A gas-assisted co-extrusion multi-component plastic rod forming system

Abstract

The present invention relates to the technical field of plastic molding, and discloses a gas-assisted co-extrusion multi-component plastic rod forming system, which includes a gas-assisted part. The gas-assisted part is located at a position of the extruder body close to the discharge port, and the gas-assisted part includes fixing plates evenly embedded in the inner wall of the extruder body. The composite pipe of the invention adopts a design in which an L pipe, a middle pipe and a nozzle are sequentially arranged from top to bottom. When the internal pressure changes, the bending structure of the composite pipe plays a buffering role. When the gas flows through the bending part, its flow direction changes multiple times, which makes the gas molecules collide with the pipe wall and each other more frequently, thereby dissipating part of the gas kinetic energy. The bending part further hinders the melt backflow. When the melt attempts to backflow, the bending part forces it to change direction, increasing the flow resistance of the melt. The complex flow path formed by the bending also enables the gas to exert a reaction force on the melt, further preventing it from flowing backward.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic molding, and particularly relates to a multi-component plastic rod forming system for gas-assisted co-extrusion. Background Art

[0002] Due to the integration of the characteristics of multiple plastics, multi-component plastic rods have more excellent and diverse properties, showing unique advantages in application scenarios. Because of the complex composition of multi-component plastics and the differences in the fluidity of each component, uneven flow is likely to occur during molding, resulting in uneven density and properties in different parts of the rod. Therefore, during the extrusion process, the gas pressure and flow rate are adjusted by gas assistance. In the areas where the melt flow is slow, the gas exerts a greater pressure to promote the uniform flow of the melt, so that each part of the rod is filled evenly. Gas-assisted co-extrusion can form an air cushion film layer between the melt and the die wall, making the melt flow more smoothly, reducing the friction between the melt and the die, and avoiding defects such as surface scratches and weld marks, thereby obtaining a smoother and flatter surface quality and improving the mechanical and physical properties of the product.

[0003] However, during the extrusion process, because the melt has a certain viscosity under high temperature and high pressure, when the gas flow rate is insufficient or the melt temperature and pressure fluctuate, the temperature in the extruder decreases and the pressure changes. The residual melt, impurities in the raw materials, and additive aggregates are likely to enter the internal gas-assisted structure. Especially at the moment of shutdown, the melt pressure is unstable, and the residual melt and impurities will enter the gas-assisted structure along the gas channel, gradually blocking the gas channel. Summary of the Invention

[0004] Technical Problems to be Solved

[0005] Aiming at the above-mentioned disadvantages of the prior art, the present invention provides a multi-component plastic rod forming system for gas-assisted co-extrusion, which can effectively solve the problem that the gas channel in the prior art is easily blocked.

[0006] To achieve the above object, the present invention is realized through the following technical solutions:

[0007] The present invention provides a multi-component plastic rod forming system for gas-assisted co-extrusion, including an extruder main body;

[0008] A feed port, which is located at one end of the extruder main body for transporting multi-component plastic raw materials;

[0009] A discharge port, which is located at the other end of the extruder main body for outputting the molten raw materials;

[0010] The gas-assisted part is located at the position of the extruder main body close to the discharge port. The gas-assisted part includes a fixing plate evenly embedded in the inner wall of the extruder main body. A composite pipeline for ejecting gas is arranged on the inner wall of the fixing plate. The composite pipeline includes an L-shaped pipe, a middle pipe, and a nozzle arranged in sequence from top to bottom. Gas flows along the inner walls of the L-shaped pipe, the middle pipe, and the nozzle, changing the flow direction and accelerating the flow during the flow process, thereby increasing the difficulty of melt backflow;

[0011] Wherein, the composite pipeline (55) further includes a rotating ball (556) arranged inside the nozzle (553). The relative movement between the rotating ball (556) and the nozzle (553) cleans the inner wall of the nozzle (553);

[0012] A first positioning ring (5531) is fixedly connected to the top end of the nozzle (553). A fixing frame (555) is fixedly connected to the top end of the first positioning ring (5531). The top end of the fixing frame (555) is rotatably connected to the bottom end of the middle pipe (552);

[0013] A fixing shaft (5541) is fixedly connected to the middle of the top end of the fixing frame (555). Vanes (554) are fixedly connected to the outer wall of the fixing shaft (5541). The vanes (554) are located at the central position of the inner cavity of the middle pipe (552).

