Production of a rotary screen printing system using 3D printing

Abstract

This invention is entitled Design and Production of Rotary Screen Printing System by 3D Printing for Printing Multilayers for Manufacturing Various Energy Equipment by Combining 3D Printing and Rotary Screen. First, all components were designed based on the common nickel mesh environment used in rotary printing. Finally, the parts were manufactured by a 3D printer using acrylonitrile butadiene styrene (ABS) filament and after assembling the components, the printing templates were attached to a metal chassis and the rotary screen printing system was started. Different patterns were printed on PET film using conductive inks and a flexible electrode suitable for solar cell manufacturing was produced and its properties were compared with the commercial product Flextrode. The results showed that the electrical resistance of PET film printed with graphite ink (semi-transparent) or PEDOT:PSS polymer was about 350 and 500 ohms / square, respectively, higher than the commercial product Flextrode, but its surface resistance with silver was about 76% lower. Also, the light transmission rate in the printed electrode was about 15-35% higher than that of the Flextrode at wavelengths of 550 and 1000 nm, and its reflection rate was about 75% lower.

Description

Description of the invention Title of the invention Design and manufacture of a rotary screen printing machine consisting of ABS polymer components using 3D printing Designing and manufacturing a rotary screen printing machine consisting of ABS polymer components using 3D printing Technical background of the relevant invention The present invention concerns the printing of electrodes and multilayer structures for the industrial production of various electronic equipment or equipment used in the energy field, such as solar cells, by combining the rotary screen printing process and 3D printing. Technical problem and stating the objectives of the invention The technology of silk printing, which is several thousand years old, was first invented in Japan and later became popular in France. The main advantage of silk printing is its economy, as it does not require a large capital to set up a silk printing unit. In the silk printing process, first a fabric or mesh with very fine pores is prepared and attached to a mold or frame made of wood or metal, and in the next step it is impregnated with a photosensitive resin and finally washed with water after exposure. To make a stencil, a frame is first made as the initial chassis of the stencil to attach the mesh to it. The stencil frame is made of metal or wood, on which a fabric mesh is evenly stretched and installed. Silk printing is usually done in two ways: manual and machine. In machine methods that perform printing operations with great speed and accuracy, there are usually four types of categories, which are: flat screen printing machine, rotary screen printing machine, roller printing machine and digital printing machine.Usually, in these devices, all the stencils are placed in one direction and on a flat surface, and the substrate to be printed passes horizontally under the stencils. In rotary printing, the squeegee is located inside the stencils, and unlike other silk-screen printing methods where the stencil is fixed and the squeegee moves, in this method, the stencil moves in a circular motion and the squeegee is fixed. In the present invention, 3D printing, which is a new and widely used technology, has been used to reduce the costs of producing and setting up a rotary screen printing system. The most important feature of 3D printing is its high printing speed and accuracy, and its low cost. By using 3D printing technology and using polymer materials, which are much cheaper and easier to process than the metal materials used in the manufacture of rotary printing systems, the costs associated with this printing method are reduced.Using 3D printing technology and the ability to produce parts at a lower cost, if this technology can be used to manufacture equipment related to industrial rotary printing machines, the costs of building and operating a rotary screen printing system will be significantly reduced. On the other hand, a rotary silk screen printing system has not been built for printing electronic equipment so far. The advantage of the silk screen printing method is the ease of printing operations and the greater accuracy of the printing process. Given that in electronic equipment such as solar cells, the precise arrangement of layers and their thickness are of great importance, using the rotary silk screen printing method allows for precise control over these factors. A description of the state of the prior art and the history of developments related to the claimed invention. Screen printing (traditionally called silkscreen printing) is a printing method that uses a mesh (with micron-sized pores) to transfer printing ink (or dye) onto a substrate (substrate). First, to create a printing pattern, some of the mesh openings in specific areas are blocked with resin, making these areas impermeable to ink [1]. After the mesh is prepared and placed inside a frame and a stencil is produced, a blade or squeegee moves across the stencil to force the printing ink placed on the stencil surface through the open mesh openings and print the desired pattern onto the substrate [2]. In silkscreen printing, the drying of the printed layer can be accelerated by blowing hot air onto the substrate, and the thickness of the printed layer is greater than that of other printing methods. The quality of the print is determined by the material, the fineness and thickness of the mesh, the distance between the top and bottom of the mesh holder plate, and the mesh openings [3]. Screen printing is a versatile and simple process for transferring ink to the surface of substrates. This method can print on a wide range of substrates, from paper to ceramics, metal, polymeric materials, and ...This technology also enables printing of various inks on flexible surfaces[4]. The applications of this printing method are very diverse and include artistic, textile, industrial, printing of electronic components (printed circuit fibers), etc. The advantages of this printing method are the possibility of producing new electronic products such as electromagnetic enclosures, capacitors, batteries, solar cells, etc. with high speed and accuracy [2, 5]. So far, reports have been presented in registered patents regarding rotary screen printing machines. Benjamin et al. presented a method for screen printing using a metal plate made through electroforming. This design consisted of separated openings of a 3D printing plate, with an attached stencil with or without a negative of an image to be printed and having a flat surface on the squeegee side, where on the screen printing side, the screen had a 3D structure[6]. The advantage of the present invention is the simplicity of the device manufacturing process compared to the mentioned reference. In reference 6, special equipment such as a vacuum is required, but in the present invention, the only equipment required is a 3D printer.Drax reported a rotary screen printing machine for printing sheet-type materials. The machine comprises a main frame on which at least one screen printing unit is mounted and includes a stencil, a stencil holder, a driving means for rotatably moving the stencil. A squeegee system, a squeegee suspension system, a pressure roller and a printing paste supply system, characterized in that the stencil, the stencil holder, the squeegee, the squeegee suspension system and the printing paste supply system are located in a sub-frame. All the items of the invention are nickel-plated and made of metal [7]. In this invention, metal plating is used and one of the problems of metals is their rusting over a long period of time due to contact with moisture. Since most of the chemicals used in the manufacture of water-based solar cells have been mentioned, the advantage of the present invention is the use of polymeric materials and the elimination of the problem of rusting of the machine parts. In an invention by Linter et al., a rotary screen printing machine with a modular design is reported.This invention claims that by using a digital network system, it is possible to precisely control the printing mechanism and other functions of the printing machine[8]. Precise control over the printing mechanism has many complexities. The advantage of the present invention is the design and printing of parts of the printing system with 3D printers. If fine nozzles are used to print the parts and precise design is made on the parts, as a result, there is the possibility of complete and effective control over the printing system. In another invention, the construction of a rotary screen printing machine equipped with a printing roller with a separate ink injection tank is reported by Wittich. In this invention, it is claimed that the printing roller is equipped with at least two separate areas for ink injection and its advantage is increased printing speed[9]. One of the disadvantages of reference number 9 is the mixing of colors during the printing process and the reduction of the accuracy of the printed patterns. To solve this problem, the roller must be constantly washed, which in turn reduces the production speed. In the present invention, a separate source is installed for each stencil, so that no interference occurs during the printing process.Also, Carlos et al. have developed a rotary printing machine equipped with two belts, one of which is a temporary substrate carrying belt and the other is a special printing belt. In this machine, the purpose of installing a special printing belt is to allow the angle between the printing roller and the substrate to be adjusted

