JP2000288751A - Laser marking method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To perform good marking by preventing heat generation of a workpiece. SOLUTION: A work piece 2 made of a metal material and having a relatively small size is replaced with a coolant 3 having a property of not being ignited by heat.
The workpiece 2 is irradiated with a laser beam in this state to apply a desired marking to the surface of the marking portion of the workpiece 2 exposed from the coolant 3. It is characterized by performing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser marking method, and more particularly to a laser marking method for irradiating a workpiece made of a material having a relatively small size with a laser beam to perform desired marking such as characters and figures. It relates to a laser marking method.

[0002]

2. Description of the Related Art Conventionally, a laser marking device for drawing predetermined characters or figures on the surface of a workpiece using a laser beam has been widely used. Many YAG lasers using an Nd: YAG crystal as an active medium from which an output is easily obtained are used.

In such a conventional laser marking device, the Q switch is operated in a state where sufficient excitation energy for oscillating predetermined solid-state laser light is accumulated in the YAG rod by irradiation with light from an excitation lamp. When the switch is turned off, the loss of the Q switch is set to 0, and the light traveling in the axial direction is allowed to pass through the output mirror without being diffracted and oscillate as a solid laser light at a stretch. And
By irradiating the surface of the workpiece with the solid-state laser light passing through the output mirror, the workpiece is marked.

FIG. 3 shows an example in which a workpiece made of metal is marked by using such a laser marking apparatus. In this case, first, a relatively heat conductive material such as copper is used. A support table 10 made of a material having a good rate is used, and a workpiece 11 is placed and held on the upper surface of the support table 10. In this state, the laser marking device 12 is operated to irradiate the workpiece 11 with laser light, whereby desired marking of characters, figures, and the like is performed on the surface of the workpiece 11. .

[0005] The laser light irradiation causes the marked portion of the workpiece 11 to become extremely hot, but is generated on the workpiece 11 by forming the support base 10 from a material having good thermal conductivity. The heat is transmitted to the support base 10 so that the heat generated in the workpiece 11 can be efficiently radiated.

[0006]

However, in the above-mentioned marking means, when the workpiece 11 made of a metal material is irradiated with a laser beam to perform marking, the workpiece 11 is heated to an extremely high temperature. It will be heated.

In this case, when the size of the workpiece 11 is relatively large with respect to the marking portion, the heat generated by the irradiation of the laser beam is diffused to other portions of the workpiece 11, so that the support The heat can be radiated by the table 10 so that marking can be performed without any problem. However, for example, in the case of a work 11 made of a metal material and having a relatively small size, such as a crown or a ring of a watch, when the work 11 is heated by laser light irradiation, the work 11
Since the heat diffusion inside the workpiece becomes insufficient, the workpiece 1
1 has an extremely high temperature, and there is a problem that the laser beam irradiation site on the workpiece 11 and its surroundings melt and swell. As a result, as shown in FIG. 4, the marked characters and the like become unreadable, and the melting of the marking portion causes the marking portion of the workpiece 11 to be rough, resulting in a poor touch. have. Furthermore, since the temperature of the marking portion becomes high, the metal at that portion is oxidized by oxygen in the air, and there is a problem that good marking cannot be performed, such as discoloration.

The present invention has been made in view of the above points, and has as its object to provide a laser marking method capable of preventing heat generation of a workpiece and performing good marking.

[0009]

According to a first aspect of the present invention, there is provided a laser marking method for applying a laser beam to a relatively small workpiece made of a metal material. By irradiating, in a laser marking method for performing desired marking of characters, figures, etc. on the surface of the workpiece, the workpiece is marked with a coolant that does not ignite by heat. Soak only the part exposed from the coolant,
In this state, the workpiece is irradiated with laser light to perform desired marking on the surface of the marking portion exposed from the coolant of the workpiece. is there.

According to the first aspect of the present invention, the workpiece is immersed in the cooling fluid, and only the marking portion of the workpiece is exposed from the surface of the cooling fluid. Laser light is applied to the surface of the workpiece to perform the desired marking, so that the workpiece is cooled with a cooling liquid, and the marking portion of the workpiece that generates heat when irradiated with the laser light. Can be efficiently cooled, and melting of the marking portion due to heat generation at the time of marking can be reliably prevented.

As a result, the marked characters and the like can be read well, and the marked portion of the workpiece does not melt and swell, so that the marked portion has no rough feeling and has a good touch. Obtainable. Furthermore, since the marking portion can be cooled efficiently, oxidation at that portion can be prevented, and the occurrence of discoloration or the like can be reliably prevented, and extremely excellent marking can be performed.

[0012]

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

FIG. 1 shows an embodiment of a laser marking method according to the present invention. A laser marking device 1 used in the laser marking method according to the present invention comprises:
Although not shown in detail, the irradiation of light by an excitation lamp causes a state in which sufficient excitation energy to oscillate predetermined solid-state laser light is accumulated in a YAG rod, which is one of laser crystals having excellent optical characteristics. The Q switch is turned off to reduce the loss of the Q switch to 0, and the light traveling in the axial direction passes through the output mirror without being diffracted, and oscillates as a solid laser beam at a stretch. It can be irradiated with laser light.

