Supercritical injection molding mechanism

Abstract

The invention discloses a supercritical injection molding mechanism, and relates to the technical field of injection molding mechanisms, the supercritical injection molding mechanism comprises a first channel and a second channel, and the first channel is internally provided with a conveying assembly. Through cooperative arrangement of the conveying assembly, the injection assembly and the auxiliary assembly, the mixing uniformity can be improved, the product quality can be guaranteed, through a three-stage progressive mixing mechanism, after nitrogen is injected into a first channel and a gas filling pipe, a motor drives a first threaded blade rod to rotate, and raw materials and nitrogen are preliminarily stirred; when the primarily mixed raw materials enter the second channel through the connecting pipe, the second threaded blade rod is driven to rotate by virtue of self impact force, so that secondary stirring is completed; and in the injection molding stage, the oil cylinder pushes the pushing block to extrude the raw materials, the raw materials flow to drive the second threaded blade rod again, three-time stirring is achieved, nitrogen and the raw materials are extremely and evenly mixed through three-stage stirring, product bubbles are eliminated, the mechanical property and size precision are improved, and the rejection rate is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of injection molding mechanism, in particular to a supercritical injection molding mechanism. BACKGROUND

[0002] In modern manufacturing industry, injection molding technology as a kind of efficient and precise plastic product processing method is widely used in many fields such as automobile, electronics, medical treatment, household appliances and so on. With the continuous improvement of the downstream industry's requirements on product performance, precision and lightweight, the traditional injection molding technology gradually exposes many limitations, and the supercritical injection molding technology emerges as the times require and becomes the key direction of industry research and development. The core principle of supercritical injection molding technology is to mix supercritical fluid (such as nitrogen, carbon dioxide, etc.) into polymer melt, and to improve the fluidity of the melt by using the low viscosity and high diffusivity characteristics of supercritical fluid, reduce the molding pressure and temperature, and at the same time realize the lightweight of the product, eliminate internal bubbles and improve the mechanical properties. However, in the practical application process of supercritical injection molding technology, the uniformity of the mixing of supercritical fluid and polymer raw materials has always been the key bottleneck restricting the development of the technology.

[0003] The traditional supercritical injection molding equipment mostly adopts single stirring structure or static mixing method, which is difficult to realize the sufficient fusion of supercritical fluid and raw materials. On the one hand, if the mixing is not sufficient, the supercritical fluid in the melt is easy to form agglomeration or uneven distribution, which leads to the problems such as density difference, mechanical property fluctuation and so on of the molded product, seriously affecting the product quality stability, especially in the fields of high-precision electronic component shell, medical precision parts and other performance requirements, such defects often lead to product scrap; on the other hand, in order to improve the mixing effect, some equipment will additionally increase the power-driven stirring device, which not only increases the structural complexity and manufacturing cost of the equipment, but also consumes more energy, which does not meet the current green and low-carbon development trend of manufacturing industry.

[0004] Therefore, it is necessary to propose a supercritical injection molding mechanism to solve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a supercritical injection molding mechanism to solve the problem that the supercritical fluid in the melt is easy to form agglomeration or uneven distribution, which leads to the problems such as density difference, mechanical property fluctuation and so on of the molded product, seriously affecting the product quality stability.

[0006] To achieve the above object, the present application provides the following technical solutions: The supercritical injection molding mechanism comprises a first channel and a second channel, the inside of the first channel is provided with a conveying assembly, and the top of the first channel is fixedly connected with a gas inlet pipe; the side of the first channel is fixedly connected with a one-way valve, the side of the one-way valve is fixedly connected with a connecting pipe, and one end of the connecting pipe is fixedly connected with the bottom of the second channel;

[0007] The inside of the second channel is provided with an injection assembly, and the inside of the second channel is provided with an auxiliary assembly, the auxiliary assembly comprises a fixed block, a rotating shaft and a second threaded blade rod, the outside of the fixed block is fixedly connected with the inner wall of the second channel, the inside of the fixed block is rotatably connected with the outside of the rotating shaft, one end of the rotating shaft is fixedly connected with the side of the second threaded blade rod, and the second threaded blade rod is located at the top of one end of the connecting pipe.

[0008] Preferably, the conveying assembly comprises a motor, the side of the motor is fixedly connected with the side of the first channel, one end of the motor output shaft is fixedly connected with a first threaded blade rod, and the first threaded blade rod is arranged in the inside of the first channel.

[0009] Preferably, the injection assembly comprises an oil cylinder, the side of the oil cylinder is fixedly connected with the side of the second channel, the telescopic end of the oil cylinder is fixedly connected with a pushing block, and the outside of the pushing block is fixedly installed with a sealing ring.