[10] . In another invention, the construction of a squeegee for rotary printing with the ability to properly spread the printing ink is reported. In this invention, it is claimed that the special design of the squeegee prevents ink from dripping during the printing operation and, as a result, the printing process stops due to cleaning excess ink, and on the other hand, the printing speed and uniformity of the printing operation are increased

[11] . In the present invention, special bases are provided for applying appropriate pressure to the squeegee, and as a result, the printing ink is spread properly. Compared to reference 11 and the design of a special squeegee base, the complexity of the system construction has been reduced. Similarly, in another invention, the construction of a squeegee with the ability to adjust the angle and accurately control the pressure on the printing roller is reported.In this invention, it is claimed that a squeegee designed with an adjustable angle enables precise and uniform printing

[12] . In another invention, a method for controlling the passage of the substrate under the rotary printing rollers has been presented by Gerardos et al. In this invention, the substrate is first unrolled from a primary roller before entering the stencil, and after passing through a special area called a guide that electronically controls the substrate, it is guided under the printing rollers, and then the printing operation is performed on it

[13] . In another invention, Hans et al. discussed the steps of making integrated stencils for rotary printing and reported the process of making a metal stencil in an integrated manner using the molding method and then making the stencil (impregnating the stencil with a photosensitive or heat-sensitive resin, creating a design on the resin, and finally revealing the design)

