JPH04319087A - Method for cutting object by laser beam - Google Patents

Abstract

PURPOSE:To enhance a molten material removing effect by a gas jet in the method to irradiate an object with a laser beam to cut the object and inject the gas jet to a part to be cut to remove a welded material by force of the jet. CONSTITUTION:The specified jet 8 is injected aslant toward the front from the rear in the cutting proceeding direction for the part while being cut. An intersection point Q between an optical axis of the laser beam 4 and the central axis of the gas jet 8 is set at the specified depth position of the inside of the object 5.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method of cutting an object by focusing a laser beam on the object and, in particular, a method of cutting the object by injecting a gas jet into the cut portion to remove the molten material. Regarding improvements.

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 allows for faster cutting.

[0003] Also, what is very important for efficiently cutting concrete and the like is that the concrete, etc. that has been melted by the beam irradiation (called molten dross) is quickly removed from the beam irradiation position, and the unmelted portion is exposed to the laser beam. The aim is to be exposed to the beam.

[0004] Regarding this point, Japanese Patent Application Laid-Open No. 63-97392
No. (B23K26/16), there is a method in which the cutting groove is gradually widened using multiple laser beams, and the molten material is smoothly removed to the sides and downwards through the cutting groove. Are known. Also, special fair 2-
As in the publication No. 6044 (B23K26/00), a gas jet from a jet nozzle is injected onto the cut portion to actively remove the molten material by the air flow.

[0005]

[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.

[0006] Conventionally, the method of ejecting the molten material by injecting a gas jet has not been sufficiently effective in cutting thick objects because the method of injecting the gas jet was not appropriate. In other words, in conventional technology, the gas jet is generally injected from the front to the rear in the cutting direction to the part being cut, and even when injecting from the back to the front, the gas jet The intersection with the central axis of was aligned with the surface of the concrete mass. As a result, the gas jet was diffused on the surface of the concrete mass and did not penetrate deep enough into the cutting groove. Therefore, even if a powerful gas jet is used, it is possible to quickly remove the molten material near the surface of the concrete mass, but as the melting point becomes deeper, the effect of the gas jet on removing the molten material decreases.

[0007] This invention was made in view of the above-mentioned conventional problems, and its purpose is to effectively utilize a gas jet so that even if the melted part of the cut object becomes deep, the melted material can be quickly removed. An object of the present invention is to provide a method for cutting gas using a laser beam.

[0008]

[Means for Solving the Problems] Therefore, in this invention, a gas jet is ejected obliquely from the rear to the front in the cutting progress direction to the part being cut, and the optical axis of the laser beam and the center of the gas jet are The intersection point with the axis was set at a predetermined depth position inside the object to be cut.

[0009]

[Operation] By arranging the positional relationship between the laser beam and the gas jet as described above, the gas jet passes through the groove that has already been cut and enters the part being cut without any hindrance, reducing the melting point during cutting. Even at depth, the force of the gas jet effectively acts on the melt.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a method of cutting an object using a laser beam to which the present invention is applied. Processing head 1
A focusing lens 2 is built into the housing, and the parallel laser beam 3 from the laser beam oscillator is focused on the lens 2.
It is converted into a focused laser beam 4 and irradiated onto a concrete mass 5, which is the object to be cut. Pressurized gas is supplied to the leading edge of the housing of the processing head 1 through an air pipe 6.
The pressurized gas is blown out from the laser beam 4 exit window. This is to prevent various flying objects and spatters from entering the processing head 1 during cutting of the concrete mass 5.

A jet nozzle 7 is arranged near the machining head 1, and a gas jet 8 ejected from the nozzle 7 is injected onto the part of the concrete mass 5 that is being cut. In this example, the concrete block 5 is moved to the right side of the figure at an appropriate speed,
The concrete block 5 is cut from right to left. Reference numeral 9 in the figure indicates a groove that has already been cut.

As shown in the figure, the jet nozzle 7 is configured to spray the gas jet 8 obliquely from the rear to the front in the direction of cutting, onto the part of the concrete mass 5 that is being cut.
The position of is set. More specifically, the jet nozzle 7 is arranged so that the intersection Q between the optical axis of the laser beam 4 and the central axis of the gas jet 8 is located inside the concrete mass 5 by a distance d from the surface thereof. This dimension d is appropriately set within the range of 1/10 to 1/2 of the thickness of the concrete mass 5. Further, the angle θ between the optical axis of the laser beam 4 and the central axis of the gas jet 8 is appropriately set in the range of 10° to 60°. In this embodiment, the focal point of the laser beam 4 (the focal point of the lens 2) is aligned with the intersection point Q, but the invention is not limited to this.

[0013]

Effects of the Invention In this invention, the arrangement relationship between the laser beam for cutting the object, the gas jet for removing the molten material, and the object and its cutting direction is set as described above, so that the gas jet has already cut the object. The jet enters the cutting groove securely from above the cut groove, and the jet action effectively reaches the melting point during cutting. Therefore, even if the melting point during cutting becomes deeper, the effect of removing the molten material is extremely large, and the cutting speed can be increased.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of a method for cutting an object using a laser beam to which the present invention is applied.

[Explanation of symbols]

1 Processing head 4 Focused laser beam 5 Concrete block 7 Jet nozzle 8. Gas jet 9 Cutting groove Q Intersection

Claims (1)

[Claims] 1. A focused laser beam from a processing head is irradiated onto an object to melt the object and the beam irradiation point is moved to cut the object, and a gas jet is emitted from a jet nozzle located near the processing head. In this method, the gas jet is injected obliquely from the rear to the front in the direction of cutting with respect to the part being cut, so that the optical axis of the laser beam and the 1. A method for cutting an object using a laser beam, characterized in that an intersection point with a central axis of the gas jet is set at a predetermined depth position inside the object.