Shuttlecock preparation process adopting injection molding and integral foaming molding and shuttlecock

Abstract

The invention discloses a shuttlecock preparation process for injection molding integrated foaming forming and a shuttlecock, and relates to the field of shuttlecock processing, and the shuttlecock preparation process comprises the steps of mixed raw material preparation, mold pretreatment, dynamic injection molding foaming, gradient cooling and post-treatment mechanism. The integrated structure of the shuttlecock head and the feather piece is realized by adopting an injection molding integrated foaming molding technology, the problem of weak connection of traditional split bonding is avoided, the overall mechanical property of the shuttlecock is remarkably enhanced, the bonding strength of the feather piece and the shuttlecock head is improved, and the impact resistance is improved; through an electromagnetic response system formed by the dual phase change microcapsules and the carbon nanotube-graphene composite conductive filler, and in combination with regulation and control of an asymmetric temperature field and an alternating electromagnetic field, internal convection of the raw materials is enhanced, and foaming uniformity is improved; and a regular nano-scale bump array is formed on the surface of the vane by virtue of the guidance of the bionic feather-branch-shaped pit array of the mold cavity and the micro magnet, so that the aerodynamic performance is further optimized, and the flight stability is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of badminton shuttlecock processing, specifically to a badminton shuttlecock manufacturing process and a badminton shuttlecock produced by injection molding and foaming. Background Technology

[0002] Badminton, as a widely practiced sport globally, boasts a large participant base and market demand due to its flexibility, fun, and fitness benefits. With rising competitive levels and increasing demands for a superior sporting experience, the market is placing higher requirements on badminton shuttlecock performance, such as flight stability, impact resistance, durability, production efficiency, and environmental friendliness, driving continuous innovation in shuttlecock manufacturing processes.

[0003] Traditional badminton shuttlecock manufacturing often employs a separate process where natural feathers (such as goose or duck feathers) are glued to a rubber head. This process relies on the quality of the natural materials and involves multiple manual or semi-automated steps, including feather selection, trimming, gluing, and shaping. The process is complex and requires a high level of operator skill.

[0004] Traditional manufacturing processes have significant limitations: First, the physical properties of natural feathers vary greatly, resulting in poor consistency in badminton shuttlecocks and affecting flight stability. Second, the integrity of the separate-bonded structure is weak, with the connection between the feathers and the shuttlecock head easily detaching, resulting in insufficient impact resistance and a short lifespan. Third, production relies on manual processes, leading to low efficiency and difficulty in meeting the demands of large-scale markets. Fourth, controlling process parameters (such as feather morphology and density distribution) is difficult, making it impossible to accurately match the performance requirements of different scenarios (such as training and competition), and adhesives such as glues may pose environmental risks. Furthermore, the supply stability of natural feather resources is affected by seasons and breeding conditions, further restricting the development of traditional processes. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a manufacturing process and a shuttlecock for integrated injection molding and foaming, so as to solve the technical problem that there are certain limitations in the existing shuttlecock manufacturing process.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a process for manufacturing badminton shuttlecocks using one-piece injection molding foaming, comprising the following steps: a) Preparation of mixed raw materials: Thermoplastic polymer particles, chemical foaming agent and dual phase change microcapsules accounting for 1-3% of the total weight are mixed, and carbon nanotube-graphene composite conductive filler accounting for 0.5-1% of the total weight is added. The carbon nanotube-graphene composite conductive filler and the magnetic nanoparticles on the outer wall of the dual phase change microcapsules form an electromagnetic response system. The dual phase change microcapsules include an inner capsule and an outer capsule, and each layer encapsulates a different phase change material. b) Mold pretreatment: A biodegradable release agent is sprayed onto the surface of the feather cavity of the injection mold. After drying, a 0.01-0.03 mm film is formed. The film contains thermosensitive color-changing microspheres, accounting for 5-8% of the weight of the release agent. The color-changing temperature range matches the melting point of the inner layer of the dual phase change microcapsule. The depth of the feather cavity is designed to change in a gradient, and the surface of the cavity is provided with an array of nanoscale pits corresponding to the feather protrusions. Micro magnets are embedded at the bottom of the pits. The polarity of the magnets is opposite to that of the magnetic nanoparticles on the outer wall of the dual phase change microcapsule. c) Dynamic injection molding foaming: The mixed raw materials are injected into the mold and initially maintained at a pressure of 8-12 MPa for 10-15 seconds. Then, the pressure is reduced to 3-5 MPa and asymmetric temperature field control is activated. At the same time, an alternating electromagnetic field is applied to enhance the internal convection of the raw materials through the electromagnetic coupling effect of carbon nanotube-graphene composite conductive filler and magnetic nanoparticles. The temperature of the ball head cavity fluctuates at 60-80℃, and the temperature of the feather cavity fluctuates at 80-100℃, with a phase difference of 180° between the two, lasting for 40-80 seconds. During the process, the temperature field distribution of the feather cavity is monitored in real time through the color change of the thermosensitive color-changing microspheres. d) Gradient cooling: After the mold is cooled to 40°C, a directional magnetic field is applied to the ball head to cool it to 25°C, while the skirt is kept at 40°C for 30 seconds. At the same time, the Joule heating effect of the composite conductive filler is used to locally fine-tune the temperature of the feather root to compensate for the temperature gradient deviation during the cooling process. e) Post-processing: After removing the flash, rotate the feather and simultaneously apply a UV-curable coating containing nano-ceramic particles. The UV light intensity received by the end area of ​​the feather is twice that of the root. The photothermal conversion characteristics of the composite conductive filler are used to accelerate the curing of the coating, and the stress distribution of the feather is finely adjusted by a magnetic field during the curing process.

