A resin online modification and compression molding system and its operation method

Abstract

The present invention discloses an online resin modification and compression molding system, comprising a twin-screw extruder, a compression mold, and also comprising a storage device and a screw injection device; the twin-screw extruder is connected to the storage device, and the storage device is connected to the screw injection device; the compression mold comprises a mold feed port, a melt conveying system and a mold cavity connected in sequence; the screw injection device comprises an injection port, and the injection port is connected to the mold feed port of the compression mold; the screw injection device can mix the melt entering therein and directly convey it to the mold feed port; the melt conveying system can continuously introduce the melt in the screw injection device into the mold cavity via the mold feed port. The system of the present invention realizes that the melt entering the screw injection device can be directly conveyed to the compression mold for storage, reduces the residence time of the melt before the compression mold, and improves the product yield and performance stability.

Description

Technical Field

[0001] The invention belongs to the field of resin molding processing, and in particular relates to a resin online modification and molding system and an operation method thereof. Background Art

[0002] Modified plastics refer to general plastics and engineering plastics that have been filled, blended, reinforced, and other processes to improve the flame retardancy, strength, impact resistance, toughness, and other properties of plastics. It is particularly common to enhance the mechanical properties of plastics through fiber modification. Among them, the types of modified fibers can generally be selected from glass fiber, carbon fiber, organic fiber, etc. Modified plastics need to be prepared into plastic products that meet the requirements through a molding process. The commonly used molding methods of modified plastics in the industry are extrusion molding or online compression molding. Among them, extrusion molding is achieved by using an extruder. It is impossible to achieve online continuous production without starting from the modified granulation of the plastic; online compression molding is to extrude and cut the material melt with an extruder, and add the melt block to the mold through a manipulator for compression molding. However, this method is difficult to achieve the molding of modified plastics with high-temperature melts such as modified nylon. The reason is that the modified high-temperature melt is easily oxidized when exposed to the air for a long time, and the longer it stays in the equipment, the greater the impact on the performance of the molded body.

[0003] For existing online molding equipment, such as LFT-D molding production line equipment, whether imported from abroad or independently developed in China, the applicable resin matrix is ​​mainly PP. It is not applicable to resin matrices with high melting points and fast cold crystallization rates such as nylon. The main reason is: the current LFT-D technology adopts the following process: first, the resin matrix and functional additives such as reinforcing fibers are processed into molten composite material embryos, and then according to the size of the molded parts, the embryos are cut into blocks with a cutting machine, and then the cut blocks are placed on the mold cavity surface of the molding device by a robot for molding. This process requires the blank to be prepared in advance and placed on a conveyor belt waiting to be grabbed by the robot and sent into the mold cavity. During the waiting stage and before being grabbed by the robot and entering the mold cavity, the blank needs to be exposed to the air for a period of time. During this period of time, a considerable part of the temperature of the blank will be lost. For thermoplastic resin melts with high melting points and fast cold crystallization rates, crystallization begins before being sent to the mold cavity. Even after the melt enters the mold cavity, it has cooled and solidified into blocks before it can completely fill the mold cavity, making it impossible to mold the desired product. Furthermore, when the molten thermoplastic resin melt is exposed to the air, there is also a risk that the comprehensive performance of the molded product will be affected by oxidation problems. Most automotive plastic parts, especially structural parts, are molded with nylon substrates. Nylon is the most important engineering plastic for the automotive industry. This is also an important reason why LFT-D production line equipment has not been widely used by domestic automotive plastic parts manufacturers.

[0004] In addition, the current LFT-D production line equipment usually adds a heat preservation device in the material preparation section to ensure that the blank does not solidify prematurely, which results in high energy consumption in production and processing. At the same time, because the blank is directly placed on the surface of the mold cavity, only flat products with simple structures can be formed. For products with complex structures, the blank melt cannot flow evenly through various parts of the mold cavity, or cannot completely fill various parts of the mold cavity, resulting in missing parts or incomplete defects in the molded products.

