Metal or alloy laser etching method

FIELD: metallurgy.

SUBSTANCE: preliminary construction of calibration curve of dependence of etching depth of specimen surface of the specified metal or its alloy on parameters of incident laser radiation to surface is performed at monotonic increase in specific power of laser radiation from value of 0.1 J/cm2·s to the value at which molten drops are formed on etched surface. Then, spatial control of laser beam scanning on surface of metal or its alloy is performed at least as per one coordinate. Simultaneously with translational movement of laser beam there performed is its rotation with radius R. Radius R and angular rotation speed of laser beam is chosen considering the cut width and radius of laser beam.

EFFECT: improvement of the method.

5 cl, 3 dwg, 1 ex

 

The invention relates to methods of application on the surface of the metal or alloy alphanumeric or graphic information exposure to laser radiation. The inventive method can find application in various industries, including engineering, as well as in jewelry and medical fields.

Drawing on their surface alphanumeric or graphic information exposure to laser radiation is performed by moving the beam relative to the surface of the product. Any vector or bitmap image applied to its surface by laser engraving, consists of a set of lines of different lengths. The depth of the data lines, which can be obtained per unit of time determines the speed of cutting of metal products and wear resistance applied to the surface of the image and, in practice, is determined by the parameters of the laser gravious complex beam of laser radiation, the movement of the beam relative to the surface of the product. In order to ensure the most rapid drawing on this laser gravious complex usually choose the appropriate beam parameters of the laser radiation and the program move the beam relative to the surface of the product. The parameters of the laser beam is nogo radiation is usually determined by the technical characteristics gravious complex, and the program will move the beam relative to the surface of the product may vary almost arbitrarily by the operator.

The known method of laser engraving (see patent RU 392100, IPC WC 6/18, VM /24 published 20.06.2010), according to which pre-build a calibration curve according to the depth of engraving the surface of the sample of a given metal or alloy from the power density incident on the surface of the radiation under monotonic increase of the mentioned power density on the value of 1 j/(cm2·) to the amount by which the engraving surface, drops of the melt. Generate protective digital code using a computer, where each number corresponds to a certain depth of the engraving and the power density of the laser radiation is determined from the calibration curve, and the difference between the maximum and minimum depth of the engraving does not exceed 100 microns. Put cuts on the surface of the metal or its alloy visible to the naked eye sign, representing an alphanumeric or graphical information with a minimum size of an individual element is not less than 20 μm, the laser radiation, which move relative to the engraving surface. Then applied to the surface of the obtained visible to the naked eye sign protective digital code in the form of evidenoe to the naked eye of a sequence of recesses with a linear size of not more than 100 μm and a depth, corresponding to the specified number of protective digital code, the laser radiation is selected by the calibration curve specific power.

The known method provides a coating in one process wear marks, one of which is a sign, visible to the naked eye, and the other protective digital code, invisible to the naked eye. The disadvantage of this method is not sufficiently high engraving speed and low productivity of the process.

The known method of laser engraving (see Technological lasers. Directory./Edited Haabersti. - M.: mechanical engineering, Vol.1, ch.5, s, 1991). The method consists in scanning the laser beam in two coordinate surfaces. The image is formed a temporary interruption of the beam.

The disadvantage of this method is the low speed engraving and low capacity.

The known method of laser engraving the surface of the products and materials (see PCT application WO 2008093006, IPC VM 5/24, WK 26/00, published 07.08.2008), which consists in moving the laser beam two-dimensionally relative to stationary products.

The disadvantage of this method is the low rate of surface treatment products and materials.

The known method of laser engraving, in particular metal or alloy (see pate is t EN 2236952, IPC WV 3/00, published 20.03.2004), coinciding with the claimed invention, on the greatest number of significant features and adopted for the prototype. The method consists in the preliminary determination of the power level of laser radiation sufficient to structural changes in the irradiated area of the surface of the product due to the pulse generation mode laser radiation, and in the management of spatio-temporal characteristics of laser beam radiation. Spatial control of the scanning beam of laser radiation is performed in two coordinates, and the point image formed by an interruption of the laser radiation time per pulse generation.

There is a method allows to extend the application area and to increase the power of the laser radiation, however,' it is not enough to effectively use the energy of the beam of laser radiation.

The task of the invention was to provide such a method of laser engraving metal or alloy, which would provide a faster cut, or engraving on this laser system, i.e. the most effective used energy beam of laser radiation.

The task is solved by the method of laser engraving metal or alloy includes a preview build, depending the depth of engraving the surface of the sample of a given metal or alloy on the parameters of the incident on the surface of the radiation under monotonic increase in specific capacity values from 0.1 j/(cm 2·) to the amount by which the engraving surface formed droplets melt and spatial control of the scanning beam of laser radiation on the surface of the metal or alloy of at least one coordinate. At the same time with the translational movement of the beam of laser radiation is implemented by its rotation with a radius R. the Radius R, mm and the rotation speed of the beam of laser radiation satisfy the relations:

where d is the width of the least fine lines caused by the image, microns;

r is the radius of the beam of laser radiation microns;

V is the velocity of the translational movement of the beam of laser radiation, m/S.

Engraving of the inventive method can be continuous laser light or pulse laser radiation with a pulse duration of from 5 to 100 μs.

Engraving can be carried out when the translational movement of the beam of laser radiation with a speed of 0.1-20000 mm/S.

The translational movement of the beam of laser radiation can be done line-by-line scanning of the engraving surface.