[0014] Further, the fixing plates are evenly distributed in the circumferential direction with the geometric center of the extruder main body as the reference point, arranged in a centrosymmetric shape around the center of the extruder main body, symmetrically surrounding the inner wall of the extruder main body in all directions. A fixing ring is snap-connected to the outer wall of the fixing plate. Two fixing rings are provided, respectively located at both ends of the fixing plate.

[0015] Further, the gas-assisted part further includes an air inlet located on the outer surface of the fixing ring. The bottom end of the air inlet is connected to the port of the composite pipeline. The bottom end of the composite pipeline is flush with the bottom end of the fixing plate.

[0016] Further, the top end of the L-shaped pipe is fixedly connected to the bottom end of the air inlet. The bottom end of the nozzle is flush with the bottom end of the fixing plate. A second positioning ring is fixedly connected to the outer wall of the bottom end of the nozzle. The second positioning ring is slidably sealed with a circular groove opened at the bottom end of the fixing plate.

[0017] Further, convex blocks are arranged on the outer wall of the rotating ball. The convex blocks are designed in a hemispherical shape and are arranged in a spiral form on the outer surface of the rotating ball.

[0018] The technical solution provided by the present invention has the following beneficial effects compared with the prior art:

[0019] The composite pipeline of the present invention adopts a design in which an L-shaped pipe, a middle pipe, and a nozzle are sequentially arranged from top to bottom. When the internal pressure changes, the bending structure of the composite pipeline plays a buffering role. When the gas flows through the bending part, its flow direction changes multiple times, which makes the gas molecules collide with the pipeline wall and with each other more frequently, thereby dissipating part of the gas kinetic energy. The bending part further hinders the melt from flowing back. When the melt attempts to flow back, the bending part forces it to change direction, increasing the flow resistance of the melt. The complex flow path formed by the bending also enables the gas to exert a reaction force on the melt, further preventing it from flowing backward.

[0020] The nozzle of the present invention adopts a design with a gradually decreasing diameter. The part with a smaller diameter will increase the gas flow velocity under the condition that the gas volume flow rate remains constant. The increase in flow velocity will lead to a decrease in pressure, which helps to regulate the pressure inside the extruder and enhances the stability of the extrusion process. At the same time, in terms of preventing the melt from flowing back, the design with a smaller diameter forms a high-speed gas flow at the vent, effectively resisting the melt from flowing back as a gas barrier.

[0021] The nozzle of the present invention is arranged parallel to the inner wall of the extruder body. When the nozzle rotates, a dynamic airflow field is formed around it. The airflow field forms a barrier between the nozzle and the melt, preventing the melt from directly entering. The centrifugal force generated by the rotation will cause the melt close to the nozzle to be thrown away from the nozzle, further reducing the possibility of the melt entering the nozzle.

[0022] The present invention is provided with a rotating ball. When the nozzle rotates, the rotating ball moves relative to it. The protrusions and patterns on the surface of the rotating ball continuously scrape the inner wall of the nozzle, effectively removing the melt residue. This self-cleaning process continuously occurs throughout the operation of the extruder body, avoiding the blockage of the nozzle caused by the accumulation of the melt, greatly reducing the equipment maintenance frequency, and improving the production continuity and efficiency.

