Method for manufacturing flexible circuit board
Through the combination of die-cutting and etching, the problem of assembly difficulty and cost caused by the long circulation unit in the production of LED light tube flexible circuit board is solved, and an efficient and continuous production process is achieved.
Patent Information
- Application Number
- CN202411552132.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-02-11
AI Technical Summary
The prior art is difficult to effectively produce flexible circuit boards suitable for LED light pipes, especially because the circulation unit of LED light pipes is long, which makes it difficult to assemble the die-cutting device, costly, and is not conducive to continuous production.
A flexible circuit board is made by combining die-cutting and etching, and a circulation unit of the second conductive layer is made through an etching process to avoid high requirements for the die-cutting device and reduce equipment costs. At the same time, other parts adopt die-cutting processes to achieve continuous production.
It effectively reduces the equipment cost of flexible circuit board production, improves production efficiency, realizes the continuous production of flexible circuit boards for LED light pipes, and controls production costs.
Smart Images
Figure CN119421324A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of flexible circuit boards, and specifically relates to a method for manufacturing a flexible circuit board. Background Art
[0002] Flexible circuit boards are referred to as "soft boards" and are commonly known as FPCs in the industry. They are printed circuit boards made of flexible insulating substrates and have many advantages that rigid printed circuit boards do not have. For example, they can be bent, curved, and folded freely. The use of flexible circuit boards can greatly reduce the size of electronic products and meet the needs of electronic products developing in the direction of high density, miniaturization, and high reliability. Therefore, flexible circuit boards have been widely used in aerospace, military, mobile communications, laptops, computer peripherals, PDAs, digital cameras, and other fields or products.
[0003] LED light tubes are a popular field of flexible circuit board applications. They use light-emitting diodes as light sources, with higher light efficiency, more energy-saving, longer service life, and more environmentally friendly, becoming the most ideal product to replace fluorescent tubes at this stage. In LED light tubes, light-emitting diodes are welded on flexible circuit boards through special processing techniques, which is similar to the application of flexible circuit boards in light strips. Flexible circuit boards used to make LED light tubes or light strips in the prior art generally include single-layer boards and double-layer boards. A single-layer board, that is, a flexible circuit board with a metal layer, includes a first insulating layer, a metal layer, and a second insulating layer stacked in sequence. A double-layer board, that is, a flexible circuit board with two metal layers, includes a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, and a third insulating layer stacked in sequence. Whether it is a single-layer board or a double-layer board, the metal layer must be cut into a designed circuit structure, and these circuit structures are usually designed as a number of circulation units arranged along the length direction of the flexible circuit board. Unlike light strips, the circulation unit of the flexible circuit board used for LED light tubes is longer.
[0004] In order to realize the continuous production of flexible circuit boards for light strips in the prior art, a cylindrical knife roller is used for continuous die-cutting, and the cross-sectional circumference of the knife roller is adapted to the length of the circulation unit of the light strip. However, the unit length of the flexible circuit board for LED light tubes is longer than that of the light strip. If a cylindrical knife roller is used for continuous die-cutting, the cross-sectional area of the knife roller needs to be designed to be larger, which greatly increases the difficulty of assembly and is not conducive to saving production costs. Therefore, it is necessary to provide a manufacturing process for flexible circuit boards suitable for LED light tubes. Summary of the invention
[0005] The present invention aims to overcome at least one defect in the prior art and provides a method for manufacturing a flexible circuit board, which is used to manufacture a flexible circuit board with a long circulation unit such as an LED light tube.
[0006] In order to solve the above technical problems, the present invention proposes a method for manufacturing a flexible circuit board, wherein the flexible circuit board comprises a first insulating layer, a first conductive layer, a second insulating layer, a second conductive layer and a third insulating layer stacked in sequence, each of which has a length direction and a width direction. In particular, the method for manufacturing the flexible circuit board comprises the following steps:
[0007] S1. Cutting the first metal layer to form a first conductive layer attached to the first insulating layer;
[0008] S2. Etching the second metal layer to form a second conductive layer attached to the second insulating layer, and cutting through holes in the second insulating layer and the second conductive layer;
[0009] S3. Cutting component holes on the third insulating layer;
[0010] S4. Lay the first insulating layer, the first conductive layer, the second insulating layer, the second conductive layer and the third insulating layer in sequence.
[0011] This solution adopts a combination of die-cutting and etching to produce flexible circuit boards. The circulation unit of the second conductive layer is produced through an etching process, which avoids the test of the die-cutting device caused by the flexible circuit board with a longer circulation unit, which is beneficial to saving equipment costs. Except for the circulation unit, the other parts of the flexible circuit board are all produced by the die-cutting process, which can be carried out uniformly after the circulation unit is completed to achieve continuous production, which is beneficial to ensure production efficiency. Die-cutting and etching work together to control production costs.
[0012] The first conductive layer includes at least two metal strips arranged in parallel along the width direction, and the distance between two adjacent metal strips is greater than zero. The first metal layer is preferably a metal foil. Step S1 preferably includes the following steps:
[0013] S11. Cutting the metal foil into a plurality of groups of metal strips arranged in parallel along the width direction by a first die-cutting roller, each group of metal strips comprising two or more metal strips arranged in parallel along the width direction, and the distance between two adjacent metal strips is zero;
[0014] S12. Separating the plurality of metal strips obtained in step S11 by a guide roller so that the distance between two adjacent metal strips is greater than zero, thereby forming a first conductive layer. Meanwhile, the metal strips are supported by a matching member located between the first die-cutting roller and the guide roller so that the length of each metal strip between the first die-cutting roller and the guide roller is kept consistent;
[0015] S13. Lay the first conductive layer obtained in step S12 on the first insulating layer using a first embossing roller.
