JPH0788669A - Laser beam machine - Google Patents

Abstract

PURPOSE:To perform a cutting work at a high speed in a laser working method by which a mild steel is cut by irradiating it with a laser beam by using oxygen or mixed gas containing oxygen as assist gas. CONSTITUTION:A working nozzle 12 is connected on the tip side of the main body part 11 of a working head 10. A laser beam 20 converged by a condenser lens 15, is emitted from this nozzle tip part 12a toward a working point with assist gas supplied from an assist gas introducing port 14. In the working nozzle 12, an ozone introducing port 130 opening on the nozzle tip part 12a side, is provided, and ozone is supplied from an ozone generator 13 to the ozone introducing port 130. This ozone is mixed with assist gas from the nozzle tip part 12a, and is injected toward a working point. Therefore, even when an oxidation reaction is not sufficiently activated with only assist gas, the oxidation reaction between the ozone and a mild steel which is a work material, can be activated, oxidation reaction energy is increased, and an oxidation reaction speed is also increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for cutting a mild steel material by irradiating laser light with oxygen or a mixed gas containing oxygen as an assist gas.

[0002]

2. Description of the Related Art When cutting a mild steel material, as shown in FIG. 4, when the maximum machining speeds V ₁ and V ₂ existing for each plate thickness are exceeded, the relation between the laser output and the machining speed becomes non-proportional. The phenomenon occurs. Therefore, the cutting speed is naturally limited.

In the case of laser cutting, it is considered difficult to exceed the processing speed of plasma or punch press, which have competing processing purposes, unless this problem is solved.

By the way, the cutting of the mild steel material is performed not only by the laser energy (laser output) of the laser light itself, but also by the oxidation generated between the oxygen of the assist gas and the iron which is the main component of the mild steel material. The reaction energy is also greatly contributed.

[0005]

FIG. 5 is a diagram qualitatively showing the relationship between the laser energy, the oxidation reaction energy and the cutting speed. As shown in the figure, when the cutting speed increases, even if the laser energy can be sufficiently supplied, the generated oxidation reaction energy is decreased and becomes insufficient. Due to this lack of oxidation reaction energy, defective cutting occurs.

FIG. 6 shows a cutting process according to a conventional method.
It is a figure which shows a dross component qualitatively. In addition, with dross
Indicates a lump of molten metal generated during cutting. Shown in the figure
As the cutting speed increases, the oxidized iron
FeO, Fe indicating that₃0 _FourThe percentage of
The proportion of iron (Fe) that remains unoxidized increases
It In other words, at higher cutting speeds, mild steel materials
The oxidation reaction does not proceed and the amount of unreacted iron increases. others
Therefore, the cutting speed cannot be increased so much. Unopposed
Ote iron has poor fluidity compared to oxidized iron, so it is a processed material.
The material remains attached to the material, and from this point also the cutting speed is high.
Maturation is inhibited.

The present invention has been made in view of the above points, and an object thereof is to provide a laser processing apparatus capable of performing cutting processing at high speed.

[0008]

In order to solve the above-mentioned problems, the present invention provides a laser processing apparatus for irradiating a laser beam with oxygen or a mixed gas containing oxygen as an assist gas to cut a mild steel material. There is provided a laser processing apparatus characterized in that an ozone generating means for generating is supplied and ozone from the ozone generating means is supplied to the processing point and its vicinity together with the assist gas.

[0009]

Function: Ozone, which has a strong oxidizing effect, is mixed with the assist gas and supplied to the processing point and its vicinity. Therefore, even if the oxidation reaction does not proceed sufficiently with the assist gas alone, the oxidation reaction between the mild steel material as the work material and oxygen is activated, the oxidation reaction energy increases, and the oxidation reaction rate also increases. Therefore, even if the cutting speed is increased,
It is possible to perform cutting processing promptly following the processing speed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a processing head according to the laser processing apparatus of the present invention. In the figure, the processing head 10
The main body portion 11 is formed in a cylindrical shape, and an assist gas introduction port 14 is provided in a part of its side wall. Body part 1
A processing nozzle 12 is connected to and provided on the front end side of 1. The laser light 20 condensed by the condenser lens 15 is emitted from the nozzle tip portion 12a toward the processing point. Further, the assist gas introduced from the assist gas introduction port 14 is jetted toward the processing point together with the laser light 20.

