JP2690184B2 - Laser processing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a laser processing apparatus used for cutting a metal material, and more particularly to a laser processing apparatus that performs drilling at a cutting start point at high speed and safely.

[Conventional technology]

The laser cutting process is performed by irradiating a laser beam on the cutting point of the work and simultaneously blowing an assist gas. It is necessary to make a hole at the cutting start point.

When drilling a metal material, oxygen is used as an assist gas, and an oxidation reaction is made to cooperate with thermal energy processing by a laser. For this reason, the laser beam irradiation surface of the work is in a localized state of thermal machining, and thermal runaway is likely to occur. Once thermal runaway occurred, the molten metal boiled and scattered, scratching the condenser lens and making it impossible to process.

Therefore, in order to prevent this and perform stable and safe drilling, pulse processing is performed using a pulse having a very small frequency and duty. further,
A low pressure assist gas is used.

On the other hand, drilling a highly reflective material is very dangerous because the reflected light of the laser beam returns to the oscillator side. For this reason, drilling of highly reflective materials has not been actively performed. When drilling, it is necessary to avoid such a danger, and it is performed under the processing conditions of the above-mentioned pulse processing and low-pressure assist gas.

[Problems to be solved by the invention]

However, the setting of such processing conditions is very delicate,
It took time. Furthermore, since it is performed by pulse processing, it takes a long time to perform hole drilling. This tendency becomes more remarkable as the plate thickness of the work increases.

The present invention has been made in view of such a point,
An object of the present invention is to provide a laser processing apparatus capable of performing high-speed and safe drilling at a cutting start point.

[Means for solving the problem]

In the present invention, in order to solve the above problems, in a laser processing apparatus that irradiates a laser beam to cut a work, a focusing nozzle that focuses the laser beam on the work, and a focusing nozzle for the surface of the work And a tilt angle control means for controlling the tilt angle for emitting the laser beam so that the tilt angle is maintained at a predetermined tilt angle during drilling at the cutting processing start point and is kept vertical during cutting after completion of the drilling. A laser processing device characterized in that
Provided.

[Action]

The tilt angle control means keeps the tilt angle of emitting the laser beam of the condenser nozzle with respect to the surface of the work at a predetermined tilt angle during drilling at the cutting start point and vertically during cutting after completion of the drilling. To control.

This prevents the molten metal from scattering due to thermal runaway and damaging the condenser lens during drilling. Also, in the drilling process of the highly reflective material, the reflected light is prevented from returning to the oscillator side.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing a state in which the laser processing apparatus of the present invention is positioned at a drilling position. In the figure, the processing head 1 of the laser processing apparatus comprises a Z-axis 2 and a condenser nozzle 3.

A servo motor 4 is provided above the light collecting nozzle 3, and gears 5 and 6 are provided between the light collecting nozzle 3 and the servo motor 4. The condensing nozzle 3 is NC controlled and tilts according to the rotation of the servomotor 4.

A protector 7 is attached to the light collecting nozzle 3.

The laser beam 15 is guided to a drilling position 12 of the work 11 via the reflecting mirror 8 fixed to the Z axis 2, the reflecting mirror 9 in the collecting nozzle 3 and the collecting lens 10. At this time, the laser beam 15 and the work 11 are vertical.

FIG. 2 is a diagram showing a state in which the laser processing device is used for drilling.

The laser processing apparatus tilts the condenser nozzle 3 from the state shown in FIG. 1 to the state shown in FIG. 2 when starting the boring process. Depending on the inclination of the condenser nozzle 3, the laser beam 15
Tilts with respect to the workpiece 11. The tilt angle is, for example, 15
The degree is set to 25 degrees. At this time, the position of workpiece 11 is also NC
Even if the condensing nozzle 3 is controlled and tilted, the drilling position 12 of the workpiece 11 and the position irradiated by the laser beam 15 always match.

The laser processing apparatus carries out the drilling process while the laser beam 15 is inclined. When the boring process is completed, the operation of tilting the light collecting nozzle 3 described above is performed in reverse, and the light collecting nozzle 3 is returned to the vertical position. This operation is performed while the laser beam 15 is being irradiated. When the condenser nozzle 3 is kept vertical, the cutting process is started.

As described above, the boring process at the start of the cutting process is performed with the laser beam 15 tilted with respect to the work 11.
Therefore, even if the laser beam 15 irradiates the work 11 and thermal runaway occurs at the drilling position 12 and the molten metal scatters, the molten metal only hits the protector 7. Therefore, the condenser lens 10 is not affected by the molten metal and is not scratched. Also a condenser lens
The life of 10 will also be extended. In this case, the protector 7 also contributes to the safety of the operator.

Furthermore, if the workpiece 11 is a highly reflective material, such as copper, aluminum, brass or alloys thereof, the reflected light of the laser beam 15 will only hit the protector 7 as well as the molten metal. Therefore, there is no risk that the reflected light will return to the laser oscillator side via the condenser lens 10, and it is possible to perform the drilling safely.

As a result, it is not necessary to perform pulse machining, which has been conventionally performed for stable and safe drilling, and it is possible to perform continuous machining using the maximum output of the laser oscillator. Therefore, the drilling process can be performed at high speed and safely.

For example, using a carbon dioxide laser with an output of 2 KW, the plate thickness is 14 m
When performing drilling on m mild steel, it took about 30 seconds with conventional pulse processing (frequency 45 Hz, duty 20%), but with the laser processing device of the present invention, it is possible to perform It could be processed in 1 second.

Further, when performing drilling on mild steel with a plate thickness of 19 mm, it takes about 2 minutes with conventional pulse processing, but with the laser processing apparatus of the present invention, the pressure of the assist gas is slightly reduced by processing with continuous output. It was possible to process in about 1 second only by setting it high.

