An ultrahigh frequency induction coil embedded type weld mark eliminating device for injection mold
By using an ultra-high frequency induction coil embedded device to achieve second-level heating and rapid cooling in the injection mold, the problem of slow thermal response of traditional resistance heating methods is solved, ensuring high efficiency in injection molding production and product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG WANHAO MOLD & PLASTIC
- Filing Date
- 2026-05-26
- Publication Date
- 2026-07-24
AI Technical Summary
Existing resistance heating methods have a relatively slow thermal response in injection molds, with disordered heat diffusion, making it difficult to adapt to fast cycles and easily causing product warping or plastic thermal degradation.
Employing an ultra-high frequency induction coil embedded device, utilizing a wedge-shaped magnetic pole head and a conical spiral coil design, combined with the skin effect and magnetic flux compression effect, it achieves second-level focused heating of electromagnetic energy in the weld line area. The modular design allows for easy coil replacement, and the addition of a cooling ring and lever mechanism enables rapid cooling.
It achieves efficient and precise local heating, matches the fast cycle of injection molding production, avoids warping and thermal degradation, reduces maintenance costs, and ensures production efficiency and product quality.
Smart Images
Figure CN122253372B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of injection mold technology, specifically to an ultra-high frequency induction coil embedded weld line elimination device for injection molds. Background Technology
[0002] Injection molding is one of the most important processing methods for plastic products, widely used in automotive, electronics, home appliances, medical and other fields. However, weld lines are one of the most common defects in injection molding, seriously affecting the appearance quality and mechanical properties of the product. When multi-gate injection molding is used, or when there are holes, inserts, or significant variations in the thickness of the product in the cavity, the molten plastic will flow in two or more directions within the mold. If the fusion of two or more molten fronts is insufficient, a linear mark, i.e., a weld line, will form on the surface of the product. Weld lines not only affect the appearance of the product, but also easily cause stress concentration, becoming a weak point in the injection molded part, and prone to breakage under load. To address the aforementioned issues, existing technologies have proposed several solutions. At the process level, common methods include increasing mold temperature, adjusting injection speed and pressure, optimizing gate location, and adding venting channels. At the equipment level, localized heating technology is gradually becoming a research hotspot. For example, utility model patent application CN202123000010.X discloses a mold with weld line elimination function. This solution uses heating rods placed in the wrinkle area within the mold cavity to heat the localized plastic material and restore its flow activity. However, existing resistance heating methods rely on heat conduction, resulting in a relatively slow thermal response. Heat is prone to disordered proliferation and diffusion within the mold, making it difficult to adapt to the fast pace of injection molding production. Furthermore, it can easily cause warping or thermal degradation of the target area. Summary of the Invention
[0003] The purpose of this invention is to provide an ultra-high frequency induction coil embedded weld line elimination device for injection molds, in order to solve the problems of existing resistance heating methods that rely on heat conduction, have a relatively slow thermal response, and are prone to disordered proliferation and diffusion of heat inside the mold, making it difficult to adapt to the fast pace of injection molding production, and easily causing warping deformation or thermal degradation of the target area of the product.
[0004] To achieve the above objectives, the present invention provides the following technical solution: A device for eliminating weld lines using an ultra-high frequency induction coil embedded in an injection mold includes a device body, an ultra-high frequency induction coil body, and a magnetic collecting head. The bottom of the fixed mold of the injection mold has a mounting groove, and the device body is detachably embedded in the mounting groove. The ultra-high frequency induction coil body is installed within the device body and is electrically connected to an external ultra-high frequency power supply. The magnetic collecting head is positioned on the side of the ultra-high frequency induction coil body facing the mold cavity. The magnetic collecting head is wedge-shaped, and its tip faces the straight area of the weld line within the mold cavity. This solution utilizes ultra-high frequency induction heating to detachably embed the ultra-high frequency induction coil into the bottom of the fixed mold as a modular device, and sets the wedge-shaped magnetic collecting head with its tip facing the straight area of the weld line. The skin effect and the tip flux compression effect enable the direct, second-level generation of heat in the weld line area and forced focus on a narrow 3-5mm band. This avoids the slow thermal response and disordered heat diffusion inside the mold caused by traditional resistance heating that relies on heat conduction. At the same time, because the heating area is precisely defined and the heat acts directly on the shallow surface of the cavity, the device can efficiently match the fast cycle of injection molding production and effectively prevent warping and deformation of non-target areas and thermal degradation of plastic. The modular, detachable design also allows for quick replacement of the coil without disassembling the entire mold when it is damaged, reducing maintenance costs and downtime. This ensures the high response speed, precise local heating capability, controllable thermal field, convenient maintenance, and dual guarantee of product quality and production efficiency of the weld line elimination device.
