A method for making stencil using only foil material

Abstract

The present invention provides a method for making a stencil using only foil or film materials, a method for directly using software to drive a laser beam to cut and remove materials, and a method for selectively making a transparent opening in a graphic area of ​​a continuous material, replacing the traditional indirect means of blocking the mesh holes in the non-graphic area of ​​a woven screen material with transparent openings, and keeping the openings in the graphic area in a transparent state, to make a stencil. By adding a structural wire for tensioning and connecting in the opening area, the disadvantages of a screen made of metal foil or polymer film that is not suitable for patterns with a large opening aspect ratio, a large opening area, and a large opening side are overcome, and at the same time, the problem of a complex template production process and a low degree of automation is solved. The stencil produced by the present invention has high precision and quality, a simple, fast, and environmentally friendly manufacturing process, is easy to operate, and materials and equipment are easily available, and the cost is low, and it can be used for the production of various high-performance material distribution and molding stencils.

Description

Technical Field

[0001] The invention belongs to the technical field of printing plate mold manufacturing, and in particular relates to a method for manufacturing a stencil using only foil or film material. Background Art

[0002] Stencil printing, also known as screen printing or hole printing, is one of the important printing technologies. It realizes the transfer of printing materials through the openings on the top and bottom of the transparent plate to form images and texts. Stencil, also known as hole plate, screen plate, screen printing plate, and stencil printing plate, as a printing plate, has a vital impact on the quality and efficiency of printing. In addition, as a tool for selectively coating materials, stencils are also widely used in other industrial industries and are as important as molds used in other industries. For example, in the electronics industry, stencils are used to make functional patterns when producing bare circuit boards and electronic components; in the SMT technology of assembling circuit boards, stencils are used to print solder paste on PCB pads. For another example, in the photovoltaic industry, stencils are used to print conductive paste and manufacture solar cell grid lines. In these applications, stencils are used repeatedly to transfer materials to workpieces again and again, which determines the production efficiency and the performance of thousands of products, making the value of the final product far higher than the price of the plate.

[0003] The stencil is composed of a frame and a thin film material stretched on the frame, which often has a certain degree of elasticity. The thin film material can be a metal or polymer screen, foil, film, sheet, or a composite or combination of these materials. The film material around the frame forms the stencil surface. The center of the surface is the working area, also called the stencil printing area, and the area close to the frame plays the role of connection, fixation, tension, and rebound.

[0004] On the stencil printing area, there are pattern areas and non-pattern areas with transparent openings. When in use, the workpiece is placed under the stencil, the printing material is piled on the upper surface of the stencil, and the printing material piled on the upper surface of the stencil, i.e., the printing surface, is scraped with a scraper. While rolling, the printing material is subjected to the downward squeezing force and is transferred to the workpiece surface through the openings running through the upper and lower surfaces of the stencil. After printing, the workpiece surface corresponding to the transparent opening area on the stencil will receive the transferred printing material and form a printing material pattern, while the workpiece surface corresponding to the non-pattern area on the stencil without transparent openings will not have any printing material transferred.

[0005] In addition to using patterned and non-patterned areas to achieve selective material transfer, in the above-mentioned high-end applications, the stencil also has requirements for precise positioning and precise molding of materials. On the precision stencil, the transparent opening area is surrounded by a mask material with a certain thickness and taper. In fact, a cavity of a certain shape is formed, which is both a microchannel for material transfer and a locator and former for material distribution. During the printing process, after the stencil leaves the workpiece and rises, the printing material in the cavity is separated and transferred to the surface of the workpiece under the lower surface of the stencil, that is, under the contact surface of the substrate of the stencil. The shape, size, and position of the transferred printing material correspond to the shape, size, and position of the stencil cavity. In this way, each material transfer completed during the printing process affects the position, shape, and size of the material on the surface of the workpiece. In such applications, there is no doubt that the geometric shape, physical position, sidewall state, and durability of the stencil pattern will be important features for evaluating the stencil.

[0006] Common stencils can be divided into single film stencils and two film joint stencils according to the materials used in the stencil printing area and the materials used in the non-working area. Single film material stencils include polymer screen, metal screen, polymer film, metal foil, polymer film and metal foil composite film; two film joint stencils include polymer screen with metal foil as the pattern area material and polymer screen with metal screen as the pattern area material.

[0007] Stencils can also be divided into two categories according to the internal structure of the opening: stencils without structural wires for tensioning and connecting inside the opening, and stencils with structural wires for tensioning and connecting inside the opening. Stencils without structural wires inside the opening are mostly not made with silk screens. Strictly speaking, they can only be called stencils, not screens; and printing using this type of stencil is not suitable for being called silk screen printing, but only suitable for being called stencil printing, or stencil printing. Stencils with structural wires inside the opening are mostly made with silk screens. Therefore, strictly speaking, only this type of stencil can be called a stencil, a hole plate, a screen plate, or a screen printing plate; printing using this type of stencil can be called stencil printing, silk screen printing, or silk screen printing, or screen printing.