[14] . It has also been reported that a rotary printing squeegee is made of materials with high resiliency and a thin metal plate is polished and attached to it.This invention claims that this squeegee is capable of creating an angle of up to 60 to 70 degrees with the stencil and can uniformly direct the printing ink out of the stencil holes, resulting in printing with desired quality and accuracy

[15] . Another invention reports printing electronic equipment such as printed circuits using rotary roll-to-roll printing. This invention only deals with printing printed circuits with industrial and laboratory devices

[16] . Japanese inventors have described the construction of a double-deck rotary printing machine. This invention is designed for printing fabrics in the textile industry and its advantage is claimed to be faster printing speed

[17] . The advantage of the present invention is the possibility of printing on all substrates (paper, metals, polymeric materials, etc.) and, like reference 17, is not limited to the textile industry. The claim to build a rotary printing machine with the ability to print on curved and circular surfaces has been put forward by Welts et al. This invention claims that the rotary screen printing machine is capable of printing on a circular surface at a speed of at least 250 and at most 1000 pieces per minute

[18] .In the present invention, it is also possible to print on various circular surfaces, and due to the use of 3D printing technology, it is possible to change parts and adapt them based on existing needs. In another invention, a special printing device has been made that, by vibrating the stencil, causes greater ink penetration, resulting in higher quality printing. In this invention, it is claimed that because the maximum acceleration of the stencil's vibrational movement is at least ten times the acceleration due to gravity, the amount of ink penetration through the stencil pores increases, and in addition to reducing the problem of stencil clogging and frequent replacement, the quality of the printing operation also increases

[19] . In the present invention, adjustable bases are designed to apply appropriate pressure to the squeegee to ensure quality and uniform printing, and as a result, there is no need for a vibrator. In another invention, a system for washing the printing roller of rotary screen machines is described. In this invention, a special section is provided at the end of the device for washing printing stencils with water.In this part, several air cylinders connected to a water tank are used, and to wash the stencils, water is forced out of the source with the help of a stream of compressed air at high pressure, which washes the stencil and unclogs its pores

[20] . As can be seen in the history of patents, there has been no report so far on the integration of 3D printing technology and rotary screen printing. In the present invention, entitled Design and manufacture of a rotary screen printing device consisting of ABS polymer components using 3D printing, the main focus is on producing cylindrical stencils using a 3D printer, mounting the stencils on a chassis, designing and manufacturing other components of the printing system with a 3D printer, and finally performing printing operations on flexible substrates such as polyester film for the industrial production of various electronic equipment or equipment used in the energy sector such as solar cells. [1] C. J. Hawkyard and A. S. Miah, “The parameters of rotary ‐ screen printing, ” J. Soc. Dye. Colour., vol. 103, no. 1, pp. 27 – 31, 1987, doi: 10.1111 / j.1478-4408.1987.tb01082.x. [2] V. C. Martinez, H. Xie, A. Mingorance, C. Pereyra, A. Narymany, and M. M. Gómez, “Carbon-based perovskite solar cells by screen printing with preheating,” J. Phys. Conf. Ser., vol. 1433, no. 1, 2020, doi: 10.1088 / 1742-6596 / 1433 / 1 / 012009. [3] J. Wiklund et al., “A review on printed electronics: Fabrication methods, inks, substrates, applications and environmental impacts,” J. Manuf. Mater. Process., vol. 5, no. 3, 2021, doi: 10.3390 / jmmp5030089. [4] A. Larmagnac, S. Eggenberger, H. Janossy, and J. Vörös, “Stretchable electronics based on Ag-PDMS composites,” Sci. Rep., vol. 4, pp. 1–7, 2014, doi: 10.1038 / srep07254. [5] G. Wróblewski and D. Janczak, “Screen printed, transparent, and flexible electrodes based on graphene nanoplatelet pastes,” Photonics Appl. Astron. Commun. Ind. High-Energy Phys. Exp. 2012, vol. 8454, p. 84541E, 2012, doi: 10.1117 / 12.2001381. [6] C. Chua, S. Aditya, and Z. Shen, “( 12 ) Patent Application Publication ( 10 ) Pub . No .: US 2012 / 0286657 A1 Patent Application Publication,” vol. 1, no. 19, pp. 10–13, 2012. [7] J. Andreas, V. E. Polak, and B. V Charlouis, “EP000879145B1,” vol. 99, no. 19, pp. 1–13, 2000. [8] F. Application, P. Data, P. Examiner, R. Yan, D. S. Safran, and D. R. Studebaker, Universal printing process cylinder and method of making the same, “US6155165A,” no. 19, 2000. [9] K. WITTICH, Rotary screen printing cylinder having separated ink zones, US6155165A·2000, no 16

[10] J. H. Nekkers, P. E. S. Burr, and A. Boxmeer, Screen rotary printable “US19208456C,” no. 19, 1993.