[0007] In step a), the outer capsule wall thickness of the dual phase change microcapsule is 0.5-1 μm, and the inner capsule wall thickness is 0.2-0.5 μm. The surface of the outer capsule is modified with a silane coupling agent. The graphene in the carbon nanotube-graphene composite conductive filler has a wrinkled structure and a specific surface area ≥800 m². 2 / g, carbon nanotubes are spirally wound on graphene sheets.

[0008] The nanoscale pit array described in step b) is arranged in a biomimetic feather-like pattern, with a pit depth of 200-500 nm and a spacing between adjacent pits of 1.2-1.5 times the pit diameter; the micro magnet is a neodymium iron boron-polymer composite material with a magnetic induction intensity of 0.3-0.5 T, and a magnet directional locking structure is provided at the bottom of the pit.

[0009] The fluctuation frequency of the asymmetric temperature field mentioned in step c) is 0.5-1Hz, and the intensity gradient of the alternating electromagnetic field is set to 8-10kA / m in the head region and 12-15kA / m in the feather region. When the temperature deviation of the thermosensitive color-changing microsphere exceeds ±3℃, the electromagnetic field intensity of the corresponding region is automatically adjusted for compensation.

[0010] The directional magnetic field described in step d) is a pulsed gradient magnetic field with a pulse frequency of 5-10 Hz. The magnetic field strength decreases linearly from 1.2 T at the top of the sphere to 0.8 T at the neck of the sphere. The Joule heating effect is controlled by a pulsed current with an adjustable duty cycle and a current density of 3-5 A / mm². 2 .

[0011] The UV-curable coating described in step e) contains 20-30 wt% zirconia nano-ceramic particles with a particle size of 50-80 nm; the feathering rotation speed during application is 200-400 rpm, and the UV intensity gradient is achieved through a deformable mirror, with a light intensity of 80-100 mW / cm² in the root region. 2 The terminal region has a strength of 160-200 mW / cm. 2 .

[0012] During the curing process in step e), a rotating gradient magnetic field is applied. The magnetic field strength is parabolic in the direction of the feather thickness. The maximum field strength is located in the neutral layer of the feather and decreases to 0.3 kA / m to both sides. The direction of magnetic field rotation is opposite to the direction of feather rotation.

[0013] A badminton shuttlecock is prepared by an injection molding and foaming process. The shuttlecock has an injection molded head and feathers as a single foam structure. The surface of the feathers has a nano-scale array of protrusions arranged in a biomimetic feather-like pattern. The outer surface of the feathers is coated with an ultraviolet-cured coating containing zirconium oxide nano-ceramic particles. The overall density of the shuttlecock shows a gradient decreasing distribution from the head to the tip of the feathers.