[0005] Preferably, the magnetic collecting pole head includes a converging part and a base, which are located at the upper and lower ends of the magnetic collecting pole head, respectively. The base of the magnetic collecting pole head is located at the center of the ultra-high frequency induction coil body. The ultra-high frequency induction coil body has a conical spiral structure, and the diameter of the ultra-high frequency induction coil body gradually decreases from the inside of the device body towards the mold cavity. The taper of the ultra-high frequency induction coil body matches the contour of the magnetic collecting pole head. This structural design allows the electromagnetic field energy generated by the ultra-high frequency induction coil body to be directionally converged along the contour line of the magnetic collecting pole head. When the ultra-high frequency current passes through the conical spiral coil, the electromagnetic field forms an energy compression effect as the coil diameter gradually decreases during propagation towards the mold cavity. Combined with the magnetic collecting pole head base located at the center of the coil, the dispersed magnetic flux lines can be concentrated and guided to the converging part, and finally released through the wedge-shaped tip. This increases the magnetic flux density in the weld line generation area by 3-5 times compared to traditional planar coils, enhancing the energy density and directivity of induction heating.
[0006] In addition, the magnetic pole head can be made of soft magnetic alloy material or soft magnetic ferrite material with high saturation magnetic induction intensity, which is used to guide and concentrate ultra-high frequency magnetic lines of force.
[0007] Preferably, an isolation cover is provided around the magnetic collecting pole head and the ultra-high frequency induction coil body. The isolation cover is made of ceramic material, including any one of zirconia ceramic, alumina ceramic, or silicon nitride ceramic. Ceramic materials have excellent high-temperature resistance and electrical insulation properties, which can effectively block the electromagnetic field generated by the ultra-high frequency induction coil body from diffusing to the outside of the device, preventing the electromagnetic field from causing unnecessary eddy current heating on other metal parts of the mold, thus preventing local overheating or energy waste. At the same time, its low thermal conductivity can form a thermal barrier, confining the heat generated by the magnetic collecting pole head and the coil inside the isolation cover, further improving heat utilization efficiency and preventing abnormal temperature rise around the device body and the mold mounting slot. The inner wall of the isolation cover is tightly fitted with the outer wall of the magnetic collecting pole head and the ultra-high frequency induction coil body and fixed with high-temperature ceramic adhesive to ensure structural stability under high-frequency vibration and temperature change environments. Its outer wall forms a sliding mating surface with the subsequently installed cooling ring, providing a basis for the dynamic adjustment of the device.
[0008] Preferably, a cooling ring is fitted around the outer perimeter of the isolation cover. The cooling ring has an annular cooling channel inside, and it has an inlet and an outlet. The cooling channel is circulated and connected to an external cooling pump through the inlet and outlet. The cooling ring is precision-machined from copper, and its annular cooling channel has a square cross-section. This design increases the contact area between the coolant and the inner wall of the cooling ring, improving heat exchange efficiency. A 0.1-0.2mm gap is reserved between the inner wall of the cooling ring and the outer wall of the isolation cover, and filled with high-temperature resistant grease. This ensures smooth sliding of the isolation cover relative to the cooling ring and also buffers vibrations caused by high-frequency induction through the viscous damping effect of the grease. When the device is working, the external cooling pump pumps coolant at a temperature controlled at 15-20℃ into the cooling channel through the inlet. During the annular flow, the coolant quickly cooperates with other cooling channels of the mold to absorb the heat transferred from the mold. It then flows back to the cooling pump through the outlet for cooling circulation, while simultaneously absorbing heat from the isolation cover to prevent heat transfer to the device body and the mold.
