JPS5987995A - Laser and gas cutter - Google Patents

Abstract

PURPOSE:To make effective use of the heat of laser light in performing cutting by making the axial center of a condenser lens for laser light and the axial center of a nozzle for gaseous oxygen for cutting coincident with each other, and forming a firing spot by the laser light around the projection area of a nozzle. CONSTITUTION:Assist gas 4 is supplied from the spacing between an outside pipe 8 and an inside pipe 9 to the space 7 at the top end of a torch 5, and laser light 1 is radiated, via a lens 2, to a material 3 to be cut. Since the focal point of the lens is positioned lower than the top end of a nozzle 11 and a reflection plate 12 is provided in the upper part of the pipe 8, the laser light 1 irradiates the part around the projection surface of the nozzle 11 in a C shape. Then the material 3 is preheated to the temp. at which the part thereof around the projection surface of the nozzle 11 can cause combustion reaction, whereby a firing spot (b) is formed. When gaseous oxygen 10 is ejected from a nozzle 9 via the pipe 9 in this state, the oxidation and combustion reaction takes place in the spot (b) part, thereby blowing downward the formed slag. The torch 5 is then moved in an arrow (a) direction whereby cutting is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on a chemical reaction of substances, a material that can be cut by a combustion reaction;
In particular, the present invention relates to a laser/gas cutting device that cuts thick plates of mild steel using laser light and oxygen gas.

Currently, gas cutting is the mainstream method for cutting materials by combustion reaction.

As is well known, gas cutting involves preheating the area around the cutting point with a preheating flame.
The preheating flame brings the interest into a combustible state and blows high-purity oxygen gas to the cut point, thereby burning and fusing the luJ cut point.

In such gas cutting, 7.
Although it is theoretically possible to cut at a cutting speed of about 0.8 m/min, in reality the cutting speed is 0.8 to 0.0 m/min for a plate thickness of 12 tn+n.
The limit is 9 m 7 mIn. This is because the heat density of the preheating flame is low and the area around the cutting point cannot be preheated at a high speed.

On the other hand, in recent years, a method has been developed in which a heat source with a high heat density, that is, a laser beam, is used to fuse the laser beam as the main cutting energy.

In Figure 1, the laser beam (1) is focused on one cut point by the lens (2), the cut point of the material to be cut (3) is melted, and the air is
Assist gas (4) such as oxygen, argon, nitrogen, etc. is sprayed at the cutting point to blow off the molten metal, and assist gas (4) such as oxygen, argon, nitrogen, etc.
) to prevent molten metal from bouncing back. This assist gas that is not used for cutting has the disadvantage of cooling the cutting point, and the heat of the laser beam cannot be effectively used for cutting.

Furthermore, cutting thick plates with laser light requires a high-power, high-output laser oscillator, which increases running costs and equipment costs, and the maximum quality processing limit is when the plate thickness is 1.
Around 0 vomiting.

There is also a cutting method using oxygen plasma, but the q-notch cutting method results in a tapered cut surface and requires replacement of the electrode nozzle, resulting in poor operating efficiency. Further, it has drawbacks such as requiring a large amount of electric power and producing significant noise.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser gas cutting device that enables gas cutting while rapidly preheating the area around the cutting point using a laser beam. It is equipped with a lens that irradiates the material to be cut in a required area, and a cutting oxygen gas nozzle that has a smaller diameter than the laser irradiation area and is provided so that the optical axis of the lens and the TIQII center coincide with each other. L1 is characterized in that it is configured so that an ignition spot is formed around the projection surface by the laser beam and cutting oxygen gas can be ejected from the nozzle.

The present invention will be described in detail below with reference to the drawings.

In FIG. 2, reference numeral (5) indicates a torch main body, and the interior of the torch main body is hollow, into which a lens (2) and a holder (6) are fixed. 1. The tip of the -te main body (5) and the +M section are in the shape of an inverted truncated cone, and the space (7) on the tip side partitioned by the lens (2) is also shaped like an inverted circular saw truncated shape. be.

1. An outer tube (8) is fixed to the distal end of the main body (5) from the lateral direction so as to communicate with the space (7), and the outer tube (8) is connected to a gas source (not shown in the figure). When the assist gas (4) is supplied from the pipe (8), it is discharged from the opening at the tip of the main body along the inner wall of the space (7).

Further, the inner tube (9) is inserted into the outer tube (8), and the tip thereof is projected into the space (7) and bent, so that the axis of the bent portion and the original axis of the lens (2) are aligned. When mating, let its tip protrude slightly from the tip of the 1-chi main body (5). The outer surface of the inner tube (9) is plated with gold or the like so that the laser beam (1) is totally reflected, and the inner tube (9) has a double tube structure so that cooling water can be circulated. A high-purity oxygen gas source (not shown) is connected to the inner tube (()), and the inner tube (9) is connected so that the pressure-regulated oxygen gas θ0) is ejected from the tip of the inner tube (9).
The tip is used as a cutting oxygen jet nozzle (11).