[0014] In summary, the present invention has the following main advantages: The present invention employs injection molding integrated foaming technology to achieve an integrated structure of the shuttlecock head and feathers, avoiding the weak connection problem of traditional separate bonding, significantly enhancing the overall mechanical properties of the shuttlecock, improving the bonding strength between the feathers and the shuttlecock head, and increasing impact resistance. Through the electromagnetic response system formed by dual-phase change microcapsules and carbon nanotube-graphene composite conductive fillers, combined with asymmetric temperature field and alternating electromagnetic field regulation, internal convection of the raw materials is strengthened, improving foaming uniformity. The biomimetic feather-like recessed pit array and micro-magnetic guidance of the mold cavity form a regular nanoscale protrusion array on the feather surface, further optimizing aerodynamic performance and significantly improving flight stability. Detailed Implementation

[0015] The embodiments of the present invention will now be described.

[0016] Example 1 A process for manufacturing badminton shuttlecocks using injection molding and one-piece foaming includes the following steps: a) Preparation of mixed raw materials: Polypropylene granules were selected as the thermoplastic polymer base material. 100 kg of PP granules were taken, and 2 kg of dual phase change microcapsules and 0.7 kg of carbon nanotube-graphene composite conductive filler were added. The microcapsules accounted for 2% of the total weight, and the carbon nanotube-graphene composite conductive filler accounted for 0.7% of the total weight. At the same time, 3 kg of azodicarbonamide chemical foaming agent was added. The mixture was mixed in a high-speed mixer at 1500 rpm for 30 minutes to obtain a uniformly mixed raw material.

[0017] The outer capsule of the dual phase change microcapsule is made of melamine-formaldehyde resin with a wall thickness of 0.8 μm, and the inner capsule is made of gelatin-gum arabic composite wall material with a wall thickness of 0.3 μm. The outer capsule is encapsulated with polyethylene glycol with a phase change temperature of 80℃, and the inner capsule is encapsulated with paraffin wax with a phase change temperature of 60℃. The surface of the outer capsule is modified with KH550 silane coupling agent to enhance compatibility with PP substrate.

[0018] The phase change material in the dual phase change microcapsule undergoes a "heat absorption-heat release" cycle. When the material is heated to the phase change temperature, it changes from solid to liquid and absorbs heat, which can alleviate the problem of rapid decomposition of the foaming agent caused by excessively high local temperatures. When cooled, the liquid phase change material solidifies and releases heat, compensating for the temperature loss during the cooling process and avoiding uneven foaming density caused by excessively rapid local cooling. Ultimately, this makes the overall density gradient of the badminton shuttlecock more precise and improves flight stability.

[0019] Furthermore, during the foaming stage, the liquid phase change material can fill the internal voids of the raw material through flow, forming a tighter interface bond with the carbon nanotube-graphene composite conductive filler. After solidification, the solid phase change material acts as a "micro-skeleton" dispersed in the matrix. Combined with the integrated injection molding structure, it significantly improves the bonding strength between the feathers and the ball head, and enhances the impact resistance.

[0020] During the phase transition, the material expands from a solid to a liquid state, which, together with the nanoscale pit array in the mold cavity, causes the feather surface to form a more regular biomimetic bump structure. These bumps can reduce air resistance and improve flight stability, while the state change of the phase change material can ensure the consistency of the bump size.

[0021] In the carbon nanotube-graphene composite conductive filler, the graphene has a wrinkled structure, which is prepared by ultrasonic exfoliation and has a specific surface area of ​​850 m². 2 / g, multi-walled carbon nanotubes with a diameter of 10-20nm and a length of 5-10μm are spirally wound on graphene sheets and composited in situ through hydrothermal reaction, with a carbon nanotube to graphene mass ratio of 1:3.

[0022] The gradient design of microcapsule wall thickness ensures the accuracy of phase transition timing, silane modification enhances the bonding with the polymer interface, and wrinkled graphene and helical carbon nanotubes form a three-dimensional conductive network, improving the electromagnetic thermal conversion efficiency by more than 20%.

[0023] b) Mold pretreatment: The injection mold includes a ball head cavity and a feather cavity. The feather cavity can hold 16 feathers, which are symmetrically distributed. The depth of the feather cavity varies in gradient along the length direction, with a root depth of 2mm and a tip depth of 1.2mm.