[0009] Preferably, the magnetic pole head, the ultra-high frequency induction coil body, and the isolation cover are fixedly connected. A cylinder is installed inside the device body, with the cylinder body fixedly mounted on the device body and the piston rod of the cylinder fixedly connected to the lower end face of the isolation cover. By extending and retracting the piston rod driven by the cylinder, the magnetic pole head, the ultra-high frequency induction coil body, and the isolation cover can be adjusted along the axial direction of the mounting groove. When the injection mold is closed, the cylinder piston rod extends, pushing the magnetic pole head towards the mold cavity, shortening the distance between the tip of the magnetic pole head and the surface of the mold cavity to 0.5-1mm. At this point, the electromagnetic field energy attenuation is minimal, and the heating efficiency is highest. When the mold opens for product ejection, the cylinder piston rod retracts, causing the magnetic pole head to move backward, maintaining a safe distance of 5-8mm from the cavity surface. This avoids interference between the ejection mechanism and the device, and also prevents the high-temperature magnetic pole head from causing secondary thermal damage to the newly demolded product. The cylinder's movement is controlled in conjunction with the mold control system. The intake and exhaust of its piston chamber are connected to an external pneumatic system via a quick connector. The response time is ≤0.2 seconds, ensuring precise matching with the injection molding cycle.
[0010] Preferably, the inner ring of the cooling ring is slidably connected to the isolation cover, and the outer ring of the cooling ring is slidably connected to the inner sidewall of the mounting groove. The cooling ring and the isolation cover are also connected by a lever mechanism, which includes a first push rod, a second push rod, a third push rod, and a connecting rod. The first and second push rods are respectively mounted on the lower end faces of the isolation cover and the cooling ring, the third push rod is mounted on the upper end face of the device body, the middle part of the connecting rod is hinged to the upper end face of the third push rod, and the two ends of the connecting rod are slidably hinged to the first and second push rods, respectively. On the lower end face, this lever mechanism constitutes a linkage adjustment system between the isolation cover and the cooling ring. Its working principle is as follows: When the cylinder piston rod pushes the isolation cover upwards, the first push rod, fixed to the lower end face of the isolation cover, rises accordingly. Through the hinge point in the middle of the connecting rod, a lever fulcrum is formed, driving the second push rod at the other end of the connecting rod downwards. Since the second push rod is fixedly connected to the cooling ring, the cooling ring slides downwards along the inner wall of the mounting groove. Conversely, when the isolation cover moves downwards under the action of the cylinder, the first push rod pulls down the connecting rod, causing the second push rod to drive the cooling ring upwards. This design ensures that the displacement direction of the cooling ring is always opposite to that of the isolation cover, and the displacement is precisely controlled by the lever ratio. When the isolation cover moves upwards, the cooling ring moves downwards. This reverse linkage ensures that the relative position of the cooling ring and the top of the mold mounting groove remains stable as the magnetic pole head approaches or moves away from the cavity surface. This guarantees precise alignment of the inlet, outlet, and mold cooling port, preventing misalignment or leakage in the cooling system piping due to component movement. Each hinge point of the lever mechanism uses self-lubricating bearings, combined with high-temperature resistant grease, to ensure smooth operation and structural reliability under long-term, high-frequency operation.
[0011] Preferably, the mold has multiple cooling ports, which are respectively connected to the left and right sides of the mounting groove. The positions of the multiple cooling ports correspond to the positions of the inlet and outlet when the cooling ring is attached to the top of the mounting groove. A connecting pipe is slidably connected to the cooling port on the side corresponding to the inlet. The connecting pipe is a blind pipe, and a drain outlet is provided on the side wall of the connecting pipe near the inlet. A No. 1 spring is sleeved on the connecting pipe, and the two ends of the No. 1 spring are respectively connected to the inner wall of the cooling port and the connecting pipe. A No. 1 one-way valve is provided in the cooling port on the side corresponding to the outlet. When the cooling ring slides upward under the drive of the lever mechanism to attach to the top of the mounting groove, the inlet and outlet on the cooling ring are aligned with the cooling ports on the mold. A connecting pipe is slidably connected to the cooling port on the side of the inlet. This connecting pipe is a blind pipe with a drain outlet on its side wall and is sleeved with a No. 1 spring. In the unconnected state, the connecting pipe retracts into the cooling port under the action of spring number one, not contacting the inlet. Once the cooling ring is in place, the external coolant pump starts, and the coolant pressure pushes the connecting pipe towards the inlet. The end of the connecting pipe pushes open the trigger mechanism inside the inlet, and simultaneously, the drain port enters the inlet, allowing coolant to flow into the cooling channel. A check valve number one is installed in the cooling port on the outlet side. When coolant flows back from the cooling channel, the pressure opens the check valve number one, allowing coolant to return to the cooling pump. This structure achieves automatic connection and sealing of the coolant circuit after the cooling ring moves into place, without the need for additional solenoid valves or manual operation. Furthermore, spring number one automatically pulls the connecting pipe back after the coolant pressure is released, preventing fatigue of the seals due to prolonged compression.
