Radome extrusion die

Abstract

The utility model relates to the technical field of radome production, and discloses a radome extrusion die, which comprises a curved movable die and a curved fixed die, the curved fixed die is fixedly connected with an extruder, one side of the curved movable die far away from the curved fixed die is provided with an air cylinder, and the air cylinder is used for driving the curved movable die to move linearly. The movable curved mold comprises an outer mold and an inner mold, and the inner mold is connected into the outer mold in a running fit mode. According to the radome extrusion die, through the cooperative action between the built-in core rod and the outer die, a better flowing path can be provided, bubbles can be eliminated by rotating the core rod, and the surface smoothness of a product is improved. Besides, a high-precision rotating mechanism and a high-precision cooling system are utilized, the more efficient material injection molding and forming process can be achieved, and therefore the production period is shortened, and the product quality and the production efficiency are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of radome production, in particular to an extrusion die for a radome. Background Technique

[0002] Radomes are mainly made of wave-transparent polymers (such as polycarbonate PC, fluoroplastics PTFE, high-temperature nylon PA66) or composite materials. The core function is to protect the antenna from rain, sand, electromagnetic interference and mechanical damage, while maintaining the signal transmission efficiency.

[0003] Common geometric shapes of radomes include conical or hemispherical, which are suitable for short-wave communication, focusing the radiation direction and reducing sidelobe interference.

[0004] Traditional molds are composed of a rigid fixed mold and a moving mold. The mold cavity is an integral hemispherical structure without a dynamic adjustment mechanism at the top. The gap between the mold core and the mold cavity is fixed, usually 0.5 - 1.2 mm. The gating system adopts a single center gate design. Under the single gate system, the melt exhibits the characteristics of "fountain flow". The front end of the flow is blocked by the low-temperature mold wall when contacting it, hindering the subsequent filling of the melt. In actual production, when the melt radiates from the center to the surrounding, in the region of sudden change in the hemispherical curvature, such as the transition region between the top and the side wall, a flow separation phenomenon occurs:

[0005] When the front end of the melt reaches the transition region with a radius of curvature R < 30 mm, the flow velocity decreases, which may lead to the accumulation of the melt, and the air in the closed region at the top cannot be discharged, and then bubbles may be formed, resulting in a high product rejection rate. When the injection molding is completed, a long cooling process is required, increasing the production cost and having a low production efficiency.

[0006] Therefore, we propose an extrusion die for a radome to solve the problems in the above background. Content of the Utility Model

[0007] The utility model provides an extrusion die for a radome, which can solve the problems in the prior art that for the molding of complex curved surface products by a fixed mold, the fluidity inside the mold cavity at the curved surface position is poor, resulting in low production efficiency and high product rejection rate.

[0008] To solve the above technical problems, the utility model provides the following technical solutions:

[0009] An antenna radome extrusion die includes a curved movable die and a curved fixed die. The curved fixed die is fixedly connected to an extruder. A cylinder is installed on one side of the curved movable die away from the curved fixed die, and the cylinder is used to drive the linear movement of the curved movable die. The curved movable die includes an outer die and an inner die. The inner die is rotationally and fittingly connected inside the outer die. The inner wall of the inner die is a hemispherical groove. The outer surface of one end of the curved fixed die close to the curved movable die is a hemispherical surface. The curved fixed die cooperates with the inside of the curved movable die to form a hemispherical antenna radome die groove. A rod hole is opened inside the inner die, and the rod hole penetrates through both ends of the inner die. A core rod is slidably connected inside the rod hole. One end of the core rod extends into the inner part of the inner die, and the end of the core rod located inside the inner die is adapted to the inner wall radian of the inner die. When the core rod retracts into the rod hole, the inner wall of the inner die and the end of the core rod remain flat and smooth. A driving member for driving the rotation of the inner die is installed inside the outer die.