[0016] In the process of making the first conductive layer, steps S11 to S13 first cut the metal foil into multiple metal strips, and then bond them to the first insulating layer. In the process of cutting, multiple closely arranged metal strips are formed, and no metal foil waste is generated between two adjacent metal strips, which greatly improves the utilization rate of metal materials. Between cutting and bonding, the closely arranged multiple metal strips are separated by the cooperation of the guide roller and the matching part, ensuring that the metal strips are arranged in strict accordance with the design requirements. In the bonding process, the relative position relationship of the multiple metal strips arranged in accordance with the design requirements is fixed in time through the first insulating layer, ensuring that the first conductive layer meets the design requirements and the continuity of production.
[0017] A plurality of metal strips are tangent to the first die-cutting roller to form a first tangent, tangent to the matching piece to form a second tangent, and tangent to the guide roller to form a third tangent; the first tangent and the third tangent are both straight lines, the second tangent is an axisymmetric curve, the first tangent and the third tangent are parallel to the plane where the second tangent is located, and perpendicular to the symmetry axis of the second tangent; a plane rectangular coordinate system with the symmetry axis of the second tangent as the Y axis is established on the plane where the second tangent is located, and any point (x, y) on the second tangent satisfies the following formula, which is conducive to ensuring that each metal strip is in a taut state between the first die-cutting roller and the guide roller.
[0018]
[0019] Among them, h 0 The ordinate of the midpoint of the second tangent line, h 1 represents the ordinate of the projection of the first tangent line on the plane where the second tangent line lies, h 2 The ordinate of the projection of the third tangent line on the plane where the second tangent line lies, d 1 Represents the distance between the first tangent line and the plane where the second tangent line is located, d 2 represents the distance between the third tangent and the plane where the second tangent is located, W represents the sum of the target widths of all metal strips in the group, A represents the sum of the target spacings of all metal strips in the group, and B represents the target spacing between two adjacent metal strips between groups.
[0020] If the target width and target spacing of all metal strips are the same, any point (x, y) on the second tangent line satisfies the following formula to ensure that each metal strip is in a taut state between the first die-cutting roller and the guide roller.
[0021]
[0022] Among them, h 0 The ordinate of the midpoint of the second tangent line, h 1 represents the ordinate of the projection of the first tangent line on the plane where the second tangent line lies, h 2 The ordinate of the projection of the third tangent line on the plane where the second tangent line lies, d 1Represents the distance between the first tangent line and the plane where the second tangent line is located, d 2 represents the distance between the third tangent line and the plane where the second tangent line is located, w represents the target width of each metal strip, and a represents the target spacing between two adjacent metal strips.
[0023] The matching piece is preferably a toothless plate or a comb-toothed plate. The side of the toothless plate facing the metal strip is set as a smooth curved surface, and multiple metal strips are tangent to the curved surface to form a second tangent line. The side of the comb-toothed plate facing the metal strip is a toothed curved surface, and multiple metal strips are tangent to the curved surface to form a second tangent line. If the first metal layer is copper foil, the matching piece is preferably a comb-toothed plate; if the first metal layer is copper-aluminum composite foil, the matching piece is preferably a toothless plate.
[0024] The roller surface of the guide roller is provided with multiple groups of grooves arranged in parallel along the axial direction, each group of grooves includes at least two grooves arranged in parallel along the axial direction, each groove surrounds the roller surface, closes end to end to form a ring, and the plane in which it is located is perpendicular to the axis of the guide roller, the number of grooves is equal to the number of metal strips, and the width and spacing of the grooves match the target width and target spacing of the corresponding metal strips, so that multiple metal strips that are closely adjacent to each other can be separated from each other and arranged at a distance.
[0025] Step S2 preferably includes the following steps: S21. Etching the second metal layer attached to the second insulating layer by a roller etching process to form a second conductive layer on the second insulating layer; S22. Cutting through holes on the second insulating layer and the second conductive layer by a second die-cutting roller that operates intermittently. The combination of roller etching and intermittent die-cutting can not only maximize continuous production to improve production efficiency, but also avoid excessive requirements on the die-cutting device, thereby maximizing the production cost of the long unit flexible circuit board.
[0026] In step S3, preferably, a third die-cutting roller that operates intermittently cuts component holes on the third insulating layer, which is conducive to achieving continuous production, improving production efficiency, and controlling production costs.
[0027] The first die-cutting roller, the second die-cutting roller and / or the third die-cutting roller respectively include a knife roller and a smooth roller that cooperate with each other. The roller surface of the knife roller is provided with a blade, and the roller surface of the smooth roller is set as a smooth surface. The two cooperate with each other to achieve cutting. The roller surface of the smooth roller of the first die-cutting roller is dynamically wrapped with a knife pad film, and the roller surface of the smooth roller of the second die-cutting roller and / or the third die-cutting roller is dynamically wrapped with a waste discharge film, which is beneficial to avoid the knife edge of the knife roller from damaging the roller surface of the smooth roller, so as to achieve the purpose of protecting the smooth roller. At the same time, the knife edge depth of the knife roller can be designed to be slightly larger than the thickness of the metal foil, metal layer and / or insulating layer to be cut, so as to ensure that the metal foil, metal layer and / or insulating layer to be cut can be completely cut. In addition, the viscosity of the waste discharge film can also peel off the waste from the cut metal layer and / or insulating layer to achieve the purpose of waste discharge.