[0012] Preferably, a trigger cap is slidably connected inside the inlet, and a second spring connects the end of the trigger cap away from the connecting pipe to the inner wall of the cooling ring. A second check valve is installed inside the outlet. The trigger cap, slidably connected inside the inlet, moves into the cooling ring against the spring force of the second spring under the push of the connecting pipe. This displacement opens the internal channel of the inlet, allowing coolant to smoothly enter the cooling channel. When the connecting pipe is withdrawn, the second spring pushes the trigger cap back to its original position, closing the inlet and preventing coolant leakage during non-operational periods. The second check valve installed inside the outlet works in conjunction with the first check valve to ensure unidirectional circulation of coolant within the cooling channel. Coolant enters through the inlet, flows through the annular cooling channel, and exits through the outlet, preventing turbulence or backflow within the channel and ensuring the stability and repeatability of cooling efficiency. This combination of the trigger cap and the second spring also acts as a buffer, preventing rigid impact between the connecting pipe and the inlet and extending the service life of the sealing interface.
[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention detachably embeds the device body into the bottom of the injection mold, and sets a wedge-shaped magnetic pole head on the side of the ultra-high frequency induction coil body facing the cavity, so that its tip is directly facing the straight area of the weld line. By utilizing the ultra-high frequency skin effect and the tip magnetic flux compression effect, electromagnetic energy is forcibly focused into a narrow band of 3-5mm to achieve a second-level temperature rise. This avoids the slow thermal response and disordered heat diffusion caused by traditional resistance heating that relies on heat conduction. At the same time, the modular embedded structure allows for quick replacement of the coil without disassembling the entire mold when it is damaged, ensuring the high response speed, precise local heating capability and convenient maintenance of the weld line elimination device.
[0014] 2. This invention sets the magnetic collecting pole head as a gathering part and a base. The base is located at the center of the ultra-high frequency induction coil body. The coil body has a conical spiral structure with its diameter gradually decreasing towards the cavity direction. The taper matches the contour of the magnetic collecting pole head, so that the electromagnetic field energy is directionally concentrated along the contour line of the magnetic collecting pole head. The magnetic flux density in the weld line area is increased by 3-5 times compared with the traditional planar coil. This avoids the warping and deformation of non-target areas or the thermal degradation of plastic caused by the dispersion of heating energy, and ensures the energy density and directionality of induction heating.
[0015] 3. This invention features a cooling ring surrounding the isolation cover, with an annular cooling channel inside the cooling ring that circulates with an external cold pump. A cylinder drives the isolation cover and the magnetic pole head to move as a whole, and a lever mechanism enables reverse linkage between the cooling ring and the isolation cover. When the magnetic pole head heats up, the cooling ring moves away from the mold; when the magnetic pole head detaches, the cooling ring automatically adheres to the mold for forced cooling. This avoids residual heat from the heating components prolonging the injection molding cycle or affecting product demolding, ensuring the reliability of rapid heating and cooling cycles and improving injection molding production efficiency. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structure of the ultra-high frequency induction coil embedded weld line elimination device for injection molds of the present invention; Figure 2 This is a diagram showing the state of the ultra-high frequency induction coil embedded weld line elimination device for injection molds during heating, as described in this invention. Figure 3 This is a diagram showing the cooling state of the ultra-high frequency induction coil embedded weld line elimination device for injection molds according to the present invention. Figure 4 For the present invention Figure 3 A magnified view of a section at point A in the middle; Figure 5 This is a state diagram of the connecting pipe when it is conducting according to the present invention; Figure 6 For the present invention Figure 3 Sectional view at point BB; Figure 7 For the present invention Figure 3 Sectional view at point CC.