[0023] When the pressure inside the extruder fluctuates, the synergistic effect of the nozzle and the rotating ball can play a certain buffering and pressure stabilizing effect. When the pressure increases, the rotational movement of the nozzle and the rotating ball can make the gas discharge more smoothly, alleviating the sharp rise in pressure. When the pressure decreases, their movement can prevent the gas from leaking too quickly, maintaining a certain pressure level, which helps to keep the relative stability of the air pressure inside the extruder body and ensure the smooth progress of the extrusion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 Schematic diagram of the overall structure of an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the split structure of the gas-assisted part of an embodiment of the present invention;

[0027] Figure 3 Schematic diagram of the split structure of the fixing plate of an embodiment of the present invention;

[0028] Figure 4 Schematic diagram of the composite pipe structure of an embodiment of the present invention;

[0029] Figure 5 Schematic diagram of the split structure of the composite pipe of an embodiment of the present invention;

[0030] Figure 6 Schematic diagram of the internal structure cross-section of the middle pipe of an embodiment of the present invention;

[0031] Figure 7 Schematic diagram of the internal structure of the nozzle of an embodiment of the present invention.

[0032] The reference numerals in the figure respectively represent: 1, main body of the extruder; 2, feed inlet; 3, discharge outlet; 5, gas-assisted part; 51, fixing ring; 52, fixing plate; 521, circular groove; 53, air inlet; 55, composite pipe; 551, L pipe; 552, middle pipe; 553, nozzle; 5531, positioning ring one; 5532, positioning ring two; 554, blade; 5541, fixing shaft; 555, fixing frame; 556, rotating ball; 5561, convex block. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0034] The present invention will be further described below with reference to the embodiments.

[0035] Embodiment:

[0036] Please refer to Figures 1-7 , the present invention provides a technical solution for a gas-assisted co-extrusion multi-component plastic rod forming system: as Figure 1 and Figure 2As shown in the figure, the device includes an extruder body 1, a feed inlet 2, a discharge outlet 3 and a gas-assisted part 5. The feed inlet 2 is located at one end of the extruder body 1 for transporting multi-component plastic raw materials, the discharge outlet 3 is located at the other end of the extruder body 1 for discharging the molten raw materials, and the gas-assisted part 5 is located at a position of the extruder body 1 close to the discharge outlet 3 to ensure that gas can be introduced in a timely and accurate manner during the process of the melt leaving the discharge outlet 3 and entering the mold cavity. At the same time, the gas-assisted part 5 includes a fixing plate 52 evenly embedded in the inner wall of the extruder body 1. A composite pipe 55 for ejecting gas is arranged on the inner wall of the fixing plate 52. The fixing plate 52 is evenly distributed in the circumferential direction with the geometric center of the extruder body 1 as the reference point, and is arranged in a centrosymmetric shape around the center of the extruder body 1, symmetrically surrounding the inner wall of the extruder body 1 in all directions. A fixing ring 51 is snap-connected to the outer wall of the fixing plate 52. The fixing ring 51 is provided in two, and is respectively located at both ends of the fixing plate 52. The gas is distributed around the melt with a relatively stable flow rate and pressure.

[0037] In the prior art, the composite pipe 55 is arranged in a straight tube shape. During the operation of the extruder body 1, when the melt flows back due to pressure change and easily enters the composite pipe 55, first, the melt will gradually accumulate and solidify, resulting in a decrease in the inner diameter of the composite pipe 55 or even complete blockage, greatly increasing the gas flow resistance, making the pressure of the gas-assisted system unstable. In severe cases, the gas supply may be interrupted, and the effective auxiliary pushing of the melt cannot be achieved, resulting in disorder in the extrusion molding process, and defects such as bubbles, material shortage, and uneven wall thickness in the product, seriously reducing the product quality. In addition, due to its simple structure, the flow pattern of the gas in the composite pipe 55 is single and easy to form laminar flow, which is not conducive to the full mixing of the gas and the melt, resulting in poor gas-assisted effect, and it is difficult to achieve uniform pressure application and precise control of the melt. In the face of complex pressure fluctuations inside the extruder, the straight tube lacks the ability to buffer and adjust pressure changes, and cannot effectively maintain a stable gas flow rate and pressure, further exacerbating the risk of melt backflow. In view of this, the composite pipe 55 of the present invention adopts a design in which an L-shaped pipe 551, a middle pipe 552 and a nozzle 553 are arranged in sequence from top to bottom. When the pressure inside the extruder body 1 changes, the bent structure of the composite pipe 55 plays a buffering role. When the gas flows through the bent part, its flow direction changes multiple times, which makes the gas molecules collide with the pipe wall and each other more frequently, thereby dissipating part of the gas kinetic energy. The bent part further hinders the melt backflow. When the melt attempts to flow back, the bent part forces it to change direction, increasing the flow resistance of the melt. The complex flow path formed by the bend also enables the gas to exert a reaction force on the melt, further preventing it from flowing backward.