[0008] A stencil without structural wires inside the hole cannot maintain tension on the entire periphery of a larger opening geometric figure, and is only suitable for manufacturing patterns with a small aspect ratio and a small opening on the workpiece. For example, SMT technology is used to transfer and shape solder paste onto the welding pad. The pattern area of ​​this type of stencil is currently commonly made of pure metal foil. Currently, the application areas of this type of stencil are expanding from the SMT field to pan-semiconductor packaging technology and various LED technology fields involved in display manufacturing.

[0009] In the circuit board assembly, semiconductor packaging and display manufacturing industries, the precision solder paste stencils used have a small opening area, a small aspect ratio, a small side length, and a relatively simple shape, mainly rectangular and circular. Therefore, for this type of application, most stencils without structural wires inside the holes are used. The current technology is to choose metal foil as the material in the pattern area as the mainstream, such as specially treated 304 steel foil, which has good rigidity, accurate positioning, and good dimensional accuracy. There are three types of technologies for making the exposed area of ​​such a stencil: etching, electroforming, and laser. Due to technical reasons, etching and electroforming can only make the pattern area opening first, and then tighten the pattern area foil or film material that has been opened and paste it on the stencil frame, or paste it on the pre-stretched blank screen plate surface. With the laser method, you can either stretch the foil or film material first, and then stick it on the frame, or stick it on a pre-stretched blank screen plate, and then make the holes; you can also make holes in the foil or film material in the pattern area first, and then stretch the foil or film in the pattern area after the holes are opened on the stencil frame, or stick it on a pre-stretched blank screen plate.

[0010] Etching is a subtractive manufacturing method that transfers resist to the surface of stainless steel foil through photolithography, plate making, coating of photosensitive materials, exposure, and development, and then uses chemical liquid to etch away unnecessary metal to make openings. In general, it has poor accuracy, poor geometry, rough side walls of the openings, low smoothness of the hole walls, cumbersome processes, and a large environmental burden. During the printing process, the printing material sticks to the hole walls and is difficult to release, which not only makes the volume of the released solder paste uncertain, but also affects the speed of the scraper scraping across the template during printing, and the template must be wiped frequently. Therefore, the application of templates made by etching is becoming less and less.

[0011] The electroforming method is to selectively add metal on the plane according to the requirements of the design graphics. The added metal eventually forms a template, so it is also called the additive method. Like the etching method, it requires photo-drawing, plate making, coating of photosensitive materials, exposure, development, and manufacturing of mask patterns, but the pattern is transferred to the prepared core plate, and a masking film is made on the opening area to resist electroforming deposited metal; unlike the etching method, the metal is deposited on the core plate by electroforming, the masking film is removed, and the formed metal layer is peeled off from the core plate to obtain a metal plate with a hollow opening. The template obtained by this method has smooth hole walls and good performance of penetrating materials. However, the processing technology of this method is not only cumbersome, but also special, the precision is not high, the environmental burden is large, and the processing cycle is long. Electroforming templates are rarely used in practice.

[0012] In the laser method, the laser beam passes through the cutting head and is focused vertically on the surface of the material being cut, heating, melting, and evaporating the material being cut to form a slit, and the closed slit forms an opening. StencilMat of German-Chinese Technology uses laser processing directly according to CAD data. The X and Y axis accuracy can reach ±3μm, the repeatability accuracy can reach ±1μm, and the hole wall roughness can be less than 3μm. The focusing characteristics of the beam make the opening small at the top and large at the bottom, with a certain taper, which is convenient for the release of the printing material. The volume and shape of the printing material transferred to the surface of the workpiece can be controlled. This technology is environmentally friendly, has a short processing cycle, and a high speed. It can open tens of thousands of holes per hour, and can reach hundreds of thousands of small holes.

[0013] Nevertheless, in the face of more sophisticated and faster stencil production, the nature of the metal itself still limits the speed at which the scraper can scrape across the stencil, and limits the speed and smoothness with which the printing material is released from the openings. It is also necessary to wipe the plate from time to time to remove the printing material stuck to the hole walls.

[0014] In order to improve the performance of metal stencils, two methods have emerged: coating a nanomaterial layer on the metal stencil and a polymer stencil. Among them, nano-processing technology can be used to treat the metal surface to increase the hardness of the metal; or a hydrophobic layer can be coated on the metal surface using spraying, vacuum and other technologies to change the metal surface state, reduce the friction coefficient of the scraping surface, and increase the smoothness of the printing material release, so as to achieve the purpose of being suitable for high-speed scraping and reducing the frequency of wiping the stencil. However, most of the nano-coatings on the market today cannot change the roughness of the hole wall, are afraid of strong acids, high temperatures, and are not resistant to strong friction. In addition, the processing and coating methods are complicated, and the equipment investment cost is high.