[11] I. C. Roman, “United States Patent 19,11 Patent Number : BATTERY-49,” United States Pat., no. 19, pp. 3–5, 1999, Available:https: / / patentimages.storage.googleapis.com / 84 / e6 / 5f / 65765dbc491a4f / US5347263.pdf.

[12] F. Application, P. Data, and R. Cited, “United States Patent (19),” no. 19, 1976.

[13] V. MO. GERARDUS, DE. V. PIETER, Method for controlling the passage of fabric through a rotary screen printing installation, US4928585A, 1990.

[14] S . HANS-GEORG, S. KARL-WILHELM, Process for producing a base mold for electrolytically producing seamless rotary screen printing stencils, US-5972194-A, 1994.

[15] “ Macraild , Machilan, Garry, rotary printing, CA2375284A1, 2000.

[16] P. O. R. Coated, “(12) Patent Application Publication (10) Pub. No.: US 2009 / 0145314 A1,” vol. 1, no. 19, 2009.

[17] Chu su, We die, rotary screen cylindrical, “ CN201304754Y, 2010.

[18] "K. Melvin, We. Marwin, direct rotary screen printing on cylindrical articles, 1997. CA2305132A1." .

[19] H. Kudlich, PES Burr, F. Application, and P. Data, Screen rotary system “US135288651A,” no. 54 19, 1975.