[0038] Reference Figure 3 、 Figure 4 、 Figure 5 and Figure 6, the gas-assisted part 5 further includes an air inlet 53 located on the outer surface of the fixed ring 51. The bottom end of the air inlet 53 is connected to the port of the composite pipe 55. The bottom end of the composite pipe 55 is flush with the bottom end of the fixed plate 52. The top end of the L-shaped pipe 551 is fixedly connected to the bottom end of the air inlet 53. The bottom end of the nozzle 553 is flush with the bottom end of the fixed plate 52. A second positioning ring 5532 is fixedly connected to the outer wall of the bottom end of the nozzle 553. The second positioning ring 5532 is slidably sealed with the circular groove 521 opened at the bottom end of the fixed plate 52. A first positioning ring 5531 is fixedly connected to the top end of the nozzle 553. A fixing frame 555 is fixedly connected to the top end of the first positioning ring 5531. The top end of the fixing frame 555 is rotatably connected to the bottom end of the middle pipe 552. A fixing shaft 5541 is fixedly connected to the middle of the top end of the fixing frame 555. A blade 554 is fixedly connected to the outer wall of the fixing shaft 5541. The blade 554 is located at the central position of the inner cavity of the middle pipe 552.

[0039] The bottom end of the nozzle 553 is flush with the bottom end of the fixed plate 52. The gas discharged from the nozzle 553 can be combined with the melt more smoothly, without disturbing the normal flow path of the melt due to the protrusion of the nozzle 553, which helps to maintain the stable flow of the melt in the extruder body 1, reduces the melt turbulence and fluctuations caused by the air flow impact, and is more beneficial for the molding of products with high requirements for surface quality and dimensional accuracy. The flush design can avoid the formation of a melt retention area around the nozzle 553, reducing the risk of melt accumulation, solidification near the nozzle 553 and affecting gas discharge and subsequent extrusion process, which is conducive to maintaining the stability and continuity of the gas-assisted extrusion process; the nozzle 553 flush with the inner wall is more convenient for cleaning and maintenance of the extruder body 1, without dead corners that are difficult to reach due to the protrusion of the nozzle 553, which can effectively reduce melt residue and dirt accumulation, and reduce the maintenance cost and difficulty.

[0040] Gas is introduced at the air inlet 53. The gas flows in the composite pipe 55. The blade 554 arranged inside the middle pipe 552 rotates under the impact of the air flow, providing a direct power source for the rotating nozzle 553. The interaction area and angle between the blade 554 and the air flow are reasonably designed to ensure that sufficient torque is generated at a certain air flow speed and pressure. At this time, the blade 554 drives the fixing shaft 5541 to rotate, the fixing shaft 5541 drives the fixing frame 555 to rotate, and the fixing frame 555 drives the nozzle 553 to rotate stably, so that the nozzle 553 rotates at a set speed and direction, ensuring the operation stability of the gas-assisted system.

