Roller surface laser texturing apparatus and method

Abstract

The present application relates to the technical field of texturing, and discloses a kind of laser texturing equipment and method for roll surface, comprising: according to the pixel specification of blank picture of the development size of target roll surface to be processed and laser spot related parameters determination;According to the pixel in the blank picture is valued according to the microstructure feature expected to be realized, obtain the digitized image of the microstructure of the target roll surface to be processed;According to the digital image, the target roll surface to be processed is textured;Ensure that each pixel of blank picture does not repeat the region representing the surface to be processed, then set the pixel in the blank picture according to the need of microstructure feature, finally by laser equipment according to the pixel parameter in the picture corresponding texturing processing, thereby realizing the laser texturing method of efficiently, high quality according to any specified microstructure to the surface of roll texturing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of texturing, in particular to a roller surface laser texturing equipment and method. BACKGROUND

[0002] The microstructure of the surface profile has an important influence on the surface characteristics of the material. For example, many experts and scholars are inspired by the natural biological world and have carried out a large number of material bionic structure design and tests. Through reasonable design of the surface microstructure, the friction, wear resistance, wetting, gloss, fluid drag reduction, and adhesion of the material surface can be significantly improved.

[0003] Taking a steel plate as an example, different users have different concerns about the surface characteristics of the steel plate. For example, some users are concerned about the oil storage capacity of the steel plate surface, some users are concerned about the anti-friction and wear resistance of the steel plate surface, some users are concerned about the gloss of the steel plate surface, and some users are concerned about the painting effect of the steel plate surface. Therefore, reasonable design and control of the microstructure of the steel plate surface will be beneficial to further improve the use effect of the steel plate at the user end.

[0004] The microstructure of the surface profile of the steel plate is generally transferred from the surface of the roller through rolling or flattening during the production process of the steel plate, and the microstructure of the surface profile of the roller is obtained by texturing the surface of the roller. The existing roller texturing technology mainly includes shot blasting / sand blasting texturing, electric spark texturing, laser texturing, electron beam texturing, and chromium plating texturing. However, these existing roller texturing technologies have the problem of difficult free control of the texturing microstructure, and often have inherent characteristics of the technology. For example, the formation process of the texturing microstructure of shot blasting / sand blasting texturing, electric spark texturing, and chromium plating texturing is completely random, so the microstructure of the texturing structure cannot be accurately controlled. The shape of the texturing pit of laser texturing and electron beam texturing is biased to be ordered, and the microstructure of the texturing point generated by each energy pulse is the same or similar, so the microstructure of the texturing morphology cannot be freely controlled and adjusted.

[0005] The patent with publication number CN104884180B discloses a surface structure with regular texture, which to some extent solves the problem of the existing roller texturing technology in the control of the surface microstructure. However, the surface microstructure is regular and repetitive texture, and the microstructure of the roller surface cannot be freely controlled.

[0006] In summary, reasonable control of the microstructure of the steel plate surface is a key means to improve the surface characteristics of the steel plate. However, the existing roller texturing technology cannot freely control the microstructure of the roller surface, so it is difficult to fully meet the needs of different users for different surface characteristics. SUMMARY

[0007] The application aims to provide a roller surface laser texturing device and method, and solve the following technical problems:

[0008] How to provide a laser texturing method capable of efficiently and high-quality texturing the roller surface according to any specified microstructure.

[0009] The purpose of the application can be achieved by the following technical solutions:

[0010] A roller surface laser texturing method, comprising:

[0011] Step S1, determining the pixel specification of a blank picture according to the unfolded size of the target roller surface to be processed and laser spot related parameters;

[0012] Step S2, assigning values to the pixels in the blank picture according to the desired microstructure characteristics, to obtain a digital image of the microstructure of the target roller surface to be processed;

[0013] Step S3, texturing the target roller surface to be processed according to the digital image;

[0014] Wherein, the laser spot related parameters include the effective ablation area of the laser spot and the spot overlap coefficient, and each pixel in the digital image corresponds to a region of the target roller surface to be processed.

[0015] Through the above technical solutions, before texturing, a blank picture corresponding to the target roller surface to be processed is established, ensuring that each pixel of the blank picture represents a region of the surface to be processed without repetition, then the pixels in the blank picture are set according to the needs of the microstructure characteristics, and finally the laser equipment performs corresponding texturing processing according to the pixel parameters in the picture. Due to the flexible assignment of pixel values and the adaptation of the number of pixels to the surface to be processed of the target roller, the precision is high, thereby realizing a laser texturing method capable of efficiently and high-quality texturing the roller surface according to any specified microstructure.

[0016] As a further scheme of the application: in step S1, the method for determining the pixel specification of the blank picture comprises:

[0017]

[0018] Wherein, L is the number of pixels in the length direction of the blank picture, L roll is the length dimension in the unfolded size of the target roller surface to be processed, W is the number of pixels in the width direction of the blank picture, W roll is the width dimension in the unfolded size of the target roller surface to be processed, d l is the length direction dimension of the effective ablation area of the laser spot, and dw A width direction dimension of an effective ablation area of the laser spot, and η is the spot overlap coefficient.

[0019] As a further aspect of the present application, the step S2 comprises:

[0020] According to the desired microstructure features, a corresponding three-dimensional topographic structure is established;

[0021] The height of the three-dimensional topographic structure perpendicular to the pixel plane is determined;

[0022] The image corresponding to the three-dimensional topographic structure is converted to a two-dimensional image containing height information with the pixel plane as the reference plane;

[0023] The two-dimensional image is placed on the blank picture in a random and non-overlapping manner to obtain the digitized image.

[0024] As a further aspect of the present application, the height information is the gray data of the pixels in the two-dimensional image.

[0025] As a further aspect of the present application, the step S2 further comprises:

[0026] The specified area of the digitized image is evaluated for roughening;

[0027] The evaluation score of the roughening evaluation is compared with a preset threshold value, and if the preset condition is met, the roughening processing can be performed, otherwise the generation of the digitized image is re-performed.

[0028] A roll surface laser roughening device, comprising:

[0029] A roll lathe, a roll, a short pulse laser, a laser roughening head and a control system;

[0030] The roll is arranged on the roll lathe, and the roll lathe drives the roll to rotate;

[0031] The short pulse laser and the laser roughening head are installed on the horizontal drag plate of the roll lathe and are perpendicular to the roll surface, and the horizontal drag plate drives the laser roughening head to move horizontally along the axis direction of the roll;

[0032] A rotary encoder is arranged on the main shaft of the roll lathe driving the roll to rotate, and a grating ruler is arranged below the horizontal drag plate;

[0033] The control system obtains the relative position relationship between the laser texturing head and the roll surface by collecting the information of the rotary encoder and the grating ruler, and controls the short pulse laser to emit and turn off the laser pulse according to the digital image, so that the emitted laser pulse is focused through the laser texturing head to ablate the roll surface, and the texturing of the roll is realized.

[0034] The present application has the following advantages: the present application establishes a blank picture corresponding to the surface of the target roll to be processed before texturing, ensures that each pixel of the blank picture represents the area of the surface to be processed without repetition, then sets the pixels in the blank picture according to the needs of the microstructure characteristics, and finally performs corresponding texturing processing according to the pixel parameters in the picture by the laser equipment. Since the pixel assignment in the picture is flexible and the number of pixels is adapted to the surface to be processed of the target roll, the precision is high, so that the laser texturing method for texturing the roll surface according to any specified microstructure is realized with high efficiency and high quality. BRIEF DESCRIPTION OF DRAWINGS

[0035] The present application will be further described below with reference to the accompanying drawings.

[0036] Figure 1 It is a flow chart of the roll surface laser texturing method in the present application.

[0037] Figure 2 It is a three-dimensional schematic diagram of a single three-dimensional topography structure in the present embodiment.

[0038] Figure 3 It is a two-dimensional schematic diagram of a single three-dimensional topography structure in the present embodiment.

[0039] Figure 4 It is a partial digital image of the target texturing topography of the roll surface.

[0040] Figure 5 It is a schematic diagram of the actual microstructure of the corresponding position of the roll after processing in the present application.

[0041] Figure 6 It is a schematic diagram of the laser texturing equipment structure of the roll surface in the present application.

[0042] BRIEF DESCRIPTION OF DRAWINGS: 1, roll lathe; 101, rotary encoder; 102, horizontal drag plate; 103, grating ruler; 2, roll; 3, short pulse laser; 4, laser texturing head; 5, control system. DETAILED DESCRIPTION

[0043] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0044] Please refer to Figure 1 The present application is a kind of roll surface laser texturing method, comprising:

[0045] Step S1, according to the development size of the target roll surface to be processed and the laser spot related parameters to determine the pixel specification of the blank picture;

[0046] Step S2, according to the desired microstructure characteristics to assign values to the pixels in the blank picture, to obtain the digital image of the target roll surface to be processed microstructure;

[0047] Step S3, according to the digital image to the target roll surface to be processed texturing processing;

[0048] Wherein, the laser spot related parameters include laser spot effective ablation area and spot overlap coefficient, each pixel in the digital image corresponds to a region of the target roll surface to be processed.

[0049] Through the above technical solution, before texturing, the blank picture corresponding to the target roll surface to be processed is established, ensuring that each pixel of the blank picture does not represent the region of the surface to be processed, then the pixels in the blank picture are set according to the needs of the microstructure characteristics, and finally the laser equipment performs corresponding texturing processing according to the pixel parameters in the picture. Due to the flexible assignment of picture pixels and the adaptation of pixel quantity to the surface to be processed of the target roll, the precision is high, so as to realize the laser texturing method of efficiently and high quality texturing the roll surface according to any specified microstructure.

[0050] The roll in step S1, in this embodiment of the present application, the surface can be a smooth surface, the surface roughness Ra≤0.5μm, because the initial microstructure of the roll surface will affect the final processed roll surface microstructure, so before processing, the roll surface should be polished to make the surface as smooth as possible.

[0051] In this embodiment of the present application, the method for determining the pixel specification of the blank picture comprises:

[0052]

[0053] Wherein, L is the number of pixels in the length direction of the blank picture, L rollW is the length of the unwound size of the surface of the target roll to be processed, W is the number of pixels in the width direction of the blank picture, W roll d is the width of the unwound size of the surface of the target roll to be processed, d l d is the length of the effective ablation area of the laser spot, d w d is the width of the effective ablation area of the laser spot, and η is the spot overlap coefficient.

[0054] In this embodiment, the surface roughness of the roll to be processed is 0.32 μm, the roll diameter is 506.1 mm, the roll face width is 2000 mm, the unwound size of the roll surface is 3.14*506 mm = 1588.8 mm long and 2000 mm wide. The laser spot focused by the laser texturing head is a circular spot, and the effective ablation area formed on the roll surface is a circle with a diameter of 0.01 mm. With a spot overlap coefficient of 0.1, the length of the pixel of the blank picture is calculated to be 176533, and the width of the pixel is calculated to be 222222.

[0055] The effective ablation area of the laser spot refers to the effective ablation area of the single laser pulse focused by the laser texturing head on the roll surface, and the preferred value range is 2.5*10-5-2.5*10-3 mm2. When the value is too large, the ablation area of the laser pulse is too large, the particle size of the processed surface is large, and it is not conducive to realize the complex and fine surface microstructure, and when the value is too small, the processing efficiency is low.

[0056] The spot overlap coefficient refers to the overlap ratio of the effective ablation areas of adjacent laser spots, and the value range is 0-0.3. Since the ablation effect of the edge of the laser spot is usually weaker than that of the middle area, in order to obtain a relatively uniform processing effect, a certain amount of overlap of adjacent laser spots is required, but too large overlap coefficient will cause excessive ablation in the overlap area.

[0057] In this embodiment of the present application, the step S2 comprises:

[0058] According to the desired microstructure features, a corresponding three-dimensional topographic structure is established;

[0059] The height of the three-dimensional topographic structure perpendicular to the pixel plane is determined;

[0060] The image corresponding to the three-dimensional topographic structure is converted into a two-dimensional image containing height information with the pixel plane as the reference surface;

[0061] The two-dimensional image is placed on the blank picture in a random and non-overlapping manner to obtain the digitized image.

[0062] The height information is the gray data of the pixels in the two-dimensional image.

