JPS6322920B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a laser processing nozzle used for laser cutting, welding, etc. of sheet metal.

Conventional configurations and their problems In laser processing, especially in sheet metal cutting or metal welding, which is performed using laser light focused with high energy density by a condenser lens,
Usually, a nozzle for laser processing is used.

Figure 1 shows its structure. Reference numeral 1 denotes a condenser lens for condensing a substantially parallel laser beam 2, and is fixed to a cylindrical member 4 by a retaining ring 3. Reference numeral 5 denotes a conical metal laser processing nozzle (hereinafter referred to as a nozzle) that covers the laser beam 6 after passing through the condensing lens 1 from its periphery. It has an opening 7. Reference numeral 8 denotes an assist gas inlet for introducing so-called assist gas into the space 10 within the nozzle 5, and is directly attached to the member 4. Further, the nozzle 5 is attached to the member 4 with a screw 9. 12 is a workpiece such as an iron plate.

The nozzle 5 has the function of forcefully blowing assist gas introduced into its internal space 10 at a pressure of several kg/cm ² onto the condensing section 11 where laser processing is being performed, through the opening 7. . In addition, the purpose of blowing assist gas onto the processing area is (1) When oxygen is used as the assist gas, the oxidation reaction is promoted in the laser processing area, and the accompanying oxidation reaction heat is used as energy for processing. do.

(2) By blowing away the plasma generated in the laser processing section with assist gas, the irradiation of the laser beam to the processing section is prevented from being blocked by the plasma.

(3) Prevent evaporated substances or scattered particles from the processing area from adhering to the condenser lens.

etc.

Now, for this purpose, in order to forcefully spray the assist gas onto the workpiece, the distance H between the tip of the nozzle 5 and the surface of the workpiece 12 is usually around 1 mm when cutting an iron plate. This is a small value. That is, the nozzle is used in close proximity to the workpiece 12. Therefore,
When performing laser processing by moving the workpiece two-dimensionally on an X-Y stage or by scanning the laser beam two-dimensionally on a stationary workpiece, the If a protruding object is present, sufficient care must be taken to prevent the nozzle from colliding with the protruding object.

By the way, in actual laser processing, as shown in FIG. On the surface of the workpiece 12, such as the part 16 assembled on the object 12,
There are many cases where protruding objects are present. Unlike cutting processes such as milling, laser processing does not involve cutting resistance, so the feed rate of the workpiece or the scanning speed of the beam ranges from several m/min to more than 10 m/min at high speeds. If the nozzle collides with a protrusion at such high speed,
Serious accidents may occur, such as damage to the workpiece, damage to the feed mechanism of the machine, especially the XY stage, damage to the beam scanning system, and damage to the nozzle. In particular, if the nozzle is deformed and damaged, there is a risk that the laser beam that hits the inner wall of the nozzle and is reflected will directly irradiate the human body beyond the nozzle, leading to a serious accident.

On the other hand, conventionally, sufficient measures have not been taken against nozzle collisions, despite the above-mentioned concerns.

Purpose of the Invention An object of the present invention is to provide a laser processing nozzle with a simple structure that can quickly detect a nozzle collision and bring the device to a halt, thereby ensuring the safety of workers and the device. .

Structure of the Invention The present invention has a nozzle made of metal, and an electrode is provided on the outer periphery of the nozzle via conductive rubber, thereby suppressing changes in the resistance value of the conductive rubber when a workpiece comes into contact with the electrode. It detects this and stops the operation of the device.

DESCRIPTION OF EMBODIMENTS Hereinafter, the present invention will be described in detail along with embodiments.

FIG. 3 is a sectional view of a main part of an embodiment of the present invention, and the reference numerals correspond to those in FIG. 1.

17 is a conductive rubber attached to the outer periphery of the nozzle 5, and a thin gold film 19 is coated on its surface 18.
is formed. This thin film 19 is used as an electrode facing the surface 20 of the metal nozzle 5, and the metal nozzle 5 and the thin film 19 constitute a counter electrode with the conductive rubber 17 interposed therebetween. ing.

Further, as shown in the figure, the conductive rubber 17 is connected to the nozzle 5.
The convex portion 22 provided on the inner circumferential surface of the conductive rubber 17 fits into the concave groove 21 provided on the outer circumferential surface of the nozzle 5. By fitting them together, the conductive rubber 17 is attached to the nozzle 5. 23 and 24 are lead wires provided on the opposing electrodes.