[0015] Author Hu Hongyu and others introduced a "polymer stencil suitable for high-quality and high-speed printing" (Electronic Process Technology, January 2002). The material is a translucent amber polyimide film with a thickness of 20-175 μm and a trade name of Kapton. The holes are precisely cut with a laser to make a stencil for printing. Because the material has a low affinity with the solder paste, the stencil surface is smooth, and the friction coefficient is small, the solder paste is released more easily and does not stick to the plate, which can reduce the number of times the stencil is cleaned. The speed of scraping and stripping is faster, which can be increased to 3 times that of the metal stencil. The printing quality is higher, and even the solder paste with high viscosity can achieve good printing results. However, the polymer film itself has the disadvantages of being easily scratched and punctured by mechanical hard objects and easily deformed, which limits its application range.

[0016] The stencil with structural wires inside the opening is suitable for making various opening patterns on the workpiece, but because there are structural wires inside the opening, the distribution of the structural wires is often random, which will affect the precision of material transfer and molding to some extent. The pattern area of ​​the stencil with structural wires inside the opening is often obtained by coating organic coatings on the structural wires, or laminating organic films, and then making openings on the organic coating layer or organic film. Among them, the stencil with structural wires made of polymer materials is the most widely used, and the application of the stencil with structural wires made of metal wires is also expanding from the field of solar cell manufacturing to various precision slurry transfer technologies.

[0017] In the traditional printing industry, stencil screens are used to transfer inks and create visual patterns; in the bare circuit board manufacturing industry, stencil screens are used to transfer materials such as resists, plating resists, and solder resists to create coatings that have the function of masking a certain pattern area; in the electronic components and photovoltaic industries, stencil screens are used to transfer slurries to create electrical, electromagnetic, optical, thermal and other functional coatings with a certain thickness in a certain pattern area. The opening graphics on this type of screen include various straight lines, broken lines, variable diameter lines, triangles, rectangles, circles, polygons, bows, multiple arcs, and the combined shapes of these graphics. The characteristics of this type of graphics are that the side length is long, the area is large, the aspect ratio is large, or it is complex enough. If there is no structural wire inside the pattern that plays a tensioning and connecting role, the shape cannot be maintained and the tension cannot be maintained. Therefore, this type of application mostly uses screens with structural wires inside the holes. There are two steps to make this type of screen: the first step is to make a blank plate; the second step is to make a masking pattern on the blank plate. The process of making a blank plate is generally called stretching the screen, and the steps are: after the elastic film is stretched outward in several directions along the plane of the elastic film to a certain specified tension value, the elastic film and the bottom surface of the screen frame are glued together to obtain a blank plate with the tension of the elastic film maintained at a certain value. The elastic film can be a silk screen, a polymer film, or a metal foil, or a composite or combination of these materials.

[0018] Among them, wire meshes are the most common. Wire meshes can be divided into two types of materials, organic wire meshes and metal wire meshes, including natural polymer and synthetic polymer wire meshes, stainless steel and other metal wire meshes. The common polymer wire meshes are nylon wire mesh and polyester wire mesh. They have a large elongation rate, good elongation recovery rate and resilience, but low softening point and melting point, low elastic modulus and stiffness. Therefore, the tension of stretching the wire mesh is limited, the printing position and dimensional accuracy are low, it is difficult to control the clarity and the uniformity of the printing ink thickness, and they are not suitable for manufacturing high-precision screen plates. Stainless steel wire meshes have a large strength and elastic modulus, high yield point. Even under a large tensile force, the elongation is limited, with high shape retention, fine wire diameter, can be used to manufacture high-mesh wire meshes, the wire mesh thickness is uniform, good resistance, especially strong wear resistance and good ink permeability. With the need for micro-graphic stenciling in the electronics and photovoltaic industries, their applications are increasing. However, stainless steel wire meshes have small resilience. During the printing process, the wire mesh returns slowly and is prone to plastic deformation. It is not easy to recover after stretching, which will instead affect the position and dimensional accuracy. The composite screen plate is composed of a polymer wire mesh and a stainless steel wire mesh, and is a screen plate formed by connecting two materials. Such a screen plate has a structure in the shape of a "hui" character. The outer "square" of the "hui" character is the screen frame. After the polymer wire mesh is tightened, it is fixedly connected to the screen frame with an adhesive. The area between the outer "square" and the inner "square" of the "hui" character is a pure polymer wire mesh, which plays a role in resilience and stress deformation, constituting a connection area mainly based on elasticity. The area inside the inner "square" of the "hui" character is a pure stainless steel wire mesh, which plays a role as a pattern support, constituting a printing pattern area mainly based on rigidity. And the inner "square" of the "hui" character is the area where the polymer wire mesh and the stainless steel wire mesh are composite. The two wire meshes of different materials are fixedly overlapped together with an adhesive. Such a screen plate not only has the high resilience of the polymer wire mesh, but also has the characteristics of high dimensional stability and high printing quality of the stainless steel wire mesh, and also overcomes the problems of poor resilience and easy plastic deformation under excessive stress of the pure stainless steel wire mesh. Therefore, it has become the first choice for manufacturing high-precision patterns.

