JPH04182088A - Condensing device for laser beam machining - Google Patents

Abstract

PURPOSE:To divide into two beams at an arbitrary beam intensity pattern ratio and to arbitraily select spatial distribution of beam energy by dividing a laser beam through a total reflection mirror of a specified shape into two parts. CONSTITUTION:A beam from a laser beam oscillator is reflected by the total reflection mirror 1 to be divided into two beams. This total reflection mirror 1 is a mirror having an inclination in the shape of a gable roof. The beam divided into two parts in this way is reflected respectively by other reflection mirrors 2, 3 and condensed at machining parts. Therefore, the spatial distribution of the beam energy can be set arbitrarily. Removal of a surface treated film of a surface treated metallic plate and preheating or post-heating can be performed by one side beam.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a condensing device for laser processing, and particularly to a condensing device for laser processing suitable for laser welding.

(Prior art and problems to be solved) Conventionally, laser heat sources have been used for various processing applications such as welding and surface modification, and CO2 lasers, YA
Various types such as G laser are used.

By the way, there are two types of laser beam systems in condensing devices for laser processing: beam systems that use a single beam from a laser oscillator as is, and beam systems that use a reflection mirror to split the beam into two beams. .

Conventionally, a partial reflection mirror (split mirror) has been used as the reflection mirror used to split the beam into the latter two beams. Especially in CO2 lasers, Zn
A reflective mirror whose 5e surface was coated with a dielectric film was required.

However, when a beam is split into two by a partially reflecting mirror, one beam is reflected while the other beam passes through the partially reflecting mirror.

There was a problem with the durability of the mirror. Furthermore, since the material itself, such as Zn5e, is susceptible to moisture, it has problems with durability and is expensive.

Furthermore, since the beam is split using a partially reflecting mirror, it is difficult to arbitrarily change the spatial distribution of the beam energy, which limits the use of laser processing. An inexpensive condenser for laser processing that solves the problem and has a beam system that can split the laser beam into two using mirrors made of materials that have no problems with durability, and can arbitrarily change the spatial distribution of beam energy. The purpose is to provide a device.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present inventors have conducted extensive research on laser beam systems, and have hereby accomplished the present invention.

That is, the present invention provides a laser beam system 1 in which a laser beam from a laser oscillator is split into two beams by a reflecting mirror and focused on a processing section.

The former reflection mirror uses a total reflection mirror with a gable-roof-shaped slope, and uses each slope to split into two beams, and each beam is further reflected by another reflection mirror to condense the light. The gist of the present invention is a condensing device for laser processing, which is characterized by the following features.

The present invention is also characterized in that, if necessary, an ivy adhesion prevention device is provided around the condensed beam to cause gas to flow in a direction coaxial with or perpendicular to the direction of the laser beam.

The present invention will be explained in more detail below.

(Function) As mentioned above, when splitting a laser beam into two beams, conventionally a partially reflecting mirror was used to split the laser beam into a reflected beam and a transmitted beam, but in the present invention, this partially reflecting mirror Instead, a total reflection mirror with a specific shape is used to split the beam into two reflected beams.

Since it is a total reflection mirror, the beam does not pass through the interior of the mirror, and inexpensive materials can be used. As such a total reflection mirror, for example, Cu''?A
A durable mirror whose surface is coated with a noble metal such as u can be used.

FIG. 1 shows a laser beam system of the present invention, in which a laser beam from a laser oscillator is reflected by a total reflection mirror 1 and divided into two beams.

The total reflection mirror 1 needs to be a mirror having a gable roof-like sloped surface. A gable roof is basically a triangular shape, but one reflective surface and the other reflective surface can have the same or different inclination angles, and both reflective surfaces can have the same or different lengths. It can also be of different dimensions.

The beams thus divided into two are each reflected by another reflecting mirror 2.3, as shown in FIG.
Focuses the light on the processing area. This mirror can be of any suitable shape, such as a parabolic mirror, a spherical mirror, or a semi-cylindrical mirror.

In the laser beam system having the above-mentioned configuration, the gable-roof-shaped total reflection mirror 1 can be moved parallel to the processing section. In addition, the latter reflecting mirrors 2 and 3 can be rotated or rotated in the vertical direction (perpendicular to the processed part).
Since it can also be made movable, the following usage modes are possible.

First, the laser beam from the laser oscillator has various beam energy distributions in the cross-sectional direction, as shown in an example in Fig. 2. As shown in FIG. 3, the intensity ratio between one beam and the other beam can be changed arbitrarily in the X-axis direction.

Furthermore, by rotating the latter reflecting mirror 2.3, each beam can be incident at an angle from the normal direction of the base material. Thereby, beam energy can be effectively supplied to the base material while avoiding the influence of plasma plume (metal mist) (see FIG. 4).

