JPH03165980A - Method and device for laser beam machining - Google Patents

Abstract

PURPOSE:To shorten the piercing time and to improve operability in passing through a piercing hole on a work by a laser beam by detecting a pressure drop of assisting gas generated on the inside of a laser beam nozzle by a pressure sensor. CONSTITUTION:The assisting gas pressure drop generated at the time of passing through the piercing hole 31 by the laser beam LB on the work W positioned on a work table 11 is detected and a piercing hole passing through completion signal is outputted to an I/O unit 55. Further, the signal is transferred to a control unit 53 and an ON signal is given to a laser beam oscillator 3 from an NC device 57. In order to cut the work W by the laser beam LB, the sensor 49 for detecting the pressure is provided in the laser beam nozzle 27 provided at the lower part of a machining head assembly body 13 and the pressure sensor 49 is connected with the control unit 53 which is connected with the laser beam oscillator 3 by a signal cable 51 via the NC device 57. As a result, the change of frequency of the pressure in the laser beam nozzle 27 can be detected regardless of material and thickness of the work W.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention provides a pressure detection sensor that detects whether or not the piercing is completed when a laser beam penetrates a piercing hole in a workpiece. The present invention relates to a laser processing method and an apparatus thereof.

(Prior art) With conventional laser processing means, when drilling a pierced hole by irradiating a laser beam onto a workpiece, it is difficult to determine whether the pierced hole has penetrated or not.
Since there is no detection whether or not the penetration is complete, a longer penetration completion time is set in advance and stored in the NC device, and processing is performed based on the time specified on the NC processing program.

(Problems to be Solved by the Invention) However, with conventional laser processing means, the time required to complete piercing the piercing hole must be set to a sufficient length, which wastes time and increases the processing time. was there.

In addition, the length of time required to complete piercing the piercing varies depending on the material and plate thickness, so there is a problem that requires knowledge during processing.

The purpose of this invention is to improve the above-mentioned problem by using a pressure detection sensor to detect the pressure drop in the assist gas that occurs in the laser nozzle when a laser beam passes through the piercing hole in the workpiece, thereby shortening the piercing processing time. It is an object of the present invention to provide a laser processing method and an apparatus for the same, with the aim of improving operability for an operator.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a laser processing method in which a laser beam is focused and irradiated onto a workpiece to cut the workpiece. Detects the pressure drop in the assist gas that occurs when the laser beam penetrates the piercing hole in the workpiece, transfers this detection signal to the NC device, and then cuts the workpiece with the laser beam based on the NC device's 3 NC machining program. This is a laser processing method.

Further, the present invention provides a laser processing apparatus including a laser nozzle provided at the lower part of a processing head that focuses a laser beam oscillated by a laser oscillator and irradiates the workpiece positioned on a work table. A pressure detection sensor was provided in the laser processing apparatus, the pressure detection sensor was connected to a control unit, and the control unit and laser oscillator were connected via a signal cable via an NC device, thereby constructing a laser processing apparatus.

(Function) By employing the laser processing method and its device of the present invention, it is possible to detect the pressure drop of the assist gas that occurs when the laser beam penetrates the pierced hole in the workpiece positioned on the work table, and A completion signal is transferred to the control unit, a skip signal is manually input to the NC device, an ON signal is given to the laser oscillator from the NC device, and the workpiece is cut by the laser beam.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

To facilitate understanding, the overall configuration of a general laser processing apparatus 1 that performs laser processing on a workpiece W will be briefly described.

Referring to FIG. 5, the laser processing device 1 is equipped with a laser oscillator 3, and this laser oscillator 3 is configured to oscillate a laser beam LB toward the laser processing device 1. It is attached to the side.

The laser processing apparatus 1 includes a base 5, a post 7 vertically erected from the base 5, and an overhead beam 9 supported horizontally and cantileverly above the base 5.

A work table 11 is provided on the base 5, and on the upper surface of the work table 11 there are a number of slide balls (not shown) that horizontally support a sheet-like plate material (hereinafter referred to as a work) W to be processed. (not shown) is rotatably mounted.

A processing head assembly 13 is attached to the tip of the overhead beam 9.
A mirror assembly 15 and a condensing lens 17 are housed inside.

The mirror assembly 15 is configured to reflect the laser beam LB emitted from the laser oscillator 3 toward the workpiece W.

The condensing lens 17 is arranged so as to condense the laser beam LB and to apply the laser beam LB to the workpiece W together with an assist gas (inert gas).

