Method of laser engraving

FIELD: process engineering.

SUBSTANCE: proposed method may be used for making inscriptions and symbols on various materials, for examples, on light guides, light boards operated at high levels of illumination. Prior to applying coat of background material, contrast coat is applied that features minimum light reflection factor. Processed surface is divided along two coordinates into elementary sites to displace laser beam over said sites. All area of said sites is divided into area of sign outline and sign body area. On evaporating coats by laser radiation, the number of elementary sites is reduced to zero to form multistage sign profile comprising, at least, one step produced in contrast coat. Body sign area is kept unchanged.

EFFECT: higher readability and accuracy of signs, preservation of initial colours of materials.

3 cl, 3 dwg

 

The invention relates to laser technology and can be used for making labels and signs on various materials, for example in the manufacture of signs and inscriptions on vetoproof and light displays of products, operating at high levels of illumination of the working area, inhabited compartments, salons and cabins object special purpose.

A known method of manufacturing vivid characters light oxidation (Patent Canada No. 2326290, B23K 26/18; B25H 7/04; B41M 5/26, publ. 23.05.2001), in which the metal (glass, ceramic) substrate is applied a mixture of salts and oxides, the covered area is subjected to laser exposure, which results in the oxidation of materials and formation of character. Disadvantages of analogue: chemical resistance of signs and labels is determined by the choice of the mixture of salts and oxides. It is impossible to make marks on vetoproof usage of plastic-type organic glass, polycarbonate and so on

The known method of laser surface treatment of materials (Patent RF №2086376, B23K 26/02, publ. 10.08.1997), in which the surface is divided into elementary areas and exposed to laser radiation. Disadvantages of analogue: the formation of character by giving the surface of the substrate different degrees of blackening and roughness, which limits the applicability of the label p and the readability of characters depends on the viewing angle and ambient light.

The known method of laser engraving (RF Patent No. 2080971, B23K 26/00, publ. 10.06.1997), in which the scanning surface of the workpiece to obtain a given contour. Settings engraving is selected from the conditions the accuracy of the contour (100-200 μm). The profile elements of the figure (sign) is formed by repeating the scanning procedure. When the recess in the material, the laser power and the speed of movement of the beam is increased. The purpose of the profile engraving - ensuring the rigidity of the structure, providing contrast figure (sign) by engraving with deep relief, ensuring accuracy and technical requirements, figure (sign) on the surface of the workpiece, the values of surface parameters at the bottom of the figure (sign) are secondary in nature. Disadvantages: the method is applicable only for metallic materials, the quality of the readability of the figure (sign) at an acute angle low.

The known method of laser marking (Japan Patent No. 62203691, B21C 51/00, 1987-09-08;), which is selected as a prototype, which consists in applying to a metal substrate coating that reflects the laser light (hereinafter referred to as LEE), coatings, absorbing and WHETHER subsequent selective evaporation of coatings using laser radiation. The disadvantages of the prototype: as substrate materials used throughout the world is metal material. The proposed solution requires compatibility of colors, which narrows the application of the color material background (absorbing) and the material of the working layer (reflecting) the requirements for compliance with color contrasts. Profile engraving made direct, which does not ensure the legibility of signs at an acute angle. When observed at an acute angle marks will be distorted (i.e. there is a reduced thickness region of the body of the sign in the direction of observation).

The technical result of the invention is to improve the readability of characters produced by laser engraving by providing a stepped profile of engraving and power control of laser radiation for ensuring the accuracy of signs and maximum preservation of the original color of the material. Additional technical result is the expansion of the color gamut of materials to create design solutions for design inhabited compartments, salons and cabins of special-purpose facilities, providing high legibility of characters.

The technical result is achieved in that on the surface of the substrate is applied, at least one coating of a material with high reflectivity, then apply the coating material background, the surface divided by two coordinates at the elementary PLO is ADCI, overlapping and received the platforms move the beam of pulsed laser radiation, speed of movement, the degree of overlap and the duty cycle of which is chosen such that in one pass to remove the coating layer forming step profile, which is formed by repeated passages of the beam of laser radiation, the control process carried out by computer, before coating of the material background is applied contrasting floor, characterized by a minimum reflectivity, the entire area of elementary areas is divided into a region of the contour of the sign and the body area of the sign, evaporation, laser coatings the number of points of the circuit are reduced to zero, forming a multi-profile character, and the body area of the sign is left unchanged, while the profile of the mark contains at least one step formed in contrasting the floor. Moreover, the energy of laser radiation with repeated passages in all elementary sites reduced to values close to the threshold of ablation of the coating. Moreover, after the formation of character the entire surface of the substrate is covered with a protective, translucent, matte material.

An example implementation of the proposed method is illustrated by figure 1, 2. 3.

Figure 1 p is edstaven the process of formation of the mark.

Figure 2 is an element of the mark in the context.

Figure 3 is an enlarged fragment of the mark made by contouring and divergent profile engraving.

The sample (Fig 1) is a substrate 1, on which a coating 2 of a material with high reflectivity, such as enamel white, yellow or orange flowers. On floor 2 marked contrast coating 3 made of a material with low reflectivity, such as enamel black or dark blue colors. In contrast coating 3 coating 4 of a material background with arbitrary reflectivity, such as enamel beige, gray or blue colors. Also in figure 1 shows the beam 5 LEE, region 6 outline of the sign, the area 7 of the body of the sign, the profile engraving 8, step 9 of the profile.

The proposed method is implemented as follows. On the processed surface of the substrate 1 coated 2. The principal is that contrasting floor 3 of a material with a minimum light reflectance is applied before coating 4 of a material background. Then the processed surface 4 divided by two coordinates on the elementary area (not shown)that overlap each other. At the initial stage of making the sign of the beam 5 LEE served on all received elementary Playground area of the circuit 6 and area 7 of the body of the sign. Each elementary area is exposed to at least one pulse of the beam 5. The degree of overlap of the elementary sites, duty cycle and speed of movement of the beam 5 IF chosen such that in one pass to remove the coating layer forming step 9 profile feature of the mark. The beam 5 I completely vaporizes the coating 4, partially vaporizes the coating 3, forming the delineation of character, and quite a bit vaporizes the coating 2 to ensure purification of the products of evaporation previous coatings.

The entire area of elementary areas is divided into a region of the contour of the mark 6 and the area of the body 7 of the sign. When you pass the area 6 of the outline of the sign is reduced and formed with a step profile 9. The reduction in area 6 of the outline of the sign is determined by the reduction in the number of basic sites, which are stored in computer memory. In the last passage area of the contour of the mark 6 is reduced to zero, and the area of the body 7 of the sign remains unchanged.

Due to the fact that the coating 4 of the background material with arbitrary reflection coefficient is subject to evaporation, then use the energy level of the beam 5 DOES about 100-200 MJ.

Floor 4 has a higher reflectance with respect to the coating of contrasting material 3, so the energy of evaporation of the excess to cover 4 cover 3 and presleduyuschih passes lowered to reduce thermal impact on floor 2. During the manufacturing cycle of the sign of the energy beam 5 IF all points are reduced to values close to the ablation threshold of a material with high reflectivity at the last pass. In practice, applied energy values exceeding the threshold of ablation by 5-10%, depending on the coating material.

In one pass, with the deepening of the bottom of the sign falls on 5-20 μm, with each subsequent passage area 6 contour sign narrows, becomes thinner, thus forming the steps of the profile 9. Depending on the characteristics of the mode (the radiation energy, the speed, the degree of overlap and duty cycle) of a step profile 9 can be steep 10 and 20 μm or less of the order of 5-10 microns.

The treatment program is chosen so that by the time we reach the desired depth of the area of the contour of the mark 6 has disappeared and it would read only the body area of the mark 7, which is made in accordance with the specified font or size of the sign. Multi-pass processing generates a profile engraving 8 multi-stage, with a few steps 9 is formed in a contrasting coating 3, which provides a delineation of character. The line width of the contouring of the sign is determined by the number and width of stairs 9 in contrast coating 3.

The number and width of the steps 9 profile form profile of engraving and Shire is well contouring 6 mark. When performing operations that provide the desired depth of character and the quality of its surface area 6 of the circuit is missing.

After making the sign of the entire surface of the substrate 1 is covered with a protective material (not shown), which is used as a matte, translucent lacquer (for example, UR-5311), which provides chemical resistance characters.

To ensure readability of signs at an acute angle to the surface of the workpiece it is necessary to provide a minimum depth of engraving (not more than 40 μm) or, if this is not possible, then converging to the workpiece profile engraving. To increase contrast characters perform the delineation of character color maximum contrast to the color of the sign, however, a significant limitation is the total thickness of the paint coating is not more than 160 microns. For example: yellow characters on a gray background, it is advisable to delineate a black or dark-blue material, which have a maximum contrast against the yellow color.

Light from an external source 10 (2) falls from the opposite from the observer 11 side on the area of the sign. Formed a stepped profile 8 engraving provides no shadow area 12 mark 13 and barriers 14 for the reflected rays on the observation line 15, which eliminates distortion of the observed sign at a sharp angle OBS is Denia. Perceived by the operator sign 13 contains useful information, usually on a background of white. Thus the contrast of a mark as high as possible since, first, the delineation is usually black color, which significantly improves the perceived contrast of the sign (figure 3) even when light levels more than 30,000 Lux; secondly, the material with minimum reflection coefficient, which is usually black sublayer, provides a reduction of the reflectance of the background of almost any color; third, the material treated by laser radiation with energies close to the threshold of ablation, maximally preserves the color and the original properties by reflection of light. The stepped profile of engraving and high accuracy obtained marks in conjunction with the above qualities provide the best possible readability and eliminates the dependence of the readability of angles. The latter allows to use the method of engraving for registration inhabited compartments, salons and cabins object special purpose in any color combination.

The proposed method applies to software management methods DO and can be implemented on many complexes laser processing, laser marking and engraving, with control from the computer, by controlling the amount that the EC split the beam power or speed, duty cycle pulses. In some cases, when multi-pass low-energy modes can be formed quasilattice profiles engraving of any form.

The method is applicable to any substrate material (for example, organic glass, polycarbonate, aramid etc) and paint materials (liquid enamel, powder coating and so on). When this coating materials can be used in any color. The method is chemically safe, ensures minimal impact on the environment and humans.

When making habitable compartments, salons and cabins of special facilities with the proposed method it is possible to perform design effects, determined by the width of the delineation of characters, for example, make the width of contouring to the right more than the left, or to merge surfaces contouring in the intermediate background surface.

The method can be implemented on the instrument-making enterprise using a ytterbium fiber laser or using a laser YAG:Nd.

The claimed method differs from the most similar analogues, respectively, of the claimed solution satisfy the condition of patentability "novelty."

Technical solutions are not explicitly followed the prior art. In addition, in patent search revealed no technical solutions that have the signs consistent with the distinctive features of the claimed technical solution and, therefore, it satisfies the condition of patentability "inventive step". The tests confirm the achievement of the stated result. In this regard, the invention meets the condition of patentability "industrial applicability".

1. The method of laser engraving, namely, that on the surface of the substrate is applied, at least one coating of a material with high reflectivity, then apply the coating material background, the surface divided by two coordinates on the elementary Playground, overlapping, and received the platforms move the beam of pulsed laser radiation, speed of movement, the degree of overlap and the duty cycle of which is chosen such that in one pass to remove the coating layer forming step profile, which is formed by repeated passages of the beam of laser radiation, the control process is performed with the aid of a computer, characterized in that before coating of the material background is applied contrasting floor, characterized by minimal light reflection coefficient, vs is the area of elementary areas is divided into a region of the contour of the sign and the body area of the sign, during the evaporation of laser radiation coating amount of basic sites of the circuit is reduced to zero, forming a multi-stage profile of a sign containing at least one step formed in contrasting the floor, and the body area of the sign is left unchanged.

2. The method according to claim 1, characterized in that the energy of laser radiation with repeated passages in all elementary sites reduced to values close to the threshold of ablation of the coating.

3. The method according to claim 1 or 2, characterized in that after the formation of character the entire surface of the substrate is covered with a protective, translucent, matte material.



 

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