the exit of the laser oscillator 1 becomes the X-axis direction, the direction conversion unit 11 is removed to cancel the insertion into the optical path, and the remaining optical element is removed. If the position of the plane mirror 2 and the laser oscillator 1 is adjusted by the system 10, the major axis direction of the irradiation beam also coincides with the welding direction, and good welding quality can be obtained.

Although a mechanism for inserting the direction changing unit 11 into the optical path and for releasing the direction changing unit 11 is not shown in the figure, an optimal type is adopted in consideration of the structure of the laser device to be applied, the control method, and the like. Adopt it. Further, the direction changing unit 11 may be accommodated in a container of the laser oscillator 1.

Embodiment 2 FIG. FIG. 2 is a configuration diagram showing a laser processing machine according to Embodiment 2 of the present invention. In this embodiment, a plane mirror 12 is used as a direction changing mirror in place of the direction changing unit 11 of FIG. 1, and this is arranged on the same plane (XY plane) as the plane mirrors 4 and 5. The plane mirror 12 has a reflecting surface inclined by 45 ° with respect to the Z-axis, which is the long-axis direction of the incident beam, and changes the optical axis of the laser beam L from the Y-axis direction to the Z-axis direction. The axis direction is converted from the Z axis direction to the Y axis direction.

As a result, as in the case of FIG. 1, the major axis direction of the beam irradiated on the workpiece 8 coincides with the welding direction, and good welding quality can be obtained. In this case, it is possible to change the direction of the long axis of the beam by inserting and releasing one mirror 12, and the operation is simplified, and the power loss due to the reflection loss of the mirror can be minimized.

Embodiment 3 FIG. FIG. 3 is a configuration diagram showing a laser processing machine according to Embodiment 3 of the present invention. This embodiment deals with a case where the welding direction changes with the progress of welding. That is, FIG.
The work 8 has, for example, an opening on one surface of a box-shaped body, and works 8c and 8d provided with a flange surface around the opening are overlapped with each other and welded all over the flange surface to form a gasoline tank. The welding direction is changed from the Y-axis direction (FIG. 3A) to the X-axis direction (FIG. 3A).
(2)).

As optical components of the optical system 10, a plane mirror 13 as a direction conversion mirror and a plane mirror 14 are provided on the same plane (XY plane) as the plane mirrors 4 and 5. Here, the plane mirror 13 is rotatable by 90 ° around the Z axis in accordance with the switching of the optical path described later, and the plane mirror 4 is configured to be able to advance and retreat in the X axis direction.

First, referring to FIG. 3A, in this case, it is required that the work 8 be welded along the Y-axis direction. Here, the plane mirror 4 is inserted on the optical path, and the laser beam L from the laser oscillator 1 is mirrored along the optical path shown by the solid line in the figure, mirrors 2 → 3 → 4 → 5 → 13 →
The work 8 is irradiated via 6 → 7. At this time, the reflection surface of the plane mirror 13 faces the plane mirror 5 side,
Further, the incident beam is inclined by 45 ° with respect to the major axis direction (Z-axis direction), and the optical axis of the laser beam L is shifted from the Y-axis direction by Z.
The beam is changed in the axial direction, and the major axis of the beam is converted from the Z-axis direction to the Y-axis direction.

Next, FIG. 3 (2) shows the welding of the work 8 as X
In this case, the plane mirror 4 is located at a retracted position off the optical path, and the laser beam L from the laser oscillator 1 is applied to the mirror 2 → 3 → along the optical path shown by the solid line in FIG. The work 8 is irradiated via 14 → 13 → 6 → 7. At this time, the reflecting surface of the plane mirror 13 is rotated by 90 ° around the Z axis from the position shown in FIG. 3A so as to face the plane mirror 14 and the longitudinal direction of the incident beam (Z axis direction). The laser beam L is inclined by 45 °, and changes the optical axis of the laser beam L from the X-axis direction to the Z-axis direction, and converts the long-axis direction of the beam from the Z-axis direction to the X-axis direction.

In this embodiment, by operating the plane mirrors 4 and 13 in an interlocking manner, welding work of the work 8 along two different directions can be processed under uniform conditions, and the work is stabilized and the welding quality is improved. improves.

Embodiment 4 FIG. FIG. 4 is a configuration diagram showing a laser processing machine according to Embodiment 4 of the present invention. Here, when the major axis direction of the emitted beam is shifted from the original direction (the Z-axis direction in the example in the figure) by an angle θ due to an abnormal operation of the laser oscillator 1 or the like,
A laser processing machine in which this is corrected by the optical system 10 so that the long axis direction of the irradiation beam to the work 8 always coincides with the welding direction will be described.

First, the mirror 15 is placed on the optical path of the optical system 10.
a, 15b and 15c long axis direction changing mechanism 15
Is provided. Of these, the mirror 15a is the concave mirror 3
The incident angle of the laser beam L from the XY plane can be adjusted arbitrarily in the XY plane. The mirror 15b changes the optical axis of the laser beam L from the mirror 15a in the Z-axis direction, and the mirror 15c further changes it in the Y-axis direction.
The light is incident on the plane mirror 4. When the angle of incidence of the mirror 15a changes, the mirrors 15b and 15c move integrally in the Y-axis direction accordingly, and an interlocking mechanism is provided so that the reflected light of the mirror 15a always enters the mirrors 15b and 15c.

