JPS6213117B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to metal materials, that is, primary products (e.g. slabs, billets, blooms, ingots), secondary products (e.g. steel plates, steel bars, sections, etc.) in the steel industry.
A laser marking device for (pipes), in particular a type that moves a laser spot relative to the object to be marked, and that prints dot patterns of a certain depth, such as lot numbers, product model numbers, and model names. This invention relates to a device for laser marking characters, symbols, and marks.

When marking characters, symbols, marks, etc. with laser light, it is advantageous to represent them as a dot pattern. Dot-patterned characters, symbols, and marks can be appropriately marked as desired without the need for relative movement between the laser spot and the object to be marked in a single stroke. There are almost no restrictions on the available types.

Laser marking of letters, symbols, and marks such as lot numbers, product model numbers, and model names on metal materials as described above is performed by exposing the laser-marked metal materials to the general atmosphere, shot blasting,
It is required to have a depth that will not be erased by heat treatment, etc., and generally it must be deeper than 0.1 mm, preferably about 0.5 mm. In order to laser mark metal materials with such depth, it is essential that the laser beam has a fairly high density optical energy.

In laser marking, scanning by moving the laser spot is more advantageous than scanning by fixing the laser spot and moving the workpiece in terms of ease of loading, and when the workpiece is heavy and large such as a thick steel plate. , especially so.

Conventionally, in a scanning laser marking device using a moving laser spot, a so-called There are galvanometer mirrors facing each other for Y-axis deflection, and by adjusting the angle of these mirrors, the X-axis and Y-axis scanning of the laser beam necessary for marking is performed. A laser oscillator with a condensing lens using an F/θ lens placed between the mirror and the surface to be marked has been put into practical use, and is capable of emitting low-density light energy to the extent that the marking area becomes a discolored surface due to heating and oxidation. The reality is that laser light is used. The marking is 0.1~ with the conventional one above.
When a laser beam with high density optical energy is emitted to a depth of about 0.5 mm, in the former type, the laser beam is focused by a condenser lens and the laser beam with high density optical energy hits the galvano mirror. The mirror will be damaged in a very short time, and in the latter type, the F/θ lens is exposed to a laser beam with high density optical energy, and the adhesive in the lens group absorbs the laser beam. As a result, the lens group will likely come off due to burnout.

That is, it is impossible to perform laser marking with relatively deep concave marks of about 0.1 to 0.5 mm using the prior art described above, and it is not possible to perform such relatively deep laser marking on metal materials using a moving laser spot. The current situation is that nothing has been established yet.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a laser marking device which is of a moving laser spot type and is capable of laser marking a relatively deep concave mark as described above on a metal material.

In the metal material laser marking device of the present invention, an optical splitting means for splitting a laser beam emitted from a high-output laser oscillator into a plurality of beams is optically connected to the laser oscillator, and the splitting means splits the laser beam into a plurality of beams. On the projection line of each divided laser beam, a shutter that is opened and closed at appropriate time intervals during projection of the laser beam to turn the laser beam into a dot mode, and an optical fiber that follows this are placed, and the optical fibers are arranged in parallel. The distal end of the laser head is assembled into a bundle, which includes a condenser lens as a component, and is movable in the X-axis direction (left-right direction) and Y-axis direction (front-back direction) on the surface to be marked. It is characterized by being connected to the laser beam incident side of the condensing lens.

According to the present invention, the laser beam enters the condensing lens in the laser head as a dot mode by opening and closing the shutter on the laser beam projection line,
By moving the laser head in the X- and Y-axis directions along the surface to be marked, the laser spot is moved, thus marking desired characters, symbols, marks, etc. as a dot pattern on the surface to be marked. be done.

In the present invention, during the laser marking process,
A high-power laser beam (generally a pulsed laser with an average output of 200W and a peak output of 60KW) is emitted from a high-power laser oscillator, and it is focused on the surface to be marked using a condensing lens. It is ensured that the depth of the recess of the laser marking on the marking surface is relatively deep, on the order of 0.1 to 0.5 mm.

In this way, a high-power laser beam is applied in the present invention, and the laser beam can be split using an optical splitting means (generally, a combination of a beam splitting mirror, a beam steering mirror, and a beam reflecting mirror). ), the beam is divided into multiple beams, for example 4 to 8 beams, preferably 6 beams, and transmitted to the condenser lens of the laser head, so that the shutter on the projection line of the divided beams is exposed to high-density optical energy. It has been established that it can withstand long-term use without any problems, can perform loser marking processing of dot patterns with recesses of the required depth without any problems, and has high operational safety because the laser beam is transmitted using optical fiber.