[0005] In the prior art, there are also some plastic molding devices, such as Patent Document 1 (Chinese invention patent with publication number CN 101484299 A), which discloses a device and method for processing thermosetting plastics. An embodiment is given in its specific implementation method, which includes an extrusion device, an injection mold and a storage device, and an injection device with high injection pressure is added between its storage device and the injection mold. The storage device stores the extruded material of the extruder for a short time to achieve the purpose of continuous operation of the extruder. The injection device injects the melt into the injection mold through a one-time injection to realize the injection molding process. However, when used in modified plastics with high-temperature melts such as nylon, on the one hand: during the operation of this set of equipment, part of the extrudate produced by the extruder will remain in the storage device. Since the residence time of this part of the high-temperature melt is different from the residence time of the extrudate directly produced by the extruder, the performance of the polymer melt is different; on the other hand: the melt in its plunger-type storage device, the extruder separately extrude the extrudate injected into the injection device, the contact position of the melt extruded by the extruder and the melt released by the storage device, the melt pressures at the three positions are different, which will also make the polymer melt performance at the three positions different. When the melt in the above two situations enters the injection device, the degree of homogenization between the melts with different performance differences is not enough, resulting in uneven internal performance of the final molded product, an increased probability of producing defective products, and a large amount of property loss and waste of resources. Summary of the invention

[0006] In order to overcome the problems that the existing online molding equipment cannot be applied to high-temperature melts, the residence time of the melt in the process before entering the molding die is too long, and the product performance is uneven, the purpose of the present invention is to provide a resin online modification and molding system that can be used for online molding of high-temperature melts of resin, the residence time of the process before the melt enters the molding die is short, and the product performance is uniform and stable, which is specifically achieved through the following technical solutions:

[0007] A resin online modification and compression molding system, comprising a twin-screw extruder, a compression mold, a material storage device and a screw injection device; the twin-screw extruder is connected to the material storage device, and the material storage device is connected to the screw injection device;

[0008] The storage device can temporarily store the melt extruded by the twin-screw extruder when the amount of melt in the molding die is sufficient, and output the stored melt when the next injection process starts;

[0009] The compression mold comprises a mold feed port, a melt delivery system and a mold cavity which are connected in sequence;

[0010] The screw injection device comprises an injection port, which is connected to a mold feed port of the molding mold;

[0011] The screw injection device can mix the melt entering therein and directly convey it to the mold feed port;

[0012] The melt delivery system can continuously introduce the melt in the screw injection device into the mold cavity through the mold feed port.

[0013] Optionally, the screw injection device is a single screw injection device or a twin screw injection device, which can mix the melt through the screw to avoid uneven product performance, and can also directly transport the melt entering therein to the mold feed port to shorten the melt residence time.

[0014] Optionally, the screw injection device is provided with one or more feeding ports to facilitate the addition of auxiliary materials.

[0015] Optionally, the feed port includes a fiber feed port and / or a toner feed port. Fiber reinforcements such as glass fiber can be added to the fiber feed port to avoid the problem of short glass fiber size in the final product and limited mechanical property enhancement effect caused by adding glass fiber in the initial twin-screw extruder. Toner can be added to the melt through the toner feed port, which can greatly shorten the residence time of the toner in the high-temperature system, reduce the color deviation of the product, improve the brightness and color of high-temperature melt products such as nylon, expand the color category of existing high-temperature melt products such as nylon, and expand the application range of its products.

[0016] Optionally, the screw injection device is further provided with an exhaust hole, so that if there is mixed gas in the screw injection device, the gas can be discharged through the exhaust hole.

[0017] Optionally, the aforementioned storage device is a single-screw storage device or a plunger storage device.

[0018] Optionally, the melt delivery system includes a melt flow channel, a mold cavity feed port connected to the melt flow channel, and a valve body structure matched with the mold cavity feed port; the mold cavity feed port and the valve body structure cooperate to control the melt to flow into the mold cavity. The melt can flow from the inside of the molding die into the mold cavity, avoiding oxidation of the high-temperature melt due to contact with air or affecting the melt state, thereby improving the product yield and stability.

[0019] Optionally, the aforementioned molding die includes a movable die and a fixed die, the movable die is fixed on a movable die seat, a mold cavity is provided in the movable die, a mold cavity is provided in the fixed die, the fixed die is fixed on the fixed die seat, and the mold cavity matches the mold cavity;

[0020] The fixed mold is provided with a melt delivery system, which includes a melt flow channel, a mold cavity feed port connected to the melt flow channel, and a valve body structure matched with the mold cavity feed port, and the valve body structure includes a needle valve and a cylinder for controlling the needle valve to realize the opening and closing of the mold cavity feed port. A structural method is specifically described that can realize the flow of melt from the inside of the molding die into the mold cavity, avoid oxidation of high-temperature melt contacting the air or affecting the melt state, and improve the product yield and stability.

[0021] Optionally, the aforementioned mold cavity and the matching mold cavity are one or more. Multiple products can be molded simultaneously in the same compression mold, making full use of the pressure, temperature and other facilities in the compression mold, improving its resource utilization, saving energy, and greatly improving production efficiency.

[0022] Optionally, the mold cavity is connected to one or more mold cavity feed ports. For similar situations where the mold cavity area is large or it is difficult to obtain sufficient melt in some places inside the mold cavity, injection can be performed from multiple positions to ensure that there is melt in all positions of the mold cavity and the amount of melt meets the requirements of product molding, thereby improving the product yield rate.

[0023] Optionally, the above-mentioned resin online modification and compression molding system also includes a fiber mixing device, and the fiber mixing device is arranged in the connecting section between the screw injection device and the compression mold. It can overcome the problems of poor fiber reinforcement effect (such as short glass fiber length), long overall process time, low production efficiency, etc. in the prior art that the fiber reinforcement and resin matrix are modified and granulated before other molding steps, and the fiber reinforcement parameters (such as glass fiber length) can be selected and controlled according to needs, reducing the time consumption of plastic modification and compression molding process, improving production efficiency, and reducing intermediate storage and other management costs.

[0024] The present application also provides an operating method of the above-mentioned resin online modification and compression molding system, which is characterized by comprising the following steps:

[0025] S1, resin modification: the resin raw material and the modified material are continuously mixed and plasticized into a melt and extruded by a twin-screw extruder;

[0026] S2, melt delivery: The melt is delivered to the mold cavity of the compression mold through the screw injection device, and the melt flows through the screw injection device, the injection port, the mold feed port, the melt delivery system and the mold cavity in sequence;

[0027] When the amount of melt in the mold cavity is sufficient, the melt generated by the twin-screw extruder during continuous operation is temporarily stored by the storage device, and the stored melt is output when the next injection process starts; the melt output by the storage device and the melt generated by the twin-screw extruder are mixed together through the screw injection device and conveyed to the mold cavity of the molding die, and the melt flows through the screw injection device, the injection port, the mold feed port, the melt conveying system and the mold cavity in sequence;

[0028] S3, compression molding.

[0029] Compared with the prior art, the resin online modification and compression molding system described in the present application abandons the conveyor belts, mechanical grippers and other equipment in the existing LFT-D production line, saves energy, and avoids the oxidation caused by the high-temperature melt exposed to the air, which affects the performance and yield of the product. The screw injection device and the melt delivery system and the mold cavity in the compression mold, and the injection port of the screw injection device are connected to the melt delivery system, so that the melt entering the screw injection device can be directly transported to the compression mold for storage, reducing the residence time of the melt before the compression mold, and improving the yield and performance stability of the product. This technical effect can only be achieved by the cooperation of the screw injection device and the melt delivery system. The effect that can be achieved by this combination cannot be achieved by disassembling any one of the technical features alone.

[0030] In addition, the injection device adopts a screw injection device, which directly mixes the melt entering therein and injects it into the melt conveying system. On the one hand, compared with the plunger type injection device, there is no need to store materials, which shortens the residence time of the melt in front of the molding die, and improves the product qualification rate and quality stability. On the other hand, the screw injection device has the functions of conveying and mixing, which can overcome the problem that the plunger type injection device cannot mix materials, which easily leads to uneven performance in different parts of the product.

[0031] When it is necessary to prepare colored products through high-temperature melts such as nylon, the existing technology is to add color powder to the additives when preparing the modified fiber melt in the twin-screw extruder. However, due to the premature addition of color powder, the continuous high temperature in the subsequent injection molding process such as storage and injection will partially degrade the color powder, resulting in the final product being dark or with large deviations. On the one hand, it may not meet customer needs, and on the other hand, it is impossible to prepare products with bright colors. The present application can be provided with a color powder feeding port on the screw injection device. It can greatly shorten the residence time of the color powder in the high-temperature system, reduce the color deviation of the product, improve the brightness and color of the color of high-temperature melt products such as nylon, expand the color categories of existing high-temperature melt products such as nylon, and expand its application range.

[0032] The resin online modification and compression molding system described in the present application can be used not only for the online modification and compression molding of conventional plastics, but is particularly suitable for the online modification and compression molding of resin materials with high-temperature melts such as nylon. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the resin online modification and compression molding system described in Example 1.

[0034] Figure 2 This is a schematic diagram of the fixed mold base structure of the molding die described in Example 1.

[0035] Figure 3 This is a schematic diagram of the movable mold base structure of the molding die described in Example 1.

[0036] Figure 4 This is a schematic diagram of the structure of the melt delivery system of the molding die described in Example 1.

[0037] Figure 5 This is a cross-sectional view of the melt delivery system of the molding die described in Example 1.

[0038] Figure 6 This is a schematic diagram of the structure of the cavity feed port of the compression mold described in Example 1.

[0039] Figure 7 This is a schematic diagram of the internal structure of the mold cavity feed port of the molding die described in Example 1.

[0040] Figure 8 This is a schematic diagram of the resin online modification and molding system described in Example 2.

[0041] Fig. 9 This is a schematic diagram of the resin online modification and compression molding system described in Example 3.

[0042] In the figure, the reference numerals are: 1-twin-screw extruder, 101-feeding hopper, 2-fiber mixing device, 3-storage device, 4-screw injection device, 401-injection port, 402-color powder feeding port, 403-fiber feeding port, 404-exhaust hole, 5-molding mold, 501-movable mold, 502-fixed mold, 503-movable mold seat, 504-cavity, 505-mold cavity, 506-fixed mold seat, 507-melt flow channel, 508-mold cavity feed port, 509-needle valve, 510-cylinder, 511-mold feed port, 512-flow channel through hole. DETAILED DESCRIPTION

[0043] The specific implementation methods of the present application are described in detail below through examples, but the specific implementation of the present application does not serve as a limitation on the technical solution of the present application. Any non-substantial changes such as replacing common technical solutions in the field with the technical solutions described in the examples of the present application are within the scope of protection of the present application.

[0044] Example 1.

[0045] like Figure 1 A resin online modification and molding system shown in the figure includes a twin-screw extruder 1, a storage device 3, a screw injection device 4 and a molding die 5, wherein the twin-screw extruder 1 is provided with a feeding hopper 101 for adding resin and additives, and the twin-screw extruder 1 is connected to the storage device 3 through a pipeline. In this embodiment, the storage device 3 is a plunger-type storage device, and the outlet of the storage device 3 and the screw injection device 4 are connected through a pipeline. Through valve control, the melt of the twin-screw extruder 1 is directly added to the screw injection device 3 through the pipeline, or enters the plunger-type storage device for storage. When the storage is completed and the next injection process begins, the melt can pass through the pipeline and mix with the melt in the plunger-type storage device to enter the screw injection device 4.

[0046] In this embodiment, the screw injection device 4 adopts a twin-screw injection device, including an injection port 401, a color powder feeding port 402 and a fiber feeding port 403. The positions of the color powder feeding port 402 and the fiber feeding port 403 can be set as needed. For example, the color powder feeding port 402 and the fiber feeding port 403 can be set at the rear section of the screw storage device 4 to reduce the shearing process of the fiber and reduce the high temperature degradation of the color powder. The screw injection device 4 can also be provided with an exhaust hole 404 as needed.

[0047] The twin-screw injection device directly delivers the melt entering therein to the compression mold 5 through the injection port 401, without the short storage process of the plunger-type structure. The screw injection device 4 can mix the melt entering therein on the one hand, and reduce the residence time of the melt on the other hand.

[0048] like Figure 2~Figure 7 The molding die 5 shown includes a movable die 501 and a fixed die 502. The movable die 501 is fixed on a movable die seat 503. A cavity 504 is provided in the movable die 501. A cavity 505 is provided in the fixed die 502. The fixed die 502 is fixed on a fixed die seat 506. The cavity 505 matches the cavity 504.

[0049] The fixed mold 502 is provided with a melt delivery system, which includes a melt flow channel 507, a mold cavity feed port 508 connected to the melt flow channel 507, and a valve body structure matched with the mold cavity feed port 508, wherein the valve body structure includes a needle valve 509 and a cylinder 510 for controlling the needle valve 509 to realize the opening and closing of the mold cavity feed port 508. The melt can flow from the inside of the molding die 5 into the mold cavity 505, so as to avoid the high-temperature melt from contacting the air and oxidizing or affecting the melt state, thereby improving the product yield and stability. The melt flow channel 507 is connected to the mold cavity feed port 508 through the flow channel through hole 512.

[0050] The compression mold 5 is connected to the injection port 401 in the screw injection device 4 via the mold feed port 511 provided thereon, so that the melt entering the screw injection device 4 is directly transported to the compression mold 5 without a short material storage process, thereby reducing the residence time of the melt.

[0051] Among them, the power structure of the movable mold 501, the heating and insulation system, the cooling system, the part ejection system, etc., which should also be included in the molding mold 5 in this embodiment, are all functional modules and their setting positions and control methods are well known to technical personnel in this field. Since they do not belong to the main innovation points of this application, they will not be repeated here.

[0052] The operation includes the following steps:

[0053] S1, resin modification: resin raw materials and modified materials are added to the twin-screw extruder 1 through the feeding hopper 101, and melt extrusion is formed through continuous mixing and plasticization processes;

[0054] S2, melt conveying: In this embodiment, a plunger-type storage device is used for material storage. The melt from the twin-screw extruder 1 can directly enter the screw injection device 4 through a pipeline, and then be conveyed to the mold cavity 505 of the molding mold 5 through the screw injection device 4. The melt flows through the screw injection device 4, the injection port 401, the mold feed port 511, the melt conveying system and the mold cavity 505 in sequence;

[0055] When the amount of melt in the mold cavity 505 is sufficient, the melt generated by the twin-screw extruder 1 during continuous operation is temporarily stored in the plunger-type storage device through the pipeline by the storage device 3, and the stored melt is output when the next injection process starts; the melt output by the storage device 3 and the melt generated by the twin-screw extruder 1 are mixed together through the screw injection device 4 and conveyed to the mold cavity 505 of the molding die 5, and the melt flows through the screw injection device 4, the injection port 401, the mold feed port 511, the melt conveying system and the mold cavity 505 in sequence;

[0056] S3, compression molding: The movable mold 501 is first opened to a distance from the fixed mold 502. When the melt is delivered to the mold cavity 505 in sufficient quantity, the air pump 510 drives the needle valve 509 to close the mold cavity feed port 508. Among them, the melt flow channel 507, the needle valve 509 and the cylinder 510 that controls the needle valve 509 to realize the operation mode of the opening and closing of the mold cavity feed port 508 can be understood by those skilled in the art based on the structural setting, and will not be repeated. The subsequent compression molding process can be implemented by those skilled in the art through experience, and will not be repeated. In addition, when the air pump 510 drives the needle valve 509 to close the mold cavity feed port 508, the screw injection device 4 stops, and the melt produced by the twin-screw extruder 1 is transferred to the storage device 3 for storage.

[0057] The specific structures involved in this embodiment can be set in number and position by those skilled in the art as needed, such as replacing the screw injection device 4 with a single screw injection device. In this embodiment, the fiber feeding port 403 provided on the screw injection device 4 is transferred to the twin-screw extruder 1 to achieve fiber modification of the resin. In this embodiment, the mold cavity 505 and the matching mold cavity 504 in the compression mold 5 are one or more. Multiple products can be molded simultaneously in the same compression mold 5, making full use of the pressure, temperature and other facilities in the compression mold 5, improving its resource utilization, saving energy, and greatly improving production efficiency.

[0058] In addition, the aforementioned mold cavity 505 is connected to one or more mold cavity feed ports 508. For similar situations where the mold cavity 505 is large in area or some places inside are difficult to obtain sufficient melt, injection can be performed from multiple positions to ensure that there is melt at all positions of the mold cavity 505 and the amount of melt meets the requirements of product molding, thereby improving the product yield rate.

[0059] Example 2.

[0060] like Figure 8 The resin online modification and molding system shown is different from the embodiment 1 in that a fiber mixing device 2 is provided between the screw injection device 4 and the molding die to control the parameters such as the fiber modification size and achieve the effect of long glass fiber modified resin, etc. The screw injection device 4 does not need to be provided with a fiber feeding port 403.

[0061] The other structures and operation modes of this embodiment are the same or similar to those of the embodiment 1, except that the fiber mixing device 2 is added. Those skilled in the art can understand that the fiber mixing device 2 is added during the melt flow process to modify the resin fiber reinforcement. No further description is given.

[0062] Example 3.

[0063] like Fig. 9 The resin online modification and compression molding system shown is different from Example 1 in that the storage device 3 adopts a single-screw storage device, and the outlet of the twin-screw extruder 1 is connected to the bottom position of the single-screw storage device. The single-screw storage device is used to feed and store materials in reverse to achieve continuous operation of the twin-screw extruder. The specific control method of the single-screw storage device can be understood by those skilled in the art and will not be repeated. In this embodiment, fiber reinforcements such as glass fiber can be added through the feeding hopper 101 at the rear section of the twin-screw extruder 1 to modify the resin.

[0064] The difference between this embodiment and embodiment 1 also includes that the screw injection device 4 adopts a single screw injection device, no additives are added here, and there is no need to set up structures such as fiber feeding port 403, color powder feeding port 402, exhaust port 404, etc., and only melt mixing and direct transportation are performed. The difference in the operation method from embodiment 1 caused by the structure can be known by those skilled in the art based on the structure of this embodiment combined with the use method of conventional components, and no further description is needed.

[0065] It should be noted that the components used in the above embodiments, such as a single-screw storage device or a plunger storage device, may also be a twin-screw storage device. Those skilled in the art may select or replace them according to their needs without exceeding the scope of protection of the present invention.

Claims

1. A resin online modification and compression molding system, comprising a twin-screw extruder and a compression mold, characterized in that: It also includes a material storage device and a screw injection device; the twin-screw extruder is connected to the material storage device, and the material storage device is connected to the screw injection device; The storage device can temporarily store the melt extruded by the twin-screw extruder when the amount of melt in the molding die is sufficient, and output the stored melt when the next injection process starts; The compression mold comprises a mold feed port, a melt delivery system and a mold cavity which are connected in sequence; The screw injection device comprises an injection port, which is connected to a mold feed port of the molding mold; The screw injection device can mix the melt entering therein and directly convey it to the mold feed port; The melt delivery system can continuously introduce the melt in the screw injection device into the mold cavity through the mold feed port; The screw injection device is provided with one or more feeding ports; the melt delivery system includes a melt flow channel, a mold cavity feed port connected to the melt flow channel, and a valve body structure matching the mold cavity feed port; the mold cavity feed port cooperates with the valve body structure to control the melt flowing into the mold cavity.

2. The resin online modification and molding system according to claim 1, characterized in that: The screw injection device is a single screw injection device or a twin screw injection device.

3. The resin online modification and molding system according to claim 1, characterized in that: The feeding port includes a fiber feeding port and / or a toner feeding port.

4. The resin online modification and molding system according to claim 1 or 2, characterized in that: The screw injection device is also provided with an exhaust hole.

5. The resin online modification and molding system according to claim 1, characterized in that: The material storage device is a single screw material storage device or a plunger type material storage device.

6. The resin online modification and molding system according to claim 1, characterized in that: The molding die comprises a movable die and a fixed die, wherein the movable die is fixed on a movable die seat, a mold cavity is arranged in the movable die, a mold cavity is arranged in the fixed die, the fixed die is fixed on a fixed die seat, and the mold cavity and the mold cavity match each other; A melt delivery system is provided in the fixed mold, and the melt delivery system includes a melt flow channel, a mold cavity feed port connected to the melt flow channel, and a valve body structure matching the mold cavity feed port. The valve body structure includes a needle valve and a cylinder that controls the needle valve to realize opening and closing of the mold cavity feed port.

7. The resin online modification and molding system according to claim 6, characterized in that: The mold cavity and the mold cavity matching it are one or more.

8. The resin online modification and compression molding system according to claim 7, characterized in that: The mold cavity is in communication with one or more mold cavity feed ports.

9. The resin online modification and molding system according to claim 1, characterized in that: It also includes a fiber mixing device, which is arranged in the connecting section between the screw injection device and the molding die.

10. An operating method of the resin online modification and molding system as claimed in claim 1, characterized in that: The following steps are involved: S1, resin modification: the resin raw material and the modified material are continuously mixed and plasticized into a melt and extruded by a twin-screw extruder; S2, melt delivery: The melt is delivered to the mold cavity of the compression mold through the screw injection device, and the melt flows through the screw injection device, the injection port, the mold feed port, the melt delivery system and the mold cavity in sequence; When the amount of melt in the mold cavity is sufficient, the melt generated by the twin-screw extruder during continuous operation is temporarily stored by the storage device, and the stored melt is output when the next injection process starts; the melt output by the storage device and the melt generated by the twin-screw extruder are mixed together through the screw injection device and conveyed to the mold cavity of the molding die, and the melt flows through the screw injection device, the injection port, the mold feed port, the melt conveying system and the mold cavity in sequence; S3, compression molding.

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