[0024] A biodegradable release agent is sprayed onto the surface of the feather-shaped cavity. The main component of the release agent is polylactic acid ester with a solid content of 30%. An electrostatic spraying process is used to form a 0.02 mm thick film after drying. The film contains thermosensitive color-changing microspheres, which account for 6% of the weight of the release agent. These thermosensitive color-changing microspheres have a diameter of 5 μm and are composed of urea-formaldehyde resin microspheres encapsulated with liquid crystals. The color-changing temperature range is 58-62℃, which matches the melting point of the inner phase change material. They are white at room temperature and turn blue when they reach 60℃.

[0025] The surface of the feather-shaped cavity is processed with a biomimetic array of nanoscale pits arranged in a feather-like pattern. The pits are 350 nm deep, 200 nm in diameter, and 250 nm apart. A micro magnet is embedded at the bottom of the pit. The micro magnet is made of neodymium iron boron powder and polyimide resin mixed in a mass ratio of 7:3 and pressed together. The magnetic induction intensity is 0.4 T. The magnet is oriented and locked by a bottom slot structure with a depth of 500 nm, which matches the shape of the magnet. The polarity of the magnet is opposite to that of the magnetic nanoparticles on the outer wall of the dual phase change microcapsule.

[0026] The biomimetic pit arrangement optimizes the escape path of the foamed gas, the magnetic composite structure avoids injection molding impact displacement, and the locking structure adopts an inverted cone design, which can ensure zero displacement of the magnet under 10MPa injection pressure.

[0027] c) Dynamic injection foaming: The mixed raw materials are added to the barrel of the injection molding machine. The temperatures of each zone of the injection molding machine are: 160°C in the feeding zone, 180°C in the compression zone, and 200°C in the homogenization zone. The mixture is then injected into the mold through the nozzle.

[0028] After injection molding, the pressure is first held at 10MPa for 12 seconds, then reduced to 4MPa and asymmetric temperature field control is activated. This is achieved by linking the thermocouple embedded in the mold with the heating rod: the temperature of the ball head cavity fluctuates between 60-80℃ with a fluctuation frequency of 0.8Hz, and the temperature of the feather cavity fluctuates between 80-100℃ with a fluctuation frequency of 0.8Hz. The two have a phase difference of 180°, meaning that the feather cools down when the ball head heats up.

[0029] Meanwhile, an alternating electromagnetic field is applied through an electromagnetic coil wound around the outside of the mold, with a field strength of 8-10 kA / m in the ball head region and 12-15 kA / m in the feather region. The electromagnetic coupling effect between the carbon nanotube-graphene composite conductive filler and the magnetic nanoparticles is used to enhance the internal convection of the raw material.

[0030] During the process, the color change of the thermochromic microspheres on the surface of the feather cavity is observed in real time using a high-speed camera: when the microspheres in a local area do not turn blue (temperature < 58℃) ​​or turn dark blue (temperature > 62℃), that is, when the temperature deviation exceeds ±3℃, the electromagnetic field strength of the corresponding area is automatically adjusted. A deviation of 1℃ corresponds to an adjustment of 0.5kA / m in the field strength, which lasts for 60 seconds.

[0031] A closed-loop control system for temperature and electromagnetic field was established to reduce temperature fluctuations from ±5℃ to ±3℃. The electromagnetic field gradient was set to match the changes in feather thickness, thereby enhancing the uniformity of end-foaming.

[0032] d) Gradient cooling: After the pressure holding is completed, the mold is cooled to 40°C by water cooling.

[0033] Subsequently, a pulsed gradient magnetic field was applied to the ball head by rotating a permanent magnet array. The pulse frequency was 8 Hz, and the magnetic field strength decreased linearly from 1.2 T at the top of the ball head to 0.8 T at the neck of the ball head, causing the ball head to cool down rapidly to 25 ℃; the feather skirt was kept at 40 ℃ for 30 seconds.

[0034] Simultaneously, a pulsed current is applied to the root of the pinnae, with a current density of 4 A / mm². 2 With a duty cycle of 50%, the Joule heating effect of the composite conductive filler is used for localized fine-tuning of temperature to compensate for temperature gradient deviations during the cooling process.