[0019] Making a masking pattern on a blank plate is a key step in manufacturing this type of screen. The traditional method of making a masking pattern on a blank screen plate is: coating photosensitive material - pasting film - exposure machine exposure - development - drying. The film used in the process needs to be prepared by a separate photo-drawing process based on CAD data. The specific operation is to first apply photosensitive material to the blank screen, such as applying liquid photosensitive emulsion, or pasting dry photosensitive film. At this time, the photosensitive material covers the entire layout, including blocking the mesh holes. Then, the photomask, that is, the film, is spread on the layout. The photomask consists of light-blocking patterns and light-transmitting patterns. After the exposure process, that is, after the photomask and the photosensitive material under it are projected with a suitable light source, the photosensitive material under the light-transmitting part of the mask is cured and hardened by light, while the photosensitive material under the light-blocking part of the mask is not affected by the exposure process, and maintains the original physical and chemical state, and can still be dissolved in developer or water. Finally, the screen is placed in a developer solution or water, and the photosensitive material that has not been exposed to light is dissolved, enters the developer solution, and is removed from the screen, and the originally blocked mesh holes are transparent. After drying, a screen for selective transfer of printed materials is obtained, and its pattern area is covered with photosensitive materials, and the mesh holes are masked. When scraping, it has the function of preventing the printed material from transferring downward through the mesh holes, while the mesh holes in the non-pattern area are transparent, and when scraping, it has the function of a transfer channel that transfers the printed material from the plate surface downward to the surface of the workpiece.

[0020] Digital platemaking is a laser direct imaging technology, also known as screen laser direct platemaking technology. It uses a light source with a higher light energy density to project a light beam onto the surface of a photosensitive material for direct exposure, eliminating the step of photo-painting film, improving the accuracy of masking patterns, and streamlining the process. The steps are: coating photosensitive materials - curing photosensitive materials with laser direct exposure based on CAD data - developing - drying. The digital platemaking machines on the market use semiconductor lasers with a wavelength of 405nm and a power ranging from 600mW to 24W. They can produce screens with higher resolutions, which are suitable for the needs of higher-precision printing.

[0021] At present, photosensitive materials, including photosensitive emulsions and photosensitive dry films, need to have photosensitive properties, that is, the part exposed to light can undergo physical property changes, while the part not exposed to light needs to be fluffy and swelled during the development process so that it can be dissolved in liquid or gas, or carried away from the attached screen carrier by liquid or gas flow. Under such performance requirements, before curing, photosensitive materials are often paste-like. Even after curing, compared with non-photosensitive materials and solid materials with compact structure, it is difficult to have good strength and durability at the same time. Whether it is exposed by an exposure machine or digital equipment, due to the use of photosensitive materials and the wet development process using liquid treatment, it is difficult to produce a screen with a fine and compact side wall texture, smooth and smooth, and a tapered opening shape with a narrow top and a wide bottom. Furthermore, due to the high thermal expansion coefficient and low strength of the existing polymer screen, it is difficult to produce a screen with high dimensional precision, high resilience and good shape retention whether it is exposed by an exposure machine or digital equipment. In addition, since exposure is a process in which light is projected onto a material from the outside to the inside so that the material properties change layer by layer, the light needs to pass through the surface layer and then be projected onto the inside of the material. The properties of the surface layer of the material that is projected first will change first, which will affect the light from continuing to propagate to the inner layer. Therefore, the exposure method is difficult to effectively process thick masking materials, making the exposure method unsuitable for manufacturing thick mask patterns.

[0022] In response to the high-precision demand, direct laser photolithography has emerged. Its process steps are: coating non-photosensitive materials on the blank metal screen and curing or attaching non-photosensitive films - using lasers to remove non-patterned materials based on CAD data. Lasers are selective for materials, that is, they can remove a certain type of material without damaging another type of material they are in contact with. For example, by controlling the laser power density below a certain value, it is possible to remove polymers on metal without damaging the metal. The focused laser beam is very fine, which can be as fine as less than 10 microns. The relative movement speed of the beam and the workpiece is very fast, so very fine patterns can be processed. The direct laser material removal mask pattern making equipment of German-Chinese Technology can not only selectively remove non-photosensitive materials, including PI films, but also selectively cut off metal wires to increase the transmittance of printed materials. It can make openings below 10 microns, with clear opening corners and smooth side walls. The screens made are widely used in the photovoltaic industry. However, due to the small diameter of the laser beam, a point-by-point, line-by-line, and block-by-block scanning method must be adopted when removing materials. Removing large areas of mask materials takes a long time and is slow. A large number of printed electronics require high-precision screens with a large proportion of non-pattern areas, and the proportion of mask pattern areas that need to be retained is small. To manufacture a screen, it takes laser equipment for several hours or more to complete. The long processing time has become a bottleneck in the promotion of laser direct photoetching removal platemaking technology.

[0023] To sum up, we can see that the stencil made of metal wire mesh, polymer wire mesh and other materials has good graphic adaptability, and the stencil made of pure metal foil and pure polymer film has good printing material permeability. If the advantages of the two stencils can be combined and the disadvantages and shortcomings of the two stencils can be avoided, it will be conducive to the promotion of stencil technology in a larger range and more precise technical fields.