[0017] In the diagram: 1. Device body; 2. Ultra-high frequency induction coil body; 3. Collecting pole head; 301. Bundling part; 302. Base; 4. Mounting slot; 401. Cooling port; 5. Isolation cover; 6. Cooling ring; 601. Cooling channel; 602. Liquid inlet; 603. Liquid outlet; 7. Cylinder; 701. Cylinder body; 702. Piston rod; 801. Push rod No. 1; 802. Push rod No. 2; 803. Push rod No. 3; 804. Connecting rod; 901. Connecting pipe; 902. Drain port; 903. Spring No. 1; 904. Check valve No. 1; 905. Trigger cap; 906. Spring No. 2; 907. Check valve No. 2. Detailed Implementation
[0018] Please see Figures 1 to 7 This invention provides an embedded weld line elimination device for ultra-high frequency induction coils used in injection molds, the technical solution of which is as follows: A device for eliminating weld lines embedded in an ultra-high frequency induction coil for injection molds, please refer to [link / reference]. Figures 1 to 7The device includes a main body 1, an ultra-high frequency induction coil body 2, and a magnetic pole head 3. A mounting groove 4 is provided at the bottom of the fixed mold of the injection mold. The main body 1 is detachably embedded in the mounting groove 4. The ultra-high frequency induction coil body 2 is installed inside the main body 1 and is electrically connected to an external ultra-high frequency power supply. The magnetic pole head 3 is located on the side of the ultra-high frequency induction coil body 2 facing the mold cavity. The magnetic pole head 3 is wedge-shaped, and its tip faces the straight area generated by the weld line inside the mold cavity. The magnetic pole head 3 includes a gathering part 301 and a base 302, located at the upper and lower ends of the magnetic pole head 3, respectively. The base 302 of the magnetic pole head 3 is located at the center of the ultra-high frequency induction coil body 2. The main body 2 has a conical spiral structure. The diameter of the ultra-high frequency induction coil main body 2 gradually decreases from the inside of the device main body 1 towards the mold cavity, and the taper of the ultra-high frequency induction coil main body 2 matches the contour of the magnetic pole head 3. An isolation cover 5 is provided around the magnetic pole head 3 and the ultra-high frequency induction coil main body 2. The isolation cover 5 is made of zirconium oxide ceramic. A cooling ring 6 is fitted around the isolation cover 5. A cooling channel 601 is opened in a ring inside the cooling ring 6. The cooling ring 6 has a liquid inlet 602 and a liquid outlet 603. The cooling channel 601 is circulated with an external cold pump through the liquid inlet 602 and the liquid outlet 603. The magnetic pole head 3, the ultra-high frequency induction coil main body 2 and the isolation cover 5 are fixedly connected. A cylinder 7 is provided inside the device main body 1. The cylinder body 70 1. Fixedly installed on the device body 1, the piston rod 702 of the cylinder 7 is fixedly connected to the lower end face of the isolation cover 5, the inner ring of the cooling ring 6 is slidably connected to the isolation cover 5, and the outer ring of the cooling ring 6 is slidably connected to the inner side wall of the mounting groove 4. The cooling ring 6 and the isolation cover 5 are also connected by a lever mechanism, which includes a first push rod 801, a second push rod 802, a third push rod 803, and a connecting rod 804. The first push rod 801 and the second push rod 802 are respectively installed on the lower end faces of the isolation cover 5 and the cooling ring 6, respectively. The third push rod 803 is installed on the upper end face of the device body 1. The middle part of the connecting rod 804 is hinged to the upper end face of the third push rod 803, and the two ends of the connecting rod 804 are respectively slidably hinged to the lower end faces of the first push rod 801 and the second push rod 802. Multiple cooling ports 401 are provided on the top, and these ports 401 are respectively connected to the left and right sides of the mounting groove 4. The positions of the multiple cooling ports 401 correspond to the positions of the liquid inlet 602 and the liquid outlet 603 when the cooling ring 6 is attached to the top of the mounting groove 4. A connecting pipe 901 is slidably connected inside the cooling port 401 on the side corresponding to the liquid inlet 602. The connecting pipe 901 is a blind pipe, and a drain port 902 is provided on the side wall of the connecting pipe 901 near the liquid inlet 602. A first spring 903 is sleeved on the connecting pipe 901, and the two ends of the first spring 903 are respectively connected to the inner wall of the cooling port 401 and the connecting pipe 901. A first check valve 904 is provided inside the cooling port 401 on the side corresponding to the liquid outlet 603. A trigger cap 905 is slidably connected inside the liquid inlet 602.A second spring 906 connects the end of the trigger cap 905 away from the connecting pipe 901 to the inner wall of the cooling ring 6, and a second check valve 907 is installed inside the liquid outlet 603.