Now, assume that in this nozzle, the protrusion 16 collides with the nozzle 5 as shown in FIG. At this time, the conductive rubber is compressed and deformed in the collision portion 25. As a result, as a property of the conductive rubber, the resistance value of the conductive rubber in the compressively deformed portion decreases. A detection circuit 32 connected to the lead wires 23 and 24 detects a change in the resistance value of the deformed portion as a change in resistance between the opposing electrodes, and immediately brings the device to a halt state.

It goes without saying that the thin film 19 serving as a power source can be elastically deformed together with the conductive rubber 17 in the above collision.

At this time, even if the protrusion 16 is a part of the workpiece, that is, the product, the device will stop when the conductive rubber 17 is elastically deformed, so the protrusion 16, that is, the product, may be damaged or damaged. There's nothing to do. Of course, the same applies to the nozzle 5. That is, in this embodiment, the conductive rubber also serves as a cushioning material for protecting the workpiece or the nozzle. Further, in this embodiment, since the conductive rubber is removable, it also has the advantage of being easy to replace.

In this way, in this example, a nozzle with a simple structure can reliably protect the safety of workers and the protection of machines and equipment in the event of a nozzle collision, and can be used as a nozzle for laser processing to achieve great results. It is effective.

5 and 6 show another structure of the present invention.
In FIG. 5, the electrode 19 provided on the surface of the conductive rubber 17 is a mesh made of thin metal wires, and the mesh 19 is inserted into the recess 26 on the surface of the conductive rubber by the thin metal wires 27. bound and fixed.

Further, in FIG. 6, the electrode 19 is a conical thin metal plate that matches the shape of the nozzle 5, and is fitted into a concave groove on the surface of the conductive rubber 17. It is more preferable to provide this metal thin plate 19 with a large number of holes 28 and slits 31 in order to improve its elastic deformability as shown in the developed views shown in FIGS. 7 and 8. In addition, in FIGS. 7 and 8, edge portions 29 and 30 are portions that are welded together.

Effects of the Invention In the present invention, since an electrode is formed on the outer periphery of a metal nozzle part via conductive rubber, contact of a workpiece with the nozzle part is detected by a change in the resistance value of the conductive rubber. This makes it possible to stop the operation of the device and prevent accidents such as deformation of the nozzle and damage to the workpiece.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts of a conventional laser processing nozzle, Figure 2 is a side view showing the state of laser processing,
FIG. 3 is a sectional view of a main part of a laser processing nozzle according to an embodiment of the present invention, FIG. 4 is an explanatory diagram of the operation of the embodiment of FIG. 3, and FIGS. 5 and 6 are other embodiments of the present invention. The diagrams illustrating examples, FIGS. 7 and 8, are developed views showing examples of electrode structures. 5... Laser processing nozzle, 7... Conductive rubber, 1
8... Surface of conductive rubber, 19... Electrode arranged on the surface of conductive rubber, 20... Nozzle surface, 21... Concave groove for fitting the conductive rubber convex provided on the nozzle surface, 22... Conductive A convex portion for fitting into a nozzle recess provided on the inner surface of the rubber, 23, 24...Lead wires of the counter electrode.

Claims (1)

[Scope of Claims] 1. A metal nozzle part that covers the laser beam from its periphery and has an opening near the convergence point of the laser beam, and a conductive rubber provided on the outer periphery of the metal nozzle part; A nozzle for laser processing, comprising an elastically deformable electrode provided on a surface of the conductive rubber at a portion facing the surface of the metal nozzle portion. 2. Concave and convex portions that fit into each other are provided on the outer periphery of the metal nozzle portion and the inner periphery of the conductive rubber, and by fitting the concave and convex portions, the conductive rubber is attached to the metal nozzle portion. The laser processing nozzle according to claim 1, wherein the nozzle is fixed. 3. The laser processing nozzle according to claim 1, wherein the elastically deformable electrode is a metal thin film formed on the surface of conductive rubber. 4. The elastically deformable electrode is a thin metal plate,
2. The laser processing nozzle according to claim 1, wherein a recess is formed in the outer periphery of the conductive rubber, and the thin metal plate is fitted into the recess.