Furthermore, by rotating the latter reflecting mirror 2.3, the distance between the two beams can be made closer or farther apart on the base material (see FIG. 3).

By using these usage modes alone or in combination,
Spatial distribution of beam energy (X-axis direction)

(y-axis direction, height direction) can be set arbitrarily. Therefore, using one of the beams, it is possible to remove the surface treatment film of the surface treated metal plate, and perform preheating or postheating. Furthermore, by converging the two beams so as to overlap, it becomes possible to control the penetration shape, and also to improve the bead shape and solidified structure.

In addition, when semi-cylindrical mirrors are used as the latter reflecting mirrors 2 and 3, the following effects are also possible.

Here, the semi-cylindrical mirror refers to a mirror that also has curvature in a direction orthogonal to the curvature direction of a normal cylindrical mirror. In other words, the entire mirror is shaped as shown in Figure 5, and its cross section A has a cylindrical surface (cylindrical side surface) with a curvature f as shown in Figure 6, and the cross section B has a curve as shown in Figure 7. As shown, the cylindrical surface has a curvature of aXf (1<a). The larger the value of a, the wider the beam width in the B cross-section direction (y-axis direction), as shown in FIG. Therefore, it is suitable for welding with a gap in the base metal or welding using filler wire.

FIG. 9 shows a sputter adhesion prevention device provided in the above-mentioned laser beam system. In this device, a gas distribution member 4 is arranged around a condensed beam from a semi-cylindrical mirror. When the flow is coaxial with the direction of the laser beam, the outlet of the annular member is oriented coaxially with the beam.

On the other hand, when flowing in a direction that intersects the laser beam direction, a pair of gas outlet ports and a gas suction port are placed opposite to each other around the beam in the intersecting direction, and the gas is ejected from the gas outlet port.
This is configured to be sucked into the gas suction port. Since welding spatter is scattered almost upward from the processed area, it is preferable to flow the gas in the same axis direction as the laser beam. N2 as a gas
, Ar, He, and other inert gases are used. The gas flow rate is determined as appropriate.

(Effects of the Invention) As detailed above, according to the present invention, since the beam is split into two using a total reflection mirror of a specific shape, the two beams can be split at an arbitrary beam intensity pattern ratio. In addition, various usage modes are possible, such as being able to arbitrarily select the spatial distribution of beam energy, and furthermore allowing the beam to be incident at an angle with respect to the normal direction of the target. Furthermore, it is economical because a durable and inexpensive mirror can be used and spatter adhesion can be prevented.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a laser beam system of the present invention. Figure 2 shows an example of the beam energy distribution before splitting, Figure 3 (a) to (c) shows an example of the energy distribution of each beam after splitting, and Figure 4 shows the incident direction of the beam. A diagram explaining the plume generation situation. 5 to 7 are views for explaining the semi-cylindrical mirror, in which FIG. 5 is a perspective view, FIG. 6 is a cross-sectional view of A in FIG. 5, and FIG. 7 is a cross-sectional view of B in FIG. FIG. 8 is a diagram illustrating the shape of the beam intensity distribution focused by a semi-cylindrical mirror, and FIGS. 9(a) and 9(b) are explanatory diagrams showing a sputter adhesion prevention device. 1... Total reflection mirror having a gable roof-like reflecting surface, 2
．． 3... Reflection mirror, 4... Gas distribution member. Patent applicant Takashi Nakamura, Patent attorney representing Kobe Steel, Ltd. Figure 1 Figure 2 Figure 3 (C) Figure 4↓' Figure 7 Figure 9 (C1) (b)

Claims (5)

[Claims] (1) In a laser beam system in which a laser beam from a laser oscillator is split into two beams by a reflection mirror and focused on the processing area, a total reflection mirror with a gable-roof slope is used as the former reflection mirror. A condensing device for laser processing, characterized in that it is configured to split into two beams using each inclined surface, and each beam is further reflected and condensed by another reflecting mirror. (2) The condensing device for laser processing according to claim 1, wherein the total reflection mirror having a gable-roof-like inclined surface is movable in the processing direction. (3) The condensing device for laser processing according to claim 1 or 2, wherein each of the latter reflecting mirrors is provided rotatably or movably in the vertical direction. (4) Claims 1 and 2 in which a parabolic mirror, spherical mirror or semi-cylindrical mirror is used as the latter reflecting mirror.
Or the condensing device for laser processing according to 3. (5) The condensing device for laser processing according to claim 1, further comprising a sputter adhesion prevention device that causes gas to flow in a direction coaxial with or perpendicular to the direction of the laser beam, provided around the condensed beam.