The processing nozzle 12 has a nozzle tip 12a.
An ozone inlet 130 that is open to the side is provided. Ozone from the ozone generator 13 is introduced into the ozone inlet 130, mixed with the assist gas from the nozzle tip portion 12a, and ejected toward the processing point. Ozone is a gas with a strong oxidizing action. Also, ozone changes to more stable oxygen over time, but in this embodiment,
Since the ozone generator 13 is provided to supply the ozone that has just been generated and is generated, the ozone state having a strong oxidizing action can be maintained.

The laser light 20, the assist gas, and the ozone from the ozone inlet 130 are all emitted toward the processing point or its vicinity, and the mild steel material of the work is cut by its thermal and chemical action. .

Next, the components of energy and dross generated at and near the processing point during cutting will be described.
FIG. 2 is a diagram qualitatively showing the relationship between the energy generated during cutting and the cutting speed. As shown, the laser energy can be increased in proportion to the cutting speed.

On the other hand, in this embodiment, ozone is supplied from the ozone inlet 130 when the cutting speed is increased. For this reason, the oxidation reaction energy increases as shown by the solid line, as compared with the oxidation reaction energy by the conventional assist gas shown by the broken line in the figure. That is, even if the assist gas alone does not promote the oxidation reaction,
Ozone activates the oxidation reaction with the mild steel material that is the work material, increases the oxidation reaction energy, and increases the oxidation reaction rate. Therefore, even if the processing speed of the cutting processing is increased, the cutting processing can be performed quickly following the processing speed.

FIG. 3 is a diagram qualitatively showing the dross component during the cutting process. In this embodiment, ozone is supplied from the ozone inlet 130 when the cutting speed is increased. Therefore, each component of the dross, which is shown by the broken line in the figure and only by the conventional assist gas, changes as shown by the solid line. Especially remarkable is iron (Fe) without oxidation.
The ratio of remaining as it is is greatly reduced, and FeO, which is a compound of ozone and iron, is increased instead.

As described above, the supply of ozone actively promotes the oxidation reaction with iron, and as a result, the amount of unreacted iron is greatly reduced, so that the cutting speed can be increased. In addition, unreacted iron has poor fluidity compared to oxidized iron and remains attached to the processing material, but the amount of unreacted iron is greatly reduced. Higher speed is possible.

[0017]

As described above, in the present invention, ozone having a strong oxidizing action is mixed in the assist gas and supplied to the processing point and its vicinity. For this reason, even if the oxidation reaction does not proceed sufficiently with the assist gas alone, the oxidation reaction between the mild steel material that is the work material and oxygen can be activated, the oxidation reaction energy increases, and the oxidation reaction rate also increases. Increase. Therefore, even if the processing speed of the cutting processing is increased, the cutting processing can be performed quickly following the processing speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a processing head according to a laser processing apparatus of the present invention.

FIG. 2 is a diagram qualitatively showing a relationship between energy generated during cutting and cutting speed.

FIG. 3 is a diagram qualitatively showing dross components during cutting.

FIG. 4 is a diagram showing a relationship between a laser output and a processing speed.

FIG. 5 is a diagram qualitatively showing the relationship between laser energy, oxidation reaction energy and cutting speed.

FIG. 6 is a diagram qualitatively showing a dross component during cutting processing by a conventional method.

[Explanation of symbols]

 10 Processing Head 11 Body Part 12 Processing Nozzle 12a Nozzle Tip 13 Ozone Generator 14 Assist Gas Inlet 15 Condenser Lens 20 Laser Light 130 Ozone Inlet

Claims (2)

[Claims] 1. A laser processing apparatus for cutting a mild steel material by irradiating laser light with oxygen or a mixed gas containing oxygen as an assist gas, wherein an ozone generating means for generating ozone is provided, and the ozone generating means is provided. A laser processing apparatus, wherein ozone is supplied together with the assist gas to a processing point and its vicinity. 2. The laser processing apparatus according to claim 1, wherein the ozone is supplied from an ozone introduction port provided in a processing nozzle.