[0010] Compared with the prior art, the beneficial effects achieved by the present utility model are as follows:

[0011] The antenna radome extrusion die of the present utility model effectively solves the problems of low forming efficiency and high rejection rate of complex curved surface products in traditional fixed die forming. During the injection molding stage, the curved movable die and the curved fixed die are closed to form a hemispherical antenna radome die groove. The cylinder drives the linear movement of the curved movable die. The micro electric telescopic rod pushes the core rod into the die groove. The stepping motor drives the rotation of the inner die, and the core rod also rotates accordingly. The molten material is guided to flow from the edge of the die groove to the top by centrifugal force, reducing the formation of bubbles. When the cavity filling degree reaches 95%, the core rod retracts in stages to avoid the formation of a vacuum hollow. The nanoscale fit between the end of the core rod and the cavity curved surface ensures a smooth surface. The three-dimensional heat exchange network formed by the cooperation of the inner and outer dies cools evenly through the circulating coolant, enabling the material in the cavity to cool and solidify quickly. The intelligent temperature control system dynamically adjusts the coolant flow according to the feedback of the infrared sensor to maintain the axial temperature difference in the cavity within ±2°C. During the pressure holding stage, the core rod retracts in stages. The cooling system maintains the melt crystallization temperature. The inner die compacts the product using centrifugal force. Finally, the cooling system switches to the high-speed mode, enabling the product to drop below the glass transition temperature within 30 seconds. Finally, the core rod completely retracts, and the cylinder opens the mold to take out the finished product. This dynamic rotating die core and the progressive retraction mechanism of the core rod significantly reduce the bubble occurrence rate, avoid the depression defects caused by volume shrinkage, greatly improve the forming efficiency and material utilization rate, and at the same time reduce the working pressure of the extruder, saving energy and reducing consumption. Description of the Drawings

[0012] Figure 1 It is a schematic structural diagram of one end of the fixed die of the present utility model;

[0013] Figure 2 It is a schematic external connection structural diagram of the movable die of the present utility model;

[0014] Figure 3Schematic diagram of the overall unfolded structure of the present utility model;

[0015] Figure 4 Schematic diagram of the overall sectional structure of the present utility model;

[0016] Figure 5 Schematic diagram of the overall unfolded sectional structure of the present utility model.

[0017] Wherein: 1, moving die; 2, cylinder; 3, fixed die; 4, finished radome; 11, outer die; 12, inner die; 13, core rod; 14, linkage plate; 15, micro electric telescopic rod; 16, linkage cover; 17, stepping motor; 18, diversion channel; 31, feed pipe; 32, docking valve; 33, conical interface; 34, stable seat; 35, spiral diversion pipe; 36, inlet; 37, outlet. Specific embodiments

[0018] The following describes the specific embodiments of the present utility model in detail, but it should be understood that the protection scope of the present utility model is not limited by the specific embodiments.

[0019] Embodiment 1:

[0020] Please refer to Figures 1-4 , the present utility model provides a technical solution:

[0021] A radome extrusion die includes a curved moving die 1 and a curved fixed die 3. The curved fixed die 3 is fixedly connected to an extruder. A cylinder 2 is installed on one side of the curved moving die 1 away from the curved fixed die 3. The cylinder 2 is used to drive the linear movement of the curved moving die 1. The curved moving die 1 includes an outer die 11 and an inner die 12. The inner die 12 is rotationally and slidably connected inside the outer die 11. The inner wall of the inner die 12 is a hemispherical groove. The outer surface of one end of the curved fixed die 3 close to the curved moving die 1 is hemispherical. The curved fixed die 3 cooperates with the inside of the curved moving die 1 to form a hemispherical radome die groove. A rod hole is opened inside the inner die 12. The rod hole penetrates through both ends of the inner die 12. A core rod 13 is slidably connected inside the rod hole. One end of the core rod 13 extends into the inner die 12. The end of the core rod 13 located inside the inner die 12 is adapted to the inner wall radian of the inner die 12. When the core rod 13 contracts inside the rod hole, the inner wall of the inner die 12 and the end of the core rod 13 are kept flat and smooth. A driving member for driving the rotation of the inner die 12 is installed inside the outer die 11.