[0035] Pulsed magnetic fields prevent magnetic domain overheating, linear gradient design suppresses cooling stress concentration, and Joule heating uses pulse width modulation to achieve micro-area temperature control accuracy of ±0.5℃.

[0036] e) Post-processing: After mold opening and part removal, the flash is removed by laser cutting.

[0037] The shuttlecock was fixed on a rotating platform with a rotation speed of 300 rpm. An automatic sprayer was used to apply a UV-curable coating containing nano-ceramic particles. The coating composition included 60 wt% acrylic resin, 25 wt% zirconium oxide nano-ceramic particles, 10 wt% photoinitiator, and 5 wt% additives. The coating thickness was controlled at 50-80 μm.

[0038] After application, the coating is cured with ultraviolet light: the light intensity gradient is adjusted using a deformable mirror, with a light intensity of 90 mW / cm² at the root of the feathers. 2 180mW / cm in the terminal region 2 The photothermal conversion properties of composite conductive fillers are used to accelerate the curing of coatings.

[0039] During the curing process, a rotating gradient magnetic field is applied. The electromagnet rotates in the opposite direction to the feather's rotation, with a rotation speed of 200 rpm. The magnetic field strength is parabolic in the direction of the feather's thickness, with the maximum field strength located in the neutral layer of the feather and attenuating to 0.3 kA / m towards both sides, in order to fine-tune the stress distribution of the feather.

[0040] Zirconia nanoparticles can improve the wear resistance of the feathers. The light intensity gradient matches the thickness gradient, and the rotating reverse magnetic field generates torsional load, which effectively eliminates curing shrinkage stress. Actual measurements show that it can reduce the risk of stress cracking by 35%.

[0041] In the above scheme, the addition of carbon nanotube-graphene composite conductive filler forms an electromagnetic response system with the magnetic nanoparticles of the dual phase change microcapsules. Under the action of the alternating electromagnetic field in the dynamic injection molding foaming stage, it enhances the convection of raw materials and improves the foaming uniformity. On the other hand, it can achieve local temperature regulation through the Joule heating effect in the gradient cooling stage, and accelerate the curing of the coating by photothermal conversion in the post-treatment stage, thus realizing the synergistic effect throughout the entire process from molding to post-treatment.

[0042] The thermosensitive color-changing microspheres added during mold pretreatment have a color-changing temperature that matches the melting point of the inner layer of the dual-phase-change microcapsules. This allows for real-time feedback of the cavity temperature field, providing an intuitive monitoring basis for asymmetric temperature field control. Furthermore, the interaction between the micromagnets on the cavity surface and the magnetic nanoparticles of the microcapsules can guide the microcapsules to accumulate in specific areas of the cavity, enhancing the local phase change regulation effect.

[0043] The overall solution revolves around the multi-field coupling and control of "electromagnetism-thermal-mechanical". It forms an organic whole from raw material design and mold optimization to process parameter control. It not only improves the stability of badminton shuttlecock molding quality, but also enhances the controllability of material properties through multi-field synergy, thus achieving better technical results.

[0044] Example 2 A process for manufacturing badminton shuttlecocks using one-piece injection molding foaming differs from Example 1 in that: a) Mixed raw materials: 1 kg of dual phase change microcapsules (1% of total weight), 0.5 kg of carbon nanotube-graphene composite conductive filler (0.5% of total weight); the outer wall thickness of the dual phase change microcapsules is 0.5 μm, and the inner wall thickness is 0.2 μm; the specific surface area of ​​graphene is 800 m². 2 / g, the mass ratio of carbon nanotubes to graphene is 1:4.

[0045] b) Mold pretreatment: release agent film thickness 0.01mm, thermosensitive color-changing microspheres accounting for 5% of the release agent weight; pit depth 200nm, adjacent spacing is 1.2 times the diameter; micro magnet magnetic induction intensity 0.3T.

[0046] c) Dynamic injection molding foaming: holding pressure 8MPa, holding time 10 seconds; asymmetric temperature field fluctuation frequency 0.5Hz; alternating electromagnetic field 8kA / m in the ball head region and 12kA / m in the feather region; duration 40 seconds.

[0047] d) Gradient cooling: directional magnetic field pulse frequency 5Hz, current density 3A / mm² 2 .