[0010] Preferably, the telescopic end of the oil cylinder and the pushing block are located in the inside of the second channel, and the outside of the pushing block is slidably connected with the inner wall of the second channel.

[0011] Preferably, the side of the second channel is boltedly connected with a connecting block, the side of the connecting block is fixedly connected with an injection pipe, and the outside of the injection pipe is fixedly installed with a discharge valve.

[0012] Preferably, the top of the first channel is fixedly connected with a feeding pipe.

[0013] The present application has the following technical effects and advantages:

[0014] 1. Through the cooperation of the conveying assembly, the injection assembly and the auxiliary assembly, the mixing uniformity can be improved, the product quality can be ensured, and through the "three-stage progressive mixing" mechanism, after the nitrogen gas is injected into the first channel through the gas inlet pipe, the motor drives the first threaded blade rod to rotate to preliminarily stir the raw materials and the nitrogen gas; when the preliminarily mixed raw materials enter the second channel through the connecting pipe, the second threaded blade rod is driven to rotate by the impact force of the raw materials, so that secondary stirring is completed; in the injection molding stage, the oil cylinder pushes the pushing block to extrude the raw materials, and the raw materials flow drives the second threaded blade rod again, so that three times of stirring is realized; the three-stage stirring makes the nitrogen gas and the raw materials extremely uniformly mixed, eliminates the bubbles of the product, improves the mechanical properties and the size precision, and reduces the scrap rate.

[0015] 2. It can efficiently utilize energy and reduce cost and energy consumption. The second threaded blade rod does not require additional power. It relies on the energy of two key stages during operation: the kinetic energy of the material flowing from the first channel to the second channel, and the pressure energy generated by the hydraulic cylinder squeezing the material during injection molding. This design simplifies the equipment transmission structure, reduces the number of components such as motors and reducers, reduces manufacturing costs and maintenance difficulty, and is in line with the trend of green manufacturing. Attached Figure Description

[0016] Figure 1 This is a cross-sectional schematic diagram of the supercritical injection molding mechanism of the present invention.

[0017] Figure 2 In this invention Figure 1 Enlarged diagram of point A.

[0018] Figure 3 In this invention Figure 1 Enlarged diagram of point B.

[0019] In the diagram: 1. First channel; 2. Second channel; 3. Motor; 4. First threaded blade rod; 5. Air supply pipe; 6. One-way valve; 7. Connecting pipe; 8. Feed pipe; 9. Fixing block; 10. Rotating shaft; 11. Second threaded blade rod; 12. Hydraulic cylinder; 13. Pushing block; 14. Sealing ring; 15. Connecting block; 16. Injection tube. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention provides, for example Figure 1 - Figure 3 The supercritical injection molding mechanism shown includes a first channel 1 and a second channel 2. A conveying assembly is provided inside the first channel 1, and an air supply pipe 5 is fixedly connected to the top of the first channel 1. A one-way valve 6 is fixedly connected to the side of the first channel 1, and a connecting pipe 7 is fixedly connected to the side of the one-way valve 6. One end of the connecting pipe 7 is fixedly connected to the bottom of the second channel 2. The conveying assembly includes a motor 3, and the side of the motor 3 is fixedly connected to the side of the first channel 1. A first threaded blade rod 4 is fixedly connected to one end of the output shaft of the motor 3. The first threaded blade rod 4 is disposed inside the first channel 1, and a feed pipe 8 is fixedly connected to the top of the first channel 1.

[0022] Wherein, the injection material enters the first channel 1 through the feeding pipe 8 on the top of the first channel 1, and nitrogen gas (supercritical fluid) is injected into the first channel 1 through the gas injection pipe 5 to prepare for supercritical mixing, the motor 3 fixedly connected to the side of the first channel 1 is started, the output shaft of the motor 3 drives the first threaded blade rod 4 in the first channel 1 to rotate at high speed, during the rotation of the first threaded blade rod 4, on the one hand, the stable forward conveying of the injection material in the first channel 1 is realized, and on the other hand, the injected nitrogen gas is preliminarily mixed with the injection material through the stirring action of the spiral blade, the agglomeration state of the raw material is broken, and the first stage of mixing is completed.