[0022] Further, a plurality of rod holes are provided and evenly distributed on the inner mold 12. One end of the core rod 13 located outside the inner mold 12 is fixedly connected to a linkage plate 14. One end of the inner mold 12 close to the driving member is fixedly connected to a linkage cover 16. A micro electric telescopic rod 15 is installed inside the linkage cover 16. One end of the micro electric telescopic rod 15 is fixedly connected to the outer mold 11, and the other end is fixedly connected to the linkage plate 14. The micro electric telescopic rod 15 pushes the linkage plate 14 to slide. A driving chamber is provided at a position inside the outer mold 11 close to the linkage cover 16. The driving member is installed inside the driving chamber. The driving member is a stepping motor 17. The driving end of the stepping motor 17 is fixedly connected to the center of the end of the linkage cover 16. The body of the stepping motor 17 is fixedly connected to the inside of the outer mold 11. A laser displacement sensor is installed on the linkage cover 16. The monitoring end of the laser displacement sensor faces the inner mold 12 and is used to monitor the displacement of the core rod 13.

[0023] Retractable core rods 13 are arranged in the rod holes circumferentially distributed on the inner mold 12. A plurality of core rods 13 are distributed in an array. The micro electric telescopic rod 15 realizes the synchronous telescopic control of the core rods 13 through the linkage plate 14. During the injection molding stage, the core rods 13 extend to form a dynamic stirring structure, and their rotational movement generates a centrifugal force field, effectively guiding the molten material to flow from the edge of the mold cavity to the top. When the filling degree of the mold cavity reaches 95%, the core rods 13 retract in stages according to a predetermined program to avoid forming vacuum bubbles. The nano-level matching accuracy between the end of the core rod 13 and the curved surface of the mold cavity ensures the surface finish.

[0024] The curved fixed mold 3 is fixedly connected to the extruder through a stable seat 34. The outer surface of one end of the curved fixed mold 3 close to the curved moving mold 1 is hemispherical. The inside of the curved fixed mold 3 cooperates with the curved moving mold 1 for the forming of a hemispherical radome. When performing extrusion molding, the air cylinder 2 pushes the curved moving mold 1 to close with the curved fixed mold 3. The micro electric telescopic rod 15 pushes the linkage plate 14 to slide. The linkage plate 14 pushes a plurality of core rods 13 into the hemispherical radome mold groove. At the same time, the stepping motor 17 drives the linkage cover 16 to rotate. The linkage cover 16 drives the inner mold 12 to rotate. The core rods 13 rotate simultaneously with the inner mold 12. The extruded molten material flows from the edge of the hemispherical radome mold groove to the top. The inner mold 12 drives the array-distributed core rods 13 to rotate simultaneously. By the rotation of the core rods 13, the flow of the molten material can be increased and the bubbles can be reduced. At the same time, when the hemispherical radome mold groove is almost filled with molten material, the core rods 13 gradually withdraw. By monitoring the extrusion melt volume of the extruder, the volume of the molten material inside the hemispherical radome mold groove can be obtained. It is also possible to observe the amount of molten material inside the hemispherical radome mold groove through a thermal imaging monitor;

[0025] The cylinder 2 drives the moving die 1 to linearly move to complete the mold opening and closing actions, ensuring the mold closing accuracy during the forming process of the radome finished product 4. The moving die 1 adopts an inner and outer nested structure. The outer die 11 provides rigid support, and the inner die 12 is driven by a stepping motor 17 to achieve a 360° rotation, forming a dynamic forming environment. When demolding the radome finished product 4, the cylinder 2 contracts, separating the curved moving die 1 from the curved fixed die 3. The core rod 13 is pushed by the micro electric telescopic rod 15, and the core rod 13 enters the inside of the inner die 12, which helps to separate the radome finished product 4 from the inside of the curved moving die 1.

[0026] Furthermore, a diversion channel 18 is arranged inside the inner die 12. The diversion channel 18 is distributed along the inner wall direction of the hemispherical groove of the inner die 12, and the diversion channel 18 is not communicated with the inside of the hemispherical groove. An annular channel is arranged inside the outer die 11. The diversion channel 18 is rotationally communicated with the annular channel. A liquid inlet is arranged on one side of the annular channel, and a liquid outlet is arranged on the symmetric other side. A spiral diversion pipe 35 is installed inside the curved fixed die 3. The spiral diversion pipes 35 are evenly distributed inside the curved fixed die 3. One end of the spiral diversion pipe 35 is fixedly communicated with an inlet 36, and the other end is fixedly communicated with an outlet 37. The diversion channels 18 are radially distributed from the center to the edge inside the inner die 12.