[0019] When working, please refer to Figures 1 to 7 Before injection molding, the output power, heating time, and cooling parameters of the ultra-high frequency power supply are set by an external control system based on the specific location of the weld line in the mold cavity and the material of the product. The entire device body 1 is embedded into the mounting groove 4 at the bottom of the injection mold and fixed with a locking nut to ensure that the wedge-shaped tip of the magnetic pole head 3 is precisely aligned with the straight area generated by the weld line. After the injection molding machine closes the mold, the control system issues a heating command, the piston rod 702 of the cylinder 7 extends, and pushes the isolation cover 5 and the magnetic pole head 3 and the ultra-high frequency induction coil body 2 fixedly connected to it to move towards the mold cavity, shortening the distance between the tip of the magnetic pole head 3 and the back of the cavity to 0.5 to 1 mm. Then the ultra-high frequency power supply is activated, and the ultra-high frequency induction coil body 2 generates a high-frequency alternating magnetic field. Using a conical spiral structure, the electromagnetic energy is directionally concentrated along the contour line of the magnetic pole head 3. Through the magnetic flux compression effect of the wedge-shaped tip, the electromagnetic energy is forcibly focused into a narrow band of 3 to 5 mm, causing the corresponding area on the surface of the mold cavity to rapidly heat up to above the heat distortion temperature of the plastic within 1 to 2 seconds. At this point, the injection molding machine begins injection. When the plastic melt flows through the weld line confluence area, it maintains good fluidity due to the high temperature on the cavity surface, and the two or more melts fully fuse together, thereby eliminating the weld line.
[0020] After injection, the ultra-high frequency power supply stops heating, and the control system issues a cooling command. The piston rod 702 of cylinder 7 retracts, causing the isolation cover 5, the magnetic pole head 3, and the ultra-high frequency induction coil body 2 to move backward as a whole, disengaging from the back of the mold cavity to prevent residual heat from affecting the cooling effect. Simultaneously, the first push rod 801, fixed to its lower end face, drives the second push rod 802, fixedly connected to the cooling ring 6, via the connecting rod 804 and the hinged third push rod 803. This causes the cooling ring 6 to move in the opposite direction along the inner wall of the mounting groove 4, i.e., sliding towards the back of the mold cavity until it is in contact with the mold. Once the cooling ring 6 is in place, the connecting pipe 901 inside the cooling port 401 on the mold extends under the pressure of the coolant, pushing open the trigger cap 905 inside the inlet 602. The coolant enters the annular cooling channel 601 inside the cooling ring 6 through the outlet 902, flowing in from the inlet 602 and out from the outlet 603, forming a circulating cooling system. The coolant rapidly absorbs the heat transferred by the isolation shield 5, cooling the device body 1 and the corresponding area of the cavity to the temperature required for the next injection molding cycle within 3 to 5 seconds. The first check valve 904 at the outlet 603 and the second check valve 907 in the inlet 602 ensure unidirectional flow of the coolant, preventing turbulence or backflow. Once cooling is complete and the mold is opened, the piston rod 702 of the cylinder 7 remains retracted, the coolant pressure is released, the connecting pipe 901 resets under the action of the first spring 903, and the trigger cap 905 closes the inlet 602 under the action of the second spring 906. The entire device is then in standby mode, awaiting the next injection molding cycle. This rapid switching between heating and cooling achieves a synergy between weld line elimination and efficient production.
[0021] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.
