JPH04284990A - Method for cutting matter with laser beam - Google Patents

Abstract

PURPOSE:To improve the cutting efficiency by making the sectional shape of beam to the slender shape in the direction of the cutting line on the surface of the matter, and making it to the slender beam shape in the lateral direction of the cutting line in the part over the prescribed depth of the matter. CONSTITUTION:On the surface part of the matter 2, the sectional shape of laser beam 1 is made the slender shape in the direction Y of the cutting groove 3, the energy of beam 1 is used practically so as to deepen the groove 3 exclusively. When the depth of the cutting groove 3 becomes over the prescribed depth, the sectional shape of beam 1 becomes to the slender shape in the lateral direction of the cutting groove 3 at that part, the width of groove is broadened in the deep range of the cutting groove 3. If the width groove is broadened in the deep part of the cutting groove, the molten dross becomes to be easily excluded, the useless energy to be absorbed with the molten dross become little, and the cutting efficiency is improved.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a method of focusing a laser beam and irradiating it onto an object to cut it.
Concerning how to cut thick objects such as concrete walls and floors.

0002

2. Description of the Related Art When cutting a thick object such as concrete with a laser beam, the focus of an objective optical system for beam focusing using a lens or mirror is not adjusted to the surface of the object.
/16) As seen in the publication, focusing on a predetermined depth position inside the object to be cut is more efficient in energy use and can cut at a higher speed. Also, what is very important for efficient cutting of concrete, etc. is that the concrete, etc. (molten dross) that has been melted by the beam irradiation is quickly removed from the beam irradiation position, and the unmelted parts are exposed to the laser beam. It is to do so. Regarding this point, JP-A-63-
As in Publication No. 97392 (B23K26/16), a method is devised in which multiple laser beams are used to cut the cutting groove while gradually widening it so that the molten dross is smoothly removed to the sides and downwards through the cutting groove. It has been known.

0003

[Problems to be Solved by the Invention] Although the method of gradually enlarging the cut groove using multiple laser beams is certainly effective, the efficiency of energy use is low and the cost of equipment such as laser oscillators is high, making it difficult to implement. This was not a practical method in terms of cost. The purpose of this invention is to enable cutting to proceed in a state where molten dross is easily removed from the beam irradiation position, and to efficiently cut thick objects such as concrete by effectively utilizing the energy of the laser beam. It is.

0004

[Means for Solving the Problems] Accordingly, in the present invention, as shown in FIG. 1, a laser beam 1 is focused and irradiated onto an object 2 to melt the object 2, and the beam irradiation point is directed in the cutting line direction Y. In the method of cutting the object 2 by moving the object 2, the cross-sectional shape of the beam 1 on the surface of the object 2 is elongated in the cutting line direction Y, and at a predetermined depth inside the object 2 or more, the cross-sectional shape of the beam 1 is elongated in the cutting line direction. Width direction
It has an elongated shape.

[0005]

[Operation] In order to smoothly remove molten dross from the cutting groove, it is better to widen the width of the deep part of the cutting groove. Since the molten dross immediately flows to the deep part of the groove near the surface of the object, there is no need to widen the groove width near the surface, and increasing the groove width near the surface is a waste of energy. In the method of the present invention shown in FIG. 1, since the cross-sectional shape of the laser beam 1 on the surface of the object 2 is elongated in the direction Y of the cutting groove 3, the width of the groove 3 is not increased more than necessary, and the energy of the beam 1 is is effectively used to exclusively deepen the groove 3. When the depth of the cutting groove 3 exceeds a predetermined value, the cross-sectional shape of the beam 1 at that portion becomes elongated in the width direction X of the cutting groove 3, so that the groove width is widened in the deep region of the cutting groove 3.

[0006]

[Embodiment] As shown in FIG. 1, the cross-sectional shape of the beam 1 on the surface of the object 2 is elongated in the direction Y of the cutting groove 3, and when the depth of the object 2 exceeds a predetermined depth, the cross-sectional shape of the beam 1 is elongated in the width direction X of the cutting groove 3. To make the shape elongated, a focusing optical system called astigmatism, as shown in FIG. 2, is used, for example.

In FIG. 2, as mentioned above, the direction of the cutting line of the object is Y, the width direction of the cutting groove is X, and the depth direction of the cutting groove (optical axis direction of the laser beam irradiated to the object) is Let it be Z. A parallel beam with a circular cross section from a laser oscillator is reflected by a plane mirror 4, the reflection is further reflected by a spherical concave mirror 5, and the focused beam is irradiated onto an object. If the reflected beam and the focused beam are made to pass within a vertical plane that includes the Y direction (cutting direction) line, and the reflected beam is made to enter the concave mirror 5 obliquely (θ), the cross section of the focused beam will be from the concave mirror 5. It changes depending on the distance between and becomes dissimilar. This is what is called astigmatism, and since the optical axis of the reflected beam is inclined at an angle θ with respect to the vertical plane of the concave mirror 5 in the Y direction, the focal length in the Y direction becomes long. Therefore, the focal point Z1 in the X direction is at a shallower position than the focal point Z2 in the Y direction. As a result, as shown in Figure 2,
Near the surface of the object, the beam shape becomes an ellipse with its long axis in the cutting line direction Y, and when the distance in the depth direction Z exceeds a certain distance, the beam shape becomes an ellipse with its long axis in the width direction X of the cutting line. becomes. The beam is most focused between the focus Z1 and the focus Z2. As shown in Figure 1, beam 1
Cutting is performed by setting the position where the light is narrowest and converged to approximately half the thickness of the object 2.

Note that the beam focusing optical system for carrying out the present invention is not limited to the configuration shown in FIG. 2, and there are various methods such as using an aspherical lens.

[0009]

Effects of the Invention: In this invention, the cross-sectional shape of the irradiation beam is elongated in the direction of the cutting line near the surface of the object to be cut, so the width of the cutting groove is not made larger than necessary, and the energy of the beam is reduced. is effectively used to deepen the groove. When the groove reaches a predetermined depth or more, the cross-sectional shape of the irradiation beam becomes elongated in the groove width direction, and the width of the cutting groove increases. When the groove width is widened at the deep part of the cutting groove, the molten dross is more easily removed, the wasted energy absorbed by the molten dross is reduced, and the cutting efficiency is improved.

[Brief explanation of the drawing]

[Fig. 1] An explanatory diagram of a method for cutting an object using a laser beam according to the present invention.

FIG. 2 is a perspective view showing an example of a beam focusing optical system for carrying out the cutting method of the present invention.

[Explanation of symbols]

1 Laser beam 2 Object 3 Cutting groove X Width direction of cutting line Y Cutting line direction Z Depth direction

Claims (1)

[Claims] 1. A method for cutting an object by focusing a laser beam and irradiating it onto an object to melt the object and moving the beam irradiation point in the direction of a cutting line, the method comprising: A method for cutting an object using a laser beam, characterized in that the shape is elongated in the direction of the cutting line, and the shape is elongated in the width direction of the cutting line at a predetermined depth or more inside the object.