Therefore, the laser processing apparatus 1 having the above configuration is configured to receive the laser beam LB from the laser oscillator 3 and to direct the laser beam LB onto the workpiece W via the condensing lens 17 of the processing head assembly 13.

In order to move and position the workpiece W to be processed, the laser processing apparatus 1 is provided with a first carriage 19 movably, and a second carriage holding a plurality of clamping devices 23 for clamping the workpiece W. 21. is provided.

One first carriage is movably supported by a pair of rails 25 attached parallel to each other on both sides of the upper part of the base 5, and approaches and moves away from the machining area directly under the machining head assembly 13 during driving. It is free.

The second carriage 21 holding the clamp device 23 is slidably supported on the first carriage 19, and is horizontally movable by driving in a direction perpendicular to the rail 25.

Therefore, the workpiece W gripped by the clamp device 23 can be transferred below the processing head assembly 13 on the worktable 11 by the movement of the first and second carriages 19.21.

In the above configuration, the work W is processed by the laser beam LB by positioning the work W on the work table 11 directly below the processing head assembly 13 using the first and second carriages 19.21.

Of course, the laser beam L emitted by the laser oscillator 3
B is applied to processing head assembly 13 and directed downwardly by mirror assembly 15 as shown by the arrow. After the light is focused by the focusing lens 17, the work W
Applied with hair assist gas.

A laser nozzle 27 is provided at the bottom of the processing head assembly 13.

As shown in FIG. 1, the laser nozzle 27 has a tapered conical shape, and the workpiece W located directly below it is set at an appropriate distance by means such as a distance detection sensor (not shown). It is maintained.

The size of the two light emitting ports of the laser nozzle 27 is made variable depending on the material, plate thickness, etc. of the workpiece W to be processed. Therefore, the pierced hole 31 is approximately the same size as the two light emitting ports. It will be the same.

The laser nozzle 27 has an annular double structure formed by an inner wall 33 and an inner chamber 35 and an outer chamber 37. The inner chamber 35 and the outer chamber 37 each have an assist gas (inert gas) supply pipe. (hereinafter simply referred to as gas feed pipe) 39 and 41 are directly connected.

Assist gas for cutting the workpiece is supplied from the three gas supply pipes in the inner chamber 35, and assist gas for shielding is supplied from the gas supply pipe 41 in the outer chamber 37, while adjusting the pressure inside the laser nozzle 27. It is inserted, circulates inside the inner chamber 35 and the outer chamber 37, and is ejected from the ejection port 43.45.

The assist gas for cutting the workpiece protects the condenser lens 17. Along with cooling, the melted material (slatter) during cutting of the workpiece
The shielding assist gas also serves to block outside air (air) outside the cutting section, as shown in FIG.

A bracket 47 is provided at an appropriate position near the three gas feed pipes in the inner chamber 35 of the laser nozzle 27, and a detection sensor 49 is provided on this bracket 47.

Pressure detection sensor (hereinafter simply referred to as pressure sensor) 49
And its accessories are shielded from the heat of the laser beam LB by the assist gas and are left almost unaffected by the laser beam LB, but in order to avoid the influence of radiant heat, the main body, for example, It is made of heat-resistant Teflon resin material.

Next, a method of detecting penetration of the pierced hole 31 due to gas pressure fluctuations in this embodiment will be described with reference to the block diagram shown in FIG. 2.

A pressure sensor 49 within the laser nozzle 27 is connected to a control unit 53 by a signal cable 51 and further connected to an I/O unit 55.

The control unit 53 is assembled in a strong electrical panel (not shown) installed outside the laser processing device 1, and controls communication between the I/O unit 55 and the pressure sensor 49 of the laser nozzle 27. It serves as a power source for the power sensor 49.

Further, the I/O unit 55 is assembled inside the NC console, and inputs and outputs signals from an automatic control device (hereinafter referred to as the NC device) 57.

The I/O unit 55 is connected to the NC via the signal cable 51.
It is connected to the device 57 and further connected to the operating source of the laser oscillator 3 of the laser processing device 1 .

With the above configuration, as shown in FIG. 4, first, in step S1, the workpiece W is placed at a processing position on the worktable 11, and the position of the piercing hole 31 is determined.

In step S2, the inner chamber 3 of the laser nozzle 27 is activated by the ON signal of the pressure sensor 49 from the control unit 53.
The pressure of the assist gas fed into the controller 5 is measured and an analog signal is transferred to the control unit 53 in real time.

In the control unit 53, when the signal from the pressure sensor 49 is output from the Nc device 57, the pressure sensor 49 is powered on through the I/O unit 55 and receives an analog signal.

