JPH0215892A - Laser cutting method for plate of brittle material - Google Patents

Abstract

PURPOSE:To easily and speedily cut off a plate material irrespective of its thickness with a laser beam machine of small capacity by providing a V-shaped notch in laser beams on one side of the plate material, then, lowering the temperature of this plate material to the room temperature, then, irradiating laser beams to the bottom part of the V-shaped notch again and breaking it. CONSTITUTION:The laser beams 2 emitted from a laser beam oscillator 1 is bent by a reflector 3 downward, condensed by a condenser 4 stored in a nozzle head, irradiated to a thick steel plate 5 to form a rectilinear or nearly rectilinear notch 5a on the surface of the steel plate 5. Then, this preworked steel plate 5 is returned to the original point and carbon dioxide gas laser beams 2 irradiates the lower end of the notch 5a. Then, the steel plate 5 receives a quick thermal shock, a crack is generated from the bottom of the notch 5a, arrives at the lower surface to break the steel plate instantly. In this manner, a thick plate can be cut off easily even by a laser beam machine of small capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for cutting a brittle material plate using a laser beam.

(Conventional technology) Conventionally, diamond cutters and grindstones have been used to cut brittle metal materials such as molybdenum and tungsten, and brittle non-metal materials such as glass and stone, while gas cutting has been commonly used to cut thick steel plates. Recently, laser light has also been used for thin plates.

(Problem W1 to be solved by the invention) However, these processes take time as the material becomes thicker. Moreover, the accuracy of cutting dimensions is generally poor and the cut surface is rough. Furthermore, in the case of gas cutting, there is often dross on the back side, making it unusable as is.

For this reason, cutting with the above-mentioned laser beam has recently been carried out, but even with the recently put into practical use a high-output carbon dioxide gas laser processing machine (output 10KW), a steel plate can be cut with a cutting speed of 1.2 to 16 kW. am
As with gas cutting, there are problems such as roughness of the cut surface and adhesion of dross.
Steel plates such as S41 material may crack due to the heat.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to obtain a laser cutting method for a brittle material plate that can easily and quickly cut a brittle material plate regardless of its thickness with a small amount of energy.

[Structure of the invention]

(Means and effects for solving the problem) The present invention is a method of cutting a plate made of a brittle material into a substantially straight line using a laser beam. First, a V-shaped notch is formed on one side of the plate using a laser beam, and then After cooling the board to room temperature,
This is a laser cutting method for a brittle material plate that can be easily and quickly cut by a small-capacity laser processing machine regardless of the plate thickness by irradiating the bottom of the V-shaped notch with laser light again to break it.

(Example) Hereinafter, an example of the laser cutting method for a brittle material plate according to the present invention will be described with reference to the drawings.

In FIG. 1, a laser beam 2 emitted from a laser oscillator 1 is bent downward by a reflection mirror 3 provided in a transmission path (not shown), and is focused by a condensing mirror 4 housed in a nozzle head (not shown). A thick steel plate 5 on an NC table (not shown) is irradiated with a straight or almost straight notch 5a.
is formed on the surface of the steel plate 5. And this notch 5a
According to the experimental results of the present inventors, the depth is 1 of the thickness of the steel plate 5.
Approximately 0% is preferable. (Note: If the depth is too deep, cracks may occur in the steel plate 5 due to brittleness.) Next, the previously processed steel plate 5 is returned to its origin using an NC table (not shown), and is driven by the NC tape used for the notch to output. The lower end of the notch 5a is irradiated with a carbon dioxide gas laser beam 2 of a low temperature.

Then, the steel plate 5 undergoes a sudden thermal shock, as shown in FIG.
A crack 6 occurs from the bottom of the notch 5a, reaches the lower surface, and breaks instantly.

Therefore, according to this processing method, even a steel plate of about 30 mm+, which could not be cut conventionally, can be easily cut with a 5Kli1 class laser processing machine.

FIG. 3 shows another embodiment of the laser cutting method for a brittle material plate according to the present invention.

In FIG. 3, a steel plate 5 with a linear notch 5a formed therein.
On the bottom surface, round bar jigs 7a are placed at equal intervals left and right from the perpendicular line of the notch 5a, and on the left and right of the top surface, round bar jigs 7b are placed at equal intervals. At the same time, a load is applied on the jig 7b to apply tensile stress to the upper surface of the plate material 5.

This method has the advantage that it can break even if the notch 5a is shallow or the intensity of the laser beam 1 during processing is weak compared to the method shown in FIG. 2 in which stress is not applied.

FIG. 4 shows another embodiment of the laser cutting method for a brittle material plate according to the present invention. In FIG. 4, in addition to FIG. 3, the plates 5 are cooled by being placed in a container 9 filled with a refrigerant 8 such as ice water, dry ice, or liquid nitrogen.

In this case, the thermal shock is even greater than in the method shown in FIG. 3, so that a weaker laser beam can break a thicker material. When cutting steel materials using this method, the transition temperature (approximately -40°C for structural carbon steel) that causes low-temperature embrittlement of the steel material is required.
It breaks very easily when cooled below.

Note that this cooling method can also be applied to a method in which no tensile stress is applied to the upper surface of the plate material 5 as shown in FIG.

〔Effect of the invention〕

As described above, according to the laser cutting method for a brittle material plate of the present invention, a V-shaped notch is first provided as a pre-processing on one side of a brittle material plate, and after the plate is returned to room temperature, the laser beam is applied to the V-shaped cutout again. Since the cutting was performed by irradiating the bottom of the shaped notch and taking advantage of the brittleness of the plate material, it is possible to obtain a laser cutting method for brittle material plates that can easily cut thick plates even with a small-capacity laser processing machine. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the laser cutting method for a brittle material plate according to the present invention, and FIGS. 2 to 4 are diagrams showing other embodiments of the laser cutting method for a brittle material plate according to the present invention. . 1...Laser oscillator 2...Laser light 5...Brittle material plate 5a...Notch (8733) Representative patent attorney Yoshiaki Inomata (and 1 other person) Hizuzu Figure A Figure figure

Claims (1)

[Claims] A method for laser cutting a brittle material plate by irradiating a laser beam onto the brittle material plate, comprising: providing a V-shaped notch with the laser beam along a cutting line of the plate; A method for laser cutting a brittle material plate, in which the plate is then lowered to room temperature or lower, and the cutout portion is irradiated with laser light again to break along the cutting line.