Next, reference numeral 16 denotes a beam major axis direction detector whose detailed structure is shown in FIG. 5, which detects the major axis direction of the laser beam L at the exit of the laser oscillator 1 and changes the detected value in the major axis direction. The mirror 15a adjusts the incident angle based on the detected angle θ.

In FIG. 5, reference numerals 16a to 16h denote thermocouples as laser beam detecting elements, which are arranged in a circumferential direction surrounding the optical axis.
It is arranged at an interval of 5 ° and can move forward and backward with respect to the center of the optical axis.
It is attached to a drive mechanism (not shown). Then, each thermocouple is moved inward from the outside, and when the tip reaches the outer edge of the laser beam L, the output of the thermocouple suddenly changes due to its temperature rise, and the thermocouples 16a to 16h at the time of this sudden change
The laser beam cross-sectional shape is grasped from the position information of the forward and backward directions, and the angle θ between the long axis direction and, for example, the Z axis direction is calculated at the same time.

As described above, the detection output θ of the beam major axis direction detecting device 16 is given to the major axis direction changing mechanism 15 so that the major axis direction changing mechanism 15 can change the beam length regardless of the tilt angle θ. A laser beam L whose axial direction is the X-axis direction is emitted toward the plane mirror 4. Therefore, even if an abnormality occurs in a part of the laser oscillator 1 during welding and the major axis direction of the emitted beam changes, the major axis direction changing mechanism 15 immediately responds to the deviation and corrects the deviation. The stable operation characteristic that the long axis direction of the irradiation beam always coincides with the welding direction is obtained.

When the long axis direction of the output beam from the laser oscillator 1 is kept constant, the apparatus drives the long axis direction changing mechanism 15 to forcibly change the long axis direction of the output beam. This can be applied to the work 8 in which the welding direction extends in two directions as described with reference to FIG.

Embodiment 5 FIG. In each of the above-described embodiments, a case has been described in which the long-axis direction of the laser beam irradiating the workpiece 8 is always set to coincide with the welding direction. However, depending on the processing method, the long-axis direction is opposite to the processing method. In some cases, it is always better to make them orthogonal. For example, when performing a surface heat treatment or the like by a laser beam, it is required to apply a uniform heating effect within a certain area. The present invention can be similarly applied to such a case and has the same effect.

Embodiment 6 FIG. The optical system 10 shown in each of the above embodiments is merely an example, and for example, the mirrors 2 and 3 may not be provided.
Instead of using the mirror 6 and the condenser mirror 7, a condenser lens perpendicular to the Z axis may be used.

Embodiment 7 FIG. Further, in the embodiment of FIG. 4, the long axis direction changing mechanism 15 is used in combination with the beam long axis direction detection device 16,
A configuration may be adopted in which only the long axis direction changing mechanism 15 is employed to appropriately change the long axis direction of the beam.

[0035]

As described above, the present invention relates to the optical system .
By providing a predetermined long axis direction change mechanism, the beam
Since the long axis direction can be continuously converted, and the long axis direction of the beam cross section irradiating the workpiece is made to coincide with the processing direction, uniform and high-quality processing characteristics suitable for the processing type can be obtained.

Further, the long axis direction of the beam is detected by a predetermined laser beam detecting element, and the long axis direction changing mechanism is controlled in conjunction with the detection, so that the long axis direction inclination is always kept.
It can be corrected to match the working direction of the word click.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a laser processing machine according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a laser processing machine according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating a laser processing machine according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a laser processing machine according to Embodiment 4 of the present invention.

FIG. 5 is a configuration diagram showing details of a beam long axis direction detection device 16 of FIG. 4;

FIG. 6 is a configuration diagram showing a conventional laser beam machine.

FIG. 7 is a diagram showing the relationship between the direction of the major axis of the cross section of the laser beam L at the focal position of the focusing mirror and the butting line.

FIG. 8 is a characteristic diagram showing an influence of a relationship between a longitudinal direction of a cross section of a laser beam and a welding direction on a processing condition.

[Explanation of symbols]

Reference Signs List 1 laser oscillator, 8 work, 9 laser beam cross-sectional shape, 10 optical system, 11 direction conversion unit, 11b, 12, 13 direction conversion mirror, 15 long axis direction change mechanism, 16 beam long axis direction detection device, 16a, etc. versus.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 26/00 B23K 26/06

Claims (2)

(57) [Claims] The method according to claim 1 laser beam cross section emitted from the laser oscillator is elliptical, and transmitted through the optical system in the laser processing machine so as to irradiate along the machining direction of the workpiece to be machined, the Incident angle can be converted to optical system
Of the cross section of the incident laser beam
A long axis direction changing mechanism for changing the long axis direction is provided, regardless of the long axis direction of the cross section of the laser beam at the exit of the laser oscillator, regardless of the long axis direction of the cross section of the laser beam applied to the work. A laser processing machine wherein the processing direction of the work is matched. 2. A plurality of laser beam detecting elements which are configured to be able to advance and retreat with respect to the optical axis at predetermined intervals in a circumferential direction surrounding the optical axis of the laser beam. The major axis direction of the cross section of the laser beam is detected from the detection end position, and this major axis direction is applied to the workpiece.
Laser processing machine according to claim 1, characterized in that so as to control the longitudinal direction changing mechanism to match the engineering direction.