JPH0230387A - Laser beam cutting method - Google Patents

Abstract

PURPOSE:To prevent plasma from being generated during cutting and to reduce cutting cost by mixing He gas in air to form assisting gas and carrying out laser beam cutting while injecting said assisting gas toward a work from a nozzle. CONSTITUTION:An assisting gas supply port from an assisting gas feeder 8 is arranged to the nozzle 6 and a He bomb 9 and a compressor 10 are set up on the assisting gas feeder 8. The air in an air tank 12 is sent to a mixing machine 13 and mixed with He from the bomb 9 at a prescribed mixing ratio thereby and sent to the nozzle 6. At the time of cutting the work 7, piercing is carried out by the adjusted He mixed gas and then, the assisting gas is injected by using only the air to carry out laser beam cutting. By this method, the plasma is prevented from being generated during cutting and cutting cost is reduced, as a large quantity of inexpensive air can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser cutting method for cutting a workpiece such as an Al'PAI alloy using a laser beam.

[Conventional technology]

Conventionally, when cutting a workpiece made of Al7 or Aρ alloy using a laser beam, N2, air, or the like is used as an assist gas. For example, Japanese Patent Application No. 61-205171,
Patent Application No. 1982-098293, etc.

[Problem to be solved by the invention]

However, in the cutting method using N2 as the assist gas, a large amount of N2 gas is ejected to the workpiece at high pressure while cutting, which causes an increase in running costs.

Further, in the cutting method using air as the assist gas, since plasma is generated by AfI vapor during cutting, there are problems such as a high cutting failure rate.

In order to prevent the above-mentioned problems, there is a method of using He gas, N2 gas, Ar gas, etc., which have a high degree of plasma generation.

The plasma temperature of each gas is He: 18°000°C.
, N2: 20,000°C, Ar: 21°,000°C,
Ar>N2>N2.

However, since Ar has a relatively low ionization voltage, it is easily ionized and turned into plasma more easily than He.

Therefore, in order to prevent plasma generation, He gas may be used, but since He gas is expensive like N2 gas, there is a problem that running costs increase.

This invention was made to improve the above-mentioned problems, and aims to provide a laser cutting method that has a low cutting defect rate and low running costs.

[Means and operations for solving the problems] In order to achieve the above object, the present invention includes a laser cutting method for cutting a workpiece made of Al, AD, or gold using a laser beam and an assist gas. This laser cutting method aims to reduce the defective rate by suppressing the plasma generated during cutting by mixing the assist gas and cutting the workpiece with a laser beam while jetting this assist gas toward the workpiece from a nozzle. The present invention provides a method.

〔Example〕

An embodiment of the method of this invention will be described in detail with reference to the drawings.

In the figure, 1 is a laser oscillator, and the laser beam 2 oscillated from this laser oscillator 1 is transmitted through multiple mirrors (1 in the figure).
(only one sheet is shown) 3 to the processing head 4, the light is focused by the lens 5 provided in the processing head 4, and is irradiated through the nozzle 6 toward the rework 7, where it is used for cutting the work 7. It will be done.

Further, rear assist gas is supplied to the nozzle 6 from an assist gas supply bag W8, and is ejected toward the workpiece 7 together with the laser beam 2.

The assist gas supply device 8 contains 0 gas containing 02 gas.
Equipped with 2 gas cylinders 9 and 1 konbu IO,
The air pressurized by the compressor 10 is dehydrated by a dry air unit 11 and then sent to an air tank 12.
Pressure is stored inside.

Also, the air in the air tank 12 is sent to the mixer 13,
The mixer 13 mixes the He gas supplied from the He gas cylinder 9 so that the mixing ratio of He is, for example, 40%, and then sends it to the nozzle 6 as an assist gas through the pressure adjustment circuit 14 to the workpiece 7. Served for cutting.

Next, the laser cutting method will be explained. Before cutting the workpiece 7 made of AΩ or 1 alloy, the workpiece 7 is first pierced.

In the viasing of the workpiece 7, first, the solenoid valve 15 is opened, and air mixed with He at a predetermined mixing ratio flows to the pressure regulation circuit 14.The solenoid valve 16 of the pressure regulation circuit 14 is opened, and the regulator 17 Approximately 2 kg/c
The assist gas whose pressure is regulated to j is supplied to the nozzle 6,
The laser beam 2 is ejected to the workpiece 7, and the workpiece 7
Viasing is performed.

Thereafter, cutting begins; however, if the shape of the workpiece 7 is small, the cutting speed must be slowed down due to the time lag of the mechanical system.

For this reason, there is little risk of plasma generation and poor cutting, so after piercing, close the solenoid valve 15 and close the solenoid valve 2.
2 is opened and only air is supplied to the pressure adjustment circuit 14.

In addition, in order to prevent dross from adhering to the cutting part, the solenoid valve 20 is opened, and the regulator 21 allows 8 kg /
Air regulated to a high pressure of c- is supplied to the nozzle 6 as an assist gas to cut the workpiece 7.

On the other hand, if the workpiece 7 is large, a mixed gas of air and He gas at a predetermined mixing ratio is supplied as an assist gas to the pressure adjustment circuit 14, the solenoid valve 18 is opened, and the regulator 19 is operated to / cd is supplied to the nozzle 6 to cut the workpiece 7 at a relatively high speed.

When cutting was performed using the Al1 or Ap gold alloy laser beam 2 as described above, the generation of plasma during cutting was reduced, making it possible to significantly reduce the rate of defective cutting.

Note that FIG. 2 shows the relationship between the mixing ratio of He gas and the cutting success rate.

As is clear from this figure, by increasing the He gas mixing ratio, the success rate increases almost proportionally, and
When 40% or more of He gas was mixed, the success rate was 100%, and the effect of mixing He gas could be confirmed.

Further, in the above embodiment, only air and a mixed gas of air and He can be supplied to the nozzle 6, but as shown in FIG. It may be possible to provide mutual support.

Furthermore, as shown in Fig. 4, the air is heated at a predetermined ratio in advance.
The mixed gas mixed with the e gas may be stored in the mixed gas cylinder 25, and the mixed gas may be supplied from the mixed gas cylinder 25 to the nozzle 6 as an assist gas, or the 02 gas may also be mixed and supplied to the nozzle 6. .

〔Effect of the invention〕

As detailed above, in this invention, He gas is mixed with air to form an assist gas, and the workpiece is cut with a laser beam while this assist gas is jetted onto the workpiece, so that plasma is generated during cutting. As a result, the defect rate caused by plasma can be significantly reduced, and since inexpensive air can be used as the assist gas, running costs can also be reduced.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a circuit diagram, FIG. 2 is a diagram showing the relationship between He mixing ratio and cutting success rate, and FIG.
4 and 4 are explanatory diagrams showing other embodiments. 2 is a laser beam, 6 is a nozzle, and 7 is a workpiece. Applicant Komatsu Manufacturing Co., Ltd. Representative Patent Attorney Masaaki Yonehara

Claims (2)

[Claims] (1) Al using laser beam 2 and assist gas
In a laser cutting method for cutting a workpiece made of or Al alloy, He is mixed with air to form an assist gas, and the workpiece 7 is cut by the laser beam 2 while the assist gas is jetted toward the workpiece 7 from a nozzle 6. A laser cutting method featuring: (2) The laser cutting method according to claim 1, characterized in that He is used as the assist gas.