A continuous production method and equipment for die-cutting a circuit board with a flexible die-cutting line

Abstract

This invention relates to the field of circuit board die-cutting technology, and specifically discloses a continuous production method and equipment for flexible die-cutting of circuit boards using a circular die-cutting machine. This invention integrates a flatbed die-cutting machine with a circular die-cutting machine, using flatbed die-cutting instead of laser cutting to form circuits on metal foil. While the first flatbed die-cutting machine punches a local contour, it simultaneously forms positioning holes; the second flatbed die-cutting machine uses positioning pins inserted into the positioning holes for nesting cuts. A correction device ensures the stability of the material strip's position in the width direction. A photoelectric sensor monitors the length of the buffer material strip between the flatbed and circular die-cutting machines and controls the automatic start and stop of the equipment, achieving speed matching between the two independent machines and ensuring continuous and stable operation of the production line. By sequentially performing three heating and pressing processes on the circular die-cutting machine, the composite stress is released layer by layer, improving the reliability of interlayer bonding. Ultimately, it achieves integrated continuous production of the entire process, including punching, lamination, forming, testing, and printing.

Description

Technical Field

[0001] This invention relates to the field of circuit board die-cutting technology, and in particular to a continuous production method and equipment for flexible die-cutting of circuit boards using a punching and connecting circular knife. Background Technology

[0002] Existing flexible circuit board manufacturing processes using laser cutting of metal foil to form circuit patterns have inherent drawbacks: laser cutting of ultra-fine lines is prone to ablation, residue, and carbonization at the line edges, resulting in a high defect rate. Furthermore, the processing thickness of the metal foil is limited (below 0.12mm), and the width of the finest line is restricted (above 0.25mm), making it unsuitable for the flexible production needs of products with diverse specifications. In addition, when laser cutting is integrated with rotary cutting, there is a lack of effective mechanisms for matching the material feeding speed and connecting the material strips between the two devices, affecting production continuity and product consistency. Summary of the Invention

[0003] To overcome the problems of affecting production continuity and product consistency when laser cutting and circular die cutting are combined in the existing flexible circuit board production, this invention provides a continuous production method and equipment for flexible die-cut circuit boards using a circular die cutting tool.

[0004] In a first aspect, the present invention provides a continuous production method for flexible die-cutting circuit boards using a circular die-cutting tool, comprising: The metal foil roll is unloaded, so that the metal foil is laminated with the carrier film; The metal foil with the carrier film is conveyed to the flat knife punching station, where the metal foil is punched by the flat knife to form a circuit pattern, and the punched metal foil is automatically discharged to remove the metal waste outside the circuit pattern from the carrier film. The metal foil circuit strip, after being punched and discharged and retained on the carrier film, is conveyed to the rotary die-cutting machine, and then the metal foil circuit strip is corrected by the correction device before entering the rotary die-cutting machine. On the circular die-cutting machine, the metal foil circuit is heated and pressed together with the first insulating film to transfer the metal foil circuit onto the first insulating film. The metal foil circuit with the first insulating film is pressed together with the second insulating film by a second heating and pressing process to form a three-layer composite strip; The three-layer composite strip is then subjected to a third heating and pressing process. The three-layer composite strip, after being heated and pressed for the third time, is then die-cut to obtain a flexible die-cut circuit board semi-finished product.

[0005] According to one specific embodiment, in the above continuous production method, the flatbed punching station includes a first flatbed punching machine and a second flatbed punching machine; the flatbed punching of the metal foil specifically includes: The metal foil coated with the carrier film is punched for the first time using the first flat die cutter to form a partial outline of the circuit pattern and positioning holes; The second flatbed cutter is used to cut along the positioning holes to complete the overall outline punching of the circuit pattern.

[0006] According to one specific implementation, in the above continuous production method, the second flatbed cutter achieves nesting and alignment by inserting a positioning pin on the mold into the positioning hole, with a nesting accuracy of 0.03mm.

[0007] According to a specific implementation, in the above continuous production method, the flat die-cutting station and the rotary die-cutting machine are two independent devices; when the metal foil circuit strip is conveyed from the flat die-cutting station to the rotary die-cutting machine, the length of the buffer strip between the two devices is monitored by a photoelectric sensor probe. When the length of the buffer strip is lower than a preset threshold, the flat die-cutting station or the rotary die-cutting machine is controlled to start or stop, so as to achieve the matching of the online speed of the two devices.

[0008] According to one specific embodiment, in the above continuous production method, the metal foil circuit strip enters the circular die-cutting machine after being corrected by a correction device. The correction device is used to ensure that the strip is positioned stably in the width direction.

[0009] According to one specific embodiment, in the above continuous production method, when the metal foil is punched with a flat blade, the punching speed is 80 times / minute to 210 times / minute, the feeding speed is 20000Hz to 45000Hz, and the tension of the metal foil being fed out is 3N to 12N.

[0010] According to one specific embodiment, in the above continuous production method, the metal foil is any one of aluminum foil, copper foil, or stainless steel foil, the thickness of the metal foil is 0.1 mm to 0.25 mm, and the line width of the metal foil circuit is 0.1 mm to 0.25 mm.

[0011] According to one specific embodiment, in the above continuous production method, the temperatures of the first heating and pressing, the second heating and pressing, and the third heating and pressing are respectively set according to the materials of the first insulating film and the second insulating film; when the insulating film is made of PET material, the heating and pressing temperature is 120°C to 160°C; when the insulating film is made of PI material, the heating and pressing temperature is 150°C to 180°C.

[0012] According to a specific embodiment, in the above continuous production method, when the metal foil strip enters the rotary die-cutting machine, the tension of the metal foil feeding is 12N to 28N; the tensions of the first insulating film and the second insulating film feeding are 12N to 28N respectively; when the material is fed on the rotary die-cutting machine, the speed ratio of the feed roller is set to 0.9990 to 0.9999.