[0028] Compared with the prior art, this solution has the following beneficial effects: a flexible circuit board is manufactured by combining die-cutting and etching, and a circulation unit of the second conductive layer is manufactured by an etching process, thereby avoiding the test of the die-cutting device caused by the flexible circuit board with a long circulation unit, which is beneficial to saving equipment costs. Except for the circulation unit, the other parts of the flexible circuit board are all manufactured by the die-cutting process, which can be carried out uniformly after the circulation unit is manufactured to achieve continuous production, which is beneficial to ensuring production efficiency. Die-cutting and etching work together to control production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The drawings are for illustrative purposes only and should not be construed as limitations on the present invention. In order to better illustrate the present invention, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.
[0030] Figure 1 It is a structural diagram of a flexible circuit board.
[0031] Figure 2 It is a flow chart of a method for making a flexible circuit board.
[0032] Figure 3 The present invention is a flow chart of a method for manufacturing a first conductive layer of a flexible circuit board.
[0033] Figure 4 It is a schematic diagram of the operation of making the first conductive layer of a flexible circuit board.
[0034] Figure 5 It is a structural schematic diagram of the guide roller.
[0035] Figure 6 It is a top view schematic diagram of the manufacturing process of the first conductive layer of the flexible circuit board.
[0036] Figure 7 It is a structural schematic diagram of a toothless plate.
[0037] Figure 8 It is a structural schematic diagram of the comb plate.
[0038] Fig. 9 The present invention is a flow chart of a method for manufacturing a second conductive layer of a flexible circuit board.
[0039] Explanation of the reference numerals: metal foil 001, knife pad film 002, first insulating layer 010, first conductive layer 020, metal strip 021, second insulating layer 030, connecting hole 032, second conductive layer 040, circulation unit 041, connecting hole 042, third insulating layer 050, component hole 052, first die-cutting roller 110, first knife roller 111, first optical roller 112, first guide roller 113, guide roller 210, matching piece 220, toothless plate 221, comb plate 222, first embossing roller 310, first steel roller 311, first rubber roller 312. DETAILED DESCRIPTION
[0040] In order to enable those skilled in the art to better understand the present solution, the present solution is further described in detail below in conjunction with specific embodiments.
[0041] Figure 1 A possible flexible circuit board is illustrated. The flexible circuit board includes an insulating layer and a conductive layer, wherein the insulating layer includes a first insulating layer 010, a second insulating layer 030 and a third insulating layer 050, and the conductive layer includes a first conductive layer 020 and a second conductive layer 040. The first insulating layer 010, the second insulating layer 030 and the third insulating layer 050 are sequentially arranged, the first conductive layer 020 is arranged between the first insulating layer 010 and the second insulating layer 030, and the second conductive layer 040 is arranged between the second insulating layer 030 and the third insulating layer 050, thereby achieving separation and coating of the first conductive layer 020 and the second conductive layer 040, forming a structure in which the first insulating layer 010, the first conductive layer 020, the second insulating layer 030, the second conductive layer 040 and the third insulating layer 050 are sequentially stacked.
[0042] The insulating layer can be an insulating film made of an insulating material, specifically, a double-sided non-adhesive insulating film, or a single-sided or double-sided adhesive insulating film. The conductive layer is usually made of metal materials such as copper, copper-aluminum alloy, etc. The metal material can be directly deposited on the insulating film, or it can be made into a metal foil and then bonded to the insulating film. The metal foil can be bonded to the double-sided non-adhesive insulating film by an adhesive, etc., or it can be bonded to the single-sided or double-sided adhesive insulating film by hot pressing. In order to achieve continuous production, the insulating layer is preferably a single-sided or double-sided adhesive insulating film, wherein the first insulating layer 010 and the third insulating layer 050 are single-sided adhesive insulating films, and the second insulating layer 030 is double-sided adhesive insulating films. The conductive layer is bonded to the adhesive surface of the insulating film by hot pressing.
[0043] The flexible circuit board and its insulating layer and conductive layer all have a length direction and a width direction. They can be infinitely extended in the length direction and can also be rolled up around an axis parallel to the width direction. The third insulating layer 050 is provided with a component hole 052, so that components such as lamp beads and resistors can be electrically connected to the second conductive layer 040 through the third insulating layer 050; the second conductive layer 040 includes a plurality of circulation units 041 arranged along the length direction, and these circulation units 041 can realize the series connection of components; the second conductive layer 040 and the second insulating layer 030 are provided with connecting holes 042032 running through the two, so that the second conductive layer 040 can be electrically connected to the first conductive layer 020 through solder or the like; the first conductive layer 020 includes at least two metal strips 021 arranged in parallel along the width direction, and these metal strips 021 are respectively connected to the positive and negative poles of the power supply, so that the parallel connection between components can be realized.
[0044] In the first conductive layer 020, the number of metal strips 021 is usually determined by the design requirements of the flexible circuit board. For example, the first conductive layer 020 of a single-color flexible circuit board is usually designed with two metal strips 021, the first conductive layer 020 of a two-color flexible circuit board is usually designed with three metal strips 021, and the first conductive layer 020 of a three-color flexible circuit board is usually designed with four metal strips 021. At least one of these metal strips 021 is connected to the positive pole of the power supply, and at least one is connected to the negative pole of the power supply; if the first conductive layer 020 is provided with two metal strips 021, one of them is connected to the positive pole of the power supply, and the other is connected to the negative pole of the power supply; if the first conductive layer 020 is provided with three or more metal strips 021, one of them may be connected to one pole of the power supply, and the remaining metal strips 021 are connected to the other pole of the power supply.
