JPH0357579A - Laser beam machining method - Google Patents

Abstract

PURPOSE:To stably cut a material to be worked by bringing an object to be worked to piercing by a laser light, and thereafter, varing continuously or stepwise an output of the laser light to a prescribed output, and the thereafter, starting the cutting by a prescribed output. CONSTITUTION:During the time T1 required for piercing, a relative position relation of a laser light and a steel plate being an object to be worked is constant, and in a cutting start point, a through-hole is formed. After the elapse of time T1, without varying the relative position relation, during T2, an output being suitable for piercing is varied stepwise to an output being suitable for cutting. A working range by the laser light is also varied stepwise. After the elapse of time T2, during T3, by varying the position relation of the laser light and the steel plate, cutting is executed. In such a way, at the time of shifting to cutting from piercing, self-burning is prevented, and also, in a cutting start point, an excessive hole is not formed, it is unnecessary to provided the cutting start point in a place separated from a locus, and a material to be worked can be used effectively.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a laser processing method for cutting a workpiece such as a steel plate into a predetermined shape using laser light. .

(Prior art) When cutting out a predetermined shape from a metal material as a workpiece using a laser beam, it is necessary to provide a through hole at the cutting start point on the metal material, and this is generally called piercing. There is. In this piercing process, if the output of the laser beam irradiated onto the processed surface of the metal material is too large, the balance between the heat energy of the reaction between the assist gas and the metal material and the thermal diffusion rate of the metal particles will be lost, resulting in self-burning. ) occurs. Due to this self-burning, a hole larger than the diameter of the incident laser beam is formed at the piercing point on the metal material. Therefore, when the average laser output is high, such as when cutting using continuous wave (CW) laser light, it is necessary to set the laser output during the viaring process lower than the laser output during the cutting process, and the piercing process ends. After that, before moving on to the cutting process, it is necessary to switch the laser output from low output to high output. Figure 3 shows
3 is a time chart of laser output according to the laser cutting method.

Hereinafter, the conventional laser cutting method will be explained in more detail with reference to FIG.

In Figure 3, T1 is the time required for viasing processing +
T3 indicates the time required for cutting. During T1, the relative positional relationship between the laser beam and the metal material is constant, and the laser output remains lower than during T3. After T1, the laser output is instantaneously switched to high output, and then during T3, the relative positional relationship between the laser beam and the metal material changes, and cutting is started.

(Problems to be Solved by the Invention) However, in the conventional laser processing method, the laser output is instantly switched from low output to high output after the pianing process is completed, so that the processing range by the laser beam rapidly expands. For this reason, there was a problem in that the thermal energy of the reaction between the ASIS 1 gas and the metal material induced by the laser beam increased rapidly, and self-burning was likely to occur. Therefore, the present invention has been made to solve the above problems, and provides a laser that can perform good and stable cutting without self-burning when changing the laser output after the completion of the viasing process. The purpose is to provide a processing method.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides, after performing biang processing on a workpiece with a laser beam, a laser beam that has been irradiated on the workpiece. A laser processing method is provided in which the output is changed continuously or stepwise to a predetermined output over a predetermined period of time, and then cutting is started using the predetermined output.

(Function) In the laser processing method described above, by gradually changing the laser output from low to high output, the processing range by the laser beam gradually expands, so the assist induced by the laser beam It is possible to prevent the occurrence of self-burning, which occurs due to a sudden increase in the heat energy of the reaction between the gas and the workpiece.

(Example) An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a time chart of laser output in this embodiment.

In the same figure, T1 is the time required for piercing, T
2 indicates the time required to change the laser output, and T3 indicates the time required for cutting.

The laser processing method in this embodiment is performed during T1 and T3.
In the operation during T1, the relative positional relationship between the laser beam and the steel plate as the workpiece is constant, and a through hole is formed at the cutting start point. After T1, the output of the laser light penetrating the steel plate is gradually changed from an output suitable for piercing to an output suitable for cutting during T2, without changing the relative positional relationship between the laser beam and the steel plate. change to Due to this operation during T2, the processing range by the laser beam at the biang processing point also changes stepwise. After that, after T2 has elapsed, the processing range of the laser beam is in a state equivalent to the processing range of the laser beam at the laser output for cutting, and after this, during T3, the positional relationship between the laser beam and the steel plate is changed, and cutting is performed. Perform processing. As described above, in this embodiment, by providing T2 between T1 and T3, there is no sudden change in the machining range caused by the laser beam, and self-burning does not occur from piercing to cutting, and cutting can be performed smoothly. can be migrated.

In addition, as another embodiment of the present invention, as shown in FIG. 2, the effect of the present invention can be sufficiently achieved even if the laser output is changed continuously in the process of changing the laser output.

[Effects of the Invention] As explained above, according to the present invention, it is possible to prevent the occurrence of self-knocking when transitioning from the viasing process to the cutting process, and furthermore, it is possible to prevent the formation of an excessively large hole even at the cutting start point. Since there is no cutting start point, there is no need to set the cutting start point at a location away from the locus of the required cutting shape, and the workpiece can be used effectively. Furthermore, since there is no need to interrupt the cutting operation due to self-burning and the time required for its return, the cutting operation has excellent effects in terms of working efficiency, such as shortening the working time.

[Brief explanation of drawings]

6 Fig. 1 is a laser output time chart showing one embodiment of the present invention, Fig. 2 is a laser output time chart showing another embodiment of the present invention, and Fig. 3 is a conventional laser processing method. There is a laser output time chart. T1... Viasing processing time, T2... Laser output change time, T3... Cutting processing time

Claims (1)

[Claims] In a laser processing method in which cutting is performed by irradiating a laser beam onto a workpiece such as a steel plate, after piercing the workpiece with the laser beam, the output of the laser beam irradiated on the workpiece is reduced. A laser processing method characterized by changing the output to a predetermined output continuously or stepwise, and then starting cutting at the predetermined output.