JPS60250892A - Laser piercing device - Google Patents

Abstract

PURPOSE:To automate a piercing work, also to make it unnecessary to execute a through inspection, and to improve a working efficiency and a piercing accuracy by detecting a penetration of a hole by a laser piercing device without a man's help. CONSTITUTION:A laser beam 2 is irradiated from a laser beam device 1 to a work 4 held by a holding jig 5. As a result, a laser beam spot part of the work 4 is melted and evaporated, and a hole 12 is pierced gradually. In this case, an AE sensor 9 does not catch other abnormal mechanical vibration than a noise vibration. When the hole 12 passes through the work 4, the laser beam 2 irradiates a back plate 6. As a result, a micro-breakdown phenomenon and an elastic vibration are generated by a thermal influence on a photodetecting part of the back plate 6. Subsequently, the elastic vibration is caught by the AE sensor 9, tranceduced to an electric signal SA, amplified by an amplifier 10, and outputted to a comparator 11. Next, a set value VT and a voltage value V of the electric signal SA are compared by a comparator 11. In this case, the set value VT is set so as to be smaller than the voltage value V of the electric signal SA outputted from the AE sensor 9. Accordingly, from the comparator 11, a piercing signal SH is outputted to a control part 1a and a feed device 7, the laser beam 2 is stopped, and by the feed device 7, the work 4 is fed to the next piercing position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a laser drilling device for drilling through holes using laser light.

[Technical background of the invention and its problems]

The laser beam can be focused as a well-parallel, cylindrical power beam onto the surface of the workpiece as a minute spot. This minute spot portion absorbs the laser beam, is heated to a high temperature, and instantaneously evaporates or melts. Therefore, high-melting point materials, heat-resistant alloys, and ceramics that can be made using conventional methods.

It has become possible to drill holes in hard and brittle materials such as diamond.

In particular, it has now become possible to easily process minute holes, which had previously been considered extremely difficult.

However, when drilling a through hole using a laser beam, it is necessary to visually confirm whether or not the drilling process has been completed. Furthermore, due to the danger of the laser beam (d), inspectors are not allowed to approach the machined area during the drilling process.Therefore, in the past, to confirm the completion of the drilling process, the laser beam irradiation was stopped once during the drilling process. In addition, in some cases, the workpiece is removed and visually inspected to see if the hole is penetrating.As a result, machining efficiency tends to drop significantly and machining accuracy also tends to deteriorate.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances.

It is an object of the present invention to provide a laser drilling device capable of drilling a workpiece with high accuracy and efficiency using laser light.

[Summary of the invention]

In a laser drilling device that drills holes by irradiating a workpiece with a laser beam, the laser beam is attached to a member placed at a position to receive the laser beam that has passed through a hole drilled in the workpiece by the laser beam. In addition to converting the physical changes that occur when receiving light into electrical signals.

The oscillation of laser light is controlled based on this electrical signal.

[Embodiments of the invention]

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the laser drilling device of this embodiment.

This laser drilling device is a laser device (1
)have. The laser beam (2) oscillated from this laser device (1) includes, for example, carbon dioxide (CO3) laser beam, YAG (Yttrium Aluminum) laser beam, etc.
um Garnet) laser light and ruby laser light are preferred. A condensing lens (3) is disposed on the laser beam (2) output side of the laser device (1). The light output III K of this condensing lens (3) is a plate-shaped workpiece (4)
is fixed by a holding jig (5). A back plate (6) made of, for example, a steel plate, a copper plate, a ceramic plate, etc. is interposed between the bottom surface of the workpiece (4) and the first holding jig (5). Furthermore, the holding jig (5) is fed by a feeding device (force) by a predetermined amount in the direction of the arrow (8).
ustic emission) sensor (9) is glued. This AE sensor (9) has a piezoelectric vibrator as its main body, and captures the weak elastic wave vibrations generated when the back plate (6) is irradiated with the laser beam (2) to generate an electrical signal. The output side is an amplifier 0 [
is connected to the comparator αD via. This comparator αυ
It is possible to set an arbitrary set value vT, and when the voltage value V of the input electric signal exceeds vT, a drilling end signal SH is output. This comparator αυ is connected to the control unit (1) of the laser device (1) when the drilling signal SH is
1a) and the feeding device (power is output to the laser beam).The control unit (1a) controls the output or stop of the laser beam (2), the magnitude of the output energy, the pulse width, etc. It is something.