[0045] In the second conductive layer 040, the length of the circulation unit 041 is closely related to the application scenario of the flexible circuit board. For example, the length of the circulation unit 041 of the flexible circuit board for LED light tubes is much longer than that of the circulation unit 041 of the flexible circuit board for light strips. In order to achieve continuous production, the flexible circuit board for light strips can be continuously die-cut using a cylindrical knife roller, and the cross-sectional circumference of the knife roller is adapted to the length of the circulation unit 041 of the light strip. If the flexible circuit board for LED light tubes is to be made by continuous die-cutting of a knife roller, the cross-section of the knife roller needs to be designed to be larger, which greatly increases the difficulty of assembly and is not conducive to saving production costs.
[0046] Figure 2 The flowchart of the method for making a flexible circuit board is shown. The method combines etching with die cutting and is suitable for making flexible circuit boards with longer unit lengths. Figure 2 As shown, the method may include the following steps.
[0047] Step S1, cutting the first metal layer to form a first conductive layer attached to the first insulating layer.
[0048] The first conductive layer can be manufactured by continuous die cutting, specifically, it can be manufactured by the existing method of first closing and then cutting, or it can be manufactured by the method of first cutting and then cutting proposed in the present solution.
[0049] The process of first combining and then cutting is: first, a whole first metal layer is formed on the first insulating layer by deposition, lamination, etc., or the first metal layer attached to the first insulating layer is directly purchased from outside, and then the first metal layer is die-cut according to the designed circuit pattern, and finally the excess metal material is removed to obtain the first conductive layer attached to the first insulating layer. This process can ensure that the remaining metal strips after processing are arranged according to the designed circuit, but it also causes waste of metal materials.
[0050] The cut-first-then-close method uses an independent metal foil as the first metal layer to produce the first conductive layer. The metal foil can be a copper foil or a copper-aluminum composite foil, wherein the copper foil can be a rolled copper foil or an electrolytic copper foil. The process of cut-first-then-close is: first cut the metal foil into multiple metal strips, and then bond them to the first insulating layer. In the process of cutting, multiple tightly arranged metal strips are formed, and no metal foil waste is generated between two adjacent metal strips, which greatly improves the utilization rate of metal materials. Between cutting and closing, the multiple tightly arranged metal strips are separated by the cooperation of guide rollers and matching parts to ensure that the metal strips are arranged in strict accordance with the design requirements. In the process of closing, the relative position relationship of the multiple metal strips arranged according to the design requirements is promptly fixed through the first insulating layer to ensure that the first conductive layer meets the design requirements and the continuity of production. Figures 3-4 As shown, the cut-before-cut method may include steps S11 to S13.
[0051] Step S11, cutting the metal foil into a plurality of groups of metal strips arranged in parallel along the width direction by a first die-cutting roller, each group of metal strips includes two or more metal strips arranged in parallel along the width direction, and the distance between two adjacent metal strips is zero.
[0052] The width of a single flexible circuit board is relatively small, and processing and manufacturing one by one is not conducive to ensuring production efficiency and processing accuracy. Therefore, in the process of processing flexible circuit boards, multiple flexible circuit boards are usually combined and processed into a full-page flexible circuit board, and finally the strips are die-cut to form a single flexible circuit board. To this end, in this step, the metal foil 001 is cut into multiple groups of metal strips 021 arranged in parallel along the width direction. A group of metal strips 021 corresponds to a single flexible circuit board. Each group of metal strips 021 includes more than two metal strips 021 arranged in parallel along the width direction. The number of metal strips 021 in a group is determined by the design requirements of a single flexible circuit board, and finally multiple metal strips 021 arranged in parallel along the width direction are formed. The spacing between two adjacent metal strips 021 is zero, which means that the multiple metal strips 021 cut out are close to each other, avoiding the generation of excess metal foil 001 waste between the two adjacent metal strips 021 cut out, and greatly improving the utilization rate of the metal foil 001.
[0053] The metal foil 001 is cut by the first die-cutting roller 110 to achieve continuous production. The first die-cutting roller 110 and the second and third die-cutting rollers described below can be collectively referred to as die-cutting rollers. The die-cutting rollers usually include a knife roller and a smooth roller. The roller surface of the knife roller is provided with a knife edge, and the roller surface of the smooth roller is set as a smooth surface. The two cooperate with each other to achieve cutting. The knife roller of the first die-cutting roller 110 can be called the first knife roller 111. The roller surface of the first knife roller 111 is provided with a plurality of annular knife edges arranged in parallel along the axial direction and surrounding the roller surface. The plane where each knife edge is located is perpendicular to the axis of the first knife roller 111, ensuring that the metal strip 021 formed by cutting is a rectangle of infinite length. The spacing between two adjacent knife edges is adapted to the target width of the corresponding metal strip 021, so that the multiple metal strips 021 cut out are close to each other (the spacing is zero). The smooth roller of the first die-cutting roller 110 can be called the first smooth roller 112. The roller surface of the first smooth roller 112 can be dynamically wrapped with a pad knife film 002, which is beneficial to avoid the blade of the first knife roller 111 from damaging the roller surface of the first smooth roller 112, thereby achieving the purpose of protecting the first smooth roller 112. At the same time, the blade depth of the first knife roller 111 can be designed to be slightly larger than the thickness of the metal foil 001 to ensure that the metal foil 001 can be completely cut.
[0054] Step S12, separating the multiple metal strips obtained in step S11 by means of guide rollers so that the distance between two adjacent metal strips is greater than zero, thereby forming a first conductive layer. At the same time, the metal strips are supported by a matching piece located between the first die-cutting roller and the guide roller so that the length of each metal strip between the first die-cutting roller and the guide roller remains consistent.
[0055] The metal strips 021 are connected to the positive and negative electrodes of the power supply so as to supply power to components such as lamp beads electrically connected to the flexible circuit board. To avoid short circuit, a certain distance must be left between two adjacent metal strips 021, and the size of the distance is determined by the design requirements of the flexible circuit board. For a single flexible circuit board, in order to achieve complete coating of the conductive layer, a certain distance must also be left between two adjacent metal strips 021 between two adjacent groups in the entire flexible circuit board, and the size of the distance can be designed as needed. In order to reduce or even avoid the waste of metal foil 001, the metal strips 021 coming out of the first die-cutting roller 110 are close to each other in pairs. In this step, these metal strips 021 are separated in pairs (the distance is greater than zero), so that they are arranged in a distance along the width direction to form a first conductive layer 020 that meets the design requirements.
[0056] Multiple metal strips 021 that are closely connected to each other can be separated from each other and arranged at a distance by the guide roller 210. Figure 5 As shown, the roller surface of the guide roller 210 is provided with a plurality of groups of grooves arranged in parallel along the axial direction, each group of grooves includes at least two grooves arranged in parallel along the axial direction, each groove surrounds the roller surface, closes end to end into a ring, and the plane in which it is located is perpendicular to the axis of the guide roller 210. The number of grooves is equal to the number of metal strips 021. Specifically, the number of groups and the number of strips of the grooves are respectively consistent with the number of groups and the number of strips of the metal strips 021 obtained in step S11, so each metal strip 021 has a corresponding groove on the guide roller 210, and the groove carries and guides the direction of the corresponding metal strip 021. The width and spacing of the grooves match the target width and target spacing of the corresponding metal strip 021, so all metal strips 021 are separated by a certain distance in pairs under the guidance of the corresponding grooves, and are arranged at a distance in the width direction according to the design requirements to form the first conductive layer 020.
[0057] like Figure 6 As shown, at the moment of coming out of the first die-cutting roller 110, the width of all the metal strips 021 is equal to the sum of their widths, and at the moment of coming out of the guide roller 210, the width of all the metal strips 021 is equal to the sum of their widths plus the sum of their spacings, forming an isosceles trapezoid between the first die-cutting roller 110 and the guide roller 210. Since the lengths of all the metal strips 021 coming out of the first die-cutting roller 110 are substantially the same, when the metal strips 021 at the edge of the isosceles trapezoid are in a taut state, the metal strips 021 in the middle of the isosceles trapezoid are still in a loose state, which is not conducive to ensuring that the metal strips 021 in the first conductive layer 020 formed finally are arranged strictly according to the design requirements. In order to make all the metal strips 021 in a taut state between the first die-cutting roller 110 and the guide roller 210, in this step, a matching piece 220 is used between the first die-cutting roller 110 and the guide roller 210 to support the metal strips 021 so that the length of each metal strip 021 between the first die-cutting roller 110 and the guide roller 210 remains consistent.
[0058] The plurality of metal strips 021 are tangent to the first die-cutting roller 110 to form a first tangent line l 1 , tangent to the matching piece 220 to form a second tangent line l 2 , tangent to the guide roller 210 to form a third tangent line l 3 . The first tangent line 1 and the third tangent l 3 are all straight lines, the second tangent line l 2 For an axisymmetric curve, the first tangent line l 1 and the third tangent l 3 Parallel to the second tangent line l 2 The plane is perpendicular to the second tangent line l 2 A plane rectangular coordinate system with the second tangent symmetry axis as the Y axis is established on the plane where the second tangent is located, and any point (x, y) on the second tangent satisfies the following formula, which is conducive to ensuring that each metal strip 021 is in a taut state between the first die-cutting roller 110 and the guide roller 210.
[0059]
[0060] Among them, h 0 The ordinate of the midpoint of the second tangent line, h 1 represents the ordinate of the projection of the first tangent line on the plane where the second tangent line lies, h 2 The ordinate of the projection of the third tangent line on the plane where the second tangent line lies, d 1 Represents the distance between the first tangent line and the plane where the second tangent line is located, d 2 represents the distance between the third tangent and the plane where the second tangent is located, W represents the sum of the target widths of all metal strips 021 in the group, A represents the sum of the target spacings of all metal strips 021 in the group, and B represents the target spacing between two adjacent metal strips 021 between groups.
[0061] If the target widths and target spacings of all metal strips 021 are the same, any point (x, y) on the second tangent line that satisfies the following equation can ensure that each metal strip 021 is in a taut state between the first die-cutting roller 110 and the guide roller 210 .
[0062]
[0063] Among them, h 0 The ordinate of the midpoint of the second tangent line, h 1 represents the ordinate of the projection of the first tangent line on the plane where the second tangent line lies, h 2 The ordinate of the projection of the third tangent line on the plane where the second tangent line lies, d 1 Represents the distance between the first tangent line and the plane where the second tangent line is located, d 2represents the distance between the third tangent line and the plane where the second tangent line is located, w represents the target width of each metal strip 021 , and a represents the target spacing between two adjacent metal strips 021 .
[0064] The matching member 220 can be a plate or a rotating member, and the former is preferred. The plate can be a toothless plate 221 or a comb plate 222. Figure 7 As shown, the side of the toothless plate 221 facing the metal strip 021 is set as a smooth curved surface, and a plurality of metal strips 021 are tangent to the curved surface to form the above-mentioned second tangent line. Figure 8 As shown, the side of the comb plate 222 facing the metal strip 021 is a toothed curved surface, and a plurality of metal strips 021 are tangent to the curved surface to form a second tangent line. The teeth of the comb plate 222 can guide the metal strip 021, but the metal strip 021 of some materials is easily scratched by the teeth when passing through the comb plate 222. Therefore, the manufacturer can select a suitable matching piece 220 according to the material of the metal foil 001 used in the first conductive layer 020. If the metal foil 001 is a copper foil, the matching piece 220 is preferably a comb plate 222; if the metal foil 001 is a copper-aluminum composite foil, the matching piece 220 is preferably a toothless plate 221.
[0065] Step S13, laminating the first conductive layer obtained in step S12 onto the first insulating layer by a first embossing roller.
[0066] After the guide roller 210 guides all the metal strips 021 to be arranged at a distance according to the design requirements, the relative position relationship of all the metal strips 021 needs to be fixed in time to ensure that the first conductive layer 020 meets the design requirements. In this step, the first conductive layer 020 obtained in step S12 is attached to the first insulating layer 010 so that the relative position relationship of all the metal strips 021 is fixed.
[0067] The first conductive layer 020 and the first insulating layer 010 are hot-pressed and bonded (referred to as bonding) using the first embossing roller 310 to achieve continuous production. The first embossing roller 310 and the second embossing roller, the third embossing roller, and the fourth embossing roller described below can be collectively referred to as embossing rollers, and the embossing rollers include steel rollers and rubber rollers, both of which are heating elements and cooperate with each other to achieve bonding. The steel roller of the first embossing roller 310 can be referred to as the first steel roller 311, and the first steel roller 311 can increase the squeezing force of the first embossing roller 310 on the first conductive layer 020 and the first insulating layer 010, and the rubber roller of the first embossing roller 310 can be referred to as the first rubber roller 312, and the first rubber roller 312 can increase the contact area between the first embossing roller 310 and the first conductive layer 020 and the first insulating layer 010, and the synergistic effect of the two allows the first conductive layer 020 to be firmly bonded to the first insulating layer 010.
[0068] Step S2, etching the second metal layer to form a second conductive layer attached to the second insulating layer, and cutting connecting holes in the second insulating layer and the second conductive layer.
[0069] The second conductive layer with a long circulation unit is not suitable for continuous die cutting. Therefore, this step adopts a combination of etching and die cutting to process and manufacture the second conductive layer, wherein the circulation unit is manufactured by etching and the connecting hole is manufactured by die cutting, so as to control the manufacturing cost of the flexible circuit board. Fig. 9 As shown, this step may include steps S21 to S22.
[0070] Step S21 , etching the second metal layer attached to the second insulating layer by a roller etching process to form a second conductive layer on the second insulating layer.
[0071] The second insulating layer and the second metal layer can be directly purchased from outside. The purchased second insulating layer and the second metal layer can be attached to each other or independent of each other. The independent second insulating layer and the second metal layer can be attached to each other by hot pressing. Thereafter, the second metal layer attached to the second insulating layer can be etched by a roller etching process to etch away the excess metal, leaving multiple circulation units with a shape consistent with the designed circuit on the first insulating layer to form a second conductive layer. This process does not require the use of a knife roller with a large cross-sectional circumference, which is conducive to controlling the production cost of the flexible circuit board.
[0072] Step S22, cutting connecting holes on the second insulating layer and the second conductive layer by using a second die-cutting roller that operates intermittently.
[0073] The connecting hole runs through the second insulating layer and the second conductive layer, and is preferably made by die-cutting. The connecting hole and the circulation unit are both arranged in a cycle along the length direction of the flexible circuit board, and the cycle period is the same. The difference is that the length of the connecting hole is much smaller than the length of the circulation unit, and the knife edge of the die-cutting connecting hole will not cover the entire roller surface of the knife roller. A knife roller with a cross-sectional circumference smaller than the cycle period can be used to die-cut the connecting hole, which is conducive to the continuous production of the flexible circuit board. At the same time, in order to ensure that the cycle period of the die-cut connecting hole meets the design requirements and corresponds to the cycle period of the circulation unit, this step uses an intermittently operated second die-cutting roller to die-cut the connecting hole, and the periodic start and stop of the second die-cutting roller is used to ensure the periodic arrangement of the connecting holes on the second insulating layer and the second conductive layer. It should be noted that unless otherwise emphasized, other die-cutting rollers, embossing rollers, etc. all adopt a continuous operation mode.
[0074] The knife roller of the second die-cutting roller can be referred to as the second knife roller, and the smooth roller thereof can be referred to as the second smooth roller. The roller surface of the second knife roller is provided with a knife edge corresponding to the target shape of the connecting hole, ensuring that the shape of the connecting hole formed by cutting on the second insulating layer and the second conductive layer is consistent with the target shape. The waste generated after the second insulating layer and the second conductive layer are cut is discontinuous, and a waste discharge film can be dynamically wound on the roller surface of the second smooth roller, and the waste can be peeled off from the second insulating layer and the second conductive layer by the viscosity of the waste discharge film, and the waste discharge film can be collected by winding the waste roller. At the same time, the waste discharge film can also act as a knife pad film to prevent the knife edge of the second knife roller from damaging the roller surface of the second smooth roller, thereby achieving the purpose of protecting the second smooth roller, and the knife edge depth of the second knife roller can be designed to be slightly larger than the sum of the thickness of the second insulating layer and the second conductive layer, so as to ensure that the second insulating layer and the second conductive layer can be completely cut off.