[0041] The nozzle 553 rotates, enabling the gas to be ejected into the melt at different angles and directions, avoiding the problem of uneven gas distribution caused by single-direction ejection and reducing the wall thickness deviation; the nozzle 553 drives the gas to mix more fully with the melt, and the gas can penetrate deeper into the interior of the melt. When producing complex plastic products, it effectively reduces the stress concentration inside the melt, reduces the possibility of defects such as cracks and deformations in the products, and improves the mechanical properties and stability of the products; during the rotation process, relative movement occurs between the surface of the nozzle 553 and the melt that may adhere to it, which can scrape off the melt residue on the air inlet 53, preventing the melt from accumulating and blocking the nozzle 553. At the same time, the centrifugal force generated by the rotation can throw the surrounding melt away from the nozzle 553 area, keeping the area around the nozzle 553 clean, ensuring the normal operation of the gas-assisted structure, and reducing production interruptions caused by nozzle 553 blockage.

[0042] The blades 554 in the middle tube 552 rotate under the impact of the air flow, and drive the nozzle 553 to rotate through the fixed shaft 5541 and the fixed frame 555, without the need for an additional external power source, simplifying the equipment structure and reducing energy consumption; the rotation of the blades 554 stirs the gas in the middle tube 552, enabling the gas to be more fully mixed before reaching the nozzle 553, further improving the dispersion uniformity of the gas in the melt. During the gas-assisted co-extrusion of plastics of different materials, it can promote better fusion of different gases and the melt, improving the overall quality of the product; the rotation of the blades 554 changes the speed and direction of the air flow, playing a certain buffering role for the air flow. When the pressure inside the extruder fluctuates, the blades 554 can adjust the flow rate and pressure of the air flow through their own rotational changes, making the gas entering the nozzle 553 more stable, enhancing the adaptability of the gas-assisted system to pressure changes, and reducing the risk of melt backflow caused by pressure fluctuations.

[0043] Reference Figure 4 、 Figure 5 and Figure 7 For

[0044] The agitation of the rotating ball 556 disrupts the laminar state of the air flow, promoting the mixing and diffusion of the gas, enabling the gas to act on the melt more uniformly. The turbulent air flow can also increase the frictional force between the gas and the melt, enhancing the driving effect of the gas on the melt. During the relative movement, the special shape on the surface of the rotating ball 556 will generate local vortices and turbulences around it. These vortices and turbulences will interact with the mainstream air flow, further enhancing the mixing degree of the air flow and making the distribution of the gas in the nozzle 553 more uniform. When the rotating ball 556 rotates, it drives the bumps 5561 on its surface to continuously scrape the inner wall of the nozzle 553. The point-contact method enables it to cover all positions of the inner wall of the nozzle 553 during rotation. The vertices and edges of the bumps 5561 continuously scrape the inner wall of the nozzle 553, gradually cleaning the melt residues adhering to it, reducing the accumulation of the melt on the inner wall of the nozzle 553. For the relatively large melt lumps that have formed, the shear force and impact force generated by the relative movement of the rotating ball 556 can break and disperse them. These broken small melt particles are more easily carried away by the air flow, preventing the melt lumps from blocking the nozzle 553. This self-cleaning process occurs continuously throughout the operation of the extruder, avoiding the blockage of the nozzle 553 caused by melt accumulation, greatly reducing the equipment maintenance frequency, improving production continuity and efficiency. Compared with continuous planar contact, the point-contact design can effectively extend the service life of the rotating ball 556 and the nozzle 553, reducing the equipment maintenance cost.

[0045] The gaps formed between the rotating ball 556 and the inner wall of the nozzle 553 provide a clear passage for the gas, ensuring that the gas can continuously and stably pass through the nozzle 553. Even when there is a certain amount of melt residue in the nozzle 553, these gaps can prevent the gas passage from being completely blocked, maintaining the normal operation of the gas-assisted system. The complex air flow pattern and uniform gas distribution enable the gas to contact and mix with the melt more fully, improving the penetration effect of the gas in the melt, thus enhancing the gas-assisted effect, increasing the gas utilization rate, and reducing gas consumption. The uniform gas distribution and good melt fluidity enable the melt to enter the mold cavity more smoothly, reducing the resistance and non-uniformity during the melt flow process, thereby improving the molding quality of the product. During the operation of the nozzle 553, the relative movement of the rotating ball 556 can clean the inner wall of the nozzle 553 in real time, avoiding the accumulation and solidification of melt residues. This not only reduces production interruptions and equipment failures caused by melt blockage of the nozzle 553 but also improves the production efficiency and the stability of product quality. Since the rotating ball 556 can automatically clean the inner wall of the nozzle 553, it greatly reduces the frequency and workload of manual cleaning of the nozzle 553. The operator does not need to frequently stop the machine to clean and maintain the nozzle 553, reducing the labor intensity and improving the production continuity.