Next, in step S3, the laser oscillator 3 is activated, and the laser beam LB starts machining the piercing hole 31 in the workpiece W.

When the piercing hole 31 penetrates in step S4, the assist gas pressure in the inner mass 35 of the laser nozzle 27 decreases at an instant of 11 compared to before the piercing. The pressure sensor 49 detects the pressure drop and outputs a piercing hole penetration signal to the I/O unit 55.

In step S5, in the I/O unit 55, the Nc device 57
The pressure sensor 49 is turned on by the ON signal from the pressure sensor 49, and this signal is transferred to the control unit 53.

Further, the control unit 53 turns on the penetration completion signal of the piercing hole 31, and causes the Nc device 57 to input a skip signal.

Next, in step S6, the laser oscillator 3
When an ON signal is received from the laser processing device 1, the laser processing device 1 is activated, moves the workpiece W, and starts cutting the workpiece W into a predetermined shape using the laser beam LB, as shown in FIG.

As described above, in the laser processing method and its apparatus of the present embodiment, the assist 1 2 gas pressure generated when the laser beam LB penetrates the pierced hole 31 into the work W positioned on the work table 11 is Detects the drop and sends the piercing hole completion signal to I/
The lower part of the processing head assembly 13 outputs the signal to the O unit 55, further transfers the signal to the control unit 53, gives an ON signal to the laser oscillator 3 from the NC device 57, and cuts the workpiece W with the laser beam LB. A pressure detection sensor 49 is provided in the laser nozzle 27 provided in the control unit 5.
3, and the control unit 53 and the laser oscillator 3 are connected by the signal cable 51 via the NC device 57. This allows the frequency of the pressure inside the laser nozzle 27 to be controlled regardless of the material and thickness of the workpiece W. Changes can be detected. Moreover, the pressure detection sensor 49 is a spac. Stable detection is possible without being affected by dust.

It should be noted that the present invention is not limited to the embodiments described above, but can be implemented in other embodiments by making appropriate changes.

[Effects of the Invention] As can be understood from the above description of the embodiments, according to the present invention, the assist gas pressure generated when a laser beam passes through a piercing hole on a workpiece positioned on a worktable can be reduced. The drop is detected, the piercing hole completion signal is transferred to the control unit, the skip signal is manually sent to the NC device, the NC device gives an ON signal to the laser oscillator, and the laser beam is used to cut the workpiece. A pressure detection sensor is provided in the laser nozzle provided at the bottom of the head assembly, the pressure detection sensor is connected to the control unit, and the control unit and laser oscillator are connected via a signal cable via the NC device. , it is possible to detect the pressure inside the laser nozzle regardless of the material and thickness of the workpiece, and to accurately know the fact that the piercing has been completed in a short time without setting unnecessary piercing penetration time. Operator operability can be improved, and productivity of laser processing can be increased.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of a laser nozzle embodying the present invention, Fig. 2 is a block diagram illustrating an assist gas pressure detection device, and Fig. 3 is a schematic diagram showing a state in which a workpiece is cut by a laser beam. 4 is a flowchart explaining the steps of the laser processing method, and FIG. 5 is a plan view of a laser processing apparatus equipped with a laser oscillator. 1... Laser processing device, 3... Laser oscillator 11.
...Work table 27...Laser nozzle 31...
・4 pierced holes...pressure detection sensor 51...signal cable 53...control unit 55...I/O unit LB...laser beam 5
7... Automatic control device 1 Agent Patent attorney Hidekazu Miyoshi 1 5 1... Laser processing device, 3... Laser oscillator 11.
...Work table 27...Laser nozzle 31...
・Piercing hole 49...Pressure detection sensor 51...Signal cable 53...Control unit 55...! /0 unit LB...Laser beam 5
7... Automatic control device Figure 1 Figure 2

Claims (2)

[Claims] (1) In a laser processing method in which a laser beam is focused and irradiated onto the workpiece to cut the workpiece, the pressure drop in assist gas that occurs when the laser beam passes through a pierced hole in a positioned workpiece is detected. A laser machining method characterized in that a detection signal is transferred to an NC device, and then a workpiece is cut with a laser beam based on an NC machining program of the NC device. (2) In a laser processing device equipped with a laser nozzle installed at the bottom of a processing head that focuses a laser beam emitted from a laser oscillator and irradiates it onto a workpiece positioned on a worktable, pressure is detected at the laser nozzle. 1. A laser processing device comprising: a pressure detection sensor connected to a control unit; and a signal cable connecting the control unit and a laser oscillator via an NC device.