The inventive method allows for engraving the surface of metal products faster compared to, for example, a traditional scanning, suggesting that a higher efficiency of radiation lasern the th installation when implementing the inventive method.

A secondary, but no less important was the technical ability to create the claimed "3D laser engraving as well as etching of materials with low absorption (primarily gold). It appears that the total for all of the effects cause is repeated approach of laser radiation on the already irradiated surface as it rotates. The rotation of the beam of laser radiation, thus, can be regarded as a kind of mechanical modulator laser radiation.

The inventive method laser engraving metal or alloy podaetsya drawings, in which:

figure 1 is a given schematic illustration of engraving beam of laser radiation;

figure 2 shows in enlarged scale the area I shown in figure 1;

figure 3 shows an example of 3D laser engraving", obtained using the proposed method;

Figure 1 is displayed: 1 - machined metal or alloy, 2 - line engraving, 3 - trajectory distance of the beam of laser radiation, the 4 - position of the beam of laser radiation at different points in time, r is the radius of the beam of laser radiation, R is the radius of rotation of the beam, d is the width of the line caused by the image.

The inventive method is as follows. For effective power consumption of the laser radiation, and t is the train due to the fact, the physical properties of various metals and alloys, the geometrical characteristics of the processed product can vary considerably, pre-build a calibration curve according to the depth of engraving the surface of the sample of a given metal or alloy on the parameters of the incident on the surface of laser radiation under monotonic increase of the power density of the laser radiation on the value of 0.1 j/cm2·to the amount at which cuts the surface of the drops of the melt. Then carry out the generation of a digital code using a computer, where each number corresponds to a certain depth of the engraving and the power density of the laser radiation, certain of the constructed calibration curve. Digital code written in a particular number system. The radix may be selected arbitrarily, but the possibility of its use needs to be checked. After that put on the engraving surface 1 of metal or its alloy (see figure 1, figure 2) the beam of laser radiation of a given engraving, moving the beam of laser radiation translational speed V and simultaneously rotating it with radius R with angular speed ω, the magnitude of which satisfy the relations (1) and (2).

The inventive method can be carried out applying two or more from the interests of without overlap on the surface of the metal or alloy with different engraving depths sequentially or within one pass of the beam of laser radiation.

Applied image can represent text in a variety of headsets, software application which is available in computer memory, including in accordance with GOST 26.008-85, the text may be convex (relief) or in-depth.

Example. Was executed engraving measuring 10×10 mm with a depth of 250 μm on the plate thickness of 5 mm, material - steel ST20. Engraving - square stamp "Jewellery factory "Alfa" (figure 3). The engraving was done on the universal installation precision laser marking and engraving on the basis of the fiber laser "Minimarket 2" produced by LLC "Laser Center. Moving the beam of laser radiation relative to the surface of the product was carried out using a two-axis scanner-based actuators VM2500+. The duration of monopulse laser radiation was 35 NS, the modulation frequency is 75 kHz, the energy monopulse measured with a pyroelectric sensor Ophir RE 25, 0,4 MJ, the beam diameter of the laser radiation on the surface of the product 50 μm. Previously, using a sample of material was constructed calibration curve according to the depth of engraving the surface of the sample given alloy from the power density of the incident radiation on the surface of the radiation. Were selected the following parameters: the speed of the translational movement of the beam of laser radiation V=0.1 m/s, skorostrelnye beam of laser radiation ω=2500 rad/S. Based on the topology of the stamp, the radius of rotation was chosen as R=50 µm. Engraving stamp was conducted line-by-line scanning, the height of the line, therefore, was 100 μm, the total number of lines 100. The time spent on this engraving of the stamp including time on and off of the beam of laser radiation to move to the next line was 18 seconds. For comparison, was the engraving of a similar stamp on the same laser facility without rotating beam of laser radiation. In this case, to obtain the necessary depth of the engraving, the velocity of the translational movement of the beam of laser radiation amounted V=0,045 m/s, the number of rows is increased to, respectively, 200. In this case, the time spent on this engraving of the stamp including time on and off of the beam of laser radiation to move to the next line, approximately 1 minute 20 seconds. Thus, adding a rotating beam of laser radiation is allowed to apply a desired image more than 4 times faster.

1. The method of laser engraving metal or alloy, including preliminary construction of the calibration curve, the depth of engraving the surface of the sample of a given metal or alloy on the parameters of the incident surface of the laser radiation, such the AK least width of fine lines caused by the image and the radius of the beam of laser radiation, under monotonic increase of the power density of the laser radiation on the value of 0.1 j/cm2·to the amount by which the engraving surface formed droplets melt spatial management scanning beam of laser radiation on the surface of the metal or alloy of at least one coordinate, at the same time with the translational movement of the beam of laser radiation is implemented by its rotation with radius R, and the radius R and the angular velocity of rotation ω of the beam of laser radiation is chosen based on the following equation:
R=d/2-r, µm;
2πR·ω>V, m/s,
where d is the width of the least fine lines caused by the image, microns;
r is the radius of the beam of laser radiation microns;
V is the velocity of the translational movement of the beam of laser radiation, m/S.

2. The method according to claim 1, characterized in that the engraving are continuous laser radiation.

3. The method according to claim 1, characterized in that the engraving are pulsed laser radiation with a pulse duration of 5 NS to 100 μs.

4. The method according to claim 1, characterized in that the etching is carried out at the translational movement of the beam of laser radiation with a speed of 0.1-20000 mm/S.

5. The method according to claim 1, characterized in that the translational movement of the beam of laser radiation is carried out line-by-line scanning of the engraving surface.



 

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