Screen printing method capable of saving processing procedures

Abstract

The invention discloses a screen printing method capable of saving machining procedures. The screen printing method comprises the following steps that S1, feeding is conducted; s2, primary printing is conducted, specifically, S21, a screen plate containing printing main body ink and silk-screen scraping glue move downwards together, and the screen plate is pressed downwards to the height which is 2 mm + / -1 mm away from a product; s22, the silk-screen scraping glue moves downwards again till the silk-screen scraping glue is completely pressed on the screen plate, the silk-screen scraping glue moves in the horizontal direction parallel to the product and scrapes the printing main body ink in one direction, the printing main body ink overflows to the surface of the product through the film pattern which is not blocked, and the silk-screen scraping glue moves to the other end of the product and is completely pressed on the screen plate; the product is covered with printing main body ink from head to tail; s23, the silk-screen scraping glue moves upwards to the height of S21, an oil return scraper moves downwards to the position 2 mm away from the screen plate, the oil return scraper scrapes printing main body ink from the final position of the silk-screen scraping glue to the starting position, and then the oil return scraper is reset; s3, secondary printing is conducted, specifically, the step S22 and the step S23 are repeated; s4, surface drying; and S5, blanking is conducted. Cover plate glass screen printing is completed on one screen printing machine, the cost is reduced, the production efficiency is improved, and the product performance requirement is met.

Description

Technical Field

[0001] The invention relates to the technical field of glass cover plate processing, and in particular to a silk-screen printing method that saves processing steps. Background Art

[0002] Silk screen printing is the most adaptable and widely used printing method in the world. Its principle is to transfer the ink through the mesh holes of the image part to the substrate through the extrusion of the scraper, forming the same image as the original.

[0003] When screen printing the cover glass of existing mobile phones, tablets, and wearable consumer electronic products, two types of inks are basically used: printing main ink and printing laminating ink. There is no obvious color difference between the color of the printing main ink and when the display screen is not lit. When the display screen is lit, there will be no problems such as light leakage spots and edge light and shadow loops in the display edge area. In the traditional cover glass screen printing method, a layer of printing main ink is generally screen-printed with a thickness of 0.003-0.004mm. The ink is still transparent under strong light, and only two layers of ink can be added, with a total thickness of 0.008-0.015mm, to meet the ink opacity requirements.

[0004] The traditional method of screen printing on cover glass is as follows: the product is taken and placed on the suction plate, positioned by the eight claws, and then the negative pressure sucks the product tightly, the product rotates to the bottom of the screen printing machine screen, and then the machine uses the up and down lifts to press down the screen containing the main printing ink and the scraper together, the scraper scrapes the screen printing oil, and then lifts it up, the product rotates to the unloading area, unloads after screen printing, and the product is dried through the tunnel furnace, cooled, and then flows to the screen printing machine on the next machine, repeating the screen operation, that is, screen printing the second layer of ink, the same operation is completed twice, and finally the overall ink thickness reaches 0.008-0.015mm, which meets the light-shielding performance. By increasing the ink thickness, the ink can achieve higher light-shielding properties.

[0005] The traditional screen printing method for cover glass always requires two screen printings, and the investment in machines, screens, manpower, and tunnel furnaces are all doubled. A piece of cover glass product needs to be processed twice to complete the operation, which is inefficient and costly. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the present invention provides a screen printing method that saves processing steps, completes the screen printing of cover glass on one screen printing machine, reduces costs, improves production efficiency, and meets product performance requirements.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A silk screen printing method for saving processing steps comprises the following steps:

[0009] S1, loading: take the product and put it on the rotating turntable suction plate, position and fix it, and then rotate the product to the bottom of the screen printing machine screen through the turntable suction plate;

[0010] S2, one-time printing:

[0011] S21, the screen containing the main printing ink and the screen printing squeegee move downward together, and the screen is pressed down to a height of 2mm±1mm from the product;

[0012] S22, the screen printing scraper moves downward again until it is completely pressed down on the screen. The screen printing scraper moves parallel to the horizontal direction of the product and scrapes the main printing ink in one direction. The main printing ink overflows onto the product surface through the unsealed film pattern. The screen printing scraper moves to the other end of the product and covers the product from beginning to end with the main printing ink.

[0013] S23, the screen printing scraper moves upward to the height of S21, and the oil return scraper moves downward to 2mm away from the screen plate. The oil return scraper scrapes the main printing ink from the end position of the screen printing scraper to the starting position, and then the oil return scraper is reset;

[0014] S3, secondary printing:

[0015] S31, the screen printing scraper moves downward again until it is completely pressed down on the screen. The screen printing scraper moves parallel to the horizontal direction of the product and scrapes the main printing ink in one direction. The main printing ink overflows onto the surface of the product through the unsealed film pattern. The screen printing scraper moves to the other end of the product and covers the product from beginning to end with the main printing ink.

[0016] S32, the screen printing scraper moves upward to the height of S21, and the oil return scraper moves downward to 2mm away from the screen plate. The oil return scraper scrapes the main printing ink from the end position of the screen printing scraper to the starting position, and then the oil return scraper is reset;

[0017] S4, surface drying: take the product after two printings, transfer it to the tunnel surface drying furnace to complete the surface drying baking, and then pass the final baking to completely cure the main printing ink, completing the silk screen printing of the main printing ink of the product;

[0018] S5, cutting.

[0019] As a further improvement of the above technical solution, the main printing ink is high-dark-value ink.

[0020] As a further improvement of the above technical solution, the contents of matting powder and leveling agent in the printing ink are 0.2-0.4% and 0.5% respectively.

[0021] As a further improvement of the above technical solution, the mesh plate adopts a 350-mesh polyester mesh plate, and the mesh plate tension is 17±2N.

[0022] As a further improvement of the above technical solution, the scraping speed of the silk screen printing scraper in steps S22 and S31 is 170±30 mm / min.

[0023] As a further improvement of the above technical solution, the inclination angle of the silk screen scraper relative to the screen plate is 55±5°.

[0024] As a further improvement of the above technical solution, the R corner radius of the contact surface between the screen printing scraper and the screen plate is 0.05-0.15mm.

[0025] As a further improvement of the above technical solution, the Shore hardness of the silk-screen scraper is 80±5A, the width of the silk-screen scraper is 30-50mm, and the length of the silk-screen scraper is 20mm longer than the length of the product.

[0026] As a further improvement of the above technical solution, the thickness of the main printed ink on the product after completing two printing operations is 0.006-0.010mm.

[0027] As a further improvement of the above technical solution, while performing step S4, steps S1 to S3 are repeated to perform the silk screen printing operation for the next product, and the above steps are cycled to achieve continuous silk screen printing operation.

[0028] The beneficial effects of the present invention are as follows: compared with the traditional silk screen printing method, the silk screen printing method of the present invention reduces a complete silk screen printing operation, and only adds a silk screen printing glue scraping operation and an oil return scraper oil return operation, thereby realizing two ink printing silk screen operations, greatly improving production efficiency, and reducing the use of a silk screen printing machine, thereby reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0030] Figure 1 It is a flow chart of a screen printing method for saving processing steps of the present invention;

[0031] Figure 2 It is a top view of the screen printing scraper, screen plate and product during the screen printing operation of the present invention;

[0032] Figure 3 It is a front view of the screen printing scraper, screen plate and product during the screen printing operation of the present invention;

[0033] Figure 4 It is a side view of the screen printing scraper, screen plate and product during screen printing operation of the present invention;

[0034] Figure 5 It is a process comparison diagram of the screen printing method of the present invention and the traditional screen printing method;

[0035] Figure 6 It is a comparison diagram of the ink structure of the screen printing method of the present invention and the traditional screen printing method.

[0036] Figure numerals: 1. cover glass; 2. silk screen scraper; 3. screen plate; 4. oil return scraper. DETAILED DESCRIPTION

[0037] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by technicians in this field without creative work belong to the scope of protection of the present invention. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the fact that a better connection structure can be formed by adding or reducing connection accessories according to the specific implementation situation. For example, fixed connection / fixed installation can be selected according to the needs of screw connection, bolt connection, pin connection, key connection, bonding, mortise and tenon connection, welding, riveting and other methods. For example, detachable connection can be selected according to the needs of screw connection, bolt connection, threaded connection, snap connection, mortise and tenon connection, Velcro connection and other methods. The various technical features in the invention can be combined interactively without conflicting with each other.

[0038] Reference Figure 1-4 , an embodiment of the present invention provides a screen printing method that saves processing steps, comprising the following steps:

[0039] S1, loading: the product (cover glass 1) is taken by the robot and placed on the rotating turntable suction plate, and fixed by negative pressure after positioning by the eight claws, and then the cover glass 1 is rotated to the bottom of the screen printing machine screen 3 by the turntable suction plate;

[0040] S2, one-time printing:

[0041] S21, positioning: the screen plate 3 containing the main printing ink and the screen printing squeegee 2 are driven downward by the elevator on the screen printing machine until the screen plate 3 is pressed down to a height L of 2 mm ± 1 mm from the cover glass 1;

[0042] S22, scraping a layer of ink: the silk screen scraper 2 is driven by the vertical cylinder to move downward again until it is completely pressed down on the screen 3, and then the silk screen scraper 2 is driven by the horizontal cylinder to move in parallel to the horizontal direction of the cover glass 1, and scrapes the printing main body ink from one end of the cover glass 1 (the starting position) in one direction to the other end of the cover glass 1 (the end position), and the printing main body ink overflows onto the surface of the cover glass 1 through the unsealed film pattern. After the silk screen scraper 2 moves to the other end of the cover glass 1, the cover glass 1 is covered with a layer of printing main body ink from beginning to end;

[0043] S23, one oil return: the vertical cylinder drives the screen printing scraper 2 to move upward to its height in step S21, and the oil return scraper 4 is pressed down to 32mm away from the screen by air pressure, and then the oil return scraper 4 is driven to move horizontally to scrape the printed main body ink from the end position to the starting position, and the first oil return operation is performed. At this time, the thickness of the printed main body ink on the cover glass 1 is 0.003-0.004mm, and then the oil return scraper 4 is reset;

[0044] S3, secondary printing:

[0045] S31, second layer ink scraping: the screen printing scraper 2 is driven by the vertical cylinder to move downward again until it is completely pressed down on the screen plate 3, and then the screen printing scraper 2 is driven by the horizontal cylinder to move in parallel to the horizontal direction of the cover glass 1, and scrapes the printed subject from the starting position of the cover glass 1 to the end position, and the printed subject ink overflows onto the surface of the cover glass 1 through the unsealed film pattern. After the screen printing scraper 2 moves to the key position of the cover glass 1, the cover glass 1 is covered with a layer of printed subject ink from beginning to end again;

[0046] S32, secondary oil return: the vertical cylinder drives the screen printing scraper 2 to move upward to its height in step S21, and the oil return scraper 4 is pressed down to 32mm away from the screen by air pressure, and then the oil return scraper 4 is driven to move horizontally to scrape the printed main body ink from the end position to the starting position to achieve the second oil return operation. At this time, the thickness of the printed main body ink on the cover glass 1 is 0.006-0.01mm, and then the oil return scraper 4 is reset;

[0047] S4, surface drying: take out the cover glass 1 after two printings, transfer it into the tunnel surface drying furnace to complete surface drying baking, and then perform final baking to completely cure the printed main body ink, and complete the screen printing of the printed main body ink of the cover glass 1;

[0048] S5, cutting.

[0049] Furthermore, while performing step S4, steps S1 to S3 are repeated to perform the silk screen printing operation on the next cover glass 1, and the above steps are repeated to achieve continuous silk screen printing operation.

[0050] In some embodiments, the main printing ink is a high-dyne value ink, and specifically, the contents of matting powder and leveling agent in the main printing ink are 0.2-0.4% and 0.5%, respectively. High-dyne value ink has a low silicon content, and after baking, the silicon can be completely volatilized to achieve a state of no silicone oil or low silicone oil, without affecting the dyne value of the finished product. Through the arcotest dyne pen test, the dyne value of the finished product can reach ≥34A.

[0051] It can be understood that in the traditional screen printing method, in order to ensure the printing appearance, the main ink of a layer is exposed to the air and is scraped (stirred) by a manual printer every 4-12 seconds. If the silicone oil leveling agent is less than 3-5%, the main ink is easy to condense and the appearance effect is very poor, so two consecutive screen printing operations cannot be achieved. In the screen printing method of the present invention, the main body can be scraped (stirred) once every 1.5-3 seconds, and the low leveling agent is 0.5%, and the appearance effect can still achieve a good effect. The less the leveling agent is added, the less likely it is to stick to the network, the light-shielding performance can be met, and the performance of other parameters is not affected.

[0052] In addition, refer to Figure 6 In the traditional screen printing method, because of the secondary positioning, there must be a step between the first layer of main ink and the second layer of main ink, and the first layer of main ink is thin, only 0.003-0.004mm thick, and it is easy to leak light. In the screen printing method of the present invention, the positioning is disordered again, and the overall thickness is the same, reaching 0.006-0.010mm, and there will be no light leakage problem.

[0053] In some embodiments, the mesh plate 3 is a 350-mesh polyester mesh plate 3 with a tension of 17±2N. This can make the mesh plate 3 more delicate in contact with the glass, making it easier to apply oil, with less tension and less prone to mesh breakage.

[0054] In some embodiments, the scraping speed of the silk screen scraper 2 in steps S22 and S31 is 170±30 mm / min.

[0055] In some embodiments, reference Figure 3 and Figure 4 , the inclination angle W of the silk screen scraper 2 relative to the screen plate 3 is 55±5°, and the R angle radius of the contact surface between the silk screen scraper 2 and the screen plate 3 is 0.05-0.15mm. If the silk screen scraper 2 is in a vertical state, the R angle is too large, which will cause thick oil accumulation on the edge of the ink, resulting in uneven ink. If there is no R angle, the ink is thin, the contact area of ​​the scraper squeezing the ink is small, and the oil is thin. Therefore, by setting the silk screen scraper 2 to be inclined at 55±5° and the R angle of 0.05-0.15mm, the edge of the ink printed on the cover glass 1 is less likely to have sawtooth problems, and the thickness dimensional accuracy and appearance effect of the printed ink are improved.

[0056] It can be understood that by adjusting the tension parameters of the screen 3, adjusting different screen printing speeds, adjusting different chamfer R value parameters, and continuously printing two layers on a single machine, the screen printing of the cover glass 1 can be achieved, and the performance of the cover glass 1 after screen printing will not be reduced compared to the traditional screen printing method.

[0057] Specifically, the parameters of the cover glass 1 of the screen printing method of the present invention are:

[0058] 1. The thickness of the main ink is 0.006~0.010mm,

[0059] 2. Opacity of main ink: OD value ≥ 5, (testing instrument: X-Rite 341C),

[0060] 3. Adhesion between main ink and glass: 100 grids boiled in water ≥ 4B; environmental aging test, meets the general requirements of mobile phone cover.

[0061] 4. There is no white line defect on the edge of the main ink.

[0062] Furthermore, the Shore hardness of the silk-screen scraper 2 is 80±5A, the width of the silk-screen scraper 2 is 30-50 mm, and the length of the silk-screen scraper 2 is 20 mm longer than the length of the cover glass 1, so that the cover glass 1 can be fully covered when the silk-screen scraper 2 is scraping oil.

[0063] The screen printing method of the present invention reduces a complete screen printing operation and only adds a screen printing scraper 2 oil scraping operation and an oil return scraper 4 oil return operation. Figure 5 Compared with the traditional screen printing method, the screen printing method of the present invention has five less processes, namely, lifting the screen 3, unloading, drying in the furnace, loading, and positioning, which greatly improves the production efficiency and reduces the use of a screen printing machine, thereby reducing the production cost.

[0064] In factory production, the labor efficiency of the silk-screen printing operation of the present invention is improved by more than 50%, the machine cost and the machine electricity cost are reduced by 40%, and the screen cost and the ink cost are reduced by more than 40%, thereby reducing the manufacturing cost and manufacturing expenses. The product price is low while the quality remains unchanged, making the cover glass 1 more competitive in the market.

[0065] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A screen printing method that saves processing steps, characterized in that: The following steps are involved: S1, loading: take the product and put it on the rotating turntable suction plate, position and fix it, and then rotate the product to the bottom of the screen printing machine screen through the turntable suction plate; S2, one-time printing: S21, the screen containing the main printing ink and the screen printing squeegee move downward together, and the screen is pressed down to a height of 2mm±1mm from the product; S22, the screen printing scraper moves downward again until it is completely pressed down on the screen. The screen printing scraper moves parallel to the horizontal direction of the product and scrapes the main printing ink in one direction. The main printing ink overflows onto the product surface through the unsealed film pattern. The screen printing scraper moves to the other end of the product and covers the product from beginning to end with the main printing ink. S23, the screen printing scraper moves upward to the height of S21, and the oil return scraper moves downward to 2mm away from the screen plate. The oil return scraper scrapes the main printing ink from the end position of the screen printing scraper to the starting position, and then the oil return scraper is reset; S3, secondary printing: S31, the screen printing scraper moves downward again until it is completely pressed down on the screen. The screen printing scraper moves parallel to the horizontal direction of the product and scrapes the main printing ink in one direction. The main printing ink overflows onto the surface of the product through the unsealed film pattern. The screen printing scraper moves to the other end of the product and covers the product from beginning to end with the main printing ink. S32, the screen printing scraper moves upward to the height of S21, the oil return scraper moves downward to 2mm away from the screen, the oil return scraper scrapes the main printing ink from the end position of the screen printing scraper to the starting position, and then the oil return scraper is reset; S4, surface drying: take the product after two printings, transfer it to the tunnel surface drying furnace to complete the surface drying baking, and then pass the final baking to completely cure the main printing ink, completing the silk screen printing of the main printing ink of the product; S5, cutting.

2. A silk screen printing method for saving processing steps according to claim 1, characterized in that: The printing ink is a high-dark-value ink.

3. A silk screen printing method for saving processing steps according to claim 2, characterized in that: The contents of matting powder and leveling agent in the printing ink are 0.2-0.4% and 0.5% respectively.

4. A silk screen printing method for saving processing steps according to claim 3, characterized in that: The mesh plate is a 350-mesh polyester mesh plate, and the mesh plate tension is 17±2N.

5. A silk screen printing method for saving processing steps according to claim 4, characterized in that: The scraping speed of the silk screen printing scraper in steps S22 and S31 is 170±30 mm / min.

6. A silk screen printing method for saving processing steps according to claim 4, characterized in that: The inclination angle of the silk screen scraper relative to the screen plate is 55±5°.

7. A silk screen printing method for saving processing steps according to claim 4, characterized in that: The R corner radius of the contact surface between the screen printing scraper and the screen plate is 0.05-0.15mm.

8. The screen printing method for saving processing steps according to claim 1, characterized in that: The Shore hardness of the silk-screen scraper is 80±5A, the width of the silk-screen scraper is 30-50mm, and the length of the silk-screen scraper is 20mm longer than the length of the product.

9. The screen printing method for saving processing steps according to claim 1, characterized in that: After completing two printing operations, the thickness of the main printing ink on the product is 0.006-0.010mm.

10. The screen printing method for saving processing steps according to claim 1, characterized in that: While performing step S4, steps S1 to S3 are repeated to perform the silk screen printing operation for the next product, and the above steps are cycled to achieve continuous silk screen printing operation.

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