[0075] Step S3, cutting component holes on the third insulating layer.
[0076] The component holes are located on the third insulating layer and can be made by die-cutting. The component holes are also arranged in a cycle along the length direction of the flexible circuit board, and its cycle period is the same as the cycle period of the cycle unit. The difference is that the length of the component hole is smaller than the length of the cycle unit, and the blade of the die-cut component hole will not cover the entire roller surface of the knife roller. A knife roller with a cross-sectional circumference smaller than the cycle period can be used to die-cut the component holes, which is conducive to the continuous production of flexible circuit boards. At the same time, in order to ensure that the cycle period of the die-cut component holes meets the design requirements and corresponds to the cycle period of the cycle unit, this step can use a third die-cutting roller that operates intermittently to die-cut the component holes, and the periodic start and stop of the third die-cutting roller can be used to ensure the periodic arrangement of the component holes on the third insulating layer.
[0077] The knife roller of the third die-cutting roller can be called the third knife roller, and the smooth roller thereof can be called the third smooth roller. The roller surface of the third knife roller is provided with a knife edge corresponding to the target shape and positional relationship of the component hole, ensuring that the shape and positional relationship of the component hole formed by cutting on the third insulating layer are consistent with the target shape and positional relationship. The waste generated after the third insulating layer is cut is discontinuous, and a waste discharge film can be dynamically wound on the roller surface of the third smooth roller, and the waste can be peeled off from the third insulating layer by the viscosity of the waste discharge film, and the waste discharge film can be collected by winding the waste roller. At the same time, the waste discharge film can also act as a knife pad film to prevent the knife edge of the third knife roller from damaging the roller surface of the third smooth roller, thereby achieving the purpose of protecting the third smooth roller, and the knife edge depth of the third knife roller can be designed to be slightly larger than the thickness of the third insulating layer to ensure that the third insulating layer can be completely cut off.
[0078] Step S4, sequentially laminating the first insulating layer, the first conductive layer, the second insulating layer, the second conductive layer and the third insulating layer.
[0079] After steps S1 to S3, the first insulating layer and the first conductive layer have been combined into one to form the first part of the flexible circuit board, the second insulating layer and the second conductive layer have also been combined into one to form the second part of the flexible circuit board, and the third insulating layer exists independently to form the third part of the flexible circuit board. In this step, the three parts are bonded in the order of the first insulating layer, the first conductive layer, the second insulating layer, the second conductive layer, and the third insulating layer to complete the production of the flexible circuit board.
[0080] The above three parts of the flexible circuit board can be hot-pressed and bonded by the second die-embossing roller to achieve continuous production. The steel roller of the second die-embossing roller can be called the second steel roller, and the rubber roller can be called the second rubber roller. The second steel roller can increase the squeezing force of the second die-embossing roller on the first insulating layer, the first conductive layer, the second insulating layer, the second conductive layer and the third insulating layer. The second rubber roller can increase the contact area between the second die-embossing roller and the first insulating layer, the first conductive layer, the second insulating layer, the second conductive layer and the third insulating layer. The synergistic effect of the two makes the first insulating layer, the first conductive layer, the second insulating layer, the second conductive layer and the third insulating layer firmly bonded.
[0081] Before the second embossing roller is used to press the three parts of the flexible circuit board together, the third embossing roller can be used to press the first part and the second part of the flexible circuit board together, or the fourth embossing roller can be used to press the second part and the third part of the flexible circuit board together. The steel roller of the third embossing roller can be called the third steel roller, and the rubber roller can be called the third rubber roller. The third steel roller can increase the squeezing force of the third embossing roller on the first insulating layer, the first conductive layer, the second insulating layer and the second conductive layer. The third rubber roller can increase the contact area between the third embossing roller and the first insulating layer, the first conductive layer, the second insulating layer and the second conductive layer. The synergistic effect of the two makes the first insulating layer, the first conductive layer, the second insulating layer and the second conductive layer firmly bonded. The steel roller of the fourth embossing roller can be called the fourth steel roller, and the rubber roller can be called the fourth rubber roller. The fourth steel roller can increase the squeezing force of the fourth embossing roller on the second insulating layer, the second conductive layer and the third insulating layer. The fourth rubber roller can increase the contact area between the fourth embossing roller and the second insulating layer, the second conductive layer and the third insulating layer. The synergistic effect of the two makes the second insulating layer, the second conductive layer and the third insulating layer firmly bonded.
[0082] In the above production method, steps S1, S2, S3, S4, etc. are only used as names of corresponding steps and do not limit the order of the steps. Step S21 can be performed first, steps S1, S21 and S3 can be performed simultaneously, and step S4 is performed last.
[0083] The above-mentioned production method adopts a combination of die-cutting and etching to produce a flexible circuit board, and the circulation unit of the second conductive layer is produced by an etching process, so as to avoid the flexible circuit board with a longer circulation unit from putting a test on the die-cutting device, which is beneficial to saving equipment costs. Except for the circulation unit, the other parts of the flexible circuit board are all produced by the die-cutting process, which can be carried out uniformly after the circulation unit is produced to achieve continuous production, which is beneficial to ensuring production efficiency. Die-cutting and etching work together to control production costs.
[0084] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.
Claims
1. A method for manufacturing a flexible circuit board, characterized in that: The flexible circuit board comprises a first insulating layer, a first conductive layer, a second insulating layer, a second conductive layer and a third insulating layer stacked in sequence, each of which has a length direction and a width direction; the method comprises the following steps: S1. Cutting the first metal layer to form a first conductive layer attached to the first insulating layer; S2. Etching the second metal layer to form a second conductive layer attached to the second insulating layer, and cutting through holes in the second insulating layer and the second conductive layer; S3. Cutting component holes on the third insulating layer; S4. Lay the first insulating layer, the first conductive layer, the second insulating layer, the second conductive layer and the third insulating layer in sequence.
2. The method for manufacturing a flexible circuit board according to claim 1, characterized in that: The first conductive layer includes at least two metal strips arranged in parallel along the width direction, and the distance between two adjacent metal strips is greater than zero. The first metal layer is a metal foil. The step S1 includes: S11. Cutting the metal foil into a plurality of groups of metal strips arranged in parallel along the width direction by a first die-cutting roller, each group of metal strips comprising two or more metal strips arranged in parallel along the width direction, and the distance between two adjacent metal strips is zero; S12. Separating the plurality of metal strips obtained in step S11 by a guide roller so that the distance between two adjacent metal strips is greater than zero, thereby forming a first conductive layer. Meanwhile, the metal strips are supported by a matching member between the first die-cutting roller and the guide roller so that the length of each metal strip between the first die-cutting roller and the guide roller is kept consistent; S13. Lay the first conductive layer obtained in step S12 on the first insulating layer using a first embossing roller.
3. The method for manufacturing a flexible circuit board according to claim 2, characterized in that: The plurality of metal strips are tangent to the first die-cutting roller to form a first tangent, tangent to the matching piece to form a second tangent, and tangent to the guide roller to form a third tangent; the first tangent and the third tangent are both straight lines, the second tangent is an axisymmetric curve, the first tangent and the third tangent are parallel to the plane where the second tangent is located, and perpendicular to the symmetry axis of the second tangent; a plane rectangular coordinate system with the symmetry axis of the second tangent as the Y axis is established on the plane where the second tangent is located, then any point (x, y) on the second tangent satisfies: Among them, h0 represents the ordinate of the midpoint of the second tangent, h1 represents the ordinate of the projection of the first tangent on the plane where the second tangent is located, h2 represents the ordinate of the projection of the third tangent on the plane where the second tangent is located, d1 represents the distance between the first tangent and the plane where the second tangent is located, d2 represents the distance between the third tangent and the plane where the second tangent is located, W represents the sum of the target widths of all metal strips in the group, A represents the sum of the target spacings of all metal strips in the group, and B represents the target spacing between two adjacent metal strips between groups.
4. The method for manufacturing a flexible circuit board according to claim 3, characterized in that: If all metal bars have the same target width and target spacing, then any point (x, y) on the second tangent line satisfies: Among them, h0 represents the ordinate of the midpoint of the second tangent, h1 represents the ordinate of the projection of the first tangent on the plane where the second tangent is located, h2 represents the ordinate of the projection of the third tangent on the plane where the second tangent is located, d1 represents the distance between the first tangent and the plane where the second tangent is located, d2 represents the distance between the third tangent and the plane where the second tangent is located, w represents the target width of each metal strip, and a represents the target spacing between two adjacent metal strips.
5. The method for manufacturing a flexible circuit board according to claim 3 or 4, characterized in that: The matching piece is a toothless plate or a comb-toothed plate; the side of the toothless plate facing the metal strip is set as a smooth curved surface, and multiple metal strips are tangent to the curved surface to form the second tangent line; the side of the comb-toothed plate facing the metal strip is a toothed curved surface, and multiple metal strips are tangent to the curved surface to form the second tangent line.
6. The method for manufacturing a flexible circuit board according to claim 5, characterized in that: If the first metal layer is copper foil, the matching piece is a comb-tooth plate; if the first metal layer is copper-aluminum composite foil, the matching piece is a toothless plate.
7. The method for manufacturing a flexible circuit board according to any one of claims 2 to 4, characterized in that: The roller surface of the guide roller is provided with a plurality of groups of grooves arranged in parallel along the axial direction, each group of grooves includes at least two grooves arranged in parallel along the axial direction, each groove surrounds the roller surface, is closed end to end to form a ring, and the plane in which it is located is perpendicular to the axis of the guide roller, the number of grooves is equal to the number of metal strips, and the width and spacing of the grooves match the target width and target spacing of the corresponding metal strips.
8. The method for manufacturing a flexible circuit board according to any one of claims 2 to 4, characterized in that: The second metal layer is attached to the second insulating layer, and the step S2 comprises: S21. Etching the second metal layer attached to the second insulating layer by a roller etching process to form a second conductive layer on the second insulating layer; S22. Cutting connecting holes in the second insulating layer and the second conductive layer through a second die-cutting roller that operates intermittently.
9. The method for manufacturing a flexible circuit board according to claim 8, characterized in that: In step S3, component holes are cut out on the third insulating layer by using a third die-cutting roller that operates intermittently.
10. The method for manufacturing a flexible circuit board according to claim 9, characterized in that: The first die-cutting roller, the second die-cutting roller and / or the third die-cutting roller respectively include a knife roller and a smooth roller that cooperate with each other, the roller surface of the knife roller is provided with a knife edge, and the roller surface of the smooth roller is set as a smooth surface; the roller surface of the smooth roller of the first die-cutting roller is dynamically wrapped with a knife pad film, and the roller surface of the smooth roller of the second die-cutting roller and / or the third die-cutting roller is dynamically wrapped with a waste discharge film.