[20] XU. JINCONG; XU. JIAMING, Water washing system of rotary screen printing machine CN203713246U·2014. Providing a solution to an existing technical problem along with an accurate, sufficient, and integrated description of the invention In the present invention, all parts and components of a printing stencil (including bearings, bearing support, gears and squeegee support bases) were designed using Solid Works software based on the perimeter of common nickel grids used in rotary printing (64 cm). The parts were then manufactured using a 3D printer using acrylonitrile butadiene styrene (ABS) polymer filaments, and after assembling the components, the printing stencils were attached to a metal chassis and the rotary screen printing system was started. Finally, using this system, various patterns were printed on PET film using conductive inks and a flexible electrode used to make polymer solar cells was produced. The 3D printing conditions are: nozzle diameter used 400 microns, layer thickness 100 microns, filling percentage 100%, nozzle printing speed 3600 mm / min, extruder temperature 240 degrees Celsius, and fluid bed temperature 110 degrees Celsius. Modeling software was used to model all components, and 3D maps were drawn from it and printed with a 3D printer under the conditions described. 1 - Description of the printing system: The printing system is designed in such a way that first the polymer roll is opened by the feeding roller and moves along the length of the machine. In the next step, the substrate is guided towards the printing rollers and different patterns are printed on the substrate using stencils as needed. The number of stencils is installed on the chassis of the machine based on the number of layers required. Also, in addition to rotary stencils, it is possible to install and install any type of equipment related to roll-to-roll printing (such as slotted coating, engraving, flexography, knife, flat plate, etc.). After exiting each stencil, the printed film first travels a path at a height (about 2 meters) so that in this part, by applying heat, the printed layer dries and the film is prepared for the printing of the next layers. In order to prevent the film from slipping and guide it properly under the printing rollers, guide rollers are used between each roller. The task of these rollers is to guide the polymer film correctly and properly.During the printing process, while the stencils rotate, the desired design is printed on the polymer film with the help of a squeegee and the uniform pressure it applies to the stencil. After printing the different layers, a protective layer (if needed) is first created on the substrate and finally it is rolled up by a collecting roller. 2 - Description of the steps for building a printing system: The following will discuss the steps involved in building a rotary screen printing system. In total, this system includes the following parts: 1 – Printed roll unwinding and rewinding systems 2 – Printing stencil 3 – Film guides and drying system 4 – Printing ink injection system Each component of this system will be described below. 2-1- Polymer roll unwinder and retractor To control the rate of unfolding of the raw polymer roll and the folding of the printed roll, two unfolding and folding systems were used, all of whose parts were produced by a 3D printer. 2-2- Printing template The printing stencil collection can be classified as follows: 1 – Endring and equalizer 2- Lace 3 - Bearing 4 – Bearing support base 5 – Squeegee assembly and its holder 2-2-1- Endring and equalizer In this invention, similar to commercial systems, metal end rings (made of aluminum called Stork) were used to hold the nickel meshes. Also, a piece called the equalizer was designed to hold the mesh and end ring assembly. The design of this piece was completely consistent with the Stork end ring. Unlike conventional commercial rotary screen printing systems in which the end ring end is connected to a gear and rotated by a motor to move the stencils, in this invention and during the design of the equalizer piece, there are grooved grooves on its front side, such as creating a groove by which the stencil can be moved by contacting the gear that is connected to the motor. To facilitate the rotation of the end ring, a continuous recess was also provided around the equalizer to make contact with the bearing (bearing channel). Due to the grooves around the synchronizer, it is possible to move the mesh and end ring assembly inside the bearing after establishing a connection between the grooves and the gear connected to the motor pulley. 2-2-2- Lace and its preparation In this invention, common nickel meshes used in the industry have been used to make the printing system compatible with industrial and commercial devices. In the rotary printing industry, nickel metal meshes are used to make stencils, the perimeter and wall diameter of which are about 64 cm and 0.1 to 0.7 mm, respectively. If larger dimensions are desired, it is possible to make a printing system in any dimension. The only difference with industrial printing devices is the width of the stencil, which, despite the width of industrial devices being about two meters, in this invention the dimensions of the device are designed on a semi-industrial scale, and as a result, the width of the stencils is about 12 cm. After the meshes were cut, the steps of creating a design on the mesh were carried out. The design creation method includes the steps of impregnating the nickel mesh with a photosensitive resin, drying the resin-impregnated mesh in a dark environment, attaching the desired design to the mesh, exposing the resin-impregnated mesh to ultraviolet rays, or directly creating the design on the mesh with a laser. Finally, after washing the mesh with pressurized water, the desired design is created on it.This invention uses three different designs: comb-like, square, and continuous. 2-2-3- Bearing Considering the rotational movement of the templates, a frame called a bearing was designed and manufactured by a 3D printer to hold the end ring and enable its rotational movement. It is worth noting that since two bearings are required for each printing template, two simple and platform models were used to design and manufacture the bearings. To facilitate the replacement of parts, the bearings were designed in multiple pieces. 2-2-4- Bearing holder base The design of the printing system in the present invention is such that the substrates to be printed during the printing operation are placed on rollers, each of which is held stationary at the bottom of the stencils. In addition to the amount of pressure applied by the squeegee, the position of the lower rollers is important in the movement of the roller itself and, as a result, the movement of the substrate. If the amount of contact between the lower roller and the stencil is not sufficient, the lower roller will not move and the substrate will not be moved. Conversely, if the amount of contact between the lower roller and the stencil is too high, the stencil movement will be disrupted, and all of the above will reduce the accuracy and quality of the applied print. For this reason, a special dual-function bearing base was designed and manufactured by a 3D printer. 2-2-5- Squeegee assembly and its holder In rotary printing, one of the most important factors is the amount of pressure applied from the squeegee to the printing roller. If the amount of pressure applied is low, the ink will not be properly ejected from the stencil holes and the printing quality will decrease. On the other hand, due to the specific design of the printing system in the present invention, the amount of pressure applied from the squeegee has a direct effect on the movement of the substrate during the printing operation. According to this design, since only the stencils move in a circular motion during the printing operation and the sample-carrying rollers are considered fixed, if the pressure applied from the squeegee to the stencil is adjusted appropriately, the contact of the stencil with the lower roller will cause it to move, and as a result, the polymer substrate to be printed will move at a uniform speed. In this invention, to solve the above-mentioned problems, a squeegee holder was designed and produced using a 3D printer. As mentioned earlier, the design of the synchronizer was done in full accordance with the Stork endring, so that the endring fits properly inside the synchronizer and due to the grooves around it, it is possible to move the mesh and endring assembly inside the bearing. The endring is driven by two gears and the motor's driving force is transmitted to the synchronizer by these gears. These gears were also designed using Solid Works software and then manufactured using a 3D printer. After connecting the motor to the bearing, these two gears with different dimensions, one with smaller dimensions (motor pulley) which is directly connected to the motor shaft and the other with larger dimensions (bearing gear) which is in contact with the motor pulley, transmit the torque generated by the motor to the synchronizer. Due to the presence of grooved grooves around the synchronizer, the teeth of the bearing gear are placed inside the grooves, causing the synchronizer to rotate, causing the end ring and the mesh connected to it to rotate. Stencil assembly After each component was manufactured, the printing stencil was produced by assembling the parts. To produce the stencil, first a patterned mesh was attached to two Stork end rings and then two aligners were attached to the end rings. In the next step, eight 6202 bearings (four for each bearing) were installed on two bearings (one simple and the other with a platform) and then the mesh, end ring and aligners assembly was mounted on these two bearings. Metric screws were used to connect the two bearings to each other. In the next step, both bearings were attached to their respective bases and then the squeegee bases were placed in their places. Finally, the squeegee was installed inside the mesh and finally the printing stencil assembly was mounted on a chassis. 2.3- Film guides and drying system One of the main factors in printing a device is the complete drying of each layer before starting to print the next layer. If during the printing operation, the previous layer is not completely dried, in addition to uneven printing on the film and spreading of the previous layers, the printed electronic device does not function properly due to the intertwining of the layers. In the present invention, in order to properly dry the printed film and prevent excessive increase in the length of the device, the path of the film was increased in height. For this purpose, after exiting the stencil, the printed polymer film was guided by rollers to the top of the device to provide more time for heat treatment and drying of the printed layer. To create this path, first the bases holding the guide rollers were designed and produced by a 3D printer. In the next step, these bases were installed after each stencil and on the chassis of the device, and then the guide rollers were connected to the bases. 2-4- Printing ink injection system For continuous injection of printing ink, a syringe injection pump was made using a 3D printer. The pump's operating mechanism was such that the force applied from the motor was transferred to the screw by the coupling, and as a result of the screw rotation (clockwise or counterclockwise), the movable part applying pressure to the syringe cylinder was pushed forward or backward, respectively, and therefore, as a result of the advancement of this part, pressure is applied to the syringe to direct the solution inside the syringe piston chamber to the outside, resulting in the injection of the solution. The toggle switch connected to the motor, by changing the direction of flow, causes the screw to move clockwise or counterclockwise, resulting in the moving part moving forward or backward, applying pressure to the syringe. A dedicated injection pump was designed and manufactured for each printing stencil. To control the injection rate of printing ink, the motor of all three injection pumps was connected to a DC motor speed control module with a volume so that the speed of the motors and, consequently, the ink injection rate during the printing operation were the same. 3 - Setting up the printing system The rotary screen printing system was set up by connecting each of the components described above to a metal chassis. In this system, three printing stencils were used, but for different applications and based on the number of layers to be printed on an electronic device, it is possible to reduce or increase the number of stencils. Explanation of shapes, maps and diagrams In this invention, a new component called an equalizer was designed and manufactured that was capable of both holding the mesh and end ring assembly inside the bearing and of causing the mesh to move and rotate inside the bearing (Figure 1). Figure 1. Technical drawing of a 3D printed aligner part that has grooved grooves and a bearing channel to move the end ring. The design of the bearing was such that the end ring and the equalizer were placed in the center. On the four sides of the bearing, a place was provided for installing four bearings so that the bearings could rotate easily around the equalizer, end ring, and mesh due to the placement of the bearings in the designed channel. If the bearing were integral, then changing the template would be difficult and would take a lot of time. Therefore, the design of the bearing was designed so that it could be opened and closed, and as a result, changing