JP2852963B2 - Laser irradiation surface protection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a protection device for a laser irradiation surface that is less likely to be stained by fumes and spatter generated during laser welding.

(Prior art and its problems) A laser welding machine is provided with, for example, a turntable in which workpieces (1 ') to be welded are arranged at regular intervals on an outer periphery thereof, and is disposed outside the turntable. A laser irradiation device (3 ') whose laser irradiation surface is directed toward the center of the turntable. And
The lens (3) built into the laser irradiation device (3 ')
In d '), the laser beam (5') is focused on the welding portion of the work (1 ') on the turntable to perform welding.

In the laser welding machine using the laser beam (5 ') as described above, the laser beam (5') is accurately focused on the welding surface of the work (1 ') to perform welding. When (5 ') is irradiated on the welding surface, the surface of the work (1') rapidly rises to generate fumes and spatters. These fumes and spatters are generated by the laser irradiation device (3 '). It adheres to the laser irradiation surface and cloudes the laser irradiation surface. Therefore,
As a conventional method, as shown in FIGS. 8 (a) and 8 (b), a protective glass plate (12 ') is slidably disposed immediately before a laser irradiation surface, and fumes and spatters generated during welding are removed from the protective glass (12). 12 '), and replaced it with a new protective glass plate (12') when it became cloudy to some extent.

In this case, the laser irradiation surface itself can be protected, but the protection glass plate (1
2 ') gradually becomes cloudy and lowers the laser output, making permanent use impossible. The laser output gradually decreases with the progress of laser welding, and replacement of the protective glass plate (12') is required. If it is late, there is a problem that poor welding continues.

In addition, in the continuous operation of laser welding, the replacement of the protective glass plate (12 ') requires a stop of the machine once and the work must be stopped.
There was also a problem that it took time to exchange 2 ′).

(Object of the Invention) The present invention has been made in view of the problems of the conventional example described above, and an object of the present invention is to perform a continuous laser welding operation for a long time with less contamination of a laser irradiation surface. An object of the present invention is to provide a protection device for a laser irradiation surface that can be performed.

(Means for Solving the Problems) In order to solve the problems of the conventional example, the protection device (A) for a laser irradiation surface according to the present invention is described in claim (1). In a laser irradiation apparatus that emits a laser beam (5) toward (1), a shielding plate (11) is disposed near the front surface of the work (1) to be irradiated with the laser beam, and the laser beam (5) is applied to the shielding plate (11). A laser passage hole (11a) having a size substantially equal to the diameter of the hole is formed, and a convex curved portion (11b) is formed in which the hole edge of the laser passage hole (11a) is curved in a bowl shape toward the work. I do.

In addition to the technical means of claim 2, the protective device for a laser irradiation surface according to claim 1 is further provided with the technical means of claim 1; A suction ring (13) is arranged so as to match the laser passage hole (11a) and surround the laser passage hole (11a), and an air ejection hole (13a) is provided on the inner periphery of the suction ring (13). Drill the air intake hole (13b).

In claim (3), the shielding plate (11) is limited. In the protection device for a laser irradiation surface according to claim (1) or (2), the shielding plate (11) is used. ) Is formed of a high melting point metal.

The technical means of:

(Operation) The work (1) is installed in front of the laser irradiation device (3), and the laser beam (5) is accurately focused on the welding point of the work (1) from the laser irradiation device (3). Then, the temperature of the welding point instantaneously rises, and fumes as metal vapor and spatters as molten metal powder are scattered from the welding point.

Most of the scattered fumes and spatters collide with the shielding plate (11) and flow along the bowl-shaped convex part (11b), and the amount of fumes and spatters passing through the laser passage hole (11a) decreases. It hardly reaches the laser-irradiated surface, whereby the welding can be performed while preventing the laser-irradiated surface from being stained.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. The laser welding machine (A) to which the present invention is applied is of a turntable type, but this is merely an example and the present invention is not limited to this. A turntable (2) is disposed at the center of the laser welding machine (A), and is intermittently rotated at a predetermined angle (in this embodiment, at an interval of 45 °).
On the outer periphery of the turntable (2), a work support (6) to be welded is set in accordance with the intermittent rotation angle so that the work (1) is mounted on the work support (6). Has become. In the center of the turntable (2)
A laser shielding block (4) is provided to shield a laser beam (5) passing substantially through the center of the turntable (2).

Next, each mechanism arranged around the turntable (2) will be briefly described.

(7) is a work supply device, which separates works and mounts them on a work support (6) of a turntable. (3) is a laser irradiation device, the irradiation surface of which is directed toward the center of the turntable. As shown in Fig.2,3, the laser irradiation device (3)
a) is built in, a reflector (3b) is installed before and after it, and the light coming from the lamp (3c) placed on the side is changed into a single-wavelength laser beam so that it can be irradiated forward. , And the laser beam (5) is condensed by the front lens (3d). The laser irradiation device (3) circulates cooling water (8) to generate heat. (9) is a power supply. The shielding plate (11) shown in the principle diagram of FIG. 3 has a convex shape in which the hole edge of the laser passage hole (11a) is bent in a bowl shape toward the work (1) as shown in FIG. A portion (11b) is formed, and is disposed near the front surface of the laser irradiation surface of the work (1). The shielding plate (11) has a size substantially equal to the diameter of the laser beam (5) (for example, if the diameter of the laser beam (5) immediately before the focal point is 0.2 to 0.1 mm, the diameter of the laser passage hole (11a) is about 2 to 3 mm). The laser passage hole (11a) is drilled. The shield plate (11) may be installed on the turntable (2), but the arm extends freely and retreats from the body of the laser irradiation device (3), and the shield plate (11) is attached to this arm. May be. Further, instead of the arm, a cylindrical body may be screwed forward and backward freely.

