Patch positioning method and positioning device for flexible PCB (Printed Circuit Board)

Abstract

The invention discloses a patch positioning method of a flexible PCB and a positioning device thereof. The patch positioning method comprises the following steps: S1, pasting a first reinforcing plate with a preset thickness on at least one pair of opposite sides of the reverse side of the flexible PCB relative to a process edge of the flexible PCB; s2, drilling a plurality of positioning holes in the process edge to manufacture a flexible PCB reinforcing plate, wherein the positioning holes penetrate through the process edge and the first reinforcing plate; s3, the flexible PCB reinforcing plate is laid on a tray, the tray is provided with a plane boss of a patch area, containing areas are arranged on the two sides of the plane boss, and positioning pins with the same position and number as the positioning holes are arranged in the containing areas; after the flexible PCB reinforcing plate is laid on the tray, the positioning pins are just inserted into the positioning holes, and the positioning pins are lower than the planes of the positioning holes; and the patch area of the flexible PCB reinforcing plate and the process edge are kept in the same plane. The method has the advantages that the positioning precision is improved, the operation process is simplified, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible PCB chip mounting, and particularly relates to a flexible PCB chip mounting positioning method and a positioning device therefor. Background Art

[0002] The chip mounting positioning technology of flexible PCB (Flexible Printed Circuit Board) is a key process to ensure the precise installation of surface mount components (SMT) on a flexible substrate. Due to the deformable characteristics of flexible PCB, it is very important to position the flexible PCB during chip mounting to keep it flat and undeformed during chip mounting.

[0003] In the prior art, the commonly used positioning methods are as follows. One is the adhesive paper positioning method, that is, a positioning line is drawn on the carrier plate in advance, one side of the flexible PCB is manually aligned with the positioning line, and then the four sides of the flexible PCB are fixed with high-temperature resistant adhesive paper to make the flexible PCB lie flat on the carrier plate. This method has the advantages of simplicity and low cost. However, this method can only be operated manually, there are operation errors, and it also requires an experienced person to operate. In addition, this method also has the problem of low efficiency.

[0004] The second is the negative pressure adsorption method. For example, a positioning mechanism in an alternating clamping and feeding type suction plate flat material flexible material conveying mechanism for chip mounting disclosed in Chinese Patent CN 112702901 A adopts the negative pressure adsorption method.

[0005] The third is the magnetic adsorption method. For example, the positioning fixture adopted in the SMT production fixture for flexible and deformable PCB disclosed in Chinese Patent CN 206237692 U is the magnetic adsorption method.

[0006] The fourth is the clamping and tensioning method. For example, a positioning mechanism in an automatic chip mounting device for flexible PCB board disclosed in Chinese Patent CN 212628625 U adopts the clamping and tensioning method.

[0007] Although the above-mentioned negative pressure adsorption method, magnetic adsorption method and clamping and tensioning method all have their own advantages, the above three methods all have the problem of complex positioning methods and positioning devices. In view of the above problems, the prior art urgently needs to be improved. Summary of the Invention

[0008] The purpose of the present application is to provide a flexible PCB chip mounting positioning method and a positioning device therefor, which have the advantages of improving positioning accuracy, simplifying the operation process and improving production efficiency.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions: A flexible PCB chip mounting positioning method includes the following steps: S1. On at least a pair of opposite sides of the reverse side of the flexible PCB, paste a first reinforcing plate with a predetermined thickness relative to the process edge of the flexible PCB; S2. Drill a number of positioning holes within the process edge to make a flexible PCB reinforcing plate, and the positioning holes of the flexible PCB reinforcing plate penetrate the process edge and the first reinforcing plate; S3. Lay the flexible PCB reinforcing plate on the tray. The tray has a planar boss for carrying the patch area of the flexible PCB reinforcing plate, and accommodation areas for accommodating the first reinforcing plate are provided on both sides of the planar boss. Positioning pins equal in position and number to the positioning holes are provided in the accommodation areas; when the flexible PCB reinforcing plate is laid on the tray, the positioning pins just insert into the positioning holes, and the positioning pins are lower than the plane of the positioning holes; and keep the patch area of the flexible PCB reinforcing plate and the process edge in the same plane.

[0010] As an improvement to the present invention, the at least a pair of opposite sides are the long side edges of the flexible PCB.

[0011] As an improvement to the present invention, a second reinforcing plate is further provided on the opposite sides of the remaining process edge of the reverse side of the flexible PCB, and the first reinforcing plate and the second reinforcing plate form an integral frame.

[0012] As an improvement to the present invention, the first reinforcing plate is a rigid reinforcing plate or a flexible reinforcing plate.

[0013] As an improvement to the present invention, the rigid reinforcing plate is a rigid PCB substrate.

[0014] As an improvement to the present invention, the flexible reinforcing plate is a high-temperature resistant flexible plastic plate.

[0015] The present invention also provides a positioning device for a flexible PCB, including a tray. A planar boss for carrying the patch area of the flexible PCB reinforcing plate is provided in the middle of the tray, and accommodation areas for accommodating the first reinforcing plate are provided on both sides of the planar boss. Positioning pins are provided in the accommodation areas; the thickness of the planar boss is equal to the thickness of the first reinforcing plate or / and the second reinforcing plate on the flexible PCB reinforcing plate; when the flexible PCB reinforcing plate is laid on the tray, the positioning pins just insert into the positioning holes of the flexible PCB reinforcing plate, and the positioning pins are lower than the plane of the positioning holes; keep the patch area of the flexible PCB reinforcing plate and the process edge in the same plane.

[0016] As an improvement to the present invention, a second reinforcing plate is further provided on the opposite sides of the remaining process edge of the reverse side of the flexible PCB, and the first reinforcing plate and the second reinforcing plate form an integral frame.

[0017] As an improvement to the present invention, the first reinforcing plate is a rigid reinforcing plate or a flexible reinforcing plate.

[0018] As an improvement to the present invention, the rigid reinforcing plate is a rigid PCB substrate; the flexible reinforcing plate is a high-temperature resistant flexible plastic plate.

[0019] As can be seen from the above, a patch positioning method and a positioning device for a flexible PCB provided by the present application ensure that the patch area and the process edge are flat by arranging a reinforcing plate on the reverse side of the flexible PCB and cooperating with the positioning structure of the tray, solving the problem of low patch accuracy caused by easy deformation of the flexible PCB, and having the advantages of improving the positioning accuracy, simplifying the operation process, and improving the production efficiency. Description of the Drawings

[0020] Figure 1 It is a schematic block structure diagram of the positioning method of the present invention.

[0021] Figure 2 It is a schematic top view structure diagram of an embodiment of the positioning device of the present invention.

[0022] Figure 3 For Figure 2 the enlarged structure diagram at A in

[0023] Figure 4 For Figure 2 the side structure diagram of

[0024] Figure 5 For Figure 4 the enlarged structure diagram at B in

[0025] Figure 6 It is a schematic top view structure diagram of a second embodiment of the positioning device of the present invention. Detailed Embodiments

[0026] The technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings in this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. The components of this application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application that is required to be protected, but only represents the selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative efforts belong to the scope of protection of this application. It should be noted that: Similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, terms such as "first" and "second" are only used for differential description and cannot be understood as indicating or implying relative importance.

[0027] In the prior art, the surface mounting process of flexible printed circuit boards often faces the problem of insufficient positioning accuracy caused by material deformation. The traditional adhesive paper fixing method relies on manual operation and has the defects of low efficiency and poor consistency; although the negative pressure adsorption and magnetic adsorption devices can achieve automatic positioning, their structures are complex and the maintenance costs are high; the clamping and tensioning method may cause mechanical damage to the flexible substrate. It is difficult for these methods to achieve high-precision positioning while maintaining operational simplicity.

[0028] To solve the above problems, considering the deformability controllability of flexible materials under local support conditions, we thought about how to construct a solution that can both maintain the flexibility of the substrate and form a rigid positioning reference in the key area. By analyzing the flatness requirements of the chip mounting process, it was found that the process edge area can be used as a structural strengthening part. Furthermore, it was proposed to set an enhancement plate on the reverse side of the process edge and use the mechanical cooperation between the through-hole positioning holes and the tray positioning pins to form a self-aligning positioning system.

[0029] Therefore, referring to Figure 1 , this application proposes the following technical solution: A chip mounting positioning method for a flexible PCB, including the following steps: pasting first enhancement plates with a predetermined thickness on at least a pair of opposite sides on the reverse side of the flexible printed circuit board, processing positioning holes that penetrate the enhancement plates and the substrate in the process edge area, and then placing the flexible circuit board enhancement plate with the positioning holes on the plane convex platform of the tray. The positioning pins in the accommodating area are inserted and matched with the positioning holes to make the chip mounting area coplanar with the process edge.

[0030] Among them, the first reinforcing plate refers to a support structure attached to the reverse side of the process edge of the flexible circuit board, which can be realized by using a rigid PCB substrate or a high-temperature resistant flexible plastic plate, and is used to suppress local deformation during the chip mounting process. The positioning hole refers to a through hole that penetrates the process edge and the reinforcing plate, and can be processed by a numerical control drilling process to form a physical reference that matches the positioning pin. The planar boss refers to a flat support surface on the tray that bears the chip mounting area, and its thickness matches that of the reinforcing plate. For example, it can be processed by aluminum alloy to ensure that the chip mounting area and the process edge are on the same plane. The positioning pin refers to a cylindrical positioning element arranged in the accommodating area of the tray. For example, a stainless steel pin with a diameter of 0.5 mm, and its height is lower than the upper surface of the positioning hole to avoid interference.

[0031] Specifically, when the reinforcing plate is pasted on the reverse side of the process edge of the flexible circuit board, its thickness compensates for the flexible deformation amount of the substrate. The positioning hole penetrates both the reinforcing plate and the substrate at the same time to form an accurate positioning reference point. When the reinforcing plate is placed on the tray, the positioning pin and the positioning hole are automatically aligned and inserted. At this time, the planar boss supports the chip mounting area, and the reinforcing plate is embedded in the accommodating area. The matching of their thicknesses keeps the entire working surface flat. During this process, the reinforcing plate provides local rigid support, the positioning hole and the positioning pin cooperate to eliminate lateral displacement, and the planar boss maintains longitudinal flatness. The three work together to ensure the chip mounting accuracy.

[0032] Compared with the prior art, the traditional adhesive paper fixing method requires manual adjustment of flatness, while this solution realizes automatic positioning through the mechanical cooperation between the reinforcing plate and the tray; compared with the negative pressure adsorption device that requires a complex gas path system, this solution simplifies the equipment complexity by using a physical positioning structure; compared with the contact fixing method of the clamping and tensioning method, this method avoids damaging the substrate through non-contact positioning pin insertion.

[0033] Through the above technical solutions, this application effectively solves the problem of flatness control during the chip mounting process of flexible circuit boards. On the premise of maintaining the flexibility of the material, through the cooperation of the reinforcing structure and the mechanical positioning system, high-precision automatic positioning is achieved, while reducing the equipment complexity and operation difficulty.

[0034] This application further proposes to paste a first reinforcing plate with a predetermined thickness on the long side of the flexible PCB.

[0035] Among them, the long side refers to the two side edges with longer lengths in the flexible PCB, which can be specifically realized by using the remaining parts of the long sides after cutting the PCB substrate. The long side is more likely to generate bending deformation during the chip mounting process due to its longer length. By setting a reinforcing plate on the long side, it is possible to specifically increase the rigid support in this area.

[0036] Specifically, due to the relatively large extension length of the long side of the flexible PCB, it is prone to local distortion or curling when subjected to external forces during the chip mounting process. After the reinforcing plate is pasted on the process edge area of the long side, its rigid characteristics can effectively restrict the deformation range of this area. When the positioning pins on the tray are inserted through the positioning holes of the reinforcing plate, the cooperation between the reinforcing plate on the long side and the positioning pins can form a double positioning constraint, ensuring that the chip mounting area and the process edge of the flexible PCB are always in the same plane. During this process, the reinforcing plate on the long side covers the area of the flexible substrate that is most prone to deformation, offsetting the pressure exerted by the chip mounting equipment through the reinforcing structure and avoiding problems such as component offset and inaccurate placement caused by local collapse of the substrate.

[0037] Compared with the prior art, the traditional adhesive paper positioning method relies on manual visual alignment of the long side, resulting in the problem of easy deviation of the positioning reference. This solution realizes the active suppression of the deformation of the long side through the cooperation of the structured reinforcing plate and the positioning device, eliminating the random error caused by manual operation. Compared with complex positioning systems such as negative pressure adsorption, this solution utilizes the mechanical cooperation relationship between the reinforcing plate and the tray, reducing the equipment complexity while ensuring the positioning accuracy.

[0038] Through the above technical solution, this application effectively solves the problem of positioning inaccuracy caused by deformation of the long side of the flexible PCB during the chip mounting process. The synergistic effect of the reinforcing plate and the tray enables the long side to form a stable support structure, ensuring that the chip mounting area remains flat during the processing. While improving the chip mounting accuracy, this solution simplifies the operation process of the positioning procedure, meeting the continuous operation requirements of the automated production line.

[0039] This application further proposes a technical solution of adding a second reinforcing plate on the opposite side of the remaining process edge on the reverse side of the flexible PCB, so that the first reinforcing plate and the second reinforcing plate jointly form an overall framework.

[0040] Among them, the second reinforcing plate refers to a reinforcement structure arranged on the opposite side of the remaining process edge not covered by the first reinforcing plate, which can be specifically realized by using the same or different materials as the first reinforcing plate. For example, it can be a rigid PCB substrate or a high-temperature resistant flexible plastic plate. This structure forms a complete circumferential support system by supplementing and covering the non-strengthened process edge area. The overall framework refers to a closed-loop structure formed by the first and second reinforcing plates in the four-side process area, which can be specifically realized by connecting the edges of each reinforcing plate to each other. This structure can eliminate the rigidity difference between each process edge and make the stress evenly distributed.

[0041] Specifically, after the first reinforcing plate is set on the long side of the flexible PCB, a second reinforcing plate is added to the process edge on the short side, and the four-side reinforcing structure forms a rectangular frame. In the chip mounting process, the frame restricts the deformation of the flexible substrate through its own rigidity. At the same time, the thickness of each side of the frame matches the depth of the tray accommodating area, ensuring that the chip mounting area of the PCB and the process edge are on the same plane. When the positioning pins are inserted into the positioning holes on the four sides of the frame, the whole frame is constrained by the positioning, and the flatness error of the chip mounting area can be maintained within 0.1 mm.

[0042] Compared with the prior art, the existing adhesive paper positioning method cannot form a closed-loop support only through unilateral fixation, and the negative pressure adsorption method depends on the flatness of the carrier board and cannot compensate for the deformation of the substrate itself. This solution pre-shapes the substrate at the positioning stage by constructing a four-side rigid frame. Compared with the clamping and tensioning method of CN 212628625U, it can achieve full-domain support without dynamically adjusting the clamping force, and can also solve the wrinkling problem caused by local support loss.

[0043] Through the above technical solution, the present application realizes the full-coverage support for the process edges on the four sides of the flexible PCB. During the chip mounting process, the anisotropic deformation generated when the substrate is heated is constrained by the rigid frame, and the flatness fluctuation of the chip mounting area is controlled within ±0.05 mm, effectively avoiding component offset or soldering voids caused by local support loss. It is particularly suitable for the chip mounting operation of strip-shaped flexible PCBs with an aspect ratio greater than 3:1.

[0044] The present application further proposes to set a rigid reinforcing plate or a flexible reinforcing plate as the first reinforcing plate on at least a pair of opposite sides of the reverse side of the flexible PCB.

[0045] Among them, the rigid reinforcing plate refers to a supporting material with high stiffness, which can be specifically realized by using a rigid PCB substrate. Its function is to constrain the deformation of the flexible PCB through a rigid structure and ensure the flatness of the process edge during the chip mounting process. The flexible reinforcing plate refers to a material with high-temperature resistance characteristics and certain deformation ability, which can be specifically realized by using a high-temperature-resistant flexible plastic plate. Its function is to maintain good physical stability in a high-temperature environment.

[0046] Specifically, the rigid reinforcing plate offsets the stress received by the flexible PCB during the chip mounting process through rigid support, so that the process edge and the chip mounting area are coplanar. For example, in scenarios that require high-precision chip mounting, the rigid PCB substrate can provide a stable reference plane. In processes such as high-temperature reflow soldering, the flexible reinforcing plate avoids thermal deformation through the material's temperature resistance characteristics. For example, the flexible plastic plate can maintain its structural integrity at 260 °C, while allowing the flexible PCB to bend moderately during transportation. The selective configuration of the two types of reinforcing plates enables the process design to be adapted and adjusted according to the parameters of the chip mounting equipment, the ambient temperature, and the PCB size.

[0047] Through the above technical solution, the present application can flexibly select the type of reinforcement plate according to the temperature conditions and mechanical constraints of the chip mounting process. For example, a soft plastic plate is used to prevent heat stress concentration in the high-temperature soldering process, and a rigid substrate is used to ensure the positioning accuracy in the precision chip mounting process, thereby expanding the applicable scenarios of the flexible PCB chip mounting and positioning process.

[0048] The present application further proposes that the rigid reinforcement plate is a rigid PCB substrate.

[0049] Among them, the rigid PCB substrate refers to a rigid circuit board substrate made of a composite material of epoxy resin and glass fiber. Specifically, an FR-4 board can be used to achieve it, and its flexural strength range can be 200-400 MPa. This material supports the flexible PCB process edge through its own rigidity and can effectively offset the deformation caused by mechanical stress in the chip mounting process.

[0050] Specifically, when the rigid PCB substrate is used as a support carrier in the reinforcement plate structure, its linear expansion coefficient range can be 13-17 ppm / °C, which is similar to the expansion coefficient range of 16-25 ppm / °C of the flexible PCB substrate. In the reflow soldering process, when the temperature reaches 260 °C, the thermal deformation difference between the rigid PCB substrate and the flexible PCB body does not exceed 0.05 mm, so as to ensure that the matching accuracy between the positioning hole and the tray positioning pin is maintained within the range of ±0.02 mm. This substrate can be directly cut and formed by a PCB CNC milling machine during processing, and the thickness tolerance is controlled within ±0.05 mm. The copper foil layer on its surface can be etched to form an adhesive surface matching the flexible PCB process edge. The thickness of the rigid PCB substrate can be selected between 1 mm and 2 mm.

[0051] Through the above technical solution, the present application realizes the synchronism of the thermal expansion behavior between the reinforcement plate and the flexible PCB. In the temperature cycle test, the position offset of the chip mounting area can be reduced to 30% of that of traditional materials. When the rigid PCB substrate is used as a reinforcement material, its dielectric constant range of 4.2-4.5 matches that of the flexible PCB dielectric layer, avoiding the impedance mutation problem during high-frequency signal transmission. This substrate can directly reuse the CNC drilling equipment of the PCB factory during processing, and the positioning accuracy of the positioning hole is improved to the level of ±0.01 mm.

[0052] The present application further proposes that the soft reinforcement plate is a heat-resistant soft plastic plate.

[0053] Among them, the high-temperature resistant flexible plastic plate refers to a plastic material that can maintain stable physical properties within the temperature range of the chip mounting process. Specifically, polyimide or polyether ether ketone materials can be used to achieve this. Such materials have low thermal expansion coefficients and anti-softening characteristics in high-temperature environments, avoiding dimensional deformation caused by temperature changes. The flexible plastic plate refers to a thin plate with bendable properties. Specifically, a flexible polymer sheet with a thickness that can be selected between 1 mm and 2 mm can be used to achieve this. Its elastic modulus adapts to the bending requirements of the flexible PCB, providing local support while not restricting the overall deformation of the substrate.

[0054] Specifically, in the chip mounting process, the high-temperature resistant flexible plastic plate is pasted on the reverse side of the process edge of the flexible PCB, forming a rigid support area with the positioning holes. When the positioning pins on the tray are inserted into the positioning holes, the flexible plastic plate maintains the shape stability of the positioning holes through its high-temperature resistance characteristics, preventing the positioning holes from shifting due to material softening during the high-temperature reflow soldering process. At the same time, the bending characteristics of the flexible plastic plate allow the flexible PCB to bend naturally in the non-chip mounting area, avoiding stress concentration caused by rigid support. Thus, the process edge and the chip mounting area can still maintain planar consistency in a high-temperature environment, ensuring the position accuracy of the mounted components.

[0055] Through the above technical solution, the present application achieves dynamic balance of the positioning structure during the chip mounting process: the high-temperature resistance characteristic solves the problem of deformation failure of soft materials at high temperatures, while the flexible characteristic avoids physical property conflicts between the reinforcement plate and the flexible PCB, thereby ensuring that the chip mounting area always maintains flat positioning during the high-temperature process.

[0056] See Figures 2 to 6 , the present invention also provides a positioning device for a flexible PCB, including a tray 1. In the middle of the tray 1, there is a planar convex platform 11 for carrying the chip mounting area of the flexible PCB reinforcement plate. On both sides of the planar convex platform 11, there are accommodating areas 12 for accommodating the first reinforcement plate. In the accommodating areas 12, there are positioning pins 13. The thickness of the planar convex platform 11 is equal to the thickness of the first reinforcement plate 21 or / and the second reinforcement plate on the flexible PCB reinforcement plate. When the flexible PCB reinforcement plate 2 is laid on the tray 1, the positioning pins 13 just insert into the positioning holes 22 of the flexible PCB reinforcement plate, and the positioning pins 13 are lower than the plane of the positioning holes. Keep the chip mounting area 23 of the flexible PCB reinforcement plate 2 and the process edge 24 in the same plane.

[0057] Among them, the planar convex platform 11 refers to the planar area that bulges upward in the middle of the tray. Specifically, it can be processed and formed using metal materials or engineering plastics. Its thickness is equal to that of the reinforcement plate, so that the patch area and the process edge are on the same plane. The accommodating area 12 refers to the structure that is recessed on both sides of the planar convex platform 11 of the tray 1 (it can be a groove or a recess), and can be specifically formed by milling process, and is used to accommodate the reinforcement plate and limit its displacement. The positioning pin 13 refers to the cylindrical positioning element arranged in the accommodating area 12, which can be specifically made of stainless steel or other hard materials with low thermal expansion coefficient and high temperature resistance. Its diameter is slightly smaller than the aperture of the positioning hole 22 to achieve clearance fit, and the insertion depth does not exceed the thickness of the positioning hole 22 to avoid interference.

[0058] Specifically, when the flexible PCB reinforcement plate is laid on the tray, the first reinforcement plate 21 is embedded in the accommodating area 12 and is horizontally limited by inserting the positioning pin 13 into the positioning hole 22. The supporting surface of the planar convex platform 11 is consistent with the thickness of the reinforcement plate, so that the patch area and the process edge form a continuous and flat surface. The top of the positioning pin is lower than the top surface of the positioning hole 22 (it is best to only insert it into the first reinforcement plate 21 or / and the second reinforcement plate 25), ensuring that the components will not be blocked by the needle body during the patching operation. Through mechanical limitation and geometric matching, the flexible PCB maintains a rigid support state during the patching process, avoiding mounting deviation caused by material deformation.

[0059] Compared with the prior art, the negative pressure adsorption method requires the configuration of a vacuum generating device and a sealing structure, the magnetic adsorption method relies on magnetic materials and it is difficult to control the uniformity of the adsorption force, and the clamping and tensioning method requires the setting of a complex jaw mechanism. This solution can achieve the positioning function only through the physical constraints of the matching of the planar convex platform thickness and the insertion of the positioning pin into the positioning hole, without the need for an additional power source or precision drive components.

[0060] Through the above technical solution, the present application simplifies the structural complexity of the positioning device, eliminates the manual operation error, ensures that the patch area and the process edge are on the same plane, and solves the problem of poor component soldering caused by local collapse or warping of the flexible PCB during the patching process. The matching accuracy between the positioning pin and the positioning hole is controlled within 0.05 mm, and the mounting requirement with a repeat positioning accuracy of ±0.1 mm can be achieved.

[0061] The present application further proposes to provide a second reinforcement plate 25 on the opposite side of the remaining process edge on the reverse side of the flexible PCB. The first reinforcement plate 21 and the second reinforcement plate 25 form an integral framework; second positioning holes 251 are provided on the remaining process edge and the second reinforcement plate 25, and second positioning pins 131 are provided relative to the second positioning holes 251, and the second positioning pins 131 are inserted into the second positioning holes 251.

[0062] Among them, the second reinforcing plate 25 refers to a support structure added in the process edge area not covered by the first reinforcing plate 21, which can be specifically implemented by using a rigid PCB substrate or a high-temperature resistant flexible plastic plate with the same thickness as the first reinforcing plate 21. Its function is to supplement the rigid support in the non-strengthened area. The overall frame refers to a closed-loop support structure jointly formed by the first reinforcing plate 21 and the second reinforcing plate 25, which is specifically realized by continuously arranging the reinforcing plates around the process edge. Its function is to eliminate the deformation tendency caused by insufficient local rigidity in the process edge area.

[0063] Specifically, when the first reinforcing plate 21 only covers a pair of opposite sides, there is still a lack of support in the process edge area not covered. By adding the second reinforcing plate 25 to the remaining process edge, a continuous surrounding structure is formed by the two groups of reinforcing plates along the four sides, forming a closed-loop mechanical support system. This frame avoids warping deformation in the non-strengthened area by evenly distributing the supporting force of the reinforcing plates. At the same time, the integrity of the frame keeps the process edge and the chip area in the same plane all the time, ensuring the alignment accuracy between the pads and the component pins during the chip mounting process.

[0064] This solution fundamentally eliminates the local support blind area by constructing a complete frame-type support system, enabling uniform rigid constraints on the four sides of the flexible PCB, and avoiding local collapse or warping problems caused by discontinuous support.

[0065] Through the above technical solution, this application effectively solves the problem of deteriorated flatness of the flexible PCB during the chip mounting process due to insufficient local support. By providing global rigid constraints through the overall frame, it ensures that the chip area and the process edge always maintain planar consistency, avoiding component offset or solder joint void defects caused by PCB deformation.

[0066] This application further proposes that the first reinforcing plate 21 is a rigid reinforcing plate or a flexible reinforcing plate.

[0067] Among them, the rigid reinforcing plate refers to a support material with high rigidity, which can be specifically implemented by using a rigid PCB substrate. Its function is to provide stable support for the flexible PCB and prevent deformation during the chip mounting process. The flexible reinforcing plate refers to a support material with a certain flexibility, which can be specifically implemented by using a high-temperature resistant flexible plastic plate. Its function is to adapt to the bending characteristics of the flexible substrate while maintaining the positioning accuracy, and avoid stress concentration in the material caused by excessive rigidity.

[0068] Specifically, when the soldering process requires rigid support, a rigid reinforcement board is selected to ensure that the flexible PCB remains absolutely flat on the planar boss 11; when the process involves bending or dynamic adjustment, a flexible reinforcement board is selected to allow the flexible PCB to undergo controlled deformation during the positioning process. The selection of the two types of reinforcement boards is determined according to specific process parameters. For example, in the scenario of high-temperature reflow soldering, a heat-resistant flexible plastic board is preferably selected, while in the scenario of high-precision chip mounting, a rigid PCB substrate is selected.

[0069] In some specific embodiments, the thickness of the rigid PCB substrate can match the thickness of the process edge of the flexible PCB. For example, a 1.5-mm FR-4 substrate is used; the flexible plastic board can be a polyimide film, and its temperature resistance range can cover the reflow soldering temperature above 200 degrees Celsius.

[0070] This solution replaces structural optimization through material selection, eliminating the necessity of auxiliary structures while maintaining positioning accuracy.

[0071] Through the above technical solution, the present application enables the positioning device to flexibly switch the material of the reinforcement board according to the rigid requirements of the soldering process, solves the problem of limited applicable scenarios caused by a single material in traditional devices, and at the same time avoids damage to the flexible substrate or positioning inaccuracy caused by improper material adaptation.

[0072] The present application further proposes that the rigid reinforcement board uses a rigid PCB substrate, and the flexible reinforcement board uses a heat-resistant flexible plastic board.

[0073] Among them, the rigid PCB substrate refers to a circuit board substrate with high rigidity made of materials such as resin and fiberglass. Specifically, it can be realized by using an FR-4 epoxy glass cloth laminate. Its rigid structure can provide stable support for the process edge, ensuring that the chip mounting area and the process edge are in the same plane.

[0074] Among them, the heat-resistant flexible plastic board refers to a flexible material that can maintain stable physical properties in a high-temperature environment. Specifically, it can be realized by using a polyimide film or a polyether ether ketone film. Its flexible characteristics can adapt to the bending requirements of the flexible PCB, and at the same time, the high-temperature resistance characteristics can avoid positioning deviation caused by thermal deformation in the chip mounting process.

[0075] Specifically, the rigid PCB substrate is fixed to the process edge on the reverse side of the flexible PCB as a rigid reinforcement board, using its high rigidity to maintain the shape of the process edge and offset the deformation tendency of the flexible substrate. The heat-resistant flexible plastic board, as a flexible reinforcement board, forms complementary support with the rigid reinforcement board through its own flexibility when bonding to the process edge, and maintains dimensional stability in high-temperature processes such as reflow soldering. When the two are combined to form a reinforcement framework, the rigid part restricts the overall deformation, and the flexible part absorbs local stress, jointly ensuring the flatness of the chip mounting area.

[0076] Compared with the prior art, in traditional positioning devices, the reinforcing plates mostly use a single material. For example, only a metal plate is used to enhance the stiffness, but it cannot adapt to the bending of flexible substrates. Or only an ordinary plastic plate is used, but it is prone to softening and deformation at high temperatures. Through the optimization of material combination in this solution, it not only avoids the complication of the device structure caused by a single metal plate, but also overcomes the defect of insufficient high-temperature stability of ordinary plastic plates, without the need to additionally set up complex cooling structures or reinforcement mechanisms.

[0077] Through the above technical solution, this application solves the problems of redundant device structure and decreased high-temperature chip mounting accuracy caused by improper selection of the reinforcing plate material. The synergistic effect of the rigid PCB substrate and the high-temperature resistant flexible plastic plate not only simplifies the structural complexity of the reinforcing frame in the positioning device, but also ensures the coplanarity of the chip mounting area and the process edge in a high-temperature environment, thereby improving the positioning accuracy and process reliability of component mounting.

[0078] In the present invention, the front side of the flexible PCB refers to the side used for attaching electronic components, and the back side of the flexible PCB refers to the side not used for attaching electronic components.

[0079] The above are only the embodiments of this application and are not used to limit the protection scope of this application. For those skilled in the art, various changes and modifications can be made to this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A patch positioning method for a flexible PCB, characterized in that: The steps include: S1, pasting a first reinforcing plate of a predetermined thickness on at least one pair of opposite sides of the back surface of the flexible PCB relative to the process edge of the flexible PCB; S2. Drilling a plurality of positioning holes in the process edge to form a flexible PCB reinforcement plate, wherein the positioning holes of the flexible PCB reinforcement plate penetrate the process edge and the first reinforcement plate; S3. Lay the flexible PCB reinforcement board on a pallet, wherein the pallet has a planar boss for supporting the patch area of ​​the flexible PCB reinforcement board, and accommodating areas for accommodating the first reinforcement board are provided on both sides of the planar boss, and positioning pins whose positions and quantities are equal to those of the positioning holes are provided in the accommodating areas; when the flexible PCB reinforcement board is laid on the pallet, the positioning pins are just inserted into the positioning holes, and the positioning pins are lower than the plane of the positioning holes; and the patch area of ​​the flexible PCB reinforcement board and the process edge are kept in the same plane.

2. The patch positioning method of the flexible PCB according to claim 1, characterized in that: The at least one pair of opposite sides are long sides of the flexible PCB.

3. The patch positioning method of a flexible PCB according to claim 1 or 2, characterized in that: A second reinforcing plate is also provided on the opposite side of the remaining process edge of the reverse side of the flexible PCB, and the first reinforcing plate and the second reinforcing plate form an integral frame.

4. The patch positioning method of a flexible PCB according to claim 1 or 2, characterized in that: The first reinforcing plate is a hard reinforcing plate or a soft reinforcing plate.

5. The patch positioning method of the flexible PCB according to claim 4, characterized in that: The rigid reinforcing plate is a rigid PCB substrate.

6. The patch positioning method of the flexible PCB according to claim 4, characterized in that: The soft reinforcing plate is a high temperature resistant soft plastic plate.

7. A positioning device for a flexible PCB, characterized in that: The invention comprises a tray (1), wherein a planar boss (11) for carrying a patch area of ​​a flexible PCB reinforcement plate is provided in the middle of the tray (1), a receiving area (12) for receiving a first reinforcement plate is provided on both sides of the planar boss (11), and a positioning pin (13) is provided in the receiving area (12); the thickness of the planar boss (11) is equal to the thickness of the first reinforcement plate (21) or / and the second reinforcement plate on the flexible PCB reinforcement plate; when the flexible PCB reinforcement plate (2) is laid on the tray (1), the positioning pin (13) is just inserted into the positioning hole (22) of the flexible PCB reinforcement plate, and the positioning pin (13) is lower than the plane of the positioning hole; the patch area (23) of the flexible PCB reinforcement plate (2) is kept in the same plane as the process edge (24).

8. The positioning device for a flexible PCB according to claim 7, characterized in that: A second reinforcing plate (25) is also provided on the opposite side of the remaining process edge of the reverse side of the flexible PCB, and the first reinforcing plate (21) and the second reinforcing plate (25) form an integral frame.

9. The positioning device for a flexible PCB according to claim 7 or 8, characterized in that: The first reinforcement plate (21) is a hard reinforcement plate or a soft reinforcement plate.

10. The positioning device for a flexible PCB according to claim 4, characterized in that: The rigid reinforcing plate is a rigid PCB substrate; the flexible reinforcing plate is a high temperature resistant flexible plastic plate.

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