[0063] In the embodiment, the microstructure features expected to be realized can be composed of a series of randomly distributed tiny circular bosses, as shown in Figure 2 As shown, the upper part of the boss has a diameter of 60 μm, the lower part has a diameter of 100 μm, and the height is 16 μm, and the rest is a plane. The bosses are randomly distributed on the surface of the roll, and there is no overlap between the bosses.

[0064] The three-dimensional image can be converted into a two-dimensional image containing height information, as shown in Figure 3 As shown, different colors and gray scales represent different heights. By randomly placing the two-dimensional image on a blank picture while avoiding overlap, a digitized image as shown in Figure 4 As shown, the different gray scales of the image represent different machining depths.

[0065] As a further aspect of the present application, the step S2 further comprises:

[0066] Performing a roughening evaluation on the specified region of the digitized image.

[0067] Comparing the evaluation score of the roughening evaluation with a preset threshold value. If the preset condition is met, the roughening processing can be performed, otherwise the generation of the digitized image is re-performed.

[0068] Specifically, the evaluation score can be calculated by the following formula:

[0069]

[0070] Wherein, D is the evaluation score, μ1 and μ2 are respectively corresponding preset weighting coefficients, M m is the average value of the distance between all two-dimensional images in the digitized image, m is the number of groups of all two-dimensional images in the digitized image, i x j is the distance between the i-th two-dimensional image and the j-th two-dimensional image in the digitized image.

[0071] P c is the gray quantization value of the C-th pixel point in the digitized image except the edge pixels, u is the total number of pixel points in the digitized image except the edge pixels, P k is the gray quantization value of the k-th pixel point in the nine pixel points around the C-th pixel point.

[0072] Through the above technical solution, in the embodiment, by ​The degree of fluctuation in the distance between any two pairs of the two-dimensional images can be obtained; the larger the result, the worse the uniformity. This reflects the difference in gray values ​​between pixels within a single two-dimensional image. The larger the result, the greater the fluctuation in height difference, indicating a larger variation in fuzzing depth and a better effect.

[0073] Therefore, in this embodiment of the present invention, the preset condition can be set as follows:

[0074] When D≥D th If the expected result of the texturing is poor, the digitized image needs to be generated again. The parameters of the two-dimensional image itself or the number of two-dimensional images added can be adjusted according to the actual situation.

[0075] When D < D th If the expected results are good, then the next step of texturing can be carried out.

[0076] Among them, D th The preset threshold is defined as follows.

[0077] A laser texturing device for the surface of a rolling mill roll includes:

[0078] 1. Roll lathe, 2. Rolls, 3. Short pulse laser, 4. Laser texturing head, and 5. Control system;

[0079] The roll 2 is mounted on the roll lathe 1, and the roll lathe 1 drives the roll 2 to rotate;

[0080] The short-pulse laser 3 and the laser texturing head 4 are mounted on the horizontal slide 102 of the roller lathe 1 and are perpendicular to the surface of the roll 2. The horizontal slide 102 drives the laser texturing head 4 to move horizontally along the axial direction of the roll 2.

[0081] A rotary encoder 101 is provided on the main shaft of the roller lathe 1 that drives the roll 2 to rotate, and a grating ruler 103 is provided under the horizontal slide 102;

[0082] The control system 5 obtains the relative positional relationship between the laser texturing head 4 and the surface of the roll 2 by collecting information from the rotary encoder 101 and the grating ruler 103. At the same time, based on the digital image, it controls the short-pulse laser 3 to emit and shut down laser pulses. The emitted laser pulses are focused by the laser texturing head 4 and ablate the surface of the roll 2 to achieve texturing of the roll 2.

[0083] In use, the laser texturing head 4 and the roller 2 surface are kept relative scanning motion, according to the relative position relationship and the digital image control short pulse laser 3 emits laser pulse to the roller 2 surface material selective ablation removal, finally in the roller 2 surface obtain the target microstructure of digital image consistent surface microstructure, complete the roller 2 surface texturing processing.