The shielding plate (11) is preferably made of, for example, a high-melting metal or a high-melting metal plated or subjected to surface treatment such as thermal spraying or hard chrome plating, or graphite because of less fume or spatter welding.

Then, the works (1) are supplied one by one to the work support (6) of the turntable (2) and fixed one by one, and then the turntable (2) is intermittently rotated to make the first laser irradiation device (3). Is moved to the front of the work (1).
When the work (1) stops, the laser beam (5) emitted from the laser irradiation device (3) is accurately focused on the welding point of the work (1), and the temperature of the welding point is raised instantaneously. At this time, fumes, which are metal vapor, and spatters, which are molten metal powder, scatter from the welding point, and most of them collide with the shielding plate (11). ), And the amount of fumes and spatter passing through the laser passage hole (11a) is reduced,
It hardly reaches the laser irradiation surface. Thus, welding is performed while preventing the laser irradiation surface from being stained.

FIG. 5 is a sectional view of the suction ring (13) shown in FIG.
A suction ring (13) is provided inside the convexly curved portion (11b). That is, the presence of the shielding plate (11) significantly reduces fumes and spatters from adhering to the laser-irradiated surface, but the laser passage hole (11a) is present, so that a certain amount of passage cannot be avoided, and long-term laser welding is not possible. Is performed, fogging of the laser irradiation surface occurs. Therefore, an air ejection hole (13a) and an air suction hole (13b) formed in the inner periphery of the suction ring (13) are formed, and compressed air is ejected from the air ejection hole (13a) and air is sucked. The fumes and spatters that have passed through the holes (13b) together with the compressed air are sucked and prevented from reaching the laser irradiation surface.

It should be noted that a certain degree of effect can be achieved only by ejection or suction. In the illustrated embodiment, the suction ring (13) is arranged inside the convex portion (11a). However, it goes without saying that the suction ring (13) may be arranged outside.

The laser irradiators (3) are installed in accordance with the number of welding locations on the work (1), and are provided at four locations in this embodiment.

(10) is a take-out device for taking out the work (1) for which welding has been completed.

(Effect) In the protection device for a laser irradiation surface of the present invention, a shielding plate is arranged near the front surface of a laser irradiation surface of a work, and a laser passage hole having a size substantially equal to the diameter of a laser beam is formed in the shielding plate. Therefore, most of the fumes and spatters generated during laser welding are blocked by the shield plate that is not located near the welded part of the work, and these are applied to the laser irradiation surface that is located away from the shield plate. There is an advantage that fumes and spatters adhere very little, and even during long-term laser welding, contamination of the laser-irradiated surface is very small, and long-term continuous laser welding can be performed.

In addition, a convex portion is formed by bending the edge of the laser passage hole toward the workpiece in a bowl shape, so the generated fumes and spatters flow along the bowl-shaped convex portion, and a plate-shaped cut-off The amount of fume and spatter passing through the laser passage hole can be reduced as compared with a plate.

Further, in claim (2), a suction ring is arranged so as to match the laser passage hole at the front and / or the back of the shielding plate and surround the laser passage hole, and air is provided around the inside of the suction ring. Since the ejection hole and the air suction hole are provided, fumes and spatters that have passed through the laser passage hole are flushed to the air suction hole side by compressed air that can be ejected, and at the same time are sucked by the air suction hole. Fumes and spatters do not reach the irradiated surface.

[Brief description of the drawings]

FIG. 1 is a plan view of a laser welding machine according to the present invention. FIG. 2 is a schematic side view of a laser welding machine according to the present invention. FIG. 3 is a principle view of a laser irradiation apparatus according to the present invention. … Schematic cross-sectional view of the second embodiment of the present invention Fig. 5 …… Cross-sectional view of suction ring used in the present invention Fig. 6 (a) (b)… Plan view and front view of conventional example (A)… ... Protection device for laser irradiation surface, (1) ... Work, (2) ... Turntable, (3) ... Laser irradiation device, (4) ... Laser shielding block, (5) ...
Laser beam, (11) ... Shielding plate, (11a) ... Laser passage hole, (11b) ... Convex curved part (11b), (13) ... Suction ring, (13a) ... Air ejection hole, (13b) ) …… Air intake hole.

Claims (3)

(57) [Claims] In a laser irradiation apparatus for emitting a laser beam toward a workpiece as a work to be welded, a shield plate is provided near a front surface of a laser irradiated surface of the work, and the shield plate has a size substantially equal to the diameter of the laser beam. A laser irradiation surface protection device characterized in that a laser passage hole is formed and a convex portion is formed in which a hole edge of the laser passage hole is convexly curved toward a workpiece. 2. A protection device for a laser irradiation surface according to claim 1, wherein a suction ring is provided so as to match the laser passage hole in front and / or behind the shielding plate and surround the laser passage hole. A protection device for a laser irradiation surface, wherein an air suction hole of an air ejection hole is formed in an inner periphery of the suction ring. 3. The protection device for a laser irradiation surface according to claim 1, wherein the shielding plate is formed of a high melting point metal.