the template during the printing operation would be easy. In the platform model, a platform-like protrusion was also designed on the back of the bearing to hold the motor, which was responsible for holding the motor. After the design was completed, simple and platform bearings were manufactured using a 3D printer. Figure 2. Technical drawing of bearings without motor (a) and with motor (b) In addition to holding the stencil, the bearing base is also able to hold the lower roller and control its height due to the movable slider built into it. This feature allows for precise control of the height of the lower roller and, as a result, the pressure applied from the squeegee to the roller. Another important advantage of the bearing base is the ability to control the location of the printing stencils. Also, given the importance of precise control over the printing of layers in an electronic device, the special design of the base allows for precise control of the printing location of the layers. Figure 3. Technical drawing of the bearing support base to increase stability and reduce bearing vibration during printing operations. The squeegee holder base is equipped with two sliders, the lower part of which is designed to hold the lower roller and the upper slider is designed to hold the squeegee (Figure 4-b). With this design and the possibility of installing screws in the upper and lower parts of the base, it is possible to adjust the height of the lower roller and also adjust the constant pressure to the squeegee. In order to ensure the appropriate pressure is applied by the squeegee, either a rubber squeegee, which is mostly used in screen printing, or a polymer squeegee can be used (Figure 4-a). The advantage of the polymer squeegee is greater friction with the mesh, and as a result, the squeegee does not slip, and as a result, more pressure is created for the ink to exit the mesh pores. It should be explained that the polymer squeegee was designed as an integral part and then produced by a 3D printer, while for the rubber squeegee, only a part was designed to hold it and then produced by a 3D printer. Figure 4. (a) Biaxial polymer squeegee with their technical drawings, (b) new squeegee holder base including lower roller holder and squeegee holder piece Figure 5. Technical drawing of the end ring gear (right) and motor pulley (left). In the present invention, two flat and curved guide rollers are designed to guide the films (Figure 6-b). The flat rollers are used to guide the printed film simply because they are in contact with the back of the film, but since in some parts the printed film passes under the roller and therefore the upper and printed part of the film is in contact with the roller, to prevent the roller from contacting the printed design, these rollers are designed to be curved so that they do not have any contact with the printed layers. After increasing the distance of the printed film, in order to properly guide the film to the next stencil, two separate supports and another guide roller, which were placed a short distance before the next stencil, were also used to prevent the film from slipping and entering the stencil improperly. Figure 7 shows a general plan of the complete diagram of the device. Figure 6. Technical drawing of (a) guide roller support base, (b) flat (left) and curved (right) rollers. Figure 7. General diagram of the complete device. A clear and precise statement of the advantages of the claimed invention over prior inventions. In the present invention, 3D printing has been used to reduce the costs of production and setup of the rotary screen printing system, the main feature of which is high printing accuracy and speed and low cost. Also, the printed layer has high accuracy and the printing speed of the layers can be controlled with this device. The reason for the specific design of this invention is the presence of multiple layers in electronic equipment. Therefore, by designing such a system, it is possible to print various solutions required for coating various electrodes at high speed on various hard and flexible substrates. Description of at least one implementation method for implementing the invention With the aforementioned system, three different layers were printed on a flexible PET film and used as a semi-transparent electrode of a polymer solar cell with an inverted structure. ITO alternative compounds such as graphite, silver and PEDOT:PSS polymer were used for printing and the PET film was first printed with a conductive material such as graphite, silver or PEDOT:PSS) and then with zinc oxide nanoparticles (electron transfer material) by the claimed rotary screen system. The electrical resistance of the PET film printed with graphite ink and with a comb-like pattern (semi-transparent) or PEDOT:PSS polymer is about 350 and 500 ohms / square, respectively, which is higher than the commercial Flextrode product. In the case of silver, the surface resistance of the printed electrode is about 76% lower than that of the Flextrode. Regarding light transmission and its reflection at wavelengths of 550 and 1000 nm, the light transmission in the printed electrode is about 15-35% higher than that of flexstrut, and its reflection is about 75% lower. Explicit mention of the industrial application of the invention The production of flexible electrodes used for polymer solar cells and solution printing on flexible films are among the industrial applications of the invention.

Claims

Claim What is claimed: Claim 1) What is claimed is the production of an integrated rotary screen printing system consisting of polymer and metal mechanical parts. The production of the integrated rotary screen printing system is carried out in 3 stages: (a) Design of the main mechanical components of the system, (b) Manufacturing of components using polymer materials and utilizing 3D printing technology, (c) Assembling the components (polymer-metal) and commissioning the system. The main components of this system, such as the motor holder, printing stencil end ring aligner, bearings, printing ink injection nozzle, squeegee holder, bearing holder base, motor pulley and gears transmitting the driving force of the DC motor, are designed. The design of the main mechanical components of the system and its dimensions are based on the type of application of the system and its final dimensions are designed using the specialized Solid Works software. Claim 2) Same as claim 1, wherein the polymer components are made based on ABS polymer. Claim 3) The system of claim 1, using a lower roller whose distance from the stencil is adjustable, is used for printing on substrates of different thicknesses. Claim 4) The system of claim 1 includes various guides before and after the printing assembly and rollers in the path of movement of the films for printing.

Images