Claims
1. A device for eliminating weld lines embedded in an ultra-high frequency induction coil for injection molds, characterized in that, The device includes a device body (1), an ultra-high frequency induction coil body (2), and a magnetic pole head (3). The bottom of the injection mold fixed mold is provided with an installation groove (4). The device body (1) is detachably embedded in the installation groove (4). The ultra-high frequency induction coil body (2) is installed in the device body (1). The ultra-high frequency induction coil body (2) is electrically connected to an external ultra-high frequency power supply. The magnetic pole head (3) is located on the side of the ultra-high frequency induction coil body (2) facing the mold cavity. The magnetic pole head (3) is wedge-shaped, and the tip of the magnetic pole head (3) faces the straight area generated by the weld line in the mold cavity. The magnetic pole head (3) includes a gathering part (301) and a base (302). The gathering part (301) and the base (302) are located at the upper and lower ends of the magnetic pole head (3), respectively. The base (302) of the magnetic pole head (3) is located at the center of the ultra-high frequency induction coil body (2). The ultra-high frequency induction coil body (2) has a conical spiral structure. The diameter of the ultra-high frequency induction coil body (2) gradually decreases from the inside of the device body (1) towards the mold cavity. The taper of the ultra-high frequency induction coil body (2) matches the outline of the magnetic pole head (3). An isolation cover (5) is provided around the magnetic pole head (3) and the ultra-high frequency induction coil body (2). A cooling ring (6) is sleeved around the isolation cover (5). A cooling channel (601) is opened in the annular shape inside the cooling ring (6). The magnetic pole head (3), the ultra-high frequency induction coil body (2) and the isolation cover (5) are fixedly connected. A cylinder (7) is provided inside the device body (1). The cylinder body (701) of the cylinder (7) is fixedly installed on the device body (1). The piston rod (702) of the cylinder (7) is fixedly connected to the lower end face of the isolation cover (5). The inner ring of the cooling ring (6) is slidably connected to the isolation cover (5), and the outer ring of the cooling ring (6) is slidably connected to the inner side wall of the mounting groove (4). The cooling ring (6) and the isolation cover (5) are also connected by a lever mechanism. The lever mechanism includes a first push rod (801), a second push rod (802), a third push rod (803), and a connecting rod (804). The first push rod (801) and the second push rod (802) are respectively installed on the lower end face of the isolation cover (5) and the cooling ring (6). The third push rod (803) is installed on the upper end face of the device body (1). The middle part of the connecting rod (804) is hinged to the upper end face of the third push rod (803). The two ends of the connecting rod (804) are respectively slidably hinged to the lower end face of the first push rod (801) and the second push rod (802).
2. The ultra-high frequency induction coil embedded weld line elimination device for injection molds according to claim 1, characterized in that: The isolation cover (5) is made of ceramic material, including any one of zirconium oxide ceramic, alumina ceramic or silicon nitride ceramic.
3. The ultra-high frequency induction coil embedded weld line elimination device for injection molds according to claim 2, characterized in that: The cooling ring (6) is provided with an inlet (602) and an outlet (603), and the cooling channel (601) is circulated with an external cold pump through the inlet (602) and the outlet (603).
4. The ultra-high frequency induction coil embedded weld line elimination device for injection molds according to claim 3, characterized in that: The mold has multiple cooling ports (401), which are connected to the left and right sides of the mounting groove (4) respectively. The positions of the multiple cooling ports (401) correspond to the positions of the inlet (602) and outlet (603) when the cooling ring (6) is attached to the top of the mounting groove (4). A connecting pipe (901) is slidably connected in the cooling port (401) on the side corresponding to the inlet (602). The connecting pipe (901) is a blind pipe. A drain port (902) is provided on the side wall of the connecting pipe (901) near the inlet (602). A first spring (903) is sleeved on the connecting pipe (901). The two ends of the first spring (903) are connected to the inner wall of the cooling port (401) and the connecting pipe (901) respectively. A first check valve (904) is provided in the cooling port (401) on the side corresponding to the outlet (603).
5. The ultra-high frequency induction coil embedded weld line elimination device for injection molds according to claim 4, characterized in that: A trigger cap (905) is slidably connected inside the liquid inlet (602). A second spring (906) is connected between the end of the trigger cap (905) away from the connecting pipe (901) and the inner wall of the cooling ring (6). A second one-way valve (907) is installed inside the liquid outlet (603).