In the present invention, a distance meter detects the distance from the laser head to the surface to be marked, and based on the distance meter detecting the distance between the laser head and the surface to be marked, the laser beam from the condensing lens in the laser head marks the surface to be marked. By adding a laser spot focusing means that moves the laser head in the direction of its optical axis so as to connect the spot to the surface, even if the surface to be marked is a curved surface or a surface that is not flat such as a wavy surface, such as a curved surface such as a pipe material, In addition, the laser spot can always be applied with high power density while the laser spot is moving, increasing the usefulness of the device of the present invention. Furthermore, the laser spot is automatically focused by following the vibrations of the material to be marked that is flowing along the production line, for example, on a roller conveyor, so that a spot with an appropriate high power density can be obtained. In this case, the laser head is moved in synchronization with the movement of the material to be marked.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 to 4, 1 is a high-power laser oscillator, 2 is an optical splitting means for a laser beam optically connected to the oscillator 1, and 3 is a laser beam 4 split by the optical splitting means 2... A shutter placed on the projection line of the laser beam optical splitting means 2
includes a beam steering mirror 2a, a beam splitting mirror 2b, and a beam reflecting mirror 2.
In the combination c, a beam reflecting mirror can be applied to the shutter 3, which is movable between two positions: on the laser beam projection line and a position deviating from the laser beam projection line (the position indicated by the chain line in FIG. 1). When the shutter 3 is located on the laser beam projection line, the shutter is closed, and when it is at the chain line position, the shutter is open.
The shutter 3 may be opened and closed by any suitable method.

Following the shutter 3, an optical fiber bar code 5 is disposed on the projection line of the divided laser beams 4. The optical fiber barcodes 5... are bundled together at their ends. Reference numeral 6 denotes a laser head, which includes as a component a condenser lens 7 that condenses a laser beam as a laser spot on a surface to be marked (not shown) of a metal material, and the laser beam of the condenser lens 7 in the laser head 6 The above-mentioned optical fiber 5 is connected to the input side with a bundle gathering portion on the end side. 8 is the summary part. Reference numeral 9 denotes an exit port for the divided laser beams 4 from the splitting means 2, and 10 represents a plug-in type coupling that is removably connected to the insertion port 11 of the exit port 9. Provided at the starting end.
Reference numerals 12 and 13 indicate removable insertion-type couplings at the end side bundle gathering portion 8 of the optical fiber bar code 5 and at the starting end side of the laser head 6.

The laser head 6 is mounted on a support 14, and the support 14 is mounted on a slide block 15 movable in the X-axis direction in FIG. 6, that is, in the left-right direction of the metal material to be marked (not shown). is mounted on a frame 16 that is movable in the Z-axis direction in FIGS. 5 and 6, that is, in the vertical direction, and the frame 1
6 is mounted on a frame 17 that is movable in the Y-axis direction of FIG. 5, that is, in the front-rear direction of the metal material to be marked. The slide block 15 is moved in the X-axis direction through a feed screw 18 on the frame 16, which is driven by an Guide rod 26, 26
The frame 16 is moved on the Z-axis through a feed screw 20 mounted on the frame 16 and a non-rotating nut 21 on the frame 17 that meshes with the feed screw 20, which is driven by a Z-axis feed servo motor (not shown). The frame 17 is moved on guide rods 27, 27 in the direction, and the frame 17 is driven by a Y-axis feed servo motor (not shown), and a pinion 22 mounted on the frame 17, and a fixed rack in a fixed position meshing with the pinion 22. 23 on the guide rails 28, 28 in the Y-axis direction, and as a result,
The laser head 6 is moved in the X-axis direction, Y-axis direction, and Z-axis direction. The above X-axis feed servo motor and Y-axis feed servo motor should be controlled by an appropriate method, such as a computer system, so that the feed movement amount corresponds to the laser marking of the required characters, symbols, and marks. Bye. The Z-axis feed servomotor performs a feed operation corresponding to the necessary laser spot focusing by an appropriate means, such as a computer system, based on the detection of the distance between the laser head 6 and the surface to be marked by an image sensor camera 24, which will be described later. What is necessary is to control the amount.

The X-axis drive system, Y-axis drive system, and Z-axis drive system of the laser head 6 are shown in FIGS. 5 and 6.