[0027] The annular channel inside the outer die 11 and the radial diversion channels 18 of the inner die 12 constitute a three-dimensional heat exchange network. The coolant is injected from the liquid inlet, rotates and flows along the annular channel and then is divided into each diversion channel 18, forming uniform cooling of the cavity surface. The coolant usually adopts ethylene glycol solution. The spiral diversion pipes 35 arranged inside the fixed die 3 are evenly surrounded inside the hemispherical fixed die 3. The coolant enters through the inlet 36 and is discharged through the outlet 37, realizing uniform cyclic cooling of the cavity surface. Furthermore, an intelligent temperature control system is installed on this extrusion die. Infrared sensors are installed on both the curved moving die 1 and the curved fixed die 3. The intelligent temperature control system dynamically adjusts the coolant flow according to the feedback of the infrared sensors, realizing that the axial temperature difference of the cavity is controlled within ±2°C.

[0028] Further, a stabilizing seat 34 is provided at one end of the curved fixed mold 3 away from the outer mold 11. The stabilizing seat 34 is used to realize the fixed connection between the curved fixed mold 3 and the extruder. Inside the end of the curved fixed mold 3 away from the outer mold 11, a feed pipe 31 is fixedly connected. One end of the feed pipe 31 away from the curved fixed mold 3 is fixedly connected with a docking valve 32. A conical interface 33 is provided at one end of the docking valve 32 facing the outside of the curved fixed mold 3. The conical interface 33 is used for plugging and communicating with the discharge end of the extruder barrel of the extruder. There are multiple feed pipes 31, which are arranged in a circumferential array centered on the docking valve 32. An electric heating type heat preservation sleeve is arranged outside the feed pipe 31. The multiple feed pipes 31 are beneficial to quickly and evenly feed the inside of the hemispherical cavity. The electric heating type heat preservation sleeve is used to adjust the temperature of the feed pipe 31 to ensure the fluidity of the molten material inside the feed pipe 31.

[0029] The specific working principle of this radome extrusion mold is as follows: In the injection molding stage, after the mold is closed, the extruder injects molten material at a pressure of 0.5 - 2 MPa. Synchronously start the rotation of the inner mold 12 and the extension of the core rod 13. The rotational shear force reduces the viscosity of the molten material and increases the flow length. The array - distributed core rods 13 form a gear - pump - like effect, continuously pumping the molten material at the edge of the cavity to the top blind area.

[0030] In the pressure - holding stage, when the cavity is filled to 90%, the core rod 13 starts to retract step - by - step at a speed of 0.1 mm / s, and the retraction amount is closed - loop controlled by a laser displacement sensor. In the initial stage of this stage, the cooling system starts circulating to maintain the crystallization temperature of the melt. In the shaping stage, after the cavity is completely filled, the rotation speed of the inner mold 12 is increased to 50 rpm and lasts for 10 seconds to compact the radome finished product 4 by using centrifugal force. The cooling system switches to the high - speed mode, so that the surface temperature of the radome finished product 4 drops below the glass transition temperature within 30 seconds. Finally, the core rod 13 completely retracts, the cylinder 2 contracts, and the mold is opened to take out the radome finished product 4.

[0031] By dynamically rotating the mold core, the bubble generation rate is reduced compared with the traditional process. The progressive retraction mechanism of the core rod 13 eliminates the depression defects caused by volume shrinkage. Compared with the traditional mold, the molding cycle is shortened, the material utilization rate is increased, and the shunt design of the diversion pipe system reduces the working pressure of the extruder, reducing energy consumption.

[0032] The above - disclosed are only several specific embodiments of the present utility model. However, the embodiments of the present utility model are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present utility model.