[0048] e) Post-treatment: Feather rotation speed 200 rpm; UV-curable coating containing 20 wt% zirconia nano-ceramic particles, root light intensity 80 mW / cm². 2 160mW / cm at the end 2 The maximum field strength of the rotating gradient magnetic field is 0.8 kA / m.

[0049] Example 3 A process for manufacturing badminton shuttlecocks using one-piece injection molding foaming differs from Example 1 in that: a) Mixed raw materials: 3 kg of dual phase change microcapsules (3% of total weight), 1 kg of carbon nanotube-graphene composite conductive filler (1% of total weight); the outer wall thickness of the dual phase change microcapsules is 1 μm, and the inner wall thickness is 0.5 μm; the specific surface area of ​​graphene is 900 m². 2 / g, the mass ratio of carbon nanotubes to graphene is 1:2.

[0050] b) Mold pretreatment: release agent film thickness 0.03mm, thermosensitive color-changing microspheres accounting for 8% of the release agent weight; pit depth 500nm, adjacent spacing is 1.5 times the diameter; micro magnet magnetic induction intensity 0.5T.

[0051] c) Dynamic injection molding foaming: holding pressure 12MPa, holding time 15 seconds; asymmetric temperature field fluctuation frequency 1Hz; alternating electromagnetic field 10kA / m in the ball head region and 15kA / m in the feather region; duration 80 seconds.

[0052] d) Gradient cooling: directional magnetic field pulse frequency 10Hz, current density 5A / mm² 2 .

[0053] e) Post-treatment: Feather rotation speed 400 rpm; UV-curable coating containing 30 wt% zirconia nano-ceramic particles, root light intensity 100 mW / cm². 2 200mW / cm at the end 2 The maximum field strength of the rotating gradient magnetic field is 1.2 kA / m.

[0054] Badminton Performance Comparison Analysis Table

[0055] In Example 3, the content of dual phase change microcapsules was the highest, and the pit depth and magnet strength were greater, resulting in the highest integrity of the protrusion array on the feather surface, a more significant density gradient, and the best flight stability and impact resistance. This indicates that a higher content of phase change material and a stronger electromagnetic effect are beneficial to improving the product's structural uniformity and mechanical properties.

[0056] In Example 2, the coating adhesion was slightly low and the flight deviation was large. The low content of conductive filler and phase change microcapsule would affect the electromagnetic coupling effect and curing uniformity.

[0057] Example 1 represents intermediate parameters, with balanced overall performance, making it suitable for mass production.

[0058] Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions, and variations to the embodiments as needed without departing from the principles and spirit of the invention, but such modifications, substitutions, and variations are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A manufacturing process for badminton shuttlecocks using one-piece injection molding foaming, characterized in that, Includes the following steps: a) Preparation of mixed raw materials: Thermoplastic polymer particles, chemical foaming agent and dual phase change microcapsules accounting for 1-3% of the total weight are mixed, and carbon nanotube-graphene composite conductive filler accounting for 0.5-1% of the total weight is added. The carbon nanotube-graphene composite conductive filler and the magnetic nanoparticles on the outer wall of the dual phase change microcapsules form an electromagnetic response system. The dual phase change microcapsules include an inner capsule and an outer capsule, and each layer encapsulates a different phase change material. b) Mold pretreatment: A biodegradable release agent is sprayed onto the surface of the feather cavity of the injection mold. After drying, a 0.01-0.03 mm film is formed. The film contains thermosensitive color-changing microspheres, accounting for 5-8% of the weight of the release agent. The color-changing temperature range matches the melting point of the inner layer of the dual phase change microcapsule. The depth of the feather cavity is designed to change in a gradient, and the surface of the cavity is provided with an array of nanoscale pits corresponding to the feather protrusions. Micro magnets are embedded at the bottom of the pits. The polarity of the magnets is opposite to that of the magnetic nanoparticles on the outer wall of the dual phase change microcapsule. c) Dynamic injection molding foaming: The mixed raw materials are injected into the mold and initially maintained at a pressure of 8-12 MPa for 10-15 seconds. Then, the pressure is reduced to 3-5 MPa and asymmetric temperature field control is activated. At the same time, an alternating electromagnetic field is applied to enhance the internal convection of the raw materials through the electromagnetic coupling effect of carbon nanotube-graphene composite conductive filler and magnetic nanoparticles. The temperature of the ball head cavity fluctuates at 60-80℃, and the temperature of the feather cavity fluctuates at 80-100℃, with a phase difference of 180° between the two, lasting for 40-80 seconds. During the process, the temperature field distribution of the feather cavity is monitored in real time through the color change of the thermosensitive color-changing microspheres. d) Gradient cooling: After the mold is cooled to 40°C, a directional magnetic field is applied to the ball head to cool it to 25°C, while the skirt is kept at 40°C for 30 seconds. At the same time, the Joule heating effect of the composite conductive filler is used to locally fine-tune the temperature of the feather root to compensate for the temperature gradient deviation during the cooling process. e) Post-processing: After removing the flash, rotate the feather and simultaneously apply a UV-curable coating containing nano-ceramic particles. The UV light intensity received by the end area of ​​the feather is twice that of the root. The photothermal conversion characteristics of the composite conductive filler are used to accelerate the curing of the coating, and the stress distribution of the feather is finely adjusted by a magnetic field during the curing process.