The support body 14 further includes a distance meter for detecting the distance from the laser head to the surface to be marked.
For example, an image sensor camera 24 and a laser oscillator 25 for irradiating the surface of the metal material to be marked with a low-power measurement laser beam for the camera are attached (FIG. 6).

In FIGS. 5 and 6, reference numeral 29 indicates a laser marking device frame, and 30 indicates a roller table pass line using a roller conveyor, which is a metal material production line. If necessary, the frame 29 can be moved to follow the movement of the metal material passing through the roller table path line 30. This can be done by using an appropriate method, for example, converting the momentum of a measuring roller (not shown) that rotates in contact with the metal material surface into an electrical or electronic displacement amount, and controlling a servo motor based on this, thereby moving the frame 29 as required. The purpose can be achieved by moving the metal material in the moving direction L at a speed. The movement of the frame 29 to follow the movement of the metal material is as follows:
As the metal material is moved, it is ensured that it receives the required laser marking.

Laser marking processing using the apparatus of the present invention having the above configuration is as follows.

A high power laser beam emitted from a high power laser oscillator 1 is split into a plurality of laser beams 4 by an optical splitting means 2, and the optical fiber 5 is split into a plurality of laser beams 4.
... is transmitted to the laser beam incident side of the condensing lens 7 in the laser head 6, and condensed by the condensing lens 7 as a laser spot on the surface to be marked. During the projection of this laser beam 4..., the shutter 3... is opened and closed at appropriate time intervals, the laser beam 4... is converted into a dot mode, and the shutter 3...
During closing, the laser head 6 is moved in the X- and Y-axis directions as described above, and the laser spot moves accordingly to write the lot number, product model number, and model name on the surface to be marked. Characters, symbols, or marks are marked with a laser as a dot pattern. Furthermore, by moving the laser head 6 in the Z-axis direction, the laser spot is automatically focused in accordance with the curve of the surface to be marked.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic diagram showing one embodiment of the present invention, Figs. 2, 3, and 4 are detailed views of the optical system in the laser marking device shown in Fig. 1, and Fig. 5 is a diagram of the laser head drive system and A front view of the roller table line system, and FIG. 6 is a side view thereof. 1 is a high-power laser oscillator, 2 is a laser beam optical splitting means, 3 is a shutter, 4 is a split laser beam, 5 is an optical fiber, 6 is a laser head, 7 is a condenser lens, 24 is an image sensor camera, 25 2 is a laser oscillator that emits a low-power measurement laser beam; 20 is a feed screw (laser spot focusing means); and 21 is a nut (laser spot focusing means).

Claims (1)

[Scope of Claims] 1. Laser beam optical splitting means for splitting a laser beam emitted from a high-power laser oscillator into a plurality of beams is optically connected to the laser oscillator, and each of the laser beams split into a plurality of beams by the splitting means is optically connected to the laser oscillator. On the projection line of the laser beam, a shutter that is opened and closed at appropriate time intervals during the projection of the laser beam to turn the laser beam into a dot mode, and an optical fiber following the shutter are arranged, and the end side of the parallel body of optical fibers is arranged. are assembled into a bundle, and the condensing lens is included in the laser head that includes the condensing lens as a component and is movable in the X-axis direction (left-right direction) and Y-axis direction (front-back direction) on the surface to be marked. A metal material laser marking device characterized in that it is connected to the laser beam incidence side. 2. A laser beam optical splitting means for splitting a laser beam emitted from a high-output laser oscillator into a plurality of beams is optically connected to the laser oscillator, and a laser beam split by the splitting means is placed on the projection line of each laser beam split into a plurality of beams. , a shutter which is opened and closed at appropriate time intervals during projection of the laser beam to make the laser beam into a dot mode, and an optical fiber following this are arranged, and the ends of the parallel body of optical fibers are bundled together. The laser head includes a condenser lens as a component and is movable in the X-axis direction (left-right direction), Y-axis direction (front-back direction), and Z-axis direction (optical axis direction) on the surface to be marked. A distance meter is connected to the laser beam incident side of the optical lens and further detects the distance from the laser head to the surface to be marked, and based on the distance meter detecting the distance between the laser head and the surface to be marked, 1. A metal material laser marking device comprising a laser spot focusing means for moving the laser head in the direction of its optical axis so that the laser beam from the condensing lens focuses the spot on the surface to be marked.