A method of producing a flexible circuit board

Abstract

The application discloses a production method of a flexible circuit board, which comprises the following steps: determining the bad board rate of each mother panel, and screening a target mother panel according to the bad board rate, wherein the target mother panel is a mother panel with a bad board rate within a preset range; performing a steel sheet reinforcing process on a non-defective unit board in the target mother panel; dividing each target mother panel to screen a non-defective unit board; combining a plurality of non-defective unit boards to form a virtual panel, and sending the virtual panel as a standard panel into an SMT production line for mounting processing to prepare a flexible circuit board. In the application, the mother panel with a too high bad board rate is accurately screened by setting the preset range, and the non-defective unit board in the mother panel is separately processed and recombined, so that the overall production efficiency and material utilization rate can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of flexible circuit board technology, and more particularly to a method for producing flexible circuit boards. Background Technology

[0002] In the production of flexible printed circuit boards (FPCs), to improve production and turnover efficiency, the conventional practice is to combine multiple independent unit boards (e.g., in the form of 4-panel panels) into a single panel for overall processing and turnover. Due to the intricate circuit design and complex manufacturing process of multilayer FPCs, their overall production yield is typically low, often below 70%. However, in existing production processes, even if a panel contains multiple defective unit boards (e.g., a 4-panel panel contains 2 or 3 defective boards), the entire board will still continue to flow into the subsequent surface mount technology (SMT) process. This forces expensive SMT equipment to perform a series of ineffective operations such as solder paste printing and component placement on a large number of defective boards that should have been discarded, severely limiting the effective capacity of the equipment and reducing overall production efficiency. Simultaneously, attaching reinforcing steel sheets and other auxiliary materials to these defective boards in earlier processes also results in direct material waste. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for producing flexible circuit boards, so as to solve the problem of equipment capacity waste and material waste caused by too many defective boards flowing into the SMT process in the existing flexible circuit board production process.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for producing a flexible circuit board, comprising:

[0005] Determine the defect rate of each mother panel, and select target mother panels based on the defect rate. The target mother panels are those with a defect rate within a preset range.

[0006] A steel sheet reinforcement process is performed on the defect-free unit plates in the target mother panel;

[0007] Each target mother panel is divided into sub-panels to select defect-free unit panels;

[0008] Multiple defect-free unit boards are combined to form a virtual panel, and the virtual panel is sent to the SMT production line as a standard panel for mounting processing to prepare flexible circuit boards.

[0009] Optionally, determining the defect rate of each mother panel includes:

[0010] Obtain the electrical performance test results of each unit board in the mother panel, and determine whether each unit board is a defective unit board based on the electrical performance test results;

[0011] The defect rate of each mother panel is determined based on the number of defective unit panels in each mother panel.

[0012] Optionally, a steel sheet reinforcement process is performed on the defect-free unit plates in the target mother panel, including:

[0013] The defective unit panels in the target mother panel are marked;

[0014] The defect-free unit plates that are not marked in the target mother panel are reinforced with steel sheets using a reinforcement machine.

[0015] Optionally, each of the target mother panels is divided into sub-panels to screen out defect-free unit panels, including:

[0016] Each of the target mother panels is punched to divide the target mother panel into multiple independent unit panels;

[0017] By determining whether each individual unit panel has been reinforced with steel sheets;

[0018] If the unit panel has been reinforced with steel sheets, the unit panels with steel sheet reinforcement are screened out, thereby selecting the defect-free unit panels.

[0019] Optionally, multiple defect-free unit boards are combined to form a virtual panel, including:

[0020] Obtain a PI carrier film, the PI carrier film corresponding to the panel layout of the mother panel, and the PI carrier film having multiple adhesive areas for temporarily fixing the defect-free unit panel;

[0021] The multiple defect-free unit boards are removably fixed to the corresponding adhesive areas of the PI carrier film to form the virtual panel.