2. The badminton shuttlecock manufacturing process according to claim 1, characterized in that: The outer capsule wall thickness of the dual phase change microcapsule described in step a) is 0.5-1 μm, the inner capsule wall thickness is 0.2-0.5 μm, and the surface of the outer capsule is modified with a silane coupling agent. The graphene in the carbon nanotube-graphene composite conductive filler has a wrinkled structure and a specific surface area ≥800 m². 2 / g, carbon nanotubes are spirally wound on graphene sheets.

3. The badminton shuttlecock manufacturing process according to claim 1, characterized in that: The nanoscale pit array described in step b) is arranged in a biomimetic feather-like pattern, with a pit depth of 200-500 nm and a spacing between adjacent pits of 1.2-1.5 times the pit diameter; the micro magnet is a neodymium iron boron-polymer composite material with a magnetic induction intensity of 0.3-0.5 T, and a magnet directional locking structure is provided at the bottom of the pit.

4. The badminton shuttlecock manufacturing process according to claim 1, characterized in that: The fluctuation frequency of the asymmetric temperature field mentioned in step c) is 0.5-1Hz, and the intensity gradient of the alternating electromagnetic field is set to 8-10kA / m in the head region and 12-15kA / m in the feather region. When the temperature deviation of the thermosensitive color-changing microsphere exceeds ±3℃, the electromagnetic field intensity of the corresponding region is automatically adjusted for compensation.

5. The badminton shuttlecock manufacturing process according to claim 1, characterized in that: The directional magnetic field described in step d) is a pulsed gradient magnetic field with a pulse frequency of 5-10 Hz. The magnetic field strength decreases linearly from 1.2 T at the top of the sphere to 0.8 T at the neck of the sphere. The Joule heating effect is controlled by a pulsed current with an adjustable duty cycle and a current density of 3-5 A / mm². 2 .

6. The badminton shuttlecock manufacturing process according to claim 1, characterized in that: The UV-curable coating described in step e) contains 20-30 wt% zirconia nano-ceramic particles with a particle size of 50-80 nm; the feathering rotation speed during application is 200-400 rpm, and the UV intensity gradient is achieved through a deformable mirror, with a light intensity of 80-100 mW / cm² in the root region. 2 The terminal region has a strength of 160-200 mW / cm. 2 .

7. The badminton shuttlecock manufacturing process according to claim 1, characterized in that: During the curing process in step e), a rotating gradient magnetic field is applied. The magnetic field strength is parabolic in the direction of the feather thickness. The maximum field strength is located in the neutral layer of the feather and decreases to 0.3 kA / m to both sides. The direction of magnetic field rotation is opposite to the direction of feather rotation.

8. The badminton shuttlecock prepared by the injection molding and foaming process according to any one of claims 1-7 is characterized in that: The badminton shuttlecock is an injection-molded foam structure with the head and feathers as one piece. The surface of the feathers has a nano-scale array of protrusions arranged in a biomimetic feather-like pattern. The outer surface of the feathers is coated with an ultraviolet-cured coating containing zirconium oxide nano-ceramic particles. The overall density of the badminton shuttlecock shows a gradient decreasing distribution from the head to the tip of the feathers.

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