[0084] The above relative position relationship refers to the current laser relative irradiation position on the roller 2 surface, which can be determined by the roller 2 rotation angle sensor (rotary encoder 101), laser head position sensor (grating ruler 103); The short pulse laser 3 used in the embodiment refers to the laser with pulse time width of 10 ns and below. In order to realize the fine processing of the roller 2 surface, the time of laser pulse acting on the material needs to be controlled in a very short time, so that the laser energy is released in a very short time, and the material is mainly evaporated and vaporized, avoiding the heat effect and the melting flow caused by the accumulation of heat, thereby affecting the fineness of the texturing microstructure.

[0085] The above selective ablation removal is determined according to the current laser relative irradiation position on the roller 2 surface and the processing depth information of the corresponding pixel position in the digital image in step S2; Its processing process can be completed in one pass according to the ablation depth of single laser pulse on the material surface, or can be completed in multiple passes. The problem that the existing roller 2 texturing technology cannot freely control the surface microstructure is solved, so that the design and processing of the roller 2 surface microstructure can be realized according to the expected surface microstructure, and the user can better improve the surface characteristics of the product. The above describes one embodiment of the present application in detail, but the content described is only the preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made according to the scope of the present application should still belong to the patent coverage of the present application.

Claims

1. A method of laser texturing a roll surface, characterized by, The method comprises the following steps: Step S1, determining the pixel specification of a blank picture according to the unfolded size of the surface to be processed of the target roller and laser spot related parameters; Step S2, assigning values to the pixels in the blank picture according to the desired microstructure features to obtain a digital image of the microstructure of the surface to be processed of the target roller; Step S3, performing roughening processing on the surface to be processed of the target roller according to the digital image; The laser spot related parameters include the effective ablation area of the laser spot and the spot overlap coefficient, and each pixel in the digital image corresponds to a region on the surface to be processed of the target roller. In step S1, the method for determining the pixel specification of the blank picture comprises: Wherein, L is the pixel number of the length direction of the blank picture, L roll is the length dimension in the unfolded size of the target roll surface to be processed, W is the pixel number of the width direction of the blank picture, W roll is the width dimension in the unfolded size of the target roll surface to be processed, d l is the length direction dimension of the effective ablation area of the laser spot, d w is the width direction dimension of the effective ablation area of the laser spot, and η is the spot overlap coefficient. Step S2 comprises: establishing a corresponding three-dimensional topography structure according to the desired microstructure features; determining the height of the three-dimensional topography structure perpendicular to the pixel plane; converting the image corresponding to the three-dimensional topography structure to a two-dimensional image containing height information with the pixel plane as the reference plane; placing the two-dimensional images on the blank picture in a random and non-overlapping manner to obtain the digital image; The height information is the gray data of the pixels in the two-dimensional image.

2. The roll surface laser texturing method according to claim 1, characterized in that, Step S2 further comprises: performing roughening evaluation on the specified region of the digital image; comparing the evaluation score of the roughening evaluation with a preset threshold value, if the preset condition is met, the roughening processing can be performed, otherwise the generation of the digital image is re-performed.

3. A laser texturing apparatus for a roll surface, characterized by, The method for roughening the surface of a roller by laser according to any one of claims 1-2, characterized in that it comprises: a roller lathe (1), a roller (2), a short pulse laser (3), a laser roughening head (4) and a control system (5); the roller (2) is arranged on the roller lathe (1), and the roller lathe (1) drives the roller (2) to rotate; the short pulse laser (3) and the laser roughening head (4) are installed on the horizontal drag plate (102) of the roller lathe (1) and are perpendicular to the surface of the roller (2), and the horizontal drag plate (102) drives the laser roughening head (4) to move horizontally along the axis direction of the roller (2); a rotary encoder (101) is arranged on the main shaft of the roller lathe (1) for driving the roller (2) to rotate, and a grating ruler (103) is arranged below the horizontal drag plate (102); the control system (5) obtains the relative position relationship between the laser roughening head (4) and the surface of the roller (2) by collecting the information of the rotary encoder (101) and the grating ruler (103), and controls the short pulse laser (3) to emit and turn off laser pulses according to the digital image, and the emitted laser pulses are focused by the laser roughening head (4) to ablate the surface of the roller (2), thereby realizing the roughening processing of the roller (2).

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