Furthermore, copper, which is the most difficult to machine in high-reflectivity materials, can be drilled with a plate thickness of 4 mm, which was previously impossible to machine, in about 2 seconds by the continuous output of 2 KW. No other damage was done.

FIG. 3 is a diagram schematically showing the overall configuration of the laser processing apparatus of the present invention. In the figure, the processor 31 is based on a control program stored in a ROM (not shown),
The processing program stored in the memory 40 is read out and the operation of the entire laser processing apparatus is controlled. The output control circuit 32 has a D / A converter built therein, and converts the output command value output from the processor 31 into a current command value and outputs the current command value. The excitation power source 33 rectifies the commercial power source and then performs a switching operation to generate a high frequency voltage, and supplies a high frequency current according to the current command value to the discharge tube 34 of the laser oscillator.

The laser gas 19 circulates inside the discharge tube 34, and when a high frequency voltage is applied from the excitation power supply 33, a discharge is generated and the laser gas 19 is excited. The rear mirror 35 is a germanium (Ge) mirror having a reflectance of 99.5%, and the output mirror 36 is a zinc selene (ZnSe) mirror having a reflectance of 65%. These mirrors form a Fabry-Perot resonator and are excited. The 10.6 μm light emitted from the laser gas molecules is amplified and a part of the light is output from the output mirror 36 to the outside as a laser beam (laser light) 15.

The output laser beam 15 has a shutter 23a described later.
When is open, change direction with the vendor mirror 28 and press Z
0 through the condenser lens 10 via the axis 2 and the condenser nozzle 3.
It is focused on a spot of 2 mm or less and irradiated on the surface of the work 11.

The memory 40 is a non-volatile memory that stores a machining program, various parameters, and the like, and a battery-backed CMOS is used. In addition, there are a ROM for storing a system program and a RAM for temporarily storing data, but these are omitted in FIG.

The position control circuit 41 controls the rotation of the servo motor 43 via the servo amplifier 42 according to a command from the processor 31, controls the movement of the table 46 by the ball screw 44 and the nut 45, and controls the position of the work 11. Although only one axis is shown in the figure, there are actually a plurality of control axes.

The position control circuit 51 controls the rotation of the servomotor 4 via the servo amplifier 52 in accordance with a command from the processor 31 to control the tilt angle of the condenser nozzle 3.

A CRT, a liquid crystal display device, or the like is used as the display device 48.

Roots blower is used for blower 20 and laser gas 19
Is circulated through coolers 21a and 21b. The cooler 21a is a cooler for cooling the laser gas 19 which has been heated to a high temperature by performing laser oscillation, and the cooler 21b is a cooler for removing compression heat generated by the blower 20.

The shutter control circuit 22 opens and closes the shutter 23a based on a command from the processor 31. The shutter 23a is made of a copper plate or an aluminum plate whose surface is gold-plated. When the shutter 23a is closed, the laser beam 15 output from the output mirror 36 is reflected and absorbed by the beam absorber 23b. When the shutter 23a is opened, the laser beam 15 is applied to the work 11.

The power sensor 24 is composed of a thermoelectric or photoelectric conversion element or the like, and inputs the laser light partially transmitted from the rear mirror 35 and output, and measures the output power of the laser beam 15. A / D
The converter 25 converts the output of the power sensor 24 into a digital value and inputs it to the processor 31.

〔The invention's effect〕

As described above, in the present invention, the drilling process at the start of the cutting process is configured to be performed in a state where the direction of the light collecting nozzle is inclined with respect to the work surface, so that even if the molten metal is scattered, During the drilling process, the condenser lens in the condenser nozzle is not affected by the molten metal and is not scratched.

Further, when the work is made of a highly reflective material, there is no risk that the reflected light of the laser beam will return to the laser oscillator side via the condenser lens, and it is possible to perform the drilling safely.

Therefore, it is not necessary to perform pulse machining which has been conventionally performed for stable and safe drilling, and it is possible to perform machining with continuous output using the maximum output of the laser oscillator. Therefore, drilling at the start of cutting can be performed at high speed and safely.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which the laser processing apparatus of the present invention is positioned at a drilling position, FIG. 2 is a diagram showing a state of drilling by the laser processing apparatus, and FIG. 3 is a laser of the present invention. It is a figure which shows roughly the whole structure of a processing apparatus. 3 ... Focusing nozzle 4, 43 ... Servo motor 5, 6 ... Gear 7 ... Protector 10 ... Focusing lens 11 ... Work 12 ... Drilling position 15 ... Laser beam 31 ... CPU 41 , 51 …… Position control circuit 42, 52 …… Servo amplifier

Claims (6)

(57) [Claims] 1. A laser processing apparatus for irradiating a laser beam to cut and process a workpiece, wherein a focusing nozzle for focusing the laser beam on the workpiece and a laser beam of the focusing nozzle for the surface of the workpiece are emitted. A laser having a tilt angle control means for controlling the tilt angle to be a predetermined tilt angle at the time of drilling at the starting point of cutting and to keep it vertical at the time of cutting after completion of the drilling. Processing equipment. 2. The laser beam is continuously irradiated when the cutting is started after the completion of the drilling at the cutting start point and the tilt angle is kept vertical. The laser processing device described. 3. The tilt angle control means, when the tilt angle is controlled and changed, so that the drilling position of the work and the position irradiated by the laser beam always coincide with each other. The laser processing apparatus according to claim 1, wherein the tilt angle of the shaft and the position of the work are controlled. 4. The laser processing apparatus according to claim 1, wherein the tilt angle control means is a numerical control device. 5. The protector for preventing molten metal from scattering is provided on the light collecting nozzle.
The laser processing apparatus according to the above. 6. The laser processing apparatus according to claim 1, wherein the boring process is performed with continuous output.