Continuous forming and crimping method for fisheye terminal and wire

Abstract

The invention discloses a continuous forming and crimping method for a fisheye terminal and a wire, and belongs to the technical field of fisheye terminal forming and crimping, and the method comprises the following steps: preparing and feeding a metal strip, and providing a continuous metal strip which is phosphor bronze, beryllium copper or copper alloy material; the multi-station continuous stamping die is adopted, stamping forming of the fisheye terminal and the procedures of automatic feeding, crimping, detecting, cutting and the like of the wire are integrated, integrated continuous production from a metal belt material to a finished product assembly is achieved, the production efficiency is greatly improved, and the labor and equipment input cost is reduced. According to the invention, the multi-stage locking structure and the asymmetric elastic sheet structure are designed at the fisheye elastic sheet part, so that the terminal generates asynchronous deformation and resilience after being inserted into a PCB hole, a torsion effect is formed, the holding force and the anti-vibration and anti-loosening performance of the terminal in the PCB hole are remarkably enhanced, and the service life of the terminal is prolonged. The problems that a traditional fisheye terminal is easy to loosen and poor in contact in a vibration or impact environment are solved.

Description

Technical Field

[0001] This invention relates to the field of fisheye terminal forming and crimping technology, and more specifically, to a continuous forming and crimping method for fisheye terminals and wires. Background Technology

[0002] Fisheye terminals, as a key electronic connection component that enables flexible connection to PCB board holes without soldering, are widely used in automotive electronics, communication equipment, industrial control, and other fields. Existing fisheye terminals are typically formed through a stamping process, followed by manual or semi-automatic crimping with wires to form terminal-wire assemblies for subsequent assembly. With the development of electronic devices towards higher integration and higher reliability, higher requirements are being placed on the connection stability, vibration resistance, electromagnetic compatibility, and production efficiency of fisheye terminals.

[0003] However, existing technologies still have significant shortcomings in terms of production processes and product structure. On the one hand, the production process of traditional fisheye terminals and wires is mostly separated into processes, with stamping, crimping, and testing carried out independently. This is not only inefficient, but also prone to damaging or deforming the precision fisheye springs during intermediate steps, affecting product consistency. On the other hand, the structural design of traditional fisheye terminals is simple, and they are prone to loosening, poor contact, or even rebound failure when subjected to vibration, insertion and extraction forces, or board tolerances, leading to signal interruption. In addition, in high-frequency circuits, ordinary fisheye terminals cannot effectively shield electromagnetic interference leaking through board holes and gaps, making it difficult to meet electromagnetic compatibility requirements. Therefore, improvements are needed.

[0004] Based on this, the present invention designs a continuous forming and crimping method for fisheye terminals and wires to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a continuous forming and crimping method for fisheye terminals and wires, so as to solve the problems mentioned in the background art.

[0006] A continuous forming crimping method for fisheye terminals and wires includes the following steps: S1: Metal strip preparation and feeding A continuous metal strip, which is phosphor bronze, beryllium copper, or copper alloy material, is provided with a thickness of 0.2 mm to 0.8 mm and a width of 5 mm to 20 mm, and is fed into a multi-station continuous stamping die. S2: Fisheye terminal body molding The metal strip is sequentially punched with guide holes, pre-bent, and precision stamped to form the main structure of the fisheye terminal. The main body of the fisheye terminal includes a fisheye spring part and a crimping part. The fisheye spring part is located at the front end of the terminal and is used to elastically contact the hole in the PCB board. The crimping part is located at the rear end of the terminal and is used to crimp the wire. S3: Multi-stage locking structure forming A multi-stage locking structure is formed by stamping on the fisheye spring section. This structure consists of a guide area, a transition area, and a locking area. The guide area is conical or arc-shaped with an angle of 15° to 30°, used to guide the terminal into the PCB board hole. The transition area has an arc-shaped transition surface, used to gradually increase the contact force. The locking area is provided with one or more protrusions or barbs to provide the final holding force. The angle and arc of the guide area, transition area, and locking area are optimized according to the PCB board hole diameter and thickness to achieve a balance between insertion force and extraction force. S4: Asymmetric spring sheet structure forming An asymmetrical spring structure is formed on the fisheye spring section, including a first spring and a second spring. The first spring and the second spring are asymmetrical in geometry, thickness or width, so that they have different stiffness. The thickness of the first spring is 0.1mm to 0.3mm and the width is 0.5mm to 1.5mm. The thickness of the second spring is 0.15mm to 0.35mm and the width is 0.8mm to 1.8mm. When the terminal is inserted into the PCB board hole, the first spring and the second spring produce asynchronous deformation and springback tendencies, forming a torsional effect between the terminal and the board hole, effectively resisting rotational loosening caused by vibration or impact. S5: Stress relief groove forming A stress relief groove is formed by stamping at the root of the spring in the fisheye spring section. The stress relief groove is an arc-shaped groove or a micro-hole structure. The radius of curvature of the arc-shaped groove is 0.05mm to 0.2mm, and the diameter of the micro-hole is 0.1mm to 0.3mm. It is used to disperse the stress concentration generated by the spring during repeated bending, and improve the fatigue resistance and insertion and extraction life of the terminal. S6: Press-fitting part forming A crimping portion is formed by stamping on the metal strip. The crimping portion includes a wire receiving groove and crimping flaps. The wire receiving groove is U-shaped or V-shaped, with a depth of 0.3 mm to 1.0 mm and a width of 0.5 mm to 2.0 mm, and is used to receive the wire. The crimping flaps are located on both sides of the wire receiving groove and are used to wrap and fix the wire during crimping. S7: Wire feeding and crimping The wire is fed to the crimping part by an automatic wire feeding device. The wire is a single-strand copper wire or a multi-strand stranded copper wire with a diameter of 0.3mm to 1.5mm. The crimping mechanism crimps the crimping fins so that the crimping fins tightly wrap the wire, forming a mechanical connection and electrical conduction. The crimping method includes cold crimping, hot crimping or ultrasonic crimping. S8: Spring Protection While the pressing step is being performed, the formed fisheye spring part is supported or shielded by the spring protection mechanism. The spring protection mechanism includes a movable support block or clamping block to prevent the fisheye spring part from being squeezed or deformed during the pressing process. S9: Online Detection The geometry, surface quality, and wire crimping firmness of the fisheye spring section are detected in real time by an online inspection station integrated into the continuous stamping die. The online inspection station includes optical sensors or electrical contact detection devices. When a defective product is detected, it is automatically marked or rejected. S10: Cutting and Collecting After passing the inspection, the formed fisheye terminal and wire assembly are cut from the metal strip by the cutting mechanism. The cutting position is located at the rear end of the crimping part, forming an independent fisheye terminal and wire assembly, which is then collected by the collecting device.

[0007] Preferably, the surface of the fisheye terminal body is provided with an electromagnetic shielding layer. The electromagnetic shielding layer is formed on the surface of the terminal body through a co-plating process, including an inner conductive substrate and an outer shielding material. The conductive substrate is phosphor bronze or beryllium copper, and the shielding material is silver, nickel, or a silver-nickel alloy. The thickness of the shielding layer is 2μm to 10μm. After the terminal is inserted into the PCB board, the electromagnetic shielding layer forms an electrical connection with the grounding copper foil on the PCB board, thereby sealing the electromagnetic leakage path around the board hole and forming a continuous electromagnetic shielding cavity, improving the electromagnetic compatibility performance of the whole machine.

[0008] Preferably, the electromagnetic shielding layer is formed by partial electroplating, with the shielding layer only set in the area that contacts the grounding copper foil after the terminal is inserted into the PCB board, while the other areas remain the substrate surface. The partial electroplating adopts mask electroplating or selective electroplating process, the shielding layer material is silver, and the thickness is 3μm to 8μm.

[0009] Preferably, the fisheye spring portion further includes at least one pair of auxiliary springs, which are located on both sides of the main spring and form a parallel elastic structure with the main spring. The thickness of the auxiliary spring is 1 / 3 to 1 / 2 of the thickness of the main spring and the width is 1 / 4 to 1 / 3 of the width of the main spring. They are used to provide auxiliary support force when the terminal is inserted into the PCB board hole, thereby further increasing the holding force.

[0010] Preferably, the crimping portion of the fisheye terminal further includes an anti-rotation structure, which is a protrusion or groove at the rear end of the crimping portion, used to form a shape fit with the wire insulation layer after crimping to prevent the wire from rotating relative to the terminal. The height of the protrusion is 0.1mm to 0.3mm, and the depth of the groove is 0.1mm to 0.3mm.

[0011] Preferably, the surface of the fisheye spring portion of the fisheye terminal is provided with a micro-rough structure, which is formed by stamping or etching process, and the surface roughness Ra is 0.8μm to 2.5μm, which is used to increase the friction coefficient with the hole wall of the PCB board and further improve the anti-loosening performance.

[0012] Preferably, the multi-station continuous stamping die includes the following stations: feeding station, guide hole punching station, preliminary bending station, precision stamping station for fisheye spring section, multi-level locking structure forming station, asymmetric spring structure forming station, stress relief groove forming station, crimping section forming station, wire feeding and crimping station, spring protection station, online detection station, and cutting station. Each station is synchronously linked through a precision feeding mechanism to ensure the processing accuracy and consistency of each station.

[0013] Preferably, the continuous stamping die is a high-speed stamping die with a stamping speed of not less than 300 times / minute, a positioning accuracy of ±0.02mm for each station in the die, and a feeding step accuracy of ±0.05mm.

[0014] Preferably, the conductor is a pre-cut conductor or a continuous conductor. When a continuous conductor is used, it is cut by a conductor cutting device after crimping. The conductor cutting device is synchronously linked with the crimping mechanism, and the cutting position accuracy is ±0.1mm.

[0015] Compared with the prior art, the advantages of this invention are: 1. This invention integrates the stamping and forming of fisheye terminals with the automatic feeding, crimping, inspection, and cutting of wires by using a multi-station continuous stamping die, realizing integrated continuous production from metal strip to finished components, greatly improving production efficiency and reducing labor and equipment input costs.

[0016] 2. This invention designs a multi-level locking structure (guide area, transition area, locking area) and an asymmetrical spring structure in the fisheye spring section, so that the terminal will deform and rebound asynchronously after being inserted into the PCB board hole, forming a torsional effect. This significantly enhances the holding force and anti-vibration and anti-loosening performance of the terminal in the board hole, and solves the problem that traditional fisheye terminals are prone to loosening and poor contact under vibration or impact environments.

[0017] 3. By setting a stress relief groove (arc groove or micro hole) at the root of the spring, the present invention effectively disperses the stress concentration generated by the spring during repeated insertion and removal, significantly improves the fatigue resistance and insertion and removal life of the terminal, and overcomes the defects of traditional terminals that are prone to breakage or failure due to long-term use or repeated insertion and removal.

[0018] 4. This invention sets an electromagnetic shielding layer (co-plated or partially electroplated with shielding materials such as silver and nickel) on the surface of the fisheye terminal body, so that the terminal forms an electrical connection with the grounded copper foil after being inserted into the PCB board, sealing the electromagnetic leakage path around the board hole and forming a continuous electromagnetic shielding cavity, thereby improving the electromagnetic compatibility performance of the whole machine and solving the problem that traditional terminals in high-frequency circuits cannot suppress electromagnetic interference.

[0019] 5. This invention integrates an online inspection station and a spring protection mechanism into a continuous stamping die, enabling real-time monitoring of the geometry, surface quality, and wire crimping firmness of the fisheye spring section. It also provides support and protection for the formed spring during the crimping process, effectively preventing damage to the precision spring structure caused by the crimping process, ensuring product consistency and high quality, and reducing the defect rate. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of a continuous forming and crimping method for fisheye terminals and wires proposed in this invention. Figure 2 This is a structural diagram of the fisheye terminal, which is a method for continuous forming and crimping of a fisheye terminal and a wire proposed in this invention. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1-2 A continuous forming crimping method for fisheye terminals and wires includes the following steps: S1: Metal strip preparation and feeding Provide a continuous metal strip, which is made of phosphor bronze, beryllium copper or copper alloy, with a thickness of 0.2 mm to 0.8 mm and a width of 5 mm to 20 mm, and feed it into a multi-station continuous stamping die; It should be noted that the feeding mechanism involved in this step, such as roller feeder or pneumatic clamp feeder, is a common standard component in the field of continuous stamping. Its specific structure and working principle are well known to those skilled in the art, and will not be described in detail here. S2: Fisheye terminal body molding The metal strip is punched with guide holes, pre-bent, and precision stamped in sequence to form the main structure of the fisheye terminal. The main body of the fisheye terminal includes a fisheye spring part and a crimping part. The fisheye spring part is located at the front end of the terminal and is used to make elastic contact with the hole in the PCB board. The crimping part is located at the rear end of the terminal and is used to crimp with the wire. Multi-station continuous stamping dies adopt a universal die frame structure, including, from top to bottom, an upper die base, an upper backing plate, an upper clamping plate, a stripper plate, a lower die plate, a lower backing plate, and a lower die base. Processes such as punching guide holes, preliminary bending, and precision stamping are all completed by the cooperation of corresponding punches (such as punching guide holes) located in the upper clamping plate and corresponding dies fixed in the lower die plate. This is a conventional technique in the stamping die industry. S3: Multi-stage locking structure forming A multi-stage locking structure is formed by stamping on the fisheye spring section. This structure consists of a guide area, a transition area, and a locking area. The guide area is conical or arc-shaped with an angle of 15° to 30°, used to guide the terminal into the PCB board hole. The transition area has an arc-shaped transition surface to gradually increase the contact force. The locking area is provided with one or more protrusions or barbs to provide the final holding force. The angle and arc of the guide area, transition area, and locking area are optimized according to the PCB board hole diameter and thickness to achieve a balance between insertion force and extraction force. Multi-stage locking structure: It consists of a guide area, a transition area and a locking area. The locking area is equipped with a protrusion or barb structure, which can provide a gradually increasing contact force after insertion into the PCB board hole, and finally form a stable holding force to prevent loosening due to vibration or impact.

[0023] S4: Asymmetric spring sheet structure forming Asymmetrical spring structures are formed on both sides by stamping on the fisheye spring section, including a first spring and a second spring. The first spring and the second spring are asymmetrical in geometry, thickness or width, so that they have different stiffness. The thickness of the first spring is 0.1mm to 0.3mm and the width is 0.5mm to 1.5mm. The thickness of the second spring is 0.15mm to 0.35mm and the width is 0.8mm to 1.8mm. When the terminal is inserted into the PCB board hole, the first spring and the second spring produce asynchronous deformation and springback tendencies, forming a torsional effect between the terminal and the board hole, effectively resisting rotational loosening caused by vibration or impact. S5: Stress relief groove forming A stress relief groove is formed by stamping at the root of the spring in the fisheye spring section. The stress relief groove is an arc-shaped groove or a micro-hole structure. The radius of curvature of the arc-shaped groove is 0.05mm to 0.2mm, and the diameter of the micro-hole is 0.1mm to 0.3mm. It is used to disperse the stress concentration generated by the spring during repeated bending, and improve the fatigue resistance and insertion and extraction life of the terminal. Stress relief groove: An arc-shaped groove or micro-hole is set at the root of the spring to disperse the stress concentration generated during repeated insertion and removal, which significantly improves the fatigue resistance and insertion and removal life of the terminal and avoids the problem of easy breakage of traditional terminals during long-term use. S6: Press-fitting part forming A crimping section is formed by stamping on a metal strip. The crimping section includes a wire receiving groove and crimping flaps. The wire receiving groove is U-shaped or V-shaped, with a depth of 0.3 mm to 1.0 mm and a width of 0.5 mm to 2.0 mm, and is used to receive the wire. The crimping flaps are located on both sides of the wire receiving groove and are used to wrap and fix the wire during crimping. S7: Wire feeding and crimping The wire is fed to the crimping section by an automatic wire feeding device. The wire is a single-strand copper wire or a multi-strand stranded copper wire with a diameter of 0.3mm to 1.5mm. The crimping mechanism crimps the crimping blades so that the crimping blades tightly wrap the wire, forming a mechanical connection and electrical conduction. The crimping methods include cold crimping, hot crimping or ultrasonic crimping. The automatic wire feeding device is a conventional wire feeding device in the field, comprising a wire feeding reel, a straightening mechanism (for eliminating wire stress), a feeding roller pair (driven by a servo motor, which precisely feeds the wire to a set length through friction), and a wire guide tube (which precisely guides the end of the wire into the wire receiving groove of the crimping part). Its working principle is as follows: the control system controls the rotation of the feeding roller pair according to the preset wire feeding length, pulling the wire out from the wire feeding reel, straightening it, passing it through the guide tube, and precisely positioning it at the terminal to be crimped.

[0024] Crimping Mechanism: The crimping mechanism is an independent unit integrated into the end of a continuous stamping die. It activates when the strip carrying the terminal advances to the crimping station and is positioned. Its structure includes: The pressing drive source can be an independent small pneumatic cylinder, hydraulic cylinder, or an auxiliary slider driven by the main press.

[0025] Crimping die head: Installed at the end of the drive source, its working surface has a groove or shape that matches the crimping blades. When the crimping die head is pressed down, it curls and deforms the crimping blades on both sides inward, so that they tightly wrap the wire. S8: Spring Protection While the crimping step is being performed, the formed fisheye spring part is supported or shielded by the spring protection mechanism. The spring protection mechanism includes a movable support block or clamping block to prevent the fisheye spring part from being squeezed or deformed during the crimping process. S9: Online Detection The geometry, surface quality, and wire crimping firmness of the fisheye spring section are detected in real time by an online inspection station integrated into the continuous stamping die. The online inspection station includes optical sensors or electrical contact detection devices. When a defective product is detected, it is automatically marked or rejected. S10: Cutting and Collecting After passing the inspection, the formed fisheye terminal and wire assembly are cut from the metal strip by the cutting mechanism. The cutting position is located at the rear end of the crimping part, forming an independent fisheye terminal and wire assembly, which is then collected by the collecting device.

[0026] The cutting mechanism is the last station in a continuous stamping die, and its structure is consistent with that of a conventional blanking die. It includes a cutting punch mounted on the upper clamping plate and a cutting die mounted on the lower die plate. The cutting position is precisely set according to the product design (i.e., the connection point between the rear end of the pressing section and the strip). As the cutting punch descends, it separates the formed terminal assembly from the metal strip. The accuracy of this station is ensured by the guide pillars and bushings of the die and the feeding stepping accuracy, ensuring a smooth, burr-free cut end.

[0027] Collection device: The collection device can be a combination of a vibratory feeder and a linear guide rail linked with the stamping machine, which arranges the finished products that fall after cutting in order for output; or it can be a conveyor belt type collection box, in which the finished products fall freely onto a slowly moving conveyor belt and are packed by manual labor or subsequent equipment.

[0028] An electromagnetic shielding layer is provided on the surface of the fisheye terminal body. The electromagnetic shielding layer is formed on the surface of the terminal body through a co-plating process. It includes an inner conductive substrate and an outer shielding material. The conductive substrate is phosphor bronze or beryllium copper, and the shielding material is silver, nickel or silver-nickel alloy. The thickness of the shielding layer is 2μm to 10μm. After the terminal is inserted into the PCB board, the electromagnetic shielding layer forms an electrical connection with the grounding copper foil on the PCB board, thereby sealing the electromagnetic leakage path around the board hole and forming a continuous electromagnetic shielding cavity, which improves the electromagnetic compatibility performance of the whole machine.

[0029] The electromagnetic shielding layer is formed by local electroplating. The shielding layer is only set in the area where the terminal contacts the grounding copper foil after being inserted into the PCB board. Other areas remain the surface of the substrate. The local electroplating adopts mask electroplating or selective electroplating process. The shielding layer material is silver and the thickness is 3μm to 8μm.

[0030] The fisheye spring section also includes at least one pair of auxiliary springs. The auxiliary springs are located on both sides of the main spring and form a parallel elastic structure with the main spring. The thickness of the auxiliary spring is 1 / 3 to 1 / 2 of the thickness of the main spring and the width is 1 / 4 to 1 / 3 of the width of the main spring. They are used to provide auxiliary support force when the terminal is inserted into the PCB board hole, and further increase the holding force.

[0031] The crimping portion of the fisheye terminal also includes an anti-rotation structure, which is a protrusion or groove at the rear end of the crimping portion. It is used to form a shape fit with the wire insulation layer after crimping to prevent the wire from rotating relative to the terminal. The height of the protrusion is 0.1mm to 0.3mm, and the depth of the groove is 0.1mm to 0.3mm.

[0032] The surface of the fisheye spring portion of the fisheye terminal is provided with a micro-rough structure. The micro-rough structure is formed by stamping or etching process, and the surface roughness Ra is 0.8μm to 2.5μm. It is used to increase the friction coefficient with the hole wall of the PCB board and further improve the anti-loosening performance.

[0033] The multi-station continuous stamping die includes the following stations: feeding station, guide hole punching station, preliminary bending station, precision stamping station for fisheye spring section, multi-level locking structure forming station, asymmetric spring structure forming station, stress relief groove forming station, crimping section forming station, wire feeding and crimping station, spring protection station, online inspection station, and cutting station. Each station is synchronized and linked through a precision feeding mechanism to ensure the processing accuracy and consistency of each station.

[0034] The continuous stamping die is a high-speed stamping die with a stamping speed of not less than 300 times / minute. The positioning accuracy of each station in the die is ±0.02mm, and the feeding step accuracy is ±0.05mm.

[0035] The conductor can be a pre-cut conductor or a continuous conductor. When a continuous conductor is used, it is cut by a conductor cutting device after crimping. The conductor cutting device is synchronized with the crimping mechanism, and the cutting position accuracy is ±0.1mm.

[0036] The working principle of this invention is based on progressive stamping and online crimping integration technology, integrating the stamping and forming of fisheye terminals with the crimping process of wires on the same continuous production line. It achieves fully automated integrated processing from metal strip to finished component through multi-station continuous stamping dies. First, a continuous metal strip passes through multiple processing stations sequentially via a precision feeding mechanism in a high-precision stepping manner. At each station, the stamping die progressively completes the forming of structures such as guide hole punching, bending, spring forming, multi-stage locking structure, asymmetrical spring, stress relief groove, and crimping part. Subsequently, at the crimping station, an automatic wire feeding device precisely feeds the wire into the wire receiving groove of the terminal crimping part. The crimping mechanism presses the crimping flaps together, tightly wrapping them to form a strong mechanical connection and electrical conduction. Simultaneously, the spring protection mechanism supports the formed fisheye spring part. The shielding prevents squeezing or deformation during the crimping process. After crimping, the online inspection station integrated into the mold monitors the geometry, surface quality, and wire crimping firmness of the fisheye spring in real time using optical sensors or electrical contact detection devices. When a defective product is detected, it is automatically marked or rejected. Finally, after passing the inspection, the formed fisheye terminal and wire assembly are cut from the metal strip by a cutting mechanism to form an independent finished assembly, which is automatically collected by a collection device. This achieves high-efficiency, high-precision, and high-consistency continuous production of fisheye terminals and wires.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for continuous forming and crimping of a fisheye terminal and a wire, characterized in that, Includes the following steps: S1: Metal strip preparation and feeding A continuous metal strip, which is phosphor bronze, beryllium copper, or copper alloy material, is provided with a thickness of 0.2 mm to 0.8 mm and a width of 5 mm to 20 mm, and is fed into a multi-station continuous stamping die. S2: Fisheye terminal body molding The metal strip is sequentially punched with guide holes, pre-bent, and precision stamped to form the main structure of the fisheye terminal. The main body of the fisheye terminal includes a fisheye spring part and a crimping part. The fisheye spring part is located at the front end of the terminal and is used to elastically contact the hole in the PCB board. The crimping part is located at the rear end of the terminal and is used to crimp the wire. S3: Multi-stage locking structure forming A multi-stage locking structure is formed by stamping on the fisheye spring section. This structure consists of a guide area, a transition area, and a locking area. The guide area is conical or arc-shaped with an angle of 15° to 30°, used to guide the terminal into the PCB board hole. The transition area has an arc-shaped transition surface, used to gradually increase the contact force. The locking area is provided with one or more protrusions or barbs to provide the final holding force. The angle and arc of the guide area, transition area, and locking area are optimized according to the PCB board hole diameter and thickness to achieve a balance between insertion force and extraction force. S4: Asymmetric spring sheet structure forming An asymmetrical spring structure is formed on the fisheye spring section, including a first spring and a second spring. The first spring and the second spring are asymmetrical in geometry, thickness or width, so that they have different stiffness. The thickness of the first spring is 0.1mm to 0.3mm and the width is 0.5mm to 1.5mm. The thickness of the second spring is 0.15mm to 0.35mm and the width is 0.8mm to 1.8mm. When the terminal is inserted into the PCB board hole, the first spring and the second spring produce asynchronous deformation and springback tendencies, forming a torsional effect between the terminal and the board hole, effectively resisting rotational loosening caused by vibration or impact. S5: Stress relief groove forming A stress relief groove is formed by stamping at the root of the spring in the fisheye spring section. The stress relief groove is an arc-shaped groove or a micro-hole structure. The radius of curvature of the arc-shaped groove is 0.05mm to 0.2mm, and the diameter of the micro-hole is 0.1mm to 0.3mm. It is used to disperse the stress concentration generated by the spring during repeated bending, and improve the fatigue resistance and insertion and extraction life of the terminal. S6: Press-fitting part forming A crimping portion is formed by stamping on the metal strip. The crimping portion includes a wire receiving groove and crimping flaps. The wire receiving groove is U-shaped or V-shaped, with a depth of 0.3 mm to 1.0 mm and a width of 0.5 mm to 2.0 mm, and is used to receive the wire. The crimping flaps are located on both sides of the wire receiving groove and are used to wrap and fix the wire during crimping. S7: Wire feeding and crimping The wire is fed to the crimping part by an automatic wire feeding device. The wire is a single-strand copper wire or a multi-strand stranded copper wire with a diameter of 0.3mm to 1.5mm. The crimping mechanism crimps the crimping fins so that the crimping fins tightly wrap the wire, forming a mechanical connection and electrical conduction. The crimping method includes cold crimping, hot crimping or ultrasonic crimping. S8: Spring Protection While the pressing step is being performed, the formed fisheye spring part is supported or shielded by the spring protection mechanism. The spring protection mechanism includes a movable support block or clamping block to prevent the fisheye spring part from being squeezed or deformed during the pressing process. S9: Online Detection The geometry, surface quality, and wire crimping firmness of the fisheye spring section are detected in real time by an online inspection station integrated into the continuous stamping die. The online inspection station includes optical sensors or electrical contact detection devices. When a defective product is detected, it is automatically marked or rejected. S10: Cutting and Collecting After passing the inspection, the formed fisheye terminal and wire assembly are cut from the metal strip by the cutting mechanism. The cutting position is located at the rear end of the crimping part, forming an independent fisheye terminal and wire assembly, which is then collected by the collecting device.

2. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 1, characterized in that, An electromagnetic shielding layer is provided on the surface of the fisheye terminal body. The electromagnetic shielding layer is formed on the surface of the terminal body through a co-plating process, including an inner conductive substrate and an outer shielding material. The conductive substrate is phosphor bronze or beryllium copper, and the shielding material is silver, nickel, or a silver-nickel alloy. The thickness of the shielding layer is 2μm to 10μm. After the terminal is inserted into the PCB board, the electromagnetic shielding layer forms an electrical connection with the grounding copper foil on the PCB board, thereby sealing the electromagnetic leakage path around the board hole and forming a continuous electromagnetic shielding cavity, improving the electromagnetic compatibility performance of the whole machine.

3. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 2, characterized in that, The electromagnetic shielding layer is formed by local electroplating. The shielding layer is only set in the area where the terminal contacts the grounding copper foil after being inserted into the PCB board, while the other areas remain the surface of the substrate. The local electroplating adopts mask electroplating or selective electroplating process. The shielding layer material is silver and the thickness is 3μm to 8μm.

4. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 1, characterized in that, The fisheye spring section also includes at least one pair of auxiliary springs. The auxiliary springs are located on both sides of the main spring and form a parallel elastic structure with the main spring. The thickness of the auxiliary spring is 1 / 3 to 1 / 2 of the thickness of the main spring and the width is 1 / 4 to 1 / 3 of the width of the main spring. They are used to provide auxiliary support force when the terminal is inserted into the PCB board hole, and further increase the holding force.

5. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 1, characterized in that, The crimping portion of the fisheye terminal also includes an anti-rotation structure, which is a protrusion or groove at the rear end of the crimping portion. It is used to form a shape fit with the wire insulation layer after crimping to prevent the wire from rotating relative to the terminal. The height of the protrusion is 0.1mm to 0.3mm, and the depth of the groove is 0.1mm to 0.3mm.

6. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 1, characterized in that, The surface of the fisheye spring portion of the fisheye terminal is provided with a micro-rough structure. The micro-rough structure is formed by stamping or etching processes, and the surface roughness Ra is 0.8μm to 2.5μm. It is used to increase the friction coefficient with the PCB board hole wall and further improve the anti-loosening performance.

7. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 1, characterized in that, The multi-station continuous stamping die includes the following stations: feeding station, guide hole punching station, preliminary bending station, precision stamping station for fisheye spring section, multi-level locking structure forming station, asymmetric spring structure forming station, stress relief groove forming station, crimping section forming station, wire feeding and crimping station, spring protection station, online detection station, and cutting station. Each station is synchronously linked through a precision feeding mechanism to ensure the processing accuracy and consistency of each station.

8. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 7, characterized in that, The continuous stamping die is a high-speed stamping die with a stamping speed of not less than 300 times / minute. The positioning accuracy of each station in the die is ±0.02mm, and the feeding step accuracy is ±0.05mm.

9. The continuous forming and crimping method for a fisheye terminal and a wire according to claim 1, characterized in that, The conductor can be a pre-cut conductor or a continuous conductor. When a continuous conductor is used, it is cut by a conductor cutting device after crimping. The conductor cutting device is synchronized with the crimping mechanism, and the cutting position accuracy is ±0.1mm.

Images