Next, the operation of the laser drilling apparatus having the above configuration will be described. Without a trench, a laser beam (2) is irradiated from a laser device (1) onto a workpiece (4) made of stainless steel, for example, which is held by a holding jig (5). The power density of 2) is, for example, 2.5 x 10'
7 W.

The pulse width is 1 ms. Further, the focal point (F') is located slightly inside the surface of the workpiece (4) and fixed at this position. With the pulsed irradiation of the laser beam (2), the laser spot portion of the workpiece (4) melts and evaporates, and the hole +12 is gradually drilled.

At this time, the AE sensor (9) does not detect abnormal mechanical vibrations other than noise vibrations. And 1. When the hole (one penetrates the workpiece (4), the laser beam (2) passes through the back plate (6)
irradiate. Then, in the portion of the back plate (6) that receives the laser beam (2), a micro-destructive phenomenon and accompanying elastic vibration occur due to the thermal influence. The elastic vibrations generated at this time are captured by the AE sensor (9) and converted into an electrical signal SA. Then, this electrical signal SA is
It is amplified by the amplifier (10) and output to the comparator (11).In this comparator Qυ, the set value ■T and the electric signal 8A
The voltage - value ■ is compared. However, the set value vT is.

The voltage value V of the electric signal SA output from the AE sensor (9) when passing through the hole α2 is also set to be smaller. Therefore, the perforation signal S from the comparator S
H is output to the control section (a) and the feeding device (7).

As a result, the emission of the laser beam (2) is stopped, and the feeding device (7) is activated to feed the workpiece (4) to the primary drilling position.

As described above, the laser drilling device of this embodiment can detect the penetration of a hole without any human intervention, and therefore, the drilling work can be completely automated.

Drilling efficiency is significantly improved. Further, since there is no need to remove the workpiece for inspection of hole penetration, drilling accuracy is also improved. For example, when drilling a hole with a diameter of 3mm using a laser beam, the range of variation is ±
The distance was 0.4m, but it improved to ±Q, 33m.

In addition, in the above embodiment, the AE sensor (9) is.

It is attached to the back plate (6) as shown in Figure 2.

Even if it is attached to the back side of the bottom plate (15a) of the holder which directly receives the laser beam (2) when the hole I passes through the workpiece (I), the same effect as in the above embodiment can be obtained. , the feeding device (force) may be omitted if there is only one perforation location. Also, the focal point (F) position of the condenser lens (3).

It may be set at any position across the machined surface. Also.

The focal point (F) may be sent into the workpiece following the progress of drilling. Furthermore, as a method for determining the penetration of a hole, instead of immediately comparing and calculating the electrical signal SA output from the amplifier 00), the electrical signal SA is processed using a smoothing circuit consisting of a filter or an effective value (RMS).
5quare)) Comparison calculation may be performed after passing through the circuit. Furthermore, instead of stopping the oscillation of the laser beam immediately after inputting the drilling signal SH, the oscillation of the laser beam may be stopped after a preset delay time to complete the machining. By doing so, it is possible to remove the melted residue attached to the inner wall surface of the hole. Further, instead of the AE sensor, another vibration detector 9 may be used, such as a photoelectric converter such as a photodiode or a transistor. In this case, the photoelectric converter is attached to a part that receives laser light directly or indirectly.

〔Effect of the invention〕

Since the laser drilling device of the present invention can detect hole penetration without manual intervention, the drilling operation can be completely automated, and the drilling efficiency is significantly improved. moreover,
There is no need to move the workpiece at all for drilling inspection until the drilling is completed.

Drilling accuracy is also improved.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a 17-laser drilling device according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining a modification of the laser drilling device of the present invention. (1): Laser device (laser oscillation unit). (2): Laser light, envelope): Workpiece. (9): AE sensor (penetration detection section). 0υ: Comparator (arithmetic processing unit). α2: Kong agent Patent attorney Kensuke Chika (1'min or 1 person) Figure 1 Figure 2

Claims (3)

[Claims] (1) A laser beam oscillation unit that irradiates a workpiece with a laser beam to make a hole, and receives the laser beam that passes through the hole when the hole drilled in the workpiece passes through the workpiece. a penetration detection unit that is attached to a member disposed at a position where the laser beam is received and converts a physical change caused by the reception of the laser beam into an electrical signal; and a penetration detection unit that converts the physical change caused by the reception of the laser beam into an electrical signal; 1. A laser drilling device comprising: a calculation processing unit that controls irradiation of laser light from the laser drilling device. (2) The laser drilling device according to claim 1, wherein the penetration detection section is an ultrasonic vibration detector. (3) The laser drilling device according to claim 1, wherein the penetration detection section is a photoelectric converter.