[0046] The relative movement of both the nozzle 553 and the rotating ball 556 causes the air flow to form a complex flow field inside the nozzle 553, greatly enhancing the stirring effect of the air flow, making the air flow more evenly distributed around the nozzle 553, improving the penetration and mixing effect of the gas on the melt in the gas-assisted system, helping to improve the internal microstructure of the product and reduce defects; the relative movement of the nozzle 553 and the rotating ball 556 can achieve a more comprehensive cleaning inside the nozzle 553, reduce the risk of nozzle 553 blockage, extend the service life of the gas-assisted system, and ensure the continuity and stability of the extrusion process; when the pressure inside the main body 1 of the extruder fluctuates, the synergistic effect of the nozzle 553 and the rotating ball 556 can play a certain buffering and pressure stabilizing effect. When the pressure increases, the rotating movement of the nozzle 553 and the rotating ball 556 can make the gas discharge more smoothly, alleviating the sharp rise in pressure; when the pressure decreases, their movement can prevent the gas from leaking too quickly, maintaining a certain pressure level, helping to keep the air pressure inside the main body 1 of the extruder relatively stable, and ensuring the smooth progress of the extrusion process.

[0047] The blade 554 indirectly provides a rotating external environment for the rotating ball 556 by driving the nozzle 553 to rotate. The rotation of the nozzle 553 will change the flow state of the air flow inside the nozzle 553, causing the air flow to impact the rotating ball 556 at different angles and speeds, thereby affecting the rotation speed and direction of the rotating ball 556. A synergistic effect is achieved between the blade 554 and the rotating ball 556 through the nozzle 553, jointly optimizing the air flow and making the air flow in the gas-assisted system more reasonable and efficient; during the extrusion process, when parameters such as the air flow pressure and flow rate change, the blade 554 and the rotating ball 556 will perform adaptive adjustments through their respective interactions with the air flow. The blade 554 will adjust its rotation speed according to the change in the air flow, thereby affecting the rotation of the nozzle 553, and the rotating ball 556 will also adjust its own rotation state according to the change in the air flow state. This adaptive adjustment ability helps the gas-assisted system maintain good performance under different working conditions, improving the adaptability and stability of the system to process parameter changes.

[0048] The cooperation of the three increases the interface area between the gas and the melt, so that the gas can more fully contact the melt and penetrate into the melt, improve the dissolution and diffusion process of the gas in the melt, enhance the gas-assisted effect, make the bubbles inside the product smaller and more uniform, reduce the phenomenon of bubble merging and rupture, and improve the appearance quality and internal structure stability of the product; the nozzle 553, the blade 554 and the rotating ball 556 will automatically adjust the rotation state according to the change of the air flow pressure. When the air pressure increases, the rotation speed of the nozzle 553 and the blade 554 will increase, and the rotation speed of the rotating ball 556 will also change accordingly, so that the gas discharge is smoother, thereby adapting to the change of pressure; conversely, when the air pressure decreases, their rotation speed will slow down, reduce the gas discharge, and maintain the stability of the air pressure. This adaptive adjustment capability can effectively cope with various fluctuations in the air pressure inside the extruder.

[0049] The gas is evenly dispersed and directed in a direction under the cooperation of the three, which can effectively reduce the viscosity of the melt and improve the fluidity of the melt. The full mixing of the gas and the melt reduces the intermolecular force inside the melt, and the melt is easier to flow in the extruder body 1, thereby reducing the extrusion pressure and improving the extrusion efficiency. At the same time, it also helps to better fill the melt in the mold and reduce molding defects such as lack of material and short shot.

[0050] The material of the protrusion 5561 is selected to have a certain elasticity, such as rubber, elastic plastic, etc. When the rotating ball 556 rotates under the action of the airflow, when the protrusion 5561 contacts the inner wall of the nozzle 553, due to the elasticity of the material, the contact part will be deformed to a certain extent, so that the gas can pass through the small gap caused by the deformation. At the same time, the deformation of the elastic material can also ensure that the protrusion 5561 has a good fit with the inner wall of the nozzle 553, ensuring the scraping and cleaning effect.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas-assisted co-extrusion multi-component plastic rod forming system, characterized in that: include: Extruder body (1); A feed inlet (2), the feed inlet (2) being located at one end of the extruder body (1) and used for transmitting a multi-component plastic raw material; A discharge port (3), the discharge port (3) being located at the other end of the extruder body (1) and used for discharging the raw material in a molten state; A gas-assisted portion (5), the gas-assisted portion (5) being located at a position of the extruder body (1) close to the discharge port (3), the gas-assisted portion (5) comprising a fixed plate (52) uniformly embedded in the inner wall of the extruder body (1), the inner wall of the fixed plate (52) being provided with a composite pipe (55) for ejecting gas, the composite pipe (55) comprising an L-tube (551), a middle tube (552) and a nozzle (553) arranged in sequence from top to bottom, the gas flows along the inner wall of the L-tube (551), the middle tube (552) and the nozzle (553), changing the flow direction and accelerating the flow during the flow process, thereby increasing the difficulty of melt reflow; The composite pipe (55) further comprises a rotating ball (556) arranged inside the nozzle (553), and the rotating ball (556) and the nozzle (553) move relative to each other to clean the inner wall of the nozzle (553); The top of the nozzle (553) is fixedly connected to a positioning ring (5531), the top of the positioning ring (5531) is fixedly connected to a fixing frame (555), and the top of the fixing frame (555) is rotatably connected to the bottom of the middle tube (552); A fixed shaft (5541) is fixedly connected to the middle of the top of the fixing frame (555), and a blade (554) is fixedly connected to the outer wall of the fixing shaft (5541), and the blade (554) is located at the center of the inner cavity of the middle tube (552).

2. The gas-assisted co-extrusion multi-component plastic rod forming system according to claim 1, characterized in that: The fixing plate (52) is evenly distributed in the circumferential direction with the geometric center of the extruder body (1) as the reference point, and is arranged in a centrally symmetrical manner around the center of the extruder body (1), and surrounds the inner wall of the extruder body (1) symmetrically in all directions. The outer wall of the fixing plate (52) is snap-connected with a fixing ring (51), and the fixing ring (51) is provided in two pieces, which are respectively located at the two ends of the fixing plate (52).

3. The gas-assisted co-extrusion multi-component plastic rod forming system according to claim 2, characterized in that: The gas-assisted portion (5) further comprises an air inlet (53) located on the outer surface of the fixing ring (51), the bottom end of the air inlet (53) being connected to the port of the composite pipe (55), and the bottom end of the composite pipe (55) being flush with the bottom end of the fixing plate (52).

4. The gas-assisted co-extrusion multi-component plastic rod forming system according to claim 3, characterized in that: The top end of the L-tube (551) is fixedly connected to the bottom end of the air inlet (53), the bottom end of the nozzle (553) is flush with the bottom end of the fixed plate (52), and a second positioning ring (5532) is fixedly connected to the outer wall of the bottom end of the nozzle (553), and the second positioning ring (5532) is slidably sealed with a circular groove (521) provided at the bottom end of the fixed plate (52).

5. The gas-assisted co-extrusion multi-component plastic rod forming system according to claim 1, characterized in that: The outer wall of the rotating ball (556) is provided with a protrusion (5561), the protrusion (5561) is designed to be hemispherical, and the protrusion (5561) is placed in the form of a spiral line on the outer surface of the rotating ball (556).

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