[0023] In addition, the second channel 2 is provided with an injection assembly and an auxiliary assembly in the inside, the auxiliary assembly comprises a fixed block 9, a rotating shaft 10 and a second threaded blade rod 11, the outside of the fixed block 9 is fixedly connected with the inner wall of the second channel 2, and the inside of the fixed block 9 is rotatably connected with the outside of the rotating shaft 10, one end of the rotating shaft 10 is fixedly connected with the side of the second threaded blade rod 11, and the second threaded blade rod 11 is located on the top of one end of the connecting pipe 7. The material preliminarily mixed by the first threaded blade rod 4 moves to the direction of the one-way valve 6 on the side of the first channel 1 under the conveying thrust of the first threaded blade rod 4, the material pushes away the one-way valve 6 (the one-way valve 6 can prevent the backflow of the subsequent material), and is guided from the first channel 1 to the inside of the second channel 2 through the connecting pipe 7 fixedly connected with the one-way valve 6 (one end of the connecting pipe 7 is fixed with the bottom of the second channel 2), when the material enters the second channel 2 from the outlet of the connecting pipe 7, the flow impact force carried by the material directly acts on the second threaded blade rod 11 located on the top of the outlet of the connecting pipe 7, since the second threaded blade rod 11 is rotatably connected with the fixed block 9 fixedly connected with the inner wall of the second channel 2 through the rotating shaft 10, the material impact force drives the second threaded blade rod 11 to rotate around the rotating shaft 10, the second stirring of the preliminarily mixed material and nitrogen gas is realized, the nitrogen gas bubbles are further refined, and the mixing uniformity is further improved, and the second stage of mixing is completed.

[0024] Finally, the injection assembly includes an oil cylinder 12, the side of the oil cylinder 12 is fixedly connected with the side of the second channel 2, and the telescopic end of the oil cylinder 12 is fixedly connected with a pushing block 13, the outside of the pushing block 13 is fixedly installed with a sealing ring 14, the telescopic end of the oil cylinder 12 and the pushing block 13 are located inside the second channel 2, the outside of the pushing block 13 is in sliding connection with the inner wall of the second channel 2, the side of the second channel 2 is boltedly connected with a connecting block 15, the side of the connecting block 15 is fixedly connected with an injection pipe 16, and the outside of the injection pipe 16 is fixedly installed with a discharge valve. The twice-mixed material is temporarily stored in the second channel 2, when injection is needed, the oil cylinder 12 fixedly connected with the side of the second channel 2 is started, the telescopic end (located inside the second channel 2) of the oil cylinder 12 pushes the pushing block 13 fixedly connected therewith, the sealing ring 14 outside the pushing block 13 is tightly attached to the inner wall of the second channel 2 (to prevent material leakage), extrusion pressure is applied to the material in the second channel 2, the material flows to the injection pipe 16 on the other side of the second channel 2 under the extrusion of the pushing block 13, when the material flows through the second screw blade rod 11, the flow trend drives the second screw blade rod 11 to rotate again, the material and nitrogen are stirred for the third time, the third stage of mixing is completed, finally, the uniformly mixed material after three times of mixing flows outwards through the injection pipe 16 (the discharge valve outside the injection pipe 16 is opened) under the continuous extrusion of the pushing block 13, is injected into a mold cavity, and the whole supercritical injection molding process is completed.

[0025] Working principle: the supercritical injection molding mechanism operates according to the process of "material conveying-three-stage mixing-injection discharge": in the material conveying and preliminary mixing stage, the injection material enters the first channel 1 through the feeding pipe 8 at the top of the first channel 1, the gas injection pipe 5 injects nitrogen, the motor 3 is started to drive the first screw blade rod 4 in the first channel 1 to rotate, and the material conveying and nitrogen preliminary mixing are realized; in the secondary mixing and material flow guiding stage, the preliminary mixed material pushes open the one-way valve 6 under the pushing of the first screw blade rod 4, enters the second channel 2 through the connecting pipe 7, the material impact force drives the second screw blade rod 11 (connected with the fixed block 9 through the rotating shaft 10) in the second channel 2 to rotate, and the secondary mixing is completed; in the third mixing and injection discharge stage, the oil cylinder 12 pushes the pushing block 13 (with the sealing ring 14) in the second channel 2 to extrude the material, when the material flows to the injection pipe 16 (connected with the second channel 2 through the connecting block 15) the second screw blade rod 11 rotates again to realize the third mixing, and finally the material is injected into a mold through the injection pipe 16, and the molding is completed.

Claims

1. A supercritical injection molding mechanism, comprising a first channel (1) and a second channel (2), characterized in that: The first channel (1) is equipped with a conveying component inside, and a gas filling pipe (5) is fixedly connected to the top of the first channel (1). A one-way valve (6) is fixedly connected to the side of the first channel (1), and a connecting pipe (7) is fixedly connected to the side of the one-way valve (6). One end of the connecting pipe (7) is fixedly connected to the bottom of the second channel (2). The second channel (2) is provided with an injection assembly and an auxiliary assembly. The auxiliary assembly includes a fixing block (9), a rotating shaft (10), and a second threaