Gas-assisted co-extrusion multi-element plastic bar forming system

Abstract

The invention relates to the technical field of plastic forming, and discloses a gas-assisted co-extrusion multi-element plastic bar forming system which comprises a gas-assisted part, the gas-assisted part is located at the position, close to a discharging port, of an extruder body, and the gas-assisted part comprises fixing plates evenly embedded in the inner wall of the extruder body. According to the composite pipeline, the design that the L pipe, the middle pipe and the nozzle are sequentially arranged from top to bottom is adopted, when the internal pressure changes, the bent structure of the composite pipeline plays a role in buffering, when gas flows through the bent position, the flowing direction of the gas is changed multiple times, and therefore gas molecules collide with the pipeline wall more frequently and collide with one another more frequently; and when the melt tries to flow back, the bending part forces the melt to change the direction, the flowing resistance of the melt is increased, and a complex flowing path formed by bending enables the gas to exert counter-acting force on the melt so as to further prevent the melt from flowing backwards.

Description

Technical Field

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

[0002] Multi-component plastic rods have more excellent and diversified performance due to the integration of the characteristics of multiple plastics, and show unique advantages in application scenarios. Due to the complex composition and different fluidity of each component of multi-component plastics, it is easy to have uneven flow during molding, resulting in uneven density and performance in different parts of the rod. Therefore, during the extrusion process, gas pressure and flow are adjusted through gas assistance. In areas where the melt flows slowly, the gas applies greater pressure to promote uniform flow of the melt and uniform filling of various parts of the rod. Gas-assisted co-extrusion can form an air cushion film layer between the melt and the die wall, making the melt flow smoother, reducing the friction between the melt and the die, and avoiding surface scratches, melt marks and other defects, 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 is insufficient or the melt temperature and pressure fluctuate, the temperature in the extruder decreases and the pressure changes, and the residual melt, impurities in the raw materials and additive agglomerates can easily enter the 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 issues solved In view of the above-mentioned shortcomings of the prior art, the present invention provides a gas-assisted co-extrusion multi-component plastic rod forming system, which can effectively solve the problem of easy blockage of the gas channel in the prior art.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: The present invention provides a gas-assisted co-extrusion multi-component plastic rod forming system, comprising an extruder main body; A feed port, the feed port being located at one end of the extruder body and used for transmitting multiple plastic raw materials; A discharge port, located at the other end of the extruder body and used to discharge the raw material in a molten state; A gas-assisted part, the gas-assisted part is located at a position of the extruder body near the discharge port, the gas-assisted part comprises a fixed plate evenly embedded in the inner wall of the extruder body, the inner wall of the fixed plate is provided with a composite pipeline for ejecting gas, the composite pipeline comprises an L-tube, a middle tube and a nozzle arranged in sequence from top to bottom, the gas flows along the L-tube, the middle tube and the inner wall of the nozzle, changes the flow direction and accelerates the flow during the flow process, thereby increasing the difficulty of melt reflow; The composite pipe further comprises a rotating ball disposed inside the nozzle, and the rotating ball and the nozzle move relative to each other to clean the inner wall of the nozzle. Furthermore, the fixed plate is evenly distributed in the circumferential direction with the geometric center of the extruder body as the reference point, and is arranged in a centrally symmetrical manner around the center of the extruder body, symmetrically surrounding the inner wall of the extruder body in all directions. The outer wall of the fixed plate is snap-connected with a fixed ring, and the fixed ring is provided in two pieces, which are respectively located at both ends of the fixed plate.

[0006] Furthermore, the gas-assisted portion also includes an air inlet located on the outer surface of the fixing ring, the bottom end of the air inlet is connected to the composite pipe port, and the bottom end of the composite pipe is flush with the bottom end of the fixing plate.

[0007] Furthermore, the top end of the L tube 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 fixed plate, and a second positioning ring is fixedly connected to the outer wall of the bottom end of the nozzle, and the second positioning ring is slidably sealed with a circular groove opened at the bottom end of the fixed plate.

[0008] Furthermore, a positioning ring 1 is fixedly connected to the top of the nozzle, a fixing frame is fixedly connected to the top of the positioning ring 1, and the top of the fixing frame is rotatably connected to the bottom end of the middle tube.

[0009] Furthermore, a fixed shaft is fixedly connected to the middle of the top end of the fixing frame, a blade is fixedly connected to the outer wall of the fixed shaft, and the blade is located at the center of the inner cavity of the middle tube.

[0010] Furthermore, the outer wall of the rotating ball is provided with a protrusion, the protrusion is designed to be hemispherical, and the protrusion is placed in a spiral form on the outer surface of the rotating ball.

[0011] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: The composite pipe of the present invention adopts a design in which an L-tube, a middle pipe and a nozzle are arranged in sequence 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 bend, 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 bend further hinders the reflux of the melt. When the melt tries to reflux, the bend 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.

[0012] The nozzle of the present invention adopts a design with a gradually decreasing diameter. The smaller diameter portion will increase the gas flow rate while keeping the gas volume flow rate constant. The increase in flow rate will cause the pressure to decrease, which is helpful to regulate the pressure inside the extruder and enhance the stability of the extrusion process. At the same time, in terms of preventing the melt from flowing back, the smaller diameter design forms a high-speed airflow at the vent, which acts as a gas barrier to effectively resist the backflow of the melt.

[0013] 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 to prevent 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.

[0014] The present invention is provided with a rotating ball, and when the nozzle rotates, the rotating ball moves relative to it, and 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 is carried out uninterruptedly during the whole operation of the extruder main body, avoiding nozzle blockage caused by melt accumulation, greatly reducing the frequency of equipment maintenance, and improving production continuity and efficiency; When the internal pressure of 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 rises, the rotating movement of the nozzle and the rotating ball can make the gas discharge more smoothly and alleviate the sharp rise in pressure; when the pressure decreases, their movement can prevent the gas from leaking too quickly and maintain a certain pressure level, which helps to keep the internal air pressure of the extruder body relatively stable and ensure the smooth progress of the extrusion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of the gas-assisted part of an embodiment of the present invention; Figure 3 It is a schematic diagram of the split structure of the fixed plate according to an embodiment of the present invention; Figure 4 A schematic diagram of a composite pipeline structure according to an embodiment of the present invention; Figure 5 A schematic diagram of a composite pipeline structure according to an embodiment of the present invention; Figure 6This is a schematic cross-sectional view of the internal structure of the middle tube according to an embodiment of the present invention; Figure 7 Schematic diagram of the internal structure of the nozzle according to an embodiment of the present invention.

[0017] The numbers in the figure represent: 1. Extruder body; 2. Feed inlet; 3. Discharge outlet; 5. Gas-assisted part; 51. Fixed ring; 52. Fixed plate; 521. Round groove; 53. Air inlet; 55. Composite pipe; 551. L-tube; 552. Middle tube; 553. Nozzle; 5531. Positioning ring one; 5532. Positioning ring two; 554. Blade; 5541. Fixed shaft; 555. Fixed frame; 556. Rotating ball; 5561. Bump. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The present invention will be further described below in conjunction with the embodiments.

[0020] Example:

[0021] See also Figure 1-Figure 7 The present invention provides a technical solution for a gas-assisted co-extrusion multi-component plastic rod forming system: Figure 1 and Figure 2 As shown, the device includes an extruder body 1, a feed port 2, a discharge port 3 and a gas-assisted part 5. The feed port 2 is located at one end of the extruder body 1 for transmitting multi-component plastic raw materials, and the discharge port 3 is located at the other end of the extruder body 1 for outputting molten raw materials. The gas-assisted part 5 is located at a position of the extruder body 1 close to the discharge port 3 to ensure that the gas can be introduced in time and accurately in the process of the melt leaving the discharge port 3 and entering the mold cavity. At the same time, the gas-assisted part 5 includes a fixed plate 52 evenly embedded in the inner wall of the extruder body 1, and the inner wall of the fixed plate 52 is provided with a composite pipe 55 for ejecting gas. The fixed plate 52 takes the geometric center of the extruder body 1 as the reference point, is evenly distributed in the circumferential direction, is arranged in a central symmetrical shape 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 fixed plate 52 is clamped and connected with a fixed ring 51, and the fixed ring 51 is provided with two, which are respectively located at both ends of the fixed plate 52, and the gas is distributed around the melt with a relatively stable flow rate and pressure.

[0022] The prior art composite pipe 55 is set in a straight cylindrical shape. During the operation of the extruder body 1, when the melt refluxes due to pressure changes and easily enters the composite pipe 55, the melt will first gradually accumulate and solidify, resulting in a reduction in the inner diameter of the composite pipe 55 or even complete blockage, which greatly increases the gas flow resistance and makes the pressure of the gas-assisted system unstable. In severe cases, the gas supply may be interrupted, and effective auxiliary promotion of the melt cannot be achieved, resulting in disorder in the extrusion molding process, and defects such as bubbles, material shortages, and uneven wall thickness appear in the products, seriously reducing the product quality. In addition, due to its simple structure, the gas has a single flow pattern in the composite pipe 55, which is easy to form a 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 and precise control of the melt. When facing the complex pressure fluctuations inside the extruder, the straight pipe The lack of buffering and regulating capabilities for pressure changes makes it impossible to effectively maintain a stable gas flow rate and pressure, further exacerbating the risk of melt reflux. In view of this, the composite pipe 55 of the present invention adopts a design in which an L-tube 551, a middle tube 552 and a nozzle 553 are arranged in sequence from top to bottom. When the internal pressure of the extruder body 1 changes, the bending structure of the composite pipe 55 plays a buffering role. When the gas flows through the bend, 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 reflux of the melt. When the melt tries to reflux, the bend 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.

[0023] refer to Figure 3 , Figure 4 , Figure 5 and Figure 6 The gas-assisted portion 5 also 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-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, a positioning ring 2 5532 is fixedly connected to the outer wall of the bottom end of the nozzle 553, the positioning ring 2 5532 is slidingly sealed with a circular groove 521 opened at the bottom end of the fixed plate 52, a positioning ring 1 5531 is fixedly connected to the top of the nozzle 553, a fixing frame 555 is fixedly connected to the top of the positioning ring 1 5531, the top end of the fixing frame 555 is rotatably connected to the bottom end of the middle tube 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, and the blade 554 is located at the center of the internal cavity of the middle tube 552.

[0024] The bottom end of the nozzle 553 is flush with the bottom end of the fixed plate 52, and the gas discharged from the nozzle 553 can combine with the melt more smoothly, and will not interfere with the normal flow path of the melt due to the protrusion of the nozzle 553, which helps to maintain the smooth flow of the melt in the extruder body 1 and reduce the turbulence and fluctuation of the melt caused by the impact of the airflow. It 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 and solidification near the nozzle 553 and affecting gas discharge and subsequent extrusion processes, which is beneficial 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, and there is no dead corner that is difficult to reach due to the protrusion of the nozzle 553, which can effectively reduce melt residue and dirt accumulation, and reduce maintenance costs and difficulties.

[0025] Gas is poured into the air inlet 53, and the gas flows in the composite pipe 55. The blades 554 arranged inside the middle pipe 552 rotate under the impact of the airflow, providing a direct power source for the rotating nozzle 553. The interaction area and angle between the blades 554 and the airflow are reasonably designed to ensure that sufficient torque is generated under a certain airflow speed and pressure. At this time, the blades 554 drive the fixed shaft 5541 to rotate, the fixed shaft 5541 drives the fixed frame 555 to rotate, and the fixed frame 555 drives the nozzle 553 to rotate stably, so that the nozzle 553 rotates at the set speed and direction, thereby ensuring the operating stability of the gas-assisted system.

[0026] The rotation of nozzle 553 enables the gas to be sprayed into the melt at different angles and directions, thus avoiding the problem of uneven gas distribution caused by spraying in a single direction and reducing wall thickness deviation; nozzle 553 drives the gas and melt to mix more fully, and the gas can penetrate more deeply into 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 deformation in the products, and improves the mechanical properties and stability of the products; during the rotation, the surface of nozzle 553 moves relative to the melt that may be attached, which can scrape off the melt residue on the air inlet 53 and prevent the melt from accumulating and clogging 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 nozzle 553 clean, ensuring the normal operation of the gas-assisted structure, and reducing production interruptions caused by clogging of nozzle 553.

[0027] The blades 554 in the middle tube 552 rotate under the impact of the airflow, and drive the nozzle 553 to rotate through the fixed shaft 5541 and the fixed frame 555. No additional external power source is required, which simplifies the equipment structure and reduces energy consumption. The rotation of the blades 554 stirs the gas in the middle tube 552, so that the gas is more fully mixed before reaching the nozzle 553, further improving the dispersion uniformity of the gas in the melt. In the process of gas-assisted co-extrusion of plastics of different materials, it can promote better fusion of different gases and melts, and improve the overall quality of the product. The rotation of the blades 554 changes the speed and direction of the airflow, and has a certain buffering effect on the airflow. When the internal pressure of the extruder fluctuates, the blades 554 can adjust the flow rate and pressure of the airflow through their own rotation changes, so that the gas entering the nozzle 553 is more stable, the adaptability of the gas-assisted system to pressure changes is enhanced, and the risk of melt reflux caused by pressure fluctuations is reduced.

[0028] refer to Figure 4 , Figure 5 and Figure 7 The outer wall of the rotating ball 556 is provided with a protrusion 5561, which is hemispherical in design and is placed in a spiral form on the outer surface of the rotating ball 556. When gas passes through the nozzle 553, the airflow pushes the rotating ball 556 to rotate freely, and the nozzle 553 and the rotating ball 556 move relative to each other. The protrusion 5561 on the surface of the rotating ball 556 will contact the inner wall of the nozzle 553 during rotation, scraping off the melt residue.

[0029] The stirring of the rotating ball 556 breaks the laminar state of the airflow, promotes the mixing and diffusion of the gas, and enables the gas to act more evenly on the melt. The turbulent airflow can also increase the friction between the gas and the melt, and improve the pushing effect of the gas on the melt. During the relative movement, the special shape of the surface of the rotating ball 556 will generate local vortices and turbulence around it. These vortices and turbulence will interact with the mainstream airflow, further enhancing the mixing degree of the airflow, and making the gas distribution in the nozzle 553 more uniform; when the rotating ball 556 rotates, it drives the protrusions 5561 on its surface to continuously scrape the inner wall of the nozzle 553. The point contact method enables it to cover various positions on the inner wall of the nozzle 553 during the rotation process. The apex and edge of the protrusion 5561 continuously scrape the inner wall of the nozzle 553, gradually cleaning up the melt residue attached to it, reducing the accumulation of the melt on the inner wall of the nozzle 553, and for the larger melt that has been formed The shear force and impact force generated by the relative movement of the rotating ball 556 can break and disperse the melt lumps, and these broken small melt particles are more easily carried away by the airflow, avoiding the blockage of the nozzle 553 by the melt lumps. This self-cleaning process is carried out uninterruptedly throughout the operation of the extruder, avoiding the blockage of the nozzle 553 due to melt accumulation, greatly reducing the frequency of equipment maintenance, and improving production continuity and efficiency. Compared with continuous plane contact, the point contact design can effectively extend the service life of the rotating ball 556 and the nozzle 553, and reduce the maintenance cost of the equipment.

[0030] The gap formed between the rotating ball 556 and the inner wall of the nozzle 553 provides 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, thereby maintaining the normal operation of the gas-assisted system; the complex gas flow pattern and uniform gas distribution enable the gas to contact and mix with the melt more fully, improving the gas penetration effect in the melt, thereby enhancing the gas-assisted effect, improving the gas utilization rate, reducing gas consumption, uniform gas distribution and good melt The fluidity enables the melt to enter the mold cavity more smoothly, reducing the resistance and unevenness 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 the melt residue, which not only reduces the production interruption and equipment failure caused by the melt blocking the nozzle 553, but also improves the production efficiency and the stability of product quality; because the rotating ball 556 can automatically clean the inner wall of the nozzle 553, the frequency and workload of manual cleaning of the nozzle 553 are greatly reduced. The operator does not need to frequently stop the machine to clean and maintain the nozzle 553, which reduces the labor intensity and improves the continuity of production.

[0031] The relative movement of the nozzle 553 and the rotating ball 556 causes the airflow to form a complex flow field inside the nozzle 553, greatly enhancing the stirring effect of the airflow, making the airflow more evenly distributed around the nozzle 553, improving the penetration and mixing effect of the gas on the melt in the gas-assisted system, and helping to improve the microstructure inside the product and reduce defects; the relative movement of the nozzle 553 and the rotating ball 556 can achieve a more comprehensive cleaning of the inside of the nozzle 553, reduce the risk of blockage of the nozzle 553, extend the service life of the gas-assisted system, and ensure the continuity and stability of the extrusion process; when the pressure inside the extruder body 1 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 rotational movement of the nozzle 553 and the rotating ball 556 can make the gas discharge more smoothly and alleviate the sharp rise in pressure; when the pressure decreases, their movement can prevent the gas from leaking too quickly, maintain a certain pressure level, and help to keep the internal air pressure of the extruder body 1 relatively stable, ensuring the smooth progress of the extrusion process.

[0032] The blade 554 drives the nozzle 553 to rotate, thereby indirectly providing a rotating external environment for the rotating ball 556. The rotation of the nozzle 553 changes the flow state of the airflow in the nozzle 553, so that the airflow impacts the rotating ball 556 at different angles and speeds, thereby affecting the rotation speed and direction of the rotating ball 556. The blade 554 and the rotating ball 556 achieve a synergistic effect through the nozzle 553, and jointly optimize the airflow, so that the flow of the airflow in the gas-assisted system is more reasonable and efficient; during the extrusion process, when the parameters such as the airflow pressure and flow rate change, the blade 554 and the rotating ball 556 will perform adaptive adjustments through their respective interactions with the airflow. The blade 554 will adjust the rotation speed according to the change of the airflow, thereby affecting the rotation of the nozzle 553, and the rotating ball 556 will also adjust its own rotation state according to the change of the airflow state. This adaptive adjustment capability helps the gas-assisted system to maintain good performance under different working conditions and improve the system's adaptability and stability to changes in process parameters.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 walls 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).

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, arranged in a centrally symmetrical manner around the center of the extruder body (1), and symmetrically surrounds the inner wall of the extruder body (1) 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 numbers, one at each end 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 a 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 top end of the nozzle (553) is fixedly connected to a positioning ring (5531), the top end of the positioning ring (5531) is fixedly connected to a fixing frame (555), and the top end of the fixing frame (555) is rotatably connected to the bottom end of the middle tube (552).

6. The gas-assisted co-extrusion multi-component plastic rod forming system according to claim 5, characterized in that: A fixed shaft (5541) is fixedly connected to the middle of the top end 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).

7. 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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