[0024] At the same time, the traditional printing industry's usual silk screen manufacturing technology uses a woven silk screen as a carrier, and requires a photosensitive material as a mask to block the holes on the silk screen in order to obtain the desired pattern. This method requires the manufacture of an original plate and exposure and development to complete the pattern transfer. It is an indirect manufacturing method with limited accuracy; the process is complex, requires more equipment and materials, has a heavy environmental burden, and has high manufacturing costs. Summary of the invention

[0025] In view of this, the present invention aims to propose a method for making a stencil using only foil or film materials, which can not only give full play to the advantages of high precision of metal foil, but also break the limitations of its graphic size and shape; it can also utilize the advantages of good stencil printing properties and low cost of polymer film to solve the problems of complex stencil manufacturing process and heavy environmental burden.

[0026] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0027] A method for making a stencil using only foil or film material, directly using software to drive a laser beam to cut and remove material, selectively making transparent openings on the graphic area of ​​a continuous material; replacing the traditional indirect means of blocking the mesh holes on the non-graphic area of ​​a woven screen material with transparent openings and keeping the openings in the graphic area transparent, to make a stencil;

[0028] Specifically, the method comprises the following steps:

[0029] (1) Prepare the blank plate: stretch the foil or film material to a certain tension and stick it on the stencil frame;

[0030] Specifically, place the rolled or sheet foil or film material flat on the frame, roughly fix the four corners, cut off the excess foil or film material, fix the four sides and stretch them to the set tension, and glue them to the four sides of the frame; or directly stick them to the stretched mesh frame, fix the four sides with glue, cut off the mesh in the middle after fixing the four sides, and realize the transfer of tension;

[0031] (2) Loading: Place the stencil frame with tension foil or film material on the workpiece table of the equipment;

[0032] Specifically, the printed surface of the blank plate is fixed downward on the laser processing system. The reason why the scraping surface is downward is that the laser processing has a characteristic that the cross section formed by laser cutting has a certain taper, and the slit width of the light incident surface is greater than the slit width of the light exiting surface. The scraping surface is downward to facilitate the demolding of the printed material.

[0033] (3) Direct laser opening: Used in CAM software to generate processing path drive equipment, through laser cutting and removal, to create openings and obtain stencils.

[0034] This step first generates laser processing path data based on the original impression data. The CAM software has an automatic calculation template. After importing the original data, input relevant parameters such as thickness, material, spot diameter, length and width limit of structural wire, and structural wire angle to automatically calculate the laser processing data. After the laser processing data is imported into the equipment computer, choose to use a positive pressure processing head or a negative pressure processing head according to the metal component ratio of the material. Turn on the laser, accurately position, and then start laser cutting. After completion, you will get a stencil.

[0035] Furthermore, in the step of generating the processing path, according to the shape of the pattern, in the openings exceeding the maximum allowable area, maximum side length, and maximum aspect ratio, a structural wire for tensioning and connecting is added. This overcomes the disadvantages of screens made of metal foil and polymer film that are not suitable for patterns with large opening aspect ratios, large opening areas, and large opening sides, and at the same time solves the problems of complex template production processes and low automation.

[0036] The method can set foils of different materials and thicknesses, the maximum area allowed for the membrane opening, the maximum side length, the maximum aspect ratio, and the width of the structural wire that plays a tensioning and connecting role.

[0037] Further, the steps for generating machining paths in CAM software are:

[0038] (1) Import equipment parameters, design requirements and pattern data, and select the material and thickness of the pattern area material according to the design requirements or the pattern thickness that needs to be transferred and formed;

[0039] (2) Set the maximum allowable opening area, maximum side length, maximum length-to-width ratio, and the width of the structural wire that serves as tension and connection;

[0040] (3) Data processing is performed on the imported pattern, and structural wires are added to the openings that exceed the maximum parameters, and structural wires are not added to the openings that are smaller than the maximum parameters;

[0041] (4) Generate a processing path based on the beam diameter, processing range of the processing head and its subsequent parameters in the equipment parameters;

[0042] (5) According to the processing path, laser cutting and removal processing are performed to produce openings on the continuous foil or film, which contain structural wires for tensioning and connecting when the maximum parameters are exceeded, and do not contain structural wires for tensioning and connecting when the maximum parameters are less than the maximum parameters.

[0043] Furthermore, when using laser for cutting and removal, the laser beam emitted from the laser is distributed and positioned by a dynamically deflected reflector, then enters a focusing mirror, and is projected toward an optical path design for the material being processed; when processing metal foil materials, a processing head design is adopted that projects laser light while blowing gas toward the processed area; when processing polymer film materials, a processing head design is adopted that projects laser light while sucking air into the processed area to form a negative pressure environment for exhaust and dust collection.

[0044] Furthermore, before using CAM software to generate a processing path, it also includes using CAM software to check the design rules and manufacturing rules of the imported data, generated data, and processing path; and generating circular holes, square holes, polygons, or other regular and irregular shapes that are spaced apart and of equal or unequal sizes to fill the pattern according to the shape of the pattern, and generating a processing path according to the shape of the new pattern; including generating opening visual inspection data.

[0045] Furthermore, the foil or film material is a metal foil, a polymer material, or a foil, film, or plate composite of metal and polymer.

[0046] It includes preparing the foil and film stretched on the screen frame before, during and after the software processes the data.

[0047] Furthermore, the method further comprises, when performing step (1), first stretching the screen material to a certain tension and then gluing it to the stencil frame; then gluing a foil or film material to the stretched screen; and then cutting or shearing off the screen in the area where the screen is bonded to the foil or film material;

[0048] After step (3), the screen is sealed by using a sealing agent to seal the transparent openings on the screen connection area between the slit printing plate frame and the slit printing area to obtain a slit printing template.

[0049] The method also includes exporting processed data and generated processing paths, sending them to equipment operating software, and performing offline processing; using the CAM software of the present invention to directly operate the equipment according to the generated processing paths, and performing online processing; and using the CAM software and equipment of the present invention to perform online visual inspection of the opening.

[0050] Compared with the prior art, the method of making a stencil using only foil or film material according to the present invention has the following advantages:

[0051] 1. By adding structural wires for tensioning and connecting in the opening area, the shortcomings of metal foil and polymer film materials that are not suitable for patterns with large opening aspect ratio, large opening area and long opening side are overcome, and the stencil can be made of only foil and film materials, which makes the materials easy to obtain and the manufacturing cost lower.

[0052] 2. Use laser to directly cut and remove materials to create transparent openings. The process is simple, the precision is higher, and the production flexibility is greater.

[0053] 3. Use opening technology to replace the plugging platemaking technology, use new CAM software, and new laser processing equipment to systematically solve the problems of complex template design and production processes and low automation, improve the accuracy and quality of the screen printing plate, simplify the production process, require less equipment, and make template production faster, more environmentally friendly, and easier to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0055] Figure 1 The original printing data of Embodiment 1 of the present invention;

[0056] Figure 2 This is the laser processing path of the structured wire in Example 1 of the present invention;

[0057] Figure 3 This is a detailed enlarged view of area A in Example 1 of the present invention;

[0058] Figure 4 This is a detailed enlarged view of area B in Example 1 of the present invention;

[0059] Figure 5 This is the final silk-screen effect diagram of Example 1 of the present invention;

[0060] Figure 6 The original printing data of Example 2 of the present invention;

[0061] Figure 7 This is the laser processing path of the structured wire in Example 2 of the present invention;

[0062] Figure 8 This is a detailed enlarged view of area C of Example 2 of the present invention. Due to the limitation of the minimum length, there is no structural wire on the contact;

[0063] Fig. 9 This is the final silk-screen effect diagram of Example 2 of the present invention.

[0064] Description of reference numerals:

[0065] 1 - Pattern area (stencil printing area); 2 - Blank area (blocking area); 3 - Laser path of the outer edge of the ellipse; 4 - Laser path of the structural wire; 5 - Laser path of the edge of the large internal square block; 6 - The edges of the three small blocks in the middle of the character "德". Detailed implementation mode

[0066] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0067] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0068] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0069] A method for making a stencil printing template only with foil or film materials, directly driving a laser beam to cut and remove materials by software, and selectively manufacturing a permeable opening on the graphic area of the continuous material; replacing the traditional indirect means of blocking the mesh holes on the non-graphic area of the woven screen material with permeable openings and keeping the openings in the graphic area permeable to make the stencil printing template.

[0070] Specifically, the method includes the following steps:

[0071] (1) Prepare a blank plate: Stretch the foil or film material to a certain tension and stick it on the stencil frame.

[0072] Specifically, place the rolled or sheet foil or film material flat on the frame, roughly fix the four corners, cut off the excess foil or film material, fix the four sides and stretch them to the set tension, and glue them to the four sides of the frame; or directly stick them to the stretched mesh frame, fix the four sides with glue, cut off the mesh in the middle after fixing the four sides, and realize the transfer of tension;

[0073] (2) Loading: Place the stencil frame with tension foil or film material on the workpiece table of the equipment;

[0074] Specifically, the printed surface of the blank plate is fixed downward on the laser processing system. The reason why the scraping surface is downward is that the laser processing has a characteristic that the cross section formed by laser cutting has a certain taper, and the slit width of the light incident surface is greater than the slit width of the light exiting surface. The scraping surface is downward to facilitate the demolding of the printed material.

[0075] (3) Direct laser opening: Used in CAM software to generate processing path drive equipment, through laser cutting and removal, to create openings and obtain stencils.

[0076] This step first generates laser processing path data based on the original impression data. The CAM software has an automatic calculation template. After importing the original data, input relevant parameters such as thickness, material, spot diameter, length and width limit of structural wire, and structural wire angle to automatically calculate the laser processing data. After the laser processing data is imported into the equipment computer, choose to use a positive pressure processing head or a negative pressure processing head according to the metal component ratio of the material. Turn on the laser, accurately position, and then start laser cutting. After completion, you will get a stencil.

[0077] Among them, in the step of generating the processing path, according to the shape of the pattern, in the openings that exceed the maximum allowable area, maximum side length, and maximum aspect ratio, structural wires for tensioning and connecting are added. This overcomes the shortcomings of screens made of metal foil and polymer film, which are not suitable for patterns with large opening aspect ratios, large opening areas, and large opening sides, and at the same time solves the problems of complex template production processes and low automation.

[0078] The method can set foils of different materials and thicknesses, the maximum area allowed for the membrane opening, the maximum side length, the maximum aspect ratio, and the width of the structural wire that plays a tensioning and connecting role.

[0079] Specifically, the steps for generating machining paths in CAM software are:

[0080] (1) Import equipment parameters, design requirements and pattern data, and select the material and thickness of the pattern area material according to the design requirements or the pattern thickness that needs to be transferred and formed;

[0081] (2) Set the maximum allowable opening area, maximum side length, maximum length-to-width ratio, and the width of the structural wire that serves as tension and connection;

[0082] (3) Data processing is performed on the imported pattern, and structural wires are added to the openings that exceed the maximum parameters, and structural wires are not added to the openings that are smaller than the maximum parameters;

[0083] (4) Generate a processing path based on the beam diameter, processing range of the processing head and its subsequent parameters in the equipment parameters;

[0084] (5) According to the processing path, laser cutting and removal processing are performed to produce openings on the continuous foil or film, which contain structural wires for tensioning and connecting when the maximum parameters are exceeded, and do not contain structural wires for tensioning and connecting when the maximum parameters are less than the maximum parameters.

[0085] When using laser for cutting and removal, the laser beam emitted from the laser is distributed and positioned by a dynamically deflected reflector, then enters a focusing mirror, and is projected toward the optical path design of the material being processed; when processing metal foil materials, a processing head design is adopted that projects laser light while blowing gas toward the processed area; when processing polymer film materials, a processing head design is adopted that projects laser light while sucking air in the processed area to form a negative pressure environment for exhaust and dust collection.

[0086] Before using CAM software to generate processing paths, the CAM software is also used to check the design rules and manufacturing rules of the imported data, generated data, and processing paths; and based on the shape of the pattern, circular holes, square holes, polygons, or other regular and irregular shapes that are spaced apart and of equal or unequal sizes are generated to fill the pattern, and the processing path is generated according to the shape of the new pattern; including the generation of opening visual inspection data.

[0087] The foil or film material is metal foil, polymer material or foil, film or plate composited with metal and polymer.

[0088] It includes preparing the foil and film stretched on the screen frame before, during and after the software processes the data.

[0089] Specifically, the method further comprises, during step (1), first stretching the screen material to a certain tension and then gluing it to the stencil frame; then gluing the foil or film material to the stretched screen; and then cutting or shearing off the screen in the bonding area between the screen and the foil or film material;

[0090] After step (3), the screen is sealed by using a sealing agent to seal the transparent openings on the screen connection area between the slit printing plate frame and the slit printing area to obtain a slit printing template.

[0091] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0092] Example 1

[0093] A method of making a stencil template for printing a company logo on a cultural shirt using only foil or film materials. Traditional such stencil templates are made by first making a film by photolithography, and then applying a photosensitive glue or sticking a photosensitive film on a screen plate, followed by exposure, development, and drying to form a stencil template. The process is very complex.

[0094] Now it is made by using a laser engraving organic film process, and its steps are as follows:

[0095] (1) Import the original DXF data of the Logo pattern to be made into the CircuitCAM data processing software. The original data is as Figure 1 shown.

[0096] After inputting relevant parameters such as the material type PI, the material thickness of 3 mil, the spot diameter of 20 μm, the width of the structural wire of 50 μm, the length of the structural wire to be greater than 0.2 mm, and the structural wire angle of 45 degrees, CircuitCAM automatically calculates the processing path. The graphic contour and the structural wire contour in the path are processed at one time. The processing path is as Figure 2 shown.

[0097] (2) Cut a suitable size from the rolled 3 - mil - thick PI film and place it flat on the screen frame. Complete gluing, drying, cutting out the internal mesh yarn, and sealing the mesh according to the normal process. The tension is set within the range of 15+ / -2 N / CM.

[0098] (3) Fix the PI screen plate with the scraping surface facing down on the ultraviolet nanosecond laser processing system, and adjust the air hood to the air - suction negative - pressure mode. After the four - corner positioning of the laser machine, the template processing is carried out. The stencil template after laser processing is rinsed and dried, and can be used after passing the automatic inspection of the equipment.

[0099] (4) Fix the PI stencil on the silk - screen printing machine, pour an appropriate amount of ink on the scraping surface, lay the cultural shirt flat and fix it well on the silk - screen printing table. After positioning, printing can be carried out. The printed pattern is as Figure 5 shown.

[0100] In Figure 3 , 4 is the laser path of the structural wire, two on the left and right, with a spacing of about 50 μm; 5 is the laser path of the edge of the large internal square block. Due to the existence of the structural wire, the stencil size is more stable; 6 is the edge of the three small blocks in the middle of the character "德". Due to the existence of the structural wire, the small blocks keep their positions fixed and are less likely to be lost. There are many similar scenarios in the figure, such as the two blocks in the middle of the character "中" and the small block at the upper end of the letter "e".

[0101] Example 2

[0102] A method for making a precision carbon ink stencil using only foil or film material. In this embodiment, a 30 μm thick steel sheet is used because of the carbon ink thickness limit set by the ceramic circuit board product. Since the maximum opening of the original pattern is 200 μm, a completely stencil cannot be used. It is necessary to add structural wire to enhance dimensional stability. The steps are as follows:

[0103] (1) Import the gerber data of the carbon ink layer into the CircuitCAM data processing software. The original data is as follows: Figure 6 shown.

[0104] (2) After inputting the material type stainless steel, material thickness 30μm, spot diameter 20μm, structure wire width 20μm, structure wire length not less than 0.2mm, structure wire angle 60 degrees and other related parameters, CircuitCAM automatically calculates the processing path. The processing path is as follows Figure 7 shown.

[0105] (3) Cut the appropriate size from the 30μm thick steel sheet stored in sheet form, place it flat on the mesh frame, and complete the gluing, drying, cutting of the internal mesh, and tension transfer according to the normal process. After the mesh is sealed, the equipment automatically checks and passes the laser processing.

[0106] (4) Fix the screen with the printing surface facing downward to the fiber laser processing system and adjust the air hood to the positive pressure blowing mode. After the laser four corners are positioned, processing can begin and the surface can be used after polishing and washing.

[0107] (5) Fix the prepared screen on the screen printing machine, pour an appropriate amount of carbon ink on the printing surface, fix the ceramic circuit board well on the screen printing table, and print after positioning. The pattern after printing is as follows Fig. 9 shown.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for making a stencil using only foil material, characterized in that: Directly use software to drive the laser beam to cut and remove materials, and selectively create transparent openings in the graphic area of ​​continuous materials; Specifically, the method comprises the following steps: (1) Prepare the blank plate: stretch the foil material to a certain tension and then stick it to the stencil frame; place the rolled or sheet foil material flat on the plate frame, roughly fix the four corners and cut the excess foil material, fix the four sides and stretch it to the set tension, and glue it to the four sides of the plate frame; you can also directly stick it to the stretched mesh frame, fix the four sides with glue and cut off the mesh in the middle to achieve the transfer of tension; When performing step (1), the screen material is first stretched to a certain tension and then adhered to the stencil frame; then the foil material is adhered to the stretched screen; and then the screen in the bonding area between the screen and the foil or film material is cut or sheared off; (2) Loading: Place the stencil frame with the tension foil material on the workpiece table of the equipment; fix the blank plate with the printing surface facing down on the laser processing system. The reason why the scraping surface is facing down is that laser processing has a characteristic that the cross-section formed by laser cutting has a certain taper. The slit width of the light incident surface is larger than the slit width of the light exiting surface. The scraping surface facing down facilitates the demolding of the printed material. (3) Direct laser opening: Use the CAM software to generate a processing path drive device, and make an opening by means of laser cutting and removal to obtain a stencil. In the step of generating the processing path, according to the shape of the pattern, in the opening that exceeds the maximum allowable area, maximum side length, and maximum aspect ratio, a structural wire for tensioning and connecting is added; The steps to generate machining paths in CAM software are: (1) Import equipment parameters, design requirements and pattern data, and select the material and thickness of the pattern area material according to the design requirements or the pattern thickness that needs to be transferred and formed; (2) Set the maximum allowable opening area, maximum side length, maximum length-to-width ratio, and the width of the structural wire that serves as tension and connection; (3) Data processing is performed on the imported pattern, and structural wires are added to the openings that exceed the maximum parameters, and structural wires are not added to the openings that are smaller than the maximum parameters; (4) Generate a processing path based on the beam diameter, processing range of the processing head and its subsequent parameters in the equipment parameters; (5) According to the processing path, laser cutting and removal processing are performed to produce openings on the continuous foil, which contain structural wires for tensioning and connecting when the maximum parameter is exceeded and do not contain structural wires for tensioning and connecting when the maximum parameter is less than the maximum parameter; After step (3), the screen is sealed by using a sealing agent to seal the transparent openings on the screen connection area between the slit printing plate frame and the slit printing area to obtain a slit printing template.

2. The method for making a stencil using only foil material according to claim 1, characterized in that: When using laser for cutting and removal, the laser beam emitted from the laser is distributed and positioned by a dynamically deflected reflector, then enters a focusing mirror, and is projected toward the optical path design of the processed material; when processing foil materials, a processing head design is used that projects laser light while blowing gas toward the processed area.

3. The method for making a stencil using only foil material according to claim 1, characterized in that: Before using CAM software to generate processing paths, the CAM software is also used to check the design rules and manufacturing rules of the imported data, generated data, and processing paths; and based on the shape of the pattern, circular holes, square holes, polygons, or other regular and irregular shapes that are spaced apart and of equal or unequal sizes are generated to fill the pattern, and the processing path is generated according to the shape of the new pattern; including the generation of opening visual inspection data.

4. The method for making a stencil using only foil material according to claim 1, characterized in that: The foil material is metal foil or a composite material of metal foil and polymer.

Images