[0022] Optionally, the adhesive area is provided with a plurality of high-temperature resistant double-sided adhesives arranged in a curved manner. The high-temperature resistant double-sided adhesives have a weak adhesive side and a strong adhesive side. The strong adhesive side is bonded to the PI carrier film, and the weak adhesive side is used to bond the defect-free unit board.

[0023] Optionally, the plurality of defect-free unit plates are removably fixed to the corresponding adhesive areas of the PI carrier film, including:

[0024] Obtain a splicing fixture, the splicing fixture including a base for fixing the PI carrier film and a cover plate detachably disposed on the base;

[0025] Based on the base and the cover plate, auxiliary operations are performed to temporarily fix the multiple defect-free unit boards onto the corresponding adhesive areas of the PI carrier film, thereby forming the virtual panel.

[0026] Optionally, auxiliary operations are performed based on the base and the cover plate to temporarily fix the plurality of defect-free unit boards to the corresponding adhesive areas of the PI carrier film, thereby forming the virtual panel, including:

[0027] The PI carrier film and the cover plate are sequentially installed on the base. The cover plate is provided with a plurality of guide holes corresponding to the positions of the adhesive areas. The guide holes are used to expose the corresponding adhesive areas on the PI carrier film.

[0028] Through the guide holes, each of the defect-free unit boards is guided one by one and placed on the corresponding adhesive area on the PI carrier film, and pressure is applied to fix it.

[0029] After all the adhesive areas on the PI carrier film are fixed with defect-free unit plates, the cover plate is removed to obtain the virtual panel.

[0030] Optionally, the base is provided with a positioning pin, and both the PI carrier film and the cover plate are provided with positioning holes; correspondingly, the PI carrier film and the cover plate are sequentially installed on the base, including:

[0031] The PI carrier film and the fixture cover are sequentially positioned on the base using the positioning PIN and the positioning hole.

[0032] Optionally, the production method may further include:

[0033] Positioning marks for SMT equipment positioning are provided on the edge of the PI carrier film, and the position of the positioning marks is consistent with the position of the board edge identification marks of the standard panel.

[0034] After the virtual panel is fed into the SMT production line, the positioning of the virtual panel is completed by identifying the positioning mark and the unit identification mark carried by each defect-free unit board, so that the SMT equipment can perform solder paste printing and component placement.

[0035] The beneficial effects of this invention are as follows: By introducing a defective board rate screening mechanism, accurate identification and pre-processing of mother panels containing defective boards are achieved. This allows for steel reinforcement only on defect-free unit boards within the target mother panel, avoiding ineffective reinforcement work on defective boards and saving on steel auxiliary material costs. Simultaneously, by recombining multiple defect-free unit boards into a virtual panel, it ensures that most panels entering the SMT production line are valid boards, preventing SMT equipment from performing ineffective placement operations on defective boards, significantly improving the effective output and equipment utilization rate of the SMT production line. In summary, by accurately screening mother panels with defective board rates within a preset range (e.g., excessively high defective board rates) and separately processing and recombining the good boards within them, mother panels with defective board rates within the preset range are prevented from directly entering the SMT production line, reducing equipment capacity waste and material waste, thereby improving the overall production process efficiency and material utilization rate. Attached Figure Description

[0036] Figure 1 This is a flowchart of the steps in one embodiment of the flexible circuit board manufacturing method described in this invention.

[0037] Figure 2 This is a schematic diagram of the structure of the PI carrier film according to one embodiment of the present invention.

[0038] Figure 3 This is a cross-sectional schematic diagram of the PI carrier film described in one embodiment of the present invention.

[0039] Figure 4 This is a cross-sectional schematic diagram of one embodiment of the splicing fixture described in this invention.

[0040] Figure 5 This is a schematic diagram of the cover plate according to one embodiment of the present invention.

[0041] Figure 6 This is a schematic diagram of the structure of the base described in one embodiment of the present invention.

[0042] Figure 7 This is a top view of the flexible circuit board manufacturing method of the present invention, after the PI carrier film is placed on the base.

[0043] Figure 8 This is a top view of the production method described in this invention, after the cover film has been placed on the base.

[0044] Figure 9 This is a schematic diagram of the defect-free unit board according to one embodiment of the present invention.

[0045] Figure 10 This is a top view of the production method described in this invention, after two defect-free unit boards are placed in the adhesive area through guide holes.

[0046] Figure 11 This is a top view of one embodiment of the virtual puzzle panel described in this invention.

[0047] Label Explanation:

[0048] 1. Virtual panel; 11. Defect-free unit panel;

[0049] 2. PI carrier film; 21. High-temperature resistant double-sided adhesive; 22. Positioning marks;

[0050] 3. Assembly fixture; 31. Base; 32. Positioning pin; 33. Cover plate; 34. Guide hole; 35. Positioning hole. Detailed Implementation

[0051] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0052] In the production of flexible printed circuit boards (FPCs), the overall yield is typically low (e.g., below 70%) due to the intricate wiring and complex processes of multilayer FPCs. In production, multiple unit boards (e.g., 4-panel boards) are usually assembled into panels for processing and transfer. In existing processes, even if a panel contains multiple defective boards (e.g., 2 or 3 defective boards in a 4-panel board), the entire board still flows into the subsequent SMT assembly process. This forces expensive SMT equipment to perform solder paste printing and component placement on a large number of invalid defective boards, severely reducing the effective capacity of the equipment and overall production efficiency. Furthermore, attaching reinforcing steel sheets and other auxiliary materials to defective boards also results in direct material waste.

[0053] Therefore, this invention provides a method for manufacturing flexible circuit boards. This method significantly improves the effective output and resource utilization of SMT (Surface Mount Technology) production lines by screening, removing defective boards, and reassembling good boards from a flexible circuit board panel before the surface mount technology (SMT) process. Specifically, please refer to... Figure 1 The method for producing flexible circuit boards provided by the present invention includes the following steps:

[0054] S1, determine the defect rate of each mother panel, and select the target mother panel based on the defect rate. The target mother panel is the mother panel with a defect rate within a preset range.

[0055] S2, perform a steel sheet reinforcement process on the defect-free unit plate 11 (i.e. good plate) in the target mother panel;

[0056] S3, each of the target mother panels is divided into panels to select defect-free unit panels 11;

[0057] S4, multiple defect-free unit boards 11 are combined to form a virtual panel 1, and the virtual panel 1 is sent to the SMT production line as a standard panel for mounting processing to prepare a flexible circuit board.

[0058] As can be seen from the above description, the beneficial effects of the present invention are as follows: By introducing a defective board rate screening mechanism, accurate identification and pre-processing of mother panels containing defective boards are achieved, thereby performing steel sheet reinforcement processes only on the defect-free unit boards 11 in the target mother panel, avoiding ineffective reinforcement operations on defective boards and saving steel sheet auxiliary material costs; at the same time, by recombining multiple defect-free unit boards 11 into a virtual panel 1, it is ensured that the panels entering the SMT production line are mostly effective boards, avoiding ineffective placement operations of defective boards by SMT equipment, and significantly improving the effective output and equipment utilization rate of the SMT production line. In summary, by accurately screening mother panels with defective board rates within a preset range (such as those with excessively high defective board rates), and separately processing and recombining the good boards among them, mother panels with defective board rates within the preset range are prevented from directly entering the SMT production line, reducing equipment capacity waste and material waste, thereby improving the efficiency of the overall production process and material utilization rate.

[0059] In an optional embodiment, determining the defect rate of each mother panel includes: obtaining the electrical performance test results of each unit board in the mother panel, determining whether each unit board is a defective unit board based on the electrical performance test results, and determining the defect rate of each mother panel based on the number of defective unit boards (i.e., defective boards) in each mother panel.

[0060] It should be noted that the term "mother panel" refers to an intermediate product in the flexible circuit board manufacturing process, where multiple independent unit panels are combined into a large panel for overall processing and transfer. In practical applications, a single mother panel can contain multiple unit panels (e.g., 4-panel panels, 6-panel panels, etc.). Therefore, the aforementioned defect rate = number of defective unit panels in each mother panel ÷ number of unit panels in each mother panel. The aforementioned preset range can be selected according to actual conditions, such as 45%-90%. For example, assuming the preset range is 45%-90%, and there are two mother panels, where the first mother panel has a defect rate of 25% calculated after electrical performance testing, and the second mother panel has a defect rate of 75%, then the second mother panel can be identified as the target mother panel.

[0061] In practical applications, the electrical performance test results refer to the data conclusions obtained from the electrical performance testing of each unit board on the entire motherboard during the manufacturing process of flexible circuit boards at key process nodes (usually before the reinforcement process). The testing mainly includes the measurement of parameters such as circuit continuity (e.g., open and short circuits), insulation resistance, and key network impedance (the specific settings can be made according to the actual situation). The test results will clearly determine whether each unit board is qualified (i.e., defect-free unit board 11 / good board) or has defects (i.e., defective unit board / bad board), and form data records that can be identified, statistically analyzed, and recalled by the process.

[0062] As described above, the objective quantification of the failure rate of each mother panel based on the electrical performance test results provides a clear and reliable data basis for selecting target mother panels, avoiding subjective judgment or random processing.

[0063] In an optional embodiment, a steel sheet reinforcement process is performed on the defect-free unit plates 11 in the target mother panel, including: marking the defective unit plates in the target mother panel; and performing a steel sheet reinforcement process on the unmarked defect-free unit plates 11 in the target mother panel using a reinforcement machine.

[0064] In practical applications, after the FPC completes its first punching process, based on the electrical performance test results, panels containing a predetermined number of defective boards (especially those containing 3 defective boards, e.g., a defect rate of 75%) are screened out. For these panels, only the good boards undergo a steel sheet reinforcement process, while the defective boards are not reinforced to save materials. These panels are then subjected to a second punching and splitting process to create independent unit boards. Afterward, all the good boards obtained after splitting are collected for subsequent reassembly and use. It should be noted that the steel sheet reinforcement process refers to attaching a reinforcing plate to specific areas of the flexible circuit board (such as connectors, component mounting areas, etc.) to increase the mechanical strength and support of that area, preventing deformation, breakage, or poor contact during subsequent processing or use.

[0065] As can be seen from the above description, the strategy of first marking the defective boards and then selectively reinforcing them directly avoids the ineffective process of attaching steel sheets to the defective unit boards, thus saving reinforcement materials and production time at the source and reducing production costs.

[0066] In an optional embodiment, each target mother panel is divided into sub-panels to select defect-free unit panels 11, including: punching each target mother panel to divide it into multiple independent unit panels; determining whether each independent unit panel has been reinforced with steel sheets; if the unit panel has been reinforced with steel sheets, selecting the unit panels with steel sheet reinforcement, thereby selecting defect-free unit panels 11.

[0067] As described above, physical separation of boards is achieved through punching, and the completion of reinforcement is used as an intuitive criterion for screening good boards. This makes the separation of good and bad boards simple and reliable, and facilitates subsequent collection and reorganization.

[0068] In optional embodiments, such as Figures 6 to 11 As shown, assembling multiple defect-free unit panels 11 to form a virtual panel 1 includes: obtaining a PI carrier film 2, the PI carrier film 2 corresponding to the panel layout of the mother panel, and the PI carrier film 2 having multiple adhesive areas for temporarily fixing the defect-free unit panels 11; and removably fixing the multiple defect-free unit panels 11 to the corresponding adhesive areas of the PI carrier film 2, thereby forming the virtual panel 1. The PI carrier film 2 is a polyimide carrier film.

[0069] As described above, the PI carrier film 2 is used as the base carrier of the virtual panel 1. The defect-free unit board 11 is temporarily fixed in a removable manner through the preset adhesive area. This not only ensures the positional stability of the unit board during the SMT processing, but also facilitates the smooth removal of the finished board after processing. At the same time, the corresponding design of the PI carrier film 2 and the mother panel layout ensures the compatibility of the virtual panel 1 with the standard panel, and it can be put into production directly without modifying the existing SMT equipment.

[0070] In optional embodiments, such as Figure 1 As shown, the adhesive area is provided with a plurality of high-temperature resistant double-sided adhesives 21 arranged in a curved manner. The high-temperature resistant double-sided adhesives 21 have a weak adhesive side and a strong adhesive side. The strong adhesive side is bonded to the PI carrier film 2, and the weak adhesive side is used to bond the defect-free unit board 11.

[0071] It should be noted that after the SMT assembly process is completed, the finished unit board needs to be removed from the PI carrier film 2. At this time, if the area of ​​the high-temperature resistant double-sided adhesive 21 on the adhesive area is too large or the adhesive force is too strong, it will cause difficulties in removing the board and may cause product wrinkles. To address this, the area of ​​the adhesive area can be reduced, such as by making the high-temperature resistant double-sided adhesive 21 curved (e.g., S-shaped), which can reduce the adhesive strength between the adhesive and the unit board, thereby ensuring smooth board removal and preventing product damage.

[0072] In practical applications, the high-temperature resistant double-sided adhesive 21 pre-placed on the PI carrier film 2 can be arranged in a local dot or frame shape to avoid contaminating the solder pads or precision areas on the unit board.

[0073] As described above, by using the high-temperature resistant double-sided adhesive 21 design, while ensuring the bonding strength meets the requirements of SMT processing, the bonding characteristics of the weak adhesive surface and the defect-free unit board 11 are utilized to achieve convenient attachment and non-destructive removal of the unit board; the curved layout reduces the contact area between the adhesive and the unit board, reduces the risk of adhesive residue, and facilitates board removal.

[0074] In optional embodiments, such as Figures 6 to 11 As shown, fixing the plurality of defect-free unit panels 11 to the corresponding adhesive areas of the PI carrier film 2 in a removable manner includes: obtaining a splicing fixture 3, the splicing fixture 3 including a base 31 for fixing the PI carrier film 2 and a cover plate 33 detachably disposed on the base 31; performing auxiliary operations based on the base 31 and the cover plate 33 to temporarily fix the plurality of defect-free unit panels 11 to the corresponding adhesive areas of the PI carrier film 2, thereby forming the virtual splice 1.

[0075] As described above, the splicing fixture 3, consisting of a base 31 and a cover plate 33, is introduced to assist in the precise assembly of the PI carrier film 2 and the defect-free unit plate 11, thereby improving the assembly efficiency and accuracy of the virtual panel 1.

[0076] In optional embodiments, such as Figures 6 to 11 As shown, auxiliary operations are performed based on the base 31 and the cover plate 33 to temporarily fix the plurality of defect-free unit plates 11 onto the corresponding adhesive areas of the PI carrier film 2, thereby forming the virtual panel 1. This includes: sequentially installing the PI carrier film 2 and the cover plate 33 onto the base 31, wherein the cover plate 33 has a plurality of guide holes 34 corresponding to the positions of the adhesive areas, the guide holes 34 being used to expose the corresponding adhesive areas on the PI carrier film 2; guiding each defect-free unit plate 11 one by one through the guide holes 34 and placing it onto the corresponding adhesive area on the PI carrier film 2, and applying pressure to fix it; after all adhesive areas on the PI carrier film 2 are fixed with defect-free unit plates 11, removing the cover plate 33 to obtain the virtual panel 1.

[0077] In practical applications, a specially made 0.1mm thick high-temperature resistant polyimide carrier film can be prepared in advance. This polyimide carrier film has high-temperature resistant double-sided adhesive 21 pre-placed at the unit board positions corresponding to the original panel layout, and four board edge positioning marks 22, identical to those on the original panel and identifiable by SMT equipment, are made on its edges. Simultaneously, a dedicated splicing fixture 3 is used, with a base 31 equipped with positioning pins 32 and a cover plate 33 equipped with guide holes 34 matching the shape of the unit board. The guide holes 34 are 0.06mm larger on each side than the FPC unit board in the critical area used for limiting the unit board, while the remaining auxiliary positioning areas can be appropriately enlarged to facilitate placement and removal. Then, the PI carrier film 2 is placed on the positioning pins 32 of the fixture base 31 and the cover plate 33 is closed. The operator uses the exposed guide holes 34 on the cover plate 33 to precisely place and adhere the boards one by one to the pre-placed adhesive areas on the carrier film. Once all the unit boards on the carrier film have been properly pasted, a "fully OK" virtual panel 1 composed of all the good boards is formed. At this point, it can be sent to the SMT production line as a standard panel for subsequent processes such as solder paste printing and component mounting.

[0078] As can be seen from the above description, the precise alignment design between the guide hole 34 on the cover plate 33 and the adhesive area enables precise guidance of the placement position of the defect-free unit board 11, avoiding the decrease in SMT mounting accuracy caused by unit board misalignment.

[0079] In optional embodiments, such as Figure 1 as well as Figure 6 As shown, a positioning pin 32 is provided on the base 31, and positioning holes 35 are provided on both the PI carrier film 2 and the cover plate 33. Correspondingly, the PI carrier film 2 and the cover plate 33 are installed on the base 31 in sequence, including: positioning the PI carrier film 2 and the fixture cover plate 33 on the base 31 in sequence through the positioning pin 32 and the positioning holes 35.

[0080] As described above, the use of the mating structure of positioning PIN 32 and positioning hole 35 enables rapid and accurate alignment between the PI carrier film 2, cover plate 33 and base 31, thereby improving positioning accuracy and assembly efficiency.

[0081] In optional embodiments, such as Figure 1As shown, the production method of the flexible circuit board may further include: setting a positioning mark 22 (such as a MARK point) for SMT equipment positioning on the edge of the PI carrier film 2, the position of the positioning mark 22 being consistent with the position of the board edge identification mark of the standard panel; after the virtual panel 1 is sent into the SMT production line, the positioning of the virtual panel 1 is completed by identifying the positioning mark 22 and the unit identification mark carried by each defect-free unit board 11, so that the SMT equipment can perform solder paste printing and component mounting.

[0082] In practical applications, the defect-free unit board 11 used for reassembly can retain unit positioning marks 22 for equipment identification, which together with the board edge positioning marks 22 on the carrier film ensure the accuracy of SMT equipment positioning.

[0083] As described above, positioning marks 22 identical to those on the standard panel are set on the PI carrier film 2, so that the recombined virtual panel 1 can be accurately identified and positioned in the SMT equipment just like the standard board, ensuring its seamless compatibility with the existing SMT production line and achieving high-precision mounting without equipment modification.

[0084] To make this application easier to understand, the following is combined with... Figures 6 to 11 An exemplary application is provided. In this exemplary application, the method for producing the flexible circuit board is mainly implemented based on an FPC reassembly device, as detailed below.

[0085] First, the FPC recombination device includes a PI carrier film 2 and a splicing fixture 3.

[0086] like Figure 1 as well as Figure 2 As shown, the PI carrier film 2 is made of high-temperature resistant polyimide material with a thickness of 0.1 mm. A localized high-temperature resistant double-sided adhesive 21 with a thickness of 0.03 mm is pre-applied to the PI carrier film 2, with the weakly adhesive side facing outwards. This allows for temporary fixation of the defect-free unit board 11 before SMT mounting and facilitates its easy removal after mounting. The edges of the PI carrier film 2 also have positioning marks 22 (such as MARK points) for SMT equipment identification and positioning.

[0087] like Figure 3 , Figure 4 as well as Figure 5As shown, the splicing fixture 3 comprises two parts: a base 31 and a cover plate 33. The base 31 is 6-8 mm thick and has positioning pins 32 consistent with standard splicing fixtures. The cover plate 33 is made of 0.4-0.5 mm thick steel plate and has guide holes 34 that correspond to the positions of standard splicing unit boards and are slightly larger than the unit boards. In use, the PI carrier film 2 is fixed to the base 31 by the positioning pins 32, and the cover plate 33 covers the PI carrier film 2, guiding the operator to accurately paste the good board onto the designated adhesive position on the PI carrier film 2 through its guide holes 34.

[0088] Second, the manufacturing method of flexible circuit boards

[0089] Taking FPC 4-panel production as an example, its overall yield is about 65%. After completing electrical performance testing and sorting, it was found that about 20% of the mother panels were in a "1 good, 3 bad" state.

[0090] Step 1: Separate these "1 good, 3 bad" mother panels and mark the bad panels (e.g., by applying black Mark points). Then proceed to the steel sheet reinforcement process. The reinforcement machine identifies the black Mark points and only applies steel sheets to the good panels that are not marked, while skipping the reinforcement process for the three marked bad panels, thus saving the corresponding materials.

[0091] Step Two: After completing all the preceding processes, the batch of mother panels is separated into individual unit panels. Defective panels without reinforcement are then removed, and all good panels are collected for later use.

[0092] Step 3: First, take a pre-made PI carrier film 2 (see...) Figure 1 The membrane has four local adhesive areas A1, A2, A3, and A4 that correspond perfectly to the standard 4-panel layout, and edge identification and positioning marks 22 (i.e., M1, M2, M3, and M4) are made on the edge. Figure 7 As shown, the PI carrier film 2 is placed on the base 31 of the splicing fixture 3 (see...). Figure 6 Place the positioning hole 35 into the positioning pin 32 of the base 31, and then cover it with the cover plate 33 (see Figure 8 Afterwards, the operator takes four well-collected boards in sequence (each board has its own cell MARK points), such as... Figure 5 , Figure 9 As shown in Figure 10, each board is accurately placed in its corresponding position and gently pressed through the corresponding positioning grooves B1, B2, B3, and B4 on the cover plate 33 (the groove size is 0.03–0.05 mm larger on each side than the unit board's outline) to ensure it is firmly adhered to the preset adhesive area of ​​the PI carrier film 2.

[0093] Step 4: Remove fixture cover plate 33 and inspect the reassembled virtual panel 1. (Example:) Figure 11 As shown, at this point, a fully-featured panel consisting of four independent good boards, equipped with a complete positioning MARK point system (including board edge MARK points M1–M4 and the unit MARK points of each good board itself), is assembled. After being sent to the SMT production line, the equipment can perform precise solder paste printing and component placement on it, just like processing standard panels.

[0094] Based on the above method, the good boards of a panel that could only produce one effective product due to three defective boards can be utilized and recombined with the good boards in other panels to form a 100% good product processing unit, thereby fully releasing the capacity of SMT equipment and improving overall production efficiency and resource utilization.

[0095] In summary, the flexible circuit board production method provided by this invention: First, by ensuring that all panels entering the SMT production line are good products, the ineffective processing of defective boards by the equipment is completely eliminated, which can increase the effective output efficiency of SMT equipment by more than 30%, especially significantly improving the production efficiency of batches with high defect rates. Second, this method enables the early identification and rejection of defective boards, avoiding the waste of valuable materials such as steel reinforcement, solder paste, and electronic components on defective boards, thereby saving production costs. In addition, the PI carrier film 2 and fixture design used in the reassembly system are fully compatible with existing SMT equipment and can be directly applied without modifying the production line. Moreover, this method is flexible and can dynamically adjust the reassembly strategy according to the actual distribution of defective boards. Finally, the fixture design takes into account ergonomics, and the guide hole 34 is appropriately enlarged to facilitate pick-and-place operations, making the overall method easy to implement in the production line and improving the convenience and stability of operation.

[0096] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for producing a flexible circuit board, characterized in that, include: Determine the defect rate of each mother panel, and select target mother panels based on the defect rate. The target mother panels are those with a defect rate within a preset range. A steel sheet reinforcement process is performed on the defect-free unit plates in the target mother panel; Each target mother panel is divided into sub-panels to select defect-free unit panels; Multiple defect-free unit boards are combined to form a virtual panel, and the virtual panel is sent to the SMT production line as a standard panel for mounting processing to prepare flexible circuit boards. The process of combining multiple defect-free unit boards to form a virtual panel includes: A PI carrier film is obtained, which corresponds to the panel layout of the mother panel and has multiple adhesive areas on it for temporarily fixing the defect-free unit panel. Multiple high-temperature resistant double-sided adhesives are arranged in a curved manner on the adhesive areas. The high-temperature resistant double-sided adhesives have a weak adhesive side and a strong adhesive side. The strong adhesive side is bonded to the PI carrier film, and the weak adhesive side is used to bond the defect-free unit panel. The multiple defect-free unit boards are removably fixed to the corresponding adhesive areas of the PI carrier film to form the virtual panel.

2. The production method according to claim 1, characterized in that, Determining the defect rate of each mother panel includes: Obtain the electrical performance test results of each unit board in the mother panel, and determine whether each unit board is a defective unit board based on the electrical performance test results; The defect rate of each mother panel is determined based on the number of defective unit panels in each mother panel.

3. The production method according to claim 1, characterized in that, A steel sheet reinforcement process is performed on the defect-free unit plates in the target mother panel, including: The defective unit panels in the target mother panel are marked; The defect-free unit plates that are not marked in the target mother panel are reinforced with steel sheets using a reinforcement machine.

4. The production method according to claim 1, characterized in that, Each target mother panel is divided into sub-panels to select defect-free unit panels, including: Each of the target mother panels is punched to divide the target mother panel into multiple independent unit panels; By determining whether each individual unit panel has been reinforced with steel sheets; If the unit panel has been reinforced with steel sheets, the unit panels with steel sheet reinforcement are screened out, thereby selecting the defect-free unit panels.

5. The production method according to claim 1, characterized in that, The plurality of defect-free unit plates are removably fixed to the corresponding adhesive areas of the PI carrier film, including: Obtain a splicing fixture, the splicing fixture including a base for fixing the PI carrier film and a cover plate detachably disposed on the base; Based on the base and the cover plate, auxiliary operations are performed to temporarily fix the multiple defect-free unit boards onto the corresponding adhesive areas of the PI carrier film, thereby forming the virtual panel.

6. The production method according to claim 5, characterized in that, Based on the base and the cover plate, auxiliary operations are performed to temporarily fix the plurality of defect-free unit boards onto the corresponding adhesive areas of the PI carrier film, thereby forming the virtual panel, including: The PI carrier film and the cover plate are sequentially installed on the base. The cover plate is provided with a plurality of guide holes corresponding to the positions of the adhesive areas. The guide holes are used to expose the corresponding adhesive areas on the PI carrier film. Through the guide holes, each of the defect-free unit boards is guided one by one and placed on the corresponding adhesive area on the PI carrier film, and pressure is applied to fix it. After all the adhesive areas on the PI carrier film are fixed with defect-free unit plates, the cover plate is removed to obtain the virtual panel.

7. The production method according to claim 5, characterized in that, The base is provided with a positioning pin, and both the PI carrier film and the cover plate are provided with positioning holes; correspondingly, the PI carrier film and the cover plate are sequentially installed on the base, including: The PI carrier film and the fixture cover are sequentially positioned on the base using the positioning PIN and the positioning hole.

8. The production method according to claim 1, characterized in that, Also includes: Positioning marks for SMT equipment positioning are provided on the edge of the PI carrier film, and the position of the positioning marks is consistent with the position of the board edge identification marks of the standard panel. After the virtual panel is fed into the SMT production line, the positioning of the virtual panel is completed by identifying the positioning mark and the unit identification mark carried by each defect-free unit board, so that the SMT equipment can perform solder paste printing and component placement.

Images