In this embodiment, first, the workpiece 2 is immersed in a coolant 3 having a property of not igniting by heat such as water or alcohol, and only the marking portion of the workpiece 2 is cooled. From the surface of the liquid.

In this state, the laser marking device 1
Is operated, the laser beam is radiated from the laser marking device 1 to the workpiece 2, and the surface of the marking portion of the workpiece 2 exposed from the cooling liquid 3 is applied as shown in FIG. Then, a desired marking such as a character or a figure is performed.

In this case, in the present embodiment, the workpiece 2 can be efficiently cooled by performing the marking while the workpiece 2 is immersed in the cooling liquid 3, so that the laser beam irradiation is performed. Thus, the marking portion of the workpiece 2 that generates heat can be efficiently cooled, and the marking portion can be prevented from melting due to heat generation at the time of marking.

In this embodiment, the workpiece 2
Is immersed in the cooling liquid 3 to perform the marking. For example, while irradiating the laser beam from the laser marking device 1, the cooling liquid 3 May be cooled.
However, if the marking is performed in a state where the workpiece 2 is completely immersed in the cooling liquid 3, the marking quality deteriorates, which is not preferable.

As the material of the workpiece 2 to which the laser marking method according to the present embodiment is applied, for example, a metal material such as brass, stainless steel, titanium, iron, gold, silver, and copper is preferable. The size of the workpiece 2 is suitable for a relatively small size such as a crown of a clock, a metal knob, a ring, a necklace, and the like.

That is, when marking is performed on the workpiece 2 made of a resin material, the workpiece 2 can be melted and marked at a relatively low temperature by a laser beam. This is because there is no need to perform cooling. Also, when marking is performed on the workpiece 2 made of a relatively large metal material, the temperature of the marking portion becomes high due to the laser beam, but if the workpiece 2 is large, the heat is diffused. This is because it is possible to prevent the marking portion from being locally heated to a high temperature, and it is not necessary to perform cooling with the cooling liquid 3.

According to the laser marking method according to the present invention, the workpiece 2 is made to be a crown of a watch made of brass, water is used as the cooling liquid 3, the current of the excitation lamp is 15 A, the Q switch is Frequency is 2 kHz
Under the condition that the scanning speed of z and laser light is 50 mm / s, marking with a character depth of about 100 μm results in good reading of the character, and the surface of the marking portion is rough. No sensation was generated at all, and extremely good marking could be performed.

Therefore, in the present embodiment, the marking is performed while the workpiece 2 is immersed in the cooling liquid 3 so that the marking portion of the workpiece 2 that generates heat by the irradiation of the laser beam can be efficiently cooled. Since it is possible to prevent the marking portion from melting due to heat generated at the time of marking, the marked characters and the like can be read well, and the marking portion of the workpiece 2 does not melt and rise. Therefore, there is no rough feeling at the marking portion, and a good touch can be obtained. further,
Since the marking area can be cooled efficiently,
Oxidation of the site can be prevented, and the occurrence of discoloration or the like can be reliably prevented, and extremely excellent marking can be performed.

In the above embodiment, the case where a YAG laser is used as the laser has been described. However, the present invention is not limited to this, and any other laser may be used. Also, the laser excitation method is not limited to the lamp excitation method, but may be changed to any other laser excitation method such as a semiconductor laser excitation method.

The present invention is not limited to the above-described embodiment, but can be modified as needed.

[0024]

As described above, in the laser marking method according to the first aspect of the present invention, the workpiece is cooled by the cooling liquid, and the marking portion of the workpiece which generates heat by irradiating the laser beam is efficiently used. It is possible to cool well, and it is possible to reliably prevent the marking part from melting due to heat generation at the time of marking, so that the marked characters etc. can be read well and the marking part of the workpiece is Since there is no melting and swelling, there is no rough feeling at the marking portion, and a good touch can be obtained. Furthermore, since the marking portion can be efficiently cooled, the oxidation of the portion can be prevented, the occurrence of discoloration or the like can be reliably prevented, and an effect such as extremely excellent marking can be achieved. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a laser marking method according to the present invention.

FIG. 2 is an explanatory view showing a marking state of a workpiece by the laser marking method of the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional laser marking method.

FIG. 4 is an explanatory view showing a marking state of a workpiece by a conventional laser marking method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser marking device 2 Workpiece 3 Coolant

Claims (1)

[Claims] 1. A laser marking method for irradiating a relatively small workpiece made of a metal material with laser light to perform desired marking of characters, figures, etc. on the surface of the workpiece. In the above, the workpiece is immersed in a coolant having a property of not being ignited by heat so that only the marking portion of the workpiece is exposed from the coolant, and in this state, a laser beam is applied to the workpiece. Irradiating the workpiece with a laser beam to perform desired marking on the surface of the marking portion exposed from the cooling liquid of the workpiece.