The focal point of the lens (2) is below the tip of the nozzle (J), and the lens is designed so that when the laser beam (1) is irradiated, the diameter of the irradiated surface is larger than the outer diameter of the nozzle (0). Determine the focal length, lens position, etc.

Here, in order to prevent the tip of the inner tube (9) from being heated by the laser beam (1), a reflection plate θ force is placed inside the outer tube (8) above the inner tube (9) (on the lens side). is inserted through the inner tube, and the distal end thereof is made to protrude into the space (7), so that the distal end of the inner tube (9) can be covered by the shadow of the reflection plate θ. The reflecting plate θ is plated with gold, etc., like the outer surface of the inner tube (9).

Next, the operation of the present invention will be explained.

Assist gas (4) is supplied to the space (7) through the gap between the outer tube (8) and the inner tube (9), and is ejected in a donut shape along the inner wall of the space (7). the lens (
2) to the moon to be cut (3). As mentioned above, since the lens (2) has its focal position 1 below the tip of the nozzle (11), the periphery of the projection plane of the nozzle αυ is irradiated in a C-shape by the shadow of the reflection plate 02 (6th (see figure)
. The laser beam (1) K is used to cut the material (3) through the nozzle (11).
) is preheated to a temperature that allows a combustion reaction, creating an ignition spot (b). When a pressure-regulated oxygen gas is ejected from the nozzle (1υ), the oxygen gas θ()-1 causes an oxidative combustion reaction with the ignition spot l-(b) of the material to be cut (3), and oxidizes. The lower blade blows off the slag generated by combustion.

Cutting is then performed by moving the torch in the direction of the arrow (CL).

Here, since the laser beam (1) 14 has a high heat density, rapid preheating is possible, and even if the moving speed of the torch is increased, the oxygen gas θO1 is always injected to a sufficiently preheated ignition spot, making it smooth. A cut I07 can be performed.

Therefore, the irradiation surface ν of the laser beam (1) and the intensity of the laser beam,
If the pressure of the oxygen sludge (00) is taken into account (~), it is possible to cut a mild steel plate up to 3 m/ml with a thickness of 50 mm.

In addition, the above-mentioned assist gas (argon, -\Ryuno 1
, oxygen, carbon dioxide, etc.), the molten metal rebounds and the nozzle 0
This is to prevent the gas from adhering to the lens (2), etc., and may be a low-pressure gas.

In the above embodiment, the reflecting plate (2) was made to protrude from the outer tube (8) into the space (7), but it was directly connected to the main body (5).
) may be provided. Moreover, if the laser beam (1) can be reflected by plating the outer surface of the inner tube (9) and the inner tube (9) can be protected,
Reflector plate 0■ is not particularly necessary. In addition, the outer tube (8) and the inner tube (
9) are separated from each other instead of having a double structure, and the torch body (5
) may be provided. It goes without saying that various other changes may be made without departing from the gist of the present invention.

As described above, according to the present invention, (1) Cutting is performed using a laser beam and oxygen gas. Instead of cutting directly with the laser beam, only preheating is required, so a low output laser is required, and the amount of heat input is small. (11) Low heat input allows cutting with high precision and low distortion; (iii) Rapid preheating is possible with laser light, greatly increasing cutting speed. I can do it (1■)
The kerf width is small, and unlike plasma cutting, an arc is used (no arc is used, so there is no fucoam) (■) Unlike plasma cutting, there is no need to replace the electrode nozzle, so unmanned operation is possible, (vi) It does not easily generate m-sounds and exhibits various excellent effects on pipes.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing conventional cutting with laser light, Figure 2
The figure is a partial schematic diagram of the present invention, and FIG. 3 is an explanatory diagram showing the shape of a heat spot in the present invention. (1) is a laser beam, (2) is a lens, (3) is a cutting target, (9) t'' is an inner tube, (IQ is oxygen gas, (11) u
Shows the nozzle.

Claims (1)

[Claims] 1) A lens that irradiates the material to be cut with a laser beam over a required area, and a cutting oxygen gas nozzle that has a smaller diameter than the diameter of the laser irradiation area and is provided so that the optical axis of the lens and the axis coincide with each other. 1. A laser gas cutting device characterized in that the laser beam is configured to form an ignition spot around the projection surface of the nozzle on a material, and the cutting oxygen gas can be ejected from the nozzle.