JPH02161411A - Laser beam machining head - Google Patents

Abstract

PURPOSE:To easily and rapidly adjust the length of a linear laser beam without entailing the wasteful loss of energy by providing a cylindrical lens which converges the output distribution of the laser beam in the direction nearly perpendicular to the linear laser beam on the optical axis of the laser beam in such a manner that the lens can be moved in its optical axis direction. CONSTITUTION:The cylindrical lens 8 which converges the output distribution of the laser beam 1 in the direction nearly perpendicular to the direction of the linear laser beam 1a is provided on the optical axis of the laser beam 1. The distance between the cylindrical lens 8 and a material 4 to be worked changes when the cylindrical lens 8 is moved in its optical axis direction. The degree of convergence on the surface of the material 4 changes correspondingly and the length of the linear laser beam 1a increases or decreases. The length adjustment of the linear laser beam is easily and continuously executed in this way without entailing the wasteful loss of the energy of the laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing head used when performing heat treatment on metal materials using a carbon dioxide laser or the like.

[Conventional technology]

When performing heat treatment using a laser beam, the type of heat treatment method and metal material to be processed.

Depending on conditions such as shape, various shapes are required for the output distribution of the laser beam irradiated onto the workpiece.

Therefore, an optical system, ie, a laser processing head, is required to shape the laser beam from the laser oscillator into laser beams having output distributions of various shapes. FIG. 3 shows, for example, [Automobile Technology J vol.

37, Oni 7, published in 1983, P2S5 is a perspective view showing the configuration of an optical system of a conventional laser processing head disclosed in Konoike. In the figure, (1) is a laser beam emitted from a laser oscillator (not shown), (2) is a metal mirror for changing the direction of the laser beam (1),
It has the role of making the laser beam (1) enter the cylindrical mirror (described later) at an acute angle. (3) is a cylindrical mirror (6) that converges a circular laser beam (1) with a substantially uniform output distribution within a circle of a constant diameter into a linear laser beam (1a) and irradiates the workpiece (4). ) is a beam length adjusting plane mirror that adjusts the length of the linear laser beam (1a).

A circular laser beam (1
) is reflected by the metal mirror for direction change (2), and then the circular beam is focused in only one direction by the cylindrical mirror (3), becoming a linear laser beam (1a) and striking the workpiece (4). ) is irradiated. Linear laser beam (1
The irradiation position a) is sequentially moved in the direction shown by the arrow (6), for example, by moving the workpiece (4) at a predetermined speed.

Also, if you want to increase or decrease the length of the linear laser beam (1a), move the beam length adjustment plane mirror (5) in the direction of the arrow (7) to increase or decrease the incident area of the laser beam (1). This is done by

As a result of the above, a linear laser beam with high energy density and adjustable length can be obtained.

[Problems to be Solved by the Invention] The conventional laser processing head is configured as described above, and the length of the linear laser beam (1a) is adjusted by the beam length adjusting plane mirror (5). Since this method is performed by shielding a part of the laser beam (1) from the oscillator, there is a problem in that the output energy of the laser beam (1) is correspondingly lost and efficiency deteriorates.

As a method that does not use the beam length adjusting plane mirror (5), a plurality of direction changing metal mirrors (3) each having a different curvature are prepared, and the length of the linear laser beam (1a) is adjusted according to the required length of the linear laser beam (1a). It is conceivable to sequentially replace the direction changing metal mirror (3), but the replacement work is complicated and rapid adjustment cannot be expected, and the adjustment must be discontinuous.

This invention was made to solve the above problems, and provides a laser processing head that can easily and quickly adjust the length of a linear laser beam without wasting energy. The purpose is to obtain.

[Means to solve the problem]

The laser processing head according to the present invention is provided with a cylindrical lens movable in the direction of the tip axis on the optical axis of the laser beam to converge its output distribution in a direction substantially perpendicular to the direction of the linear laser beam. It is something.

[For production]

When a cylindrical lens is moved in the direction of its optical axis, the distance between the cylindrical lens and the workpiece changes, and the degree of convergence on the workpiece surface changes accordingly, increasing or decreasing the length of the linear laser beam. do.

〔Example〕

FIG. 1 is a perspective view showing the configuration of an optical system of a laser processing head in an embodiment of the present invention.

In the figure, the difference from the conventional method is that a cylindrical lens (8) is provided on the optical axis of the laser beam (1). Note that the conventional beam length adjusting plane mirror (5) is no longer necessary. Here, the convergence direction of the cylindrical lens (8) is perpendicular to that of the cylindrical mirror (3). That is, the cylindrical mirror (3) converges the beam in the front-back direction in the figure, while the cylindrical lens (8) converges the beam in the left-right direction. The cylindrical lens (8) is configured to be movable in the direction of its optical axis, that is, in the direction of the arrow (9) in the figure, by a moving device (not shown).

FIG. 2 shows the shape of the linear laser beam (1a) irradiated onto the surface of the workpiece (4). That is, a circular laser beam (
1) is converged into a linear beam of width t. Furthermore, when the cylindrical lens (8) is moved in the direction of the arrow (9), the distance from the workpiece (4) changes, and the cylindrical lens (8) on the surface of the workpiece (4) changes accordingly. The degree of convergence effect changes, as shown in Figure 2.
The length of the linear laser beam (1a) varies from 11 to 42. In this case, regardless of the length l, the entire energy of the laser beam (1) from the laser oscillator will be irradiated onto the workpiece (4), and there will be no unnecessary loss as in the conventional case. do not have. Therefore, the linear laser beam (
When the length l of 1a) is shortened, the energy density of the beam (1a) increases accordingly. If it is desired to maintain a constant energy density I regardless of the length l, the output of the laser oscillator may be adjusted in conjunction with the amount of movement of the cylindrical lens (8).

In the above embodiment, in order to obtain a linear laser beam (1a), a cylindrical mirror (3) was used as an optical element that performs a certain degree of convergence. You can also use it as However, in that case, it is necessary to separately set the arrangement of each optical element.

〔Effect of the invention〕

As described above, the present invention provides a cylindrical lens on the optical axis of a laser beam that converges its output distribution in a direction substantially perpendicular to the direction of the linear laser beam, and moves this cylindrical lens in the direction of the optical axis. By adjusting the length of the linear laser beam, the length of the linear laser beam can be adjusted easily and continuously without unnecessary loss of laser beam energy. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of the optical system of a laser processing head in an embodiment of the present invention, FIG. 2 is a diagram showing the shape of the linear laser beam, and FIG. 3 is a perspective view showing the optical system of a conventional laser processing head. FIG. 2 is a perspective view showing the configuration of the system. In the figure, (1) is a laser beam, (la) is a linear laser beam, (4) is a workpiece, and (8) is a cylindrical lens. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] In a device that irradiates a workpiece with a laser beam from a laser oscillator with its output distribution converged linearly, the output distribution is focused on the optical axis of the laser beam, and the output distribution is focused on the linear laser beam. A cylindrical lens converging in a direction substantially perpendicular to the direction is provided, and by moving this cylindrical lens in the direction of the optical axis, the length of the linear laser beam irradiated to the workpiece can be adjusted. A laser processing head featuring: