FPC bending jig and method thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-03-24
AI Technical Summary
Traditional FPC bending relies on manual labor or simple tooling, which results in poor consistency of bending angle and radius, FPC displacement or wrinkling, inaccurate positioning, and shape springback, making it difficult to achieve high-precision and high-repeatability bending.
An FPC bending fixture is used, including an upper die, a lower die, and steel pins. Using guide pin positioning holes, limit pins, and heating tubes, a two-stage pressure heating process is employed to ensure precise control and shaping of the inner and outer diameters during bending.
It achieves high-precision and stable FPC bending, ensuring consistent and reliable bending shapes, simplifying the operation process, improving production efficiency, and is suitable for FPC products with different bending radii.
Smart Images
Figure CN121728671A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flexible circuit board processing technology, specifically to a fixture device for precision bending and shaping of flexible circuit boards and a bending method using the fixture. Background Technology
[0002] Flexible printed circuit boards (FPCs), with their bendability and three-dimensional wiring capabilities, have evolved from simple "wire harness replacements" to core components that determine the form factor of high-end consumer electronics, automotive electronics layouts, and the evolution of medical devices. As product forms become increasingly complex, extremely high demands are placed on the precision, consistency, and reliability of FPC bending, particularly regarding strict dimensional specifications for the inner and outer diameters at the bend points.
[0003] Traditional FPC bending relies heavily on manual labor or simple tooling, which has the following drawbacks: 1) Poor consistency in bending angle and radius, making it difficult to guarantee product yield; 2) FPC is prone to displacement or wrinkling during bending, resulting in inaccurate positioning; 3) The shape springs back after bending, making it impossible to stabilize. Therefore, there is an urgent need for a specialized fixture and method that can achieve high-precision, high-repeatability bending and perform heat setting on the bent area. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an FPC bending fixture with a reasonable structure, simple operation, and the ability to accurately control the inner and outer diameters of FPC during bending.
[0005] Another objective of this invention is to provide an FPC bending method using the above-mentioned fixture, which can effectively position, bend, and heat-press the FPC to ensure a stable and reliable bending shape.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: An FPC bending fixture includes an upper bending fixture die, a lower bending fixture die, and steel pins; The upper mold of the bending fixture is provided with guide post positioning holes, bending and shaping grooves, FPC limiting grooves and heating tubes; The lower mold of the bending fixture is provided with guide posts, positioning pins, limiting pins, bending shaping grooves and FPC limiting grooves that are adapted to the guide post positioning holes; The steel needle is disposed on the FPC limiting groove of the lower die of the bending fixture and is limited by the limiting pin; The positioning pin is used to pass through the positioning hole on the FPC to position the FPC during bending. After the upper and lower molds of the bending fixture are closed, their bending and shaping grooves together form a forming cavity. The diameter of the steel needle is equal to the inner diameter required for bending the FPC, and the diameter of the forming cavity is equal to the outer diameter required for bending the FPC.
[0007] Preferably, there are two sets of limiting pins, which are set on the outside of the FPC limiting groove to limit the steel needle from both ends; each set of limiting pins includes two pins, which are symmetrically distributed on both sides of the bending and shaping groove.
[0008] Preferably, the number of the positioning pins is at least one, and they are disposed inside the FPC limiting groove.
[0009] Preferably, the depth of the FPC limiting groove is adapted to the thickness of the FPC to be bent.
[0010] Preferably, the number of guide pillars is at least two, symmetrically arranged on the lower die of the bending fixture. Further, the number of guide pillars is four, respectively located at the four corners of the lower die of the bending fixture.
[0011] Preferably, the heating tubes are evenly distributed inside the upper mold of the bending fixture to uniformly heat the upper mold of the bending fixture.
[0012] An FPC bending method using the above-mentioned FPC bending fixture includes the following steps: S1: Lay the FPC flat in the FPC limiting groove of the lower mold of the bending fixture, so that the positioning hole at one end of the FPC is fitted onto the positioning pin. S2: Place the steel needle above the FPC and limit its two ends with the limiting pins; S3: Using the steel needle as an axis, bend the FPC 180° so that the other end of the FPC covers the starting end, and make the positioning hole of the other end of the FPC fit onto the same positioning pin. S4: Close the upper mold and lower mold of the bending fixture; S5: Perform pre-compression shaping: control the pressure to 0~5 Kg / cm², and simultaneously heat the FPC through the heating tube for 10~30 seconds; S6: Pressing and shaping: Increase the pressure to 5~10 Kg / cm², maintain heating, and continue pressing for 10~30 seconds to finalize the shape of the FPC bending area.
[0013] Preferably, in step S5, the pre-compression pressure is 1~3 Kg / cm².
[0014] Preferably, in step S6, the compression molding pressure is 6~8 Kg / cm².
[0015] Beneficial effects Compared with the prior art, the present invention has the following significant advantages: 1. High precision: The inner diameter of the bend is precisely controlled by the diameter of the steel needle, the outer diameter of the bend is precisely controlled by the bending molding groove after mold closing, and the FPC limiting groove and positioning pin ensure that the FPC does not shift during processing, resulting in excellent consistency of bending dimensions.
[0016] 2. Excellent molding effect: The process combines two-stage pressurization and heating. First, the FPC material is pre-pressed and preheated at a lower pressure to soften and initially form. Then, the material is finally pressed and shaped at a higher pressure. This effectively eliminates internal stress in the material, prevents springback, and ensures the long-term stability of the bent shape.
[0017] 3. Ingenious structure and simple operation: The two ends of the FPC after bending are fixed by sharing the same positioning pin, and the steel needle is stabilized by the limit pin group. The ingenious structural design not only ensures positioning accuracy, but also simplifies the operation process and improves production efficiency.
[0018] 4. Wide applicability: By changing the steel needles of different diameters and the corresponding upper and lower dies, it can adapt to FPC products with different bending radius requirements, making it highly versatile. Attached Figure Description
[0019] Figure 1 This is a three-dimensional structural diagram of the lower mold of the bending fixture of the present invention.
[0020] Figure 2 This is a bottom-view three-dimensional structural diagram of the upper mold of the bending fixture of the present invention.
[0021] Figure 3 A top view of an FPC example to be bent.
[0022] Figure 4 This is a cross-sectional schematic diagram of the state before mold closing and pressing (S1-S3) of the present invention.
[0023] Figure 5 This is a cross-sectional schematic diagram of the mold-closing and pressing state (S4-S6) of the present invention.
[0024] Figure 6 This is a schematic cross-sectional view of the FPC after bending. Detailed Implementation
[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0026] like Figure 1 - Figure 3 As shown, an FPC bending fixture of the present invention mainly consists of an upper bending fixture mold 1, a lower bending fixture mold 2, and a steel needle 3.
[0027] The lower die 2 of the bending fixture is provided with four guide posts 21, which are located at its four corners. An FPC limiting groove 22 is formed on the surface of the lower die 2, the depth of which is equal to the thickness of the FPC 4 to be processed. A positioning pin 23 is provided in the FPC limiting groove 22. On the outside of the FPC limiting groove 22, there are limiting pins 24. In this embodiment, there are two sets of limiting pins 24, two in each set, which are symmetrically distributed on both sides of the bending shaping groove 25 to limit the steel pins 3 from both ends.
[0028] The bending fixture has four guide post positioning holes 11 corresponding to the upper mold 1 and lower mold 2. The surface of the upper mold 1 is provided with bending shaping grooves 15 and FPC limiting grooves 12 corresponding to the lower mold 2. A heating tube 13 is embedded inside the upper mold 1 for heating the FPC during pressing. The diameter d of the steel needle 3 is selected according to the bending inner diameter required by the FPC product.
[0029] like Figure 3 In the given FPC example, a bending area 43 is provided in the middle of FPC 4, and positioning holes 41 and 42 are symmetrically provided on both sides of the bending area 43.
[0030] like Figure 4 and Figure 5 As shown, the bending method of the present invention is as follows: First, FPC 4 is laid flat in the FPC limiting groove 22 of the lower mold 2, with the positioning hole 41 at one end fitting onto the positioning pin 23 (S1). Next, a steel pin 3 of the selected diameter is placed on top of FPC 4, and its two ends are secured by the limiting pins 24 (S2). Then, the operator bends FPC 4 180° around the steel pin 3, so that the other end of FPC covers it, and the positioning hole 42 at the other end also fits onto the same positioning pin 23 (S3). After that, the upper mold 1 is pressed down, and the mold is closed by the cooperation of the guide post 21 and the guide post positioning hole 11 (S4). After the mold is closed, the equipment is started, and pre-pressing and shaping are performed: a pressure of 1~3 Kg / cm² is applied, and the heating tube 13 is started at the same time to heat the upper mold 1 to the predetermined temperature (e.g., 150°C~200°C, depending on the FPC material) for 15 seconds (S5). Finally, compression molding is performed: the pressure is increased to 6~8 Kg / cm², the temperature is maintained, and compression continues for 15 seconds to allow the FPC 4 to fully solidify under the combined action of pressure and heat (S6). After mold opening, an FPC product with a precise 180° bending angle is obtained, such as... Figure 6 As shown.
[0031] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. An FPC bending fixture, characterized in that, Includes the upper die of the bending fixture, the lower die of the bending fixture, and the steel needle; The upper mold of the bending fixture is provided with guide post positioning holes, bending and shaping grooves, FPC limiting grooves and heating tubes; The lower mold of the bending fixture is provided with guide posts, positioning pins, limiting pins, bending shaping grooves and FPC limiting grooves that are adapted to the guide post positioning holes; The steel needle is disposed on the FPC limiting groove of the lower die of the bending fixture and is limited by the limiting pin; The positioning pin is used to pass through the positioning hole on the FPC to position the FPC during bending. After the upper and lower molds of the bending fixture are closed, their bending and shaping grooves together form a forming cavity. The diameter of the steel needle is equal to the inner diameter required for bending the FPC, and the diameter of the forming cavity is equal to the outer diameter required for bending the FPC.
2. The FPC bending fixture according to claim 1, characterized in that, The number of limiting pins is two sets, which are set on the outside of the FPC limiting groove to limit the steel needle from both ends; each set of limiting pins includes two pins, which are symmetrically distributed on both sides of the bending and shaping groove.
3. The FPC bending fixture according to claim 1, characterized in that, The number of positioning pins is at least one, and they are disposed inside the FPC limiting groove.
4. The FPC bending fixture according to claim 1, characterized in that, The depth of the FPC limiting groove is adapted to the thickness of the FPC to be bent.
5. The FPC bending fixture according to claim 1, characterized in that, The number of guide pillars is at least two, symmetrically arranged on the lower mold of the bending fixture.
6. The FPC bending fixture according to claim 5, characterized in that, The number of guide pillars is four, which are respectively set at the four corners of the lower mold of the bending fixture.
7. The FPC bending fixture according to claim 1, characterized in that, The heating tubes are evenly distributed inside the upper mold of the bending fixture to uniformly heat the upper mold of the bending fixture.
8. An FPC bending method using the FPC bending fixture as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Lay the FPC flat in the FPC limiting groove of the lower mold of the bending fixture, so that the positioning hole at one end of the FPC is fitted onto the positioning pin. S2: Place the steel needle above the FPC and limit its two ends with the limiting pins; S3: Bend the FPC 180° along the steel pin so that the positioning hole at the other end of the FPC is fitted onto the corresponding positioning pin. S4: Close the upper mold and lower mold of the bending fixture; S5: Perform pre-compression shaping: control the pressure to 0~5 Kg / cm², and simultaneously heat the FPC through the heating tube for 10~30 seconds; S6: Pressing and shaping: Increase the pressure to 5~10 Kg / cm², maintain heating, and continue pressing for 10~30 seconds to finalize the shape of the FPC bending area.
9. The FPC bending method according to claim 8, characterized in that, In step S5, the pre-compression pressure is 1~3 Kg / cm².
10. The FPC bending method according to claim 8, characterized in that, In step S6, the compression molding pressure is 6~8 Kg / cm².