Claims

1. A radome extrusion die, comprising a curved movable die (1) and a curved fixed die (3), characterized in that: The curved fixed mold (3) is fixedly connected to the extruder, and a cylinder (2) is installed on the side of the curved movable mold (1) away from the curved fixed mold (3). The cylinder (2) is used to drive the curved movable mold (1) to move linearly. The curved movable mold (1) includes an outer mold (11) and an inner mold (12). The inner mold (12) is rotatably connected to the inside of the outer mold (11). The inner wall of the inner mold (12) is a hemispherical groove. The outer side of one end of the curved fixed mold (3) close to the curved movable mold (1) is a hemispherical surface. The curved fixed mold (3) cooperates with the curved movable mold (1) to form A hemispherical antenna cover mold groove, wherein a rod hole is provided inside the inner mold (12), the rod hole passes through both ends of the inner mold (12), a core rod (13) is slidably connected inside the rod hole, one end of the core rod (13) extends into the inner mold (12), one end of the core rod (13) located inside the inner mold (12) is adapted to the curvature of the inner wall of the inner mold (12), when the core rod (13) is contracted inside the rod hole, the inner wall of the inner mold (12) and the end of the core rod (13) remain flat and smooth, and a driving member for driving the inner mold (12) to rotate is installed inside the outer mold (11).

2. The radome extrusion die according to claim 1, characterized in that: A plurality of rod holes are provided and evenly distributed on the inner mold (12); one end of the core rod (13) located outside the inner mold (12) is fixedly connected to a linkage plate (14).

3. The radome extrusion die according to claim 2, characterized in that: One end of the inner mold (12) close to the driving member is fixedly connected to a linkage cover (16), a micro electric telescopic rod (15) is installed inside the linkage cover (16), one end of the micro electric telescopic rod (15) is fixedly connected to the outer mold (11), and the other end of the micro electric telescopic rod (15) is fixedly connected to the linkage plate (14), and the micro electric telescopic rod (15) pushes the linkage plate (14) to slide.

4. The radome extrusion die according to claim 3, characterized in that: A drive chamber is provided inside the outer mold (11) near the linkage cover (16), and a drive component is installed inside the drive chamber. The drive component is a stepper motor (17). The drive end of the stepper motor (17) is fixedly connected to the center of the end of the linkage cover (16), and the end of the stepper motor (17) away from the linkage cover (16) is fixedly connected to the inside of the outer mold (11).

5. The radome extrusion die according to claim 1, characterized in that: A flow guide channel (18) is provided inside the inner mold (12), the flow guide channel (18) is distributed along the inner wall direction of the hemispherical groove of the inner mold (12), and the flow guide channel (18) is not connected to the inside of the hemispherical groove.

6. The radome extrusion die according to claim 5, characterized in that: An annular channel is provided inside the outer mold (11), and the guide channel (18) is rotatably connected to the annular channel.

7. The radome extrusion die according to claim 6, characterized in that: A liquid inlet is arranged on one side of the annular channel, and a liquid outlet is arranged on the other symmetrical side thereof.

8. The radome extrusion die according to claim 1, characterized in that: A stabilizing seat (34) is provided at one end of the curved fixed die (3) away from the outer die (11), and the stabilizing seat (34) is used for being fixedly connected to the extruder.

9. The radome extrusion die according to claim 8, characterized in that: A feed pipe (31) is fixedly connected to the interior of one end of the curved fixed mold (3) away from the outer mold (11); a docking valve (32) is fixedly connected to the end of the feed pipe (31) away from the curved fixed mold (3); a conical interface (33) is provided at one end of the docking valve (32) facing the outer side of the curved fixed mold (3); the conical interface (33) is used for plugging and connecting with the discharge end of the extruder barrel of the extruder.

10. The radome extrusion die according to claim 9, characterized in that: A plurality of feed pipes (31) are provided and are distributed in a circular array with the docking valve (32) as the center. An electrically heated insulation sleeve is provided outside the feed pipe (31). A volute-shaped flow guide pipe (35) is installed inside the curved fixed mold (3). The volute-shaped flow guide pipe (35) is evenly distributed inside the curved fixed mold (3). One end of the volute-shaped flow guide pipe (35) is fixedly connected to an inlet (36), and the other end thereof is fixedly connected to an outlet (37).

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