[0013] Secondly, the present invention provides a continuous production equipment for flexible die-cutting circuit boards using a circular die-cutting tool, comprising: The flat blade punching unit is used to punch metal foil with a carrier film to form circuit patterns and automatically discharge metal waste outside the circuit patterns. A circular die-cutting machine is installed after the flat die-cutting unit; A connecting unit, connected between the flat blade punching unit and the rotary blade die-cutting machine, includes a correction device and a photoelectric sensor. The correction device is used to correct the position of the metal foil circuit material strip output from the flat blade punching unit in the width direction before feeding it into the rotary blade die-cutting machine. The photoelectric sensor is used to monitor the length of the buffer strip between the flat blade punching unit and the rotary blade die-cutting machine to achieve speed matching between the two devices. The circular die-cutting machine is equipped with: The first heating and pressing unit is used to heat and press the metal foil circuit to the first insulating film, so that the metal foil circuit is transferred to the first insulating film; The second heating and pressing unit is used to heat and press the metal foil circuit with the first insulating film onto the second insulating film to form a three-layer composite strip. The third heating and pressing unit is used to heat and press the three-layer composite strip. The forming and die-cutting unit is used to form and die-cut the three-layer composite strip after heating and pressing to obtain a flexible die-cut circuit board semi-finished product.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention integrates a flatbed die-cutting machine with a rotary die-cutting machine, replacing laser cutting with flatbed die-cutting for metal foil circuit forming. This solves the inherent defects of laser cutting ultra-fine circuits, such as ablation, residue, and edge carbonization, and avoids the problem of high circuit defect rates. By forming positioning holes while the first flatbed die-cutting machine punches the local contour, and the second flatbed die-cutting machine inserts positioning pins into the positioning holes for nesting, the correction device ensures the stability of the material strip position in the width direction, providing a precision foundation for the subsequent high-precision alignment and lamination of the insulating film and metal foil circuits. By monitoring the length of the buffer material strip between the flatbed die-cutting machine and the rotary die-cutting machine with a photoelectric sensor and controlling the automatic start and stop of the equipment, the speed matching of the two independent machines is achieved, ensuring the continuous and stable operation of the production line. By performing three heating and pressing operations sequentially on the rotary die-cutting machine, the composite stress is released layer by layer, improving the reliability of the interlayer bonding force, and finally realizing the integrated continuous production of the entire process of punching, lamination, forming, inspection, and printing. Attached Figure Description

[0015] Figure 1 A schematic flowchart of a continuous production method for flexible die-cutting circuit boards using a circular punch for punching and connecting wires, provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the flat blade punching unit and the connecting unit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the circular die-cutting machine provided in an embodiment of the present invention. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0017] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0018] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0019] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0020] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0021] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0022] This invention relates to the field of continuous production of flexible die-cut circuit boards. Flexible die-cut circuit boards refer to flexible circuit board products that use a flexible insulating film (such as polyimide PI film or polyester PET film) as the substrate and metal foil (such as copper foil or aluminum foil) as the conductive circuit layer. This invention integrates a flatbed die-cutting machine with a rotary die-cutting machine, using flatbed die-cutting to replace laser cutting for circuit shaping of the metal foil, and relying on the rotary die-cutting machine to complete subsequent processes such as insulating film lamination and shape shaping, achieving fully automated continuous production.

[0023] In the description of this invention, flatbed die cutting refers to a processing method in which a hard steel blade generates shear stress on the coil material under uniform vertical pressure at the moment the upper and lower dies of a metal die close, causing the material to separate and form along the blade contour. Flatbed die cutting equipment refers to an independent device equipped with a metal die cutting mold capable of performing the above-mentioned die cutting action. A rotary die cutting machine refers to a device that uses a cylindrical rotating blade to continuously die-cut the coil material, with multiple sets of feeding shafts, blade holders, pressure rollers, heating rollers, and other functional units arranged sequentially along the material feeding direction.

[0024] In this invention, the flat blade punching machine and the circular blade die-cutting machine are two independent pieces of equipment. They are physically connected and speed matched through a correction device and a buffer mechanism, forming a complete continuous production line.

[0025] Please refer to Figure 1 This document illustrates a flowchart of a continuous production method for flexible die-cutting circuit boards using a circular die-cutting tool according to an embodiment of the present invention. The method includes: Step 1: Unload the metal foil roll to bond the metal foil with the carrier film.

[0026] Specifically, the metal foil roll is installed on the feeding shaft at the front end of the flat knife equipment, and the carrier film is released at the same time, so that the metal foil and the carrier film are combined and laminated at the same station.

[0027] The metal foil is any one of aluminum foil, copper foil, or stainless steel foil, with a thickness of 0.1 mm to 0.25 mm. The carrier film supports the metal foil strip, enhancing its tensile strength and feeding stability, and preventing breakage or deformation during punching and conveying. The tension during metal foil feeding is set to 3 N to 12 N, and the tension during carrier film feeding is set to 15 N to 35 N to ensure the strip remains flat and without stretching or slack during punching, while also preventing stretching and deformation due to excessive tension.

[0028] Step 2: The metal foil with the carrier film is conveyed to the flat knife punching station, where the metal foil is punched by the flat knife to form a circuit pattern. The punched metal foil is then automatically discharged to remove the metal waste outside the circuit pattern from the carrier film.

[0029] Specifically, the composite strip enters the flatbed punching station. In this embodiment, the flatbed punching station includes a first flatbed punching machine and a second flatbed punching machine. The composite strip is first fed to the first flatbed punching machine for the first punching. The first flatbed punching machine is equipped with a metal punching die designed according to the local contour of the circuit pattern. During punching, the upper die moves downward, and the hard steel blade cuts into the metal foil under vertical pressure. When the shear stress exceeds the tensile strength of the metal foil, the material separates along the blade contour, forming the local contour of the circuit pattern. At the same time, the die punches positioning holes at predetermined positions on the metal foil. After punching, the metal foil waste automatically falls out through the discharge hole at the bottom of the die and is discharged into the waste hopper, while the circuit pattern retained after the first punching is retained on the carrier film.

[0030] The parameters for the first punching are set as follows: punching speed is 80 to 210 times per minute, and material feeding speed is 20,000 Hz to 45,000 Hz. Punching speed refers to the number of times the upper die descends per minute, and material feeding speed refers to the drive frequency of the feeding motor. The equipment is equipped with an adjustable button to adjust this frequency. Die depth refers to the matching stroke of the upper and lower dies. After each set of metal dies is installed, the stroke height is gradually adjusted until the die completely cuts through the metal foil. The locked stroke height at this point is the set depth of the die. For example, for a combination of PET insulating film and 0.2mm aluminum foil substrate, the depth to completely cut through the substrate is adjusted to 26.9mm.

[0031] After the first punching, the main strip enters the second flatbed die machine via the feeding shaft for a second punching, also known as a nesting cut. The second flatbed die machine is equipped with a metal punching die designed according to the overall outline of the circuit pattern, and it has positioning pins. After the strip enters the second flatbed die machine, the positioning pins on the die insert into the positioning holes formed during the first punching, achieving precise alignment between the strip and the die, with an alignment accuracy of 0.03mm. Based on the alignment completed by the positioning pins, the second flatbed die machine performs a second punching on the metal foil, completing the overall outline of the circuit pattern. The parameters for the second punching are consistent with those for the first punching: a punching speed of 80 to 210 times per minute and a drawing speed of 20,000 Hz to 45,000 Hz.

[0032] After two punching processes, a complete circuit pattern and a waste area are formed on the strip. The strip then enters the next flatbed die for waste removal, removing the metal waste outside the circuit pattern from the carrier film, leaving only the precision conductive lines with a line width of 0.1mm to 0.25mm on the carrier film.

[0033] The circuit pattern is formed by a flat-blade punching method, avoiding the ablation, residue, and edge carbonization problems associated with laser cutting. The positioning holes are formed by partial punching of the first flat-blade machine, and the positioning pins of the second flat-blade machine are inserted into the positioning holes to achieve precise nesting. This method ensures the relative positional accuracy of the circuit pattern between multiple punching operations, and keeps the key dimensional tolerances stably within ±0.03mm. The punching waste is automatically discharged through the die discharge hole, realizing the automatic separation of the circuit and the waste, eliminating the need for manual cleaning.

[0034] Step 3: The metal foil circuit strip, after being punched and discharged and retained on the carrier film, is conveyed to the rotary die-cutting machine, so that the metal foil circuit strip is corrected by the correction device and then enters the rotary die-cutting machine.

[0035] Specifically, the flatbed punching station and the rotary die-cutting machine are two independent pieces of equipment, physically connected and speed-matched by a connecting unit. The connecting unit includes a photoelectric sensor and a deviation correction device.

[0036] A photoelectric sensor is positioned in the buffer area between the flatbed die-cutting station and the rotary die-cutting machine to monitor the length of the buffer strip between the two machines. Its working principle is as follows: there may be a slight difference between the output speed of the flatbed die-cutting station and the feeding speed of the rotary die-cutting machine, causing the length of the buffer strip to change dynamically. When the length of the buffer strip is sufficient for the photoelectric sensor to detect, both machines operate normally. When the length of the buffer strip falls below a preset threshold (e.g., the strip is too short for the photoelectric sensor to detect), the photoelectric sensor sends a signal to control either the flatbed die-cutting station or the rotary die-cutting machine to pause operation. The machine automatically restarts once the length of the buffer strip returns to the normal range. This online speed matching mechanism enables automatic coordination between the two independent machines.

[0037] The web-aligning device is located before the feed inlet of the rotary die-cutting machine. After being aligned by the web-aligning device, the metal foil circuit strip enters the rotary die-cutting machine. The web-aligning device is used to ensure the stability of the strip's position in the width direction (Y direction), ensuring that the strip is always in the calibrated Y-direction position, providing a basis for positional accuracy for the subsequent alignment and bonding of the insulating film.

[0038] By monitoring the length of the buffer strip with a photoelectric sensor and controlling the start and stop of the equipment, automatic online speed matching between the flat knife punching station and the rotary knife die-cutting machine is achieved, avoiding strip breakage or accumulation caused by speed mismatch. The correction device ensures the stability of the strip position in the width direction, creating conditions for high-precision alignment and lamination of the insulating film and metal foil circuit in the subsequent process.

[0039] Step 4: On the circular die-cutting machine, the metal foil circuit and the first insulating film are subjected to a first heating and pressing process, so that the metal foil circuit is transferred onto the first insulating film.

[0040] Specifically, the first insulating film is a PI or PET film coated with thermosetting adhesive, used to cover and protect one side of the circuit pattern, serving as electrical insulation and physical support. The first insulating film is released from the feed shaft at the front end of the rotary die-cutting machine, with the feed tension set to 12N to 28N. Before entering the heating and pressing station, the first insulating film can be pre-cut in a partial shape by a pre-forming die holder to form an alignment contour that matches the circuit pattern.

[0041] The first heating and pressing process is performed on a primary heating roller. The heating roller is equipped with heating elements that heat the roller surface to a set value and maintain a constant temperature. The metal foil circuit strip and the first insulating film enter the heating roller assembly from different directions and are bonded together under the pressure of the heating roller. The temperature of the heating roller causes the thermosetting adhesive layer on the first insulating film to reach its activation temperature, producing adhesion. Under the pressure of the heating roller, the metal foil circuit is transferred from the carrier film and bonded to the first insulating film. After the transfer is complete, the carrier film is peeled off from the back of the metal foil and recycled by the take-up shaft, while the metal foil circuit remains on the first insulating film.

[0042] The temperature for the first heating and pressing is set according to the material of the first insulating film: when the insulating film is made of PET, the heating and pressing temperature is 120℃ to 160℃; when the insulating film is made of PI, the heating and pressing temperature is 150℃ to 180℃. This temperature range ensures that the thermosetting adhesive layer is fully activated to achieve a stable bond, while avoiding thermal deformation of the insulating film due to excessive temperature. The speed ratio for the first heating and pressing is set to 0.9990 to 0.9999.

[0043] By heating and pressing, the precision circuit pattern, which has been die-cut, is transferred from the carrier film to the first insulating film, thus achieving the initial composite of the circuit pattern and the insulating substrate, laying the foundation for subsequent double-sided packaging.

[0044] Step 5: The metal foil circuit with the first insulating film is pressed together with the second insulating film by a second heating and pressing process to form a three-layer composite strip.

[0045] Specifically, the second insulating film is also a PI or PET film coated with thermosetting adhesive, used to cover the other side of the circuit pattern. The second insulating film is released from the feeding shaft at the rear end of the rotary die-cutting machine, with the feeding tension set to 12N to 28N, and can also be pre-cut in part by pre-forming the shape of the die holder.

[0046] The second heating and pressing is performed on a secondary heating roller. The metal foil circuit with the first insulating film pressed on it (at this point, the circuit pattern is exposed) and the second insulating film enter the heating roller group respectively, and are bonded together under the rolling pressure of the heating rollers. The thermosetting adhesive layer on the second insulating film is activated at the heating temperature, covering and bonding the other side of the metal foil circuit pattern, thereby completely encapsulating the circuit pattern between the first and second insulating films, forming a three-layer composite strip consisting of the first insulating film, the metal foil circuit pattern, and the second insulating film.

[0047] The temperature for the second heating and pressing is the same as that for the first heating and pressing, and is also set according to the insulating film material: 120℃ to 160℃ for PET material and 150℃ to 180℃ for PI material. The first and second insulating films can be made of the same material or different materials, depending on the product design requirements. The speed ratio for the second heating and pressing is set to 0.9990 to 0.9999.

[0048] The circuit pattern is covered and encapsulated by a second heating and pressing process, forming a complete three-layer composite structure of "insulation layer-conductive layer-insulation layer", which provides double-sided electrical insulation and physical protection for the circuit pattern.

[0049] Step 6: Perform a third heating and pressing of the three-layer composite strip.

[0050] Specifically, the third heating and pressing is performed on three-stage heating rollers. After the three-layer composite strip is output from the second heating and pressing station, it directly enters the third heating and pressing station, where it undergoes heating and pressing again under the action of the heating rollers.

[0051] The temperature for the third heating and pressing is consistent with the first two heating and pressing processes, and is also set according to the insulating film material: 120℃ to 160℃ for PET material and 150℃ to 180℃ for PI material. The speed ratio for the third heating and pressing is set to be synchronized with the main traction speed.

[0052] The purpose of the third heating and pressing is to further strengthen the bonding of the three-layer material that has already undergone preliminary lamination at high temperatures. Specifically, the first two heating and pressing processes completed the transfer of side A and the bonding of side B, respectively. However, due to the limited time of each heating and pressing, the activation of the thermosetting adhesive layer may not be sufficient, and there may be tiny interfacial gaps or stress concentrations between the layers. Through the reheating and pressurization of the third heating and pressing, the thermosetting adhesive layer can be reactivated and penetrated, further eliminating tiny gaps between the layers, releasing the internal stress of the composite layer, and allowing the three-layer material to achieve a more complete bonding state.

[0053] Furthermore, process verification showed that within the set temperature range (120-160℃ for PET material and 150-180℃ for PI material), the three-stage heating rollers could achieve good composite effects using either the same temperature or differentiated temperature gradients. For example, experimental groups 7 and 8 used differentiated temperature gradients of 130℃-140℃-150℃ and 155℃-165℃-175℃ respectively, both achieving good interlayer bonding effects. This indicates that the temperature range set by the present invention has good process tolerance, further supporting the high-speed and stable operation of the production line.

[0054] By adding a third heating and pressing process as a reinforcement step, the interlayer bonding force between the first insulating film, the second insulating film and the intermediate metal foil is significantly enhanced, and the delamination and bubble defect rate is reduced to less than 1%, ensuring the reliability of composite strength under high-efficiency continuous production rhythm.

[0055] Step 7: The three-layer composite strip after the third heating and pressing is die-cut to obtain a flexible die-cut circuit board semi-finished product.

[0056] Specifically, the shape forming die-cutting is performed at the shape die-cutting station. This station is equipped with a shape punching die designed according to the final outer contour of the product. After the three-layer composite strip continuously feeds into the shape die-cutting station, the shape punching die cuts or partially cuts the strip to form the overall shape, separating independent flexible die-cut circuit board semi-finished products with the target shape from the continuous strip.

[0057] After the shape is formed and die-cut, the resulting flexible die-cut circuit board semi-finished product continues to be conveyed forward with the conveyor belt to enter the subsequent testing and marking processes.

[0058] The beneficial effect of this step is that by separating individual products from the continuous strip through shape forming die cutting, the entire forming process of flexible die-cut circuit boards from roll material to semi-finished products is completed.

[0059] In one possible implementation, after the shape forming and die-cutting, the flexible die-cut circuit board semi-finished product is further subjected to CCD size detection and marking printing.

[0060] CCD dimensional inspection is performed at the CCD inspection station. This station is equipped with a high-resolution industrial camera and a light source. When the semi-finished flexible die-cut circuit board passes through the CCD inspection station with the material conveyor belt, the industrial camera takes high-speed pictures of the key external dimensions, hole position accuracy, line spacing, and other preset inspection items of each product. The inspection system performs real-time calculation and analysis based on the captured images to determine whether the product dimensions are qualified.

[0061] The label printing is performed at the printing station, located after the CCD inspection station. Based on the inspection results of the CCD inspection system, the printing device prints corresponding label information on the surface of each passing product. For example, for products that pass inspection, a pass label and product serial number are printed; for products that fail inspection, a fail label or defect mark is printed to facilitate subsequent sorting and removal.

[0062] By integrating CCD size detection and marking printing into a continuous production line, the entire process of punching, laminating, forming, detection, and printing can be completed online in one go. This eliminates the cumbersome offline inspection and subsequent manual sorting and marking processes in traditional processes, thereby improving production efficiency and quality management.

[0063] The effectiveness of the above-mentioned process parameters of the present invention is verified by multiple sets of experimental data.

[0064] For example, this invention conducted multiple sets of experiments to verify different substrate types and process conditions. Experimental groups 1 to 10 covered various material combinations such as PET+aluminum foil, PI+copper foil, PET+stainless steel, and PI+aluminum foil, as well as different process conditions such as the median value, lower limit value, upper limit value of parameter ranges, and differentiated temperature gradients. The process parameters and processing effects of each experimental group are shown in Tables 1 and 2.

[0065] Table 1. Verification data of process parameters for flexible die-cutting circuit boards using a circular die-cutting tool.

[0066] Table 2. Verification Data of Process Parameters for Flexible Die-Cutting Circuit Boards with Circular Blade for Punching Connection (b)

[0067] Among them, experimental groups 1 and 2 used the middle value of the parameter range for standard production conditions, experimental groups 3 and 4 used the lower limit of the parameter range test, experimental groups 5 and 6 used the upper limit of the parameter range test, experimental groups 7 and 8 used the differentiated temperature gradient test, experimental group 9 used the stainless steel substrate compatibility test, and experimental group 10 used the PI+aluminum foil substrate compatibility test.

[0068] Referring to Table 1, in each experimental group, the actual line width tolerance was controlled within ±0.03mm, the critical dimension tolerance was controlled within ±0.03mm, the interlayer bonding strength reached above 0.8N / mm, the delamination and bubble defect rate was below 1%, the cutting defect rate was below 1%, the overall yield reached above 98.5%, and the production efficiency reached 3m / min to 6m / min. The verification results show that the flat blade punching parameters (punching speed 80-210 times / minute, material pulling speed 20000-45000Hz, material release tension 3-12N), the circular blade composite parameters (insulating film release tension 12-28N, carrier film release tension 15-35N, speed ratio 0.9990-0.9999), and the three hot pressing temperature ranges (PET material 120-160℃ / PI material 150-180℃) set by the present invention can stably achieve high-precision circuit forming and reliable interlayer bonding under the conditions of covering various conductive substrates such as aluminum foil, copper foil, and stainless steel foil, as well as various insulating film materials such as PET and PI.

[0069] Furthermore, for different material combinations, the present invention systematically verified the parameters of the entire process through multiple sets of embodiments.

[0070] For example, as shown in Table 3, the adaptation parameters and corresponding processing effects of seven typical material combinations are given. Among them, the basic general-purpose type uses PET thermosetting adhesive film with aluminum foil; the thin PI type uses thin PI film (≤0.05mm) with aluminum foil, suitable for high-density circuit boards; the medium-thick PI copper foil type uses medium-thick PI film (0.05mm-0.125mm) with copper foil, suitable for conventional rigid-flexible composite boards; the thick PI copper foil type uses thick PI film (≥0.125mm) with copper foil, suitable for high-rigidity flexible circuit boards; the stainless steel substrate type uses stainless steel conductive substrate with PET thermosetting adhesive film, suitable for circuit boards with high conductivity and high heat dissipation requirements; the thin copper foil PET type uses copper foil with PET thermosetting adhesive film, suitable for fine line etching; and the thick copper foil PI type uses copper foil with PI film, suitable for high-current circuits.

[0071] Table 3. Adaptation Parameters for Multi-Material Punching Circular Blade Process of Flexible Circuit Boards

[0072] Referring to Table 3, for different material combinations, the flat blade cutting speed is set to 80-210 cuts / minute, the appropriate feeding speed is set to 20000-45000Hz, the flat blade feeding shaft tension is set to 3-12N, and the circular blade feeding shaft tension is set to 12-28N. The hot pressing temperature is set according to the insulating film material: 120-150℃ or 120-160℃ for PET material and 150-180℃ for PI material. This adaptation parameter table verifies the versatility and parameter standardization of the technical solution of this invention under multiple material conditions. Switching products only requires adjusting the parameters to start production, without modifying the equipment structure.

[0073] On the other hand, the present invention also provides a continuous production equipment for die-cutting circuit boards using a circular die-cutting tool, for performing the above-described continuous production method. For example... Figure 2 and Figure 3 As shown, the equipment includes a flat blade punching unit, a connecting unit, and a circular blade die-cutting machine.

[0074] The flatbed punching unit is located at the front end of the production line and is used to punch metal foil with a carrier film to form circuit patterns, and automatically discharge metal scrap outside the circuit patterns. The flatbed punching unit includes a first flatbed punch and a second flatbed punch. The first flatbed punch is equipped with a metal punching die designed according to the partial contour of the circuit pattern, used to perform the first punching of the metal foil with the carrier film to form the partial contour of the circuit pattern and positioning holes. The second flatbed punch is equipped with a metal punching die designed according to the overall contour of the circuit pattern. The die is equipped with positioning pins, which are used to insert into the positioning holes formed by the first punching to achieve nesting and alignment, completing the overall contour punching of the circuit pattern. The nesting accuracy can reach 0.03mm.

[0075] The rotary die-cutting machine is installed after the flat die-cutting unit and is used to perform processes such as insulating film lamination and shape forming.

[0076] The connecting unit connects the flatbed die-cutting unit and the rotary die-cutting machine, and includes a correction device and a photoelectric sensor. The correction device corrects the width of the metal foil strip output from the flatbed die-cutting unit before feeding it into the rotary die-cutting machine. The photoelectric sensor monitors the length of the buffer strip between the flatbed die-cutting unit and the rotary die-cutting machine. When the length of the buffer strip is lower than a preset threshold, it controls the start / stop of the flatbed die-cutting station or the rotary die-cutting machine to achieve speed matching between the two independent devices.

[0077] The rotary die-cutting machine is equipped with the following components along the material feeding direction: The first heating and pressing unit is used to heat and press the metal foil circuit onto the first insulating film, so that the metal foil circuit is transferred onto the first insulating film. The first heating and pressing unit includes a primary heating roller, which is equipped with a heating element inside to heat the roller surface to a set temperature. The temperature is set according to the insulating film material: 120-160℃ for PET material or 150-180℃ for PI material.

[0078] The second heating and pressing unit, located after the first heating and pressing unit, is used to heat and press the metal foil circuit with the first insulating film onto the second insulating film to form a three-layer composite strip. The second heating and pressing unit includes a two-stage heating roller, and the heating temperature is consistent with that of the first heating and pressing unit.

[0079] The third heating and pressing unit, located after the second heating and pressing unit, is used to heat and press the three-layer composite strip. The third heating and pressing unit includes three stages of heating rollers, and the heating temperature is consistent with the first two heating and pressing processes.

[0080] The forming and die-cutting unit, located after the third heating and pressing unit, is used to perform shape forming and die-cutting on the three-layer composite strip after heating and pressing, to obtain a flexible die-cut circuit board semi-finished product. The forming and die-cutting unit includes a shape punching die.

[0081] Optionally, the equipment also includes a CCD detection unit and a printing unit. The CCD detection unit is located after the forming and die-cutting unit and is used to perform dimensional detection on the flexible die-cut circuit board semi-finished product. The printing unit is located after the CCD detection unit and is used to mark and print on the flexible die-cut circuit board semi-finished product after the dimensional detection has been completed.

[0082] It should be noted that the above units are arranged sequentially along the material feeding direction. The flat blade punching unit and the rotary blade die-cutting machine are connected and synchronized through the connecting unit. The roll material is continuously and uninterruptedly fed, and the entire process of continuous operation is completed in one go, including metal foil feeding, lamination with the carrier film, flat blade punching, waste removal, correction and alignment, A-side transfer, B-side bonding, three-time heating reinforcement, shape forming and die-cutting, CCD inspection and marking printing.

[0083] The following is based on Figure 2 and 3 The following explanation uses an 18-station circular die-cutting machine as an example. In actual implementation, the number of stations can be adjusted according to the specific configuration of the production line.

[0084] First, the metal foil roll is mounted on the feeding shaft at the front end of the flat-blade machine, and the carrier film is released simultaneously. The tension of the metal foil feeding shaft is set to 3~12N, and the tension of the carrier film feeding shaft is set to 15~35N to ensure that the strip is flat and free from stretching and slack during the punching process, while avoiding stretching and deformation of the strip due to excessive tension.

[0085] After the metal foil and the carrier film are laminated, they are conveyed to the flatbed punching station for circuit punching and forming. The flatbed punching station includes a first flatbed punch and a second flatbed punch. The laminated strip first enters the first flatbed punch for the first punching. The first flatbed punch is equipped with a metal punching die designed according to the local contour of the circuit pattern. During punching, the upper die moves downward, and the hard steel blade cuts into the metal foil under vertical pressure. When the shear stress exceeds the tensile strength of the metal foil, the material separates along the blade contour, forming the local contour of the circuit pattern. At the same time, the die punches positioning holes at predetermined positions on the metal foil. The parameters for the first punching are set as follows: punching speed of 80 to 210 times / minute, and material pulling speed of 20,000 Hz to 45,000 Hz. After punching, the scrap metal foil automatically falls out through the discharge hole at the bottom of the die and is discharged into the waste hopper.

[0086] After the first punching, the main strip feeds through a feed shaft into a second flatbed die for a second punching, or nesting cut. The second flatbed die is equipped with a metal punching die designed according to the overall outline of the circuit pattern, and it has positioning pins. After the strip enters the second flatbed die, the positioning pins on the die insert into the positioning holes formed during the first punching, achieving precise alignment between the strip and the die, with a nesting accuracy of 0.03mm. Based on the alignment achieved by the positioning pins, the second flatbed die performs a second punching on the metal foil, completing the overall outline of the circuit pattern. The parameter settings for the second punching are consistent with those for the first punching.

[0087] After two punching processes, the strip enters the next flatbed cutting machine for waste removal. Metal waste outside the circuit pattern is removed from the carrier film, leaving only the precision conductive lines with a forming line width of 0.1mm to 0.25mm on the carrier film.

[0088] The metal foil circuit strip, after being cut by a flatbed die-cutting machine, enters the rotary die-cutting machine through a connecting unit between two independent machines. The connecting unit includes a photoelectric sensor and a deviation correction device. The photoelectric sensor is located in the buffer area between the flatbed die-cutting station and the rotary die-cutting machine to monitor the length of the buffer strip between the two machines. When the length of the buffer strip is lower than a preset threshold, the photoelectric sensor sends a signal to control the start and stop of either the flatbed die-cutting station or the rotary die-cutting machine, achieving automatic speed matching between the two independent machines. The deviation correction device is located before the feed inlet of the rotary die-cutting machine. After being corrected by the deviation correction device, the metal foil circuit strip enters the rotary die-cutting machine. The deviation correction device ensures the stability of the strip's position in the width direction (Y direction), ensuring that the strip is always in the calibrated Y-direction position.

[0089] After correction, the metal foil circuit material strip enters the circular die-cutting machine and passes through stations G1 to G18 to complete subsequent processing.

[0090] At station G1, the feed rate of the material strip is initially adjusted after entering the rotary die-cutting machine to match the running speed of the machine.

[0091] Further, a first insulating film (A-side insulating film, which can be PET or PI film) coated with thermosetting adhesive on one side of the roll material is mounted on the feeding shaft at the front end of the rotary die-cutting machine, with the feeding shaft tension set to 12~28N. This insulating film is asynchronously die-cut at the G5 cutter holder to form the required local shape alignment contour, with the G5 cutter holder speed ratio set to 0.9990~0.9999. After die-cutting, the first insulating film's speed ratio is adjusted by the G6 cutter holder to synchronize with the main material strip.

[0092] Subsequently, the metal foil circuit strip entering the rotary die-cutting machine via the correction device merges with the first insulating film exported from the G6 cutter head at station G4. Station G4 is a primary heating roller composite station, with its speed ratio set to be synchronized with the main traction speed. The heating temperature is set according to the insulating film material: when the insulating film is made of PET, the temperature is controlled at 120~160℃; when the insulating film is made of PI, the temperature is controlled at 150~180℃. At this temperature, the thermosetting adhesive layer on the first insulating film is fully activated, allowing it to stably adhere to the metal foil circuit layer, and simultaneously transferring the metal foil circuit from the carrier film to the first insulating film, forming a preliminary single-sided composite layer structure.

[0093] Further, a second insulating film (B-side insulating film, which can be PET or PI film) coated with thermosetting adhesive on one side of the roll material is mounted on the feeding shaft at the rear end of the rotary die-cutting machine, with the feeding shaft tension set to 12~28N. This insulating film is asynchronously die-cut at the G9 cutter holder to form the required local shape alignment contour, with the G9 cutter holder speed ratio set to 0.9990~0.9999. After die-cutting, the second insulating film's speed ratio is adjusted at the G8 cutter holder to synchronize with the main material strip.

[0094] The single-sided composite layer obtained at station G4 is joined with the second insulating film at station G7. Station G7 is a two-stage heated roller composite station with a speed ratio set to 0.9990~0.9999. The heating temperature is also set according to the insulating film material: 120~160℃ for PET and 150~180℃ for PI. The thermosetting adhesive layer on the second insulating film is fully activated at this temperature, allowing it to stably bond with the other side of the metal foil circuit in the single-sided composite layer, forming a three-layer composite strip of first insulating film-metal foil-second insulating film.

[0095] Further, the three-layer composite strip enters station G10. Station G10 is a three-stage heated roller composite station, with its speed ratio set to be synchronized with the main traction. The heating temperature is still set according to the insulating film material: 120~160℃ for PET and 150~180℃ for PI. This step applies additional heat and pressure to further strengthen the bonding of the three-layer material that has completed the initial composite process at high temperature. This allows the thermosetting adhesive layer to be reactivated and penetrated, further eliminating micro-gaps between layers and releasing internal stress in the composite layer. This significantly enhances the adhesion strength between the upper and lower insulating films and the middle metal foil layer, effectively solving the problems of delamination and bubble defects, and providing a process basis for further increasing the production line operating speed.

[0096] After undergoing three stages of heating and bonding, the three-layer composite strip sequentially enters the G11, G12, G13, and G14 die holders. These stations are equipped with die-cutting molds to define the product's shape, and the speed ratios of all die holders are set to be synchronized with the main traction. Through continuous die-cutting using multiple die holders and multiple processes, the final outline of the flexible die-cut circuit board is formed. Thanks to the quantitative control of flat-blade cutting parameters, material tension, roller speed ratio, and three-stage hot-pressing temperature in the preceding processes, the operating speed of the rotary die-cutting machine in this step can be significantly improved compared to traditional processes, and the die-cutting yield can be consistently maintained at a high level, achieving high-precision and high-efficiency continuous production.

[0097] The semi-finished material strip, after completing its shape formation, enters stations G15 and G16. Here, a CCD vision inspection device integrated into these stations performs real-time synchronous inspections of key dimensions, hole positions, and line spacing, among other preset inspection items. After inspection, the strip enters stations G17 and G18. Here, a coding device integrated into these stations prints pass / fail markings, serial numbers, or batch information onto each product based on the CCD inspection results. This process achieves integrated online completion of punching, lamination, forming, inspection, and printing, eliminating the need for semi-finished product transfer and offline re-inspection, significantly improving production efficiency and reducing labor costs.

[0098] In all the above processes, to maintain the smooth operation of the material strip and the consistency of tension in each section, the corresponding feeding shafts for the metal foil, the first insulating film, the second insulating film, and the carrier film used in each process are arranged on the corresponding feeding shafts at the front, middle, or rear end of the rotary die-cutting machine. The tension of all carrier film feeding shafts is uniformly set to 15~35N, and the speed ratio of all the cutter holders through which the carrier film passes is consistent with the speed ratio of the corresponding main material cutter holder.

[0099] Based on the above technical solution, this embodiment of the invention integrates a flatbed punching machine with a rotary die-cutting machine, using flatbed punching to replace laser cutting for circuit forming on metal foil. This solves the inherent defects of laser cutting ultra-fine circuits, such as ablation, residue, and edge carbonization, achieving stable processing of metal foils with thicknesses from 0.1mm to 0.25mm and line widths from 0.1mm to 0.25mm, avoiding the problem of high circuit defect rates. By forming positioning holes while punching local contours on the first flatbed machine, and then using a second flatbed machine to insert positioning pins into the positioning holes for nesting cuts, a nesting accuracy of 0.03mm is achieved, stably controlling the product's key dimensional tolerances within ±0.03mm. The offset device ensures the stability of the material strip's position in the width direction, providing a precision foundation for the subsequent high-precision alignment and lamination of the insulating film and metal foil circuitry. A photoelectric sensor monitors the length of the buffer material strip between the flatbed and rotary die-cutting machines and controls the automatic start and stop of the equipment, achieving speed matching between the two independent devices and ensuring continuous and stable operation of the production line. By sequentially performing three heating and pressing operations on the rotary die-cutting machine, the composite stress is released layer by layer, reducing the delamination and bubble defect rate to below 1%, improving the reliability of interlayer bonding. Ultimately, it achieves integrated continuous production of the entire process from punching, lamination, forming, inspection, and printing, increasing single-line capacity by 2 to 3 times and supporting high-speed continuous material feeding of up to 6m / min.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A continuous production method for flexible die-cutting circuit boards using a circular punch, characterized in that, include: The metal foil roll is unloaded, so that the metal foil is laminated with the carrier film; The metal foil with the carrier film is conveyed to the flat knife punching station, where the metal foil is punched by the flat knife to form a circuit pattern, and the punched metal foil is automatically discharged to remove the metal waste outside the circuit pattern from the carrier film. The metal foil circuit strip, after being punched and discharged and retained on the carrier film, is conveyed to the rotary die-cutting machine, and then the metal foil circuit strip is corrected by the correction device before entering the rotary die-cutting machine. On the circular die-cutting machine, the metal foil circuit is heated and pressed together with the first insulating film to transfer the metal foil circuit onto the first insulating film. The metal foil circuit with the first insulating film is pressed together with the second insulating film by a second heating and pressing process to form a three-layer composite strip; The three-layer composite strip is then subjected to a third heating and pressing process. The three-layer composite strip, after being heated and pressed for the third time, is then die-cut to obtain a flexible die-cut circuit board semi-finished product.

2. The continuous production method for flexible die-cutting circuit boards using a circular die-cutting knife according to claim 1, characterized in that, The flatbed punching station includes a first flatbed punching machine and a second flatbed punching machine; the flatbed punching machine is used to punch the metal foil, specifically including: The metal foil coated with the carrier film is punched for the first time using the first flat die cutter to form a partial outline of the circuit pattern and positioning holes; The second flatbed cutter is used to cut along the positioning holes to complete the overall outline punching of the circuit pattern.

3. The continuous production method of flexible die-cut circuit boards using a circular die-cutting knife according to claim 2, characterized in that, The second flatbed cutter achieves nesting and alignment by inserting a positioning pin on the mold into the positioning hole, with a nesting accuracy of 0.03mm.

4. The continuous production method for flexible die-cutting circuit boards using a circular die-cutting knife according to claim 1, characterized in that, The flat die-cutting station and the rotary die-cutting machine are two independent devices. When the metal foil strip is conveyed from the flat die-cutting station to the rotary die-cutting machine, the length of the buffer strip between the two devices is monitored by a photoelectric sensor. When the length of the buffer strip is lower than a preset threshold, the flat die-cutting station or the rotary die-cutting machine is controlled to start or stop, so as to achieve the matching of the online speed of the two devices.

5. The continuous production method for flexible die-cutting circuit boards using a circular die-cutting knife according to claim 1, characterized in that, The metal foil strip enters the circular die-cutting machine after being corrected by a correction device. The correction device is used to ensure that the strip is positioned stably in the width direction.

6. The continuous production method of flexible die-cut circuit boards using a circular die-cutting knife according to claim 1, characterized in that, When punching the metal foil with a flat blade, the punching speed is 80 times / minute to 210 times / minute, the feeding speed is 20000Hz to 45000Hz, and the tension of the metal foil being fed out is 3N to 12N.

7. The continuous production method for flexible die-cutting circuit boards using a circular die-cutting knife according to claim 1, characterized in that, The metal foil is any one of aluminum foil, copper foil, or stainless steel foil, and the thickness of the metal foil is 0.1 mm to 0.25 mm; the line width of the metal foil circuit is 0.1 mm to 0.25 mm.

8. The continuous production method of flexible die-cut circuit boards using a circular die-cutting knife according to claim 1, characterized in that, The temperatures of the first heating and pressing, the second heating and pressing, and the third heating and pressing are set according to the materials of the first insulating film and the second insulating film, respectively; when the insulating film is made of PET material, the heating and pressing temperature is 120°C to 160°C; when the insulating film is made of PI material, the heating and pressing temperature is 150°C to 180°C.

9. The continuous production method of flexible die-cut circuit boards using a circular die-cutting knife according to claim 1, characterized in that, When the metal foil strip enters the rotary die-cutting machine, the tension of the metal foil feeding is 12N to 28N; the tensions of the first insulating film and the second insulating film feeding are 12N to 28N respectively; when the material is fed on the rotary die-cutting machine, the speed ratio of the feed roller is set to 0.9990 to 0.9999.

10. A continuous production equipment for die-cutting circuit boards using a circular punch for connecting wires, characterized in that, include: The flat blade punching unit is used to punch metal foil with a carrier film to form circuit patterns and automatically discharge metal waste outside the circuit patterns. A circular die-cutting machine is installed after the flat die-cutting unit; A connecting unit, connected between the flat blade punching unit and the rotary blade die-cutting machine, includes a correction device and a photoelectric sensor. The correction device is used to correct the position of the metal foil circuit material strip output from the flat blade punching unit in the width direction before feeding it into the rotary blade die-cutting machine. The photoelectric sensor is used to monitor the length of the buffer strip between the flat blade punching unit and the rotary blade die-cutting machine to achieve speed matching between the two devices. The circular die-cutting machine is equipped with: The first heating and pressing unit is used to heat and press the metal foil circuit to the first insulating film, so that the metal foil circuit is transferred to the first insulating film; The second heating and pressing unit is used to heat and press the metal foil circuit with the first insulating film onto the second insulating film to form a three-layer composite strip. The third heating and pressing unit is used to heat and press the three-layer composite strip. The forming and die-cutting unit is used to form and die-cut the three-layer composite strip after heating and pressing to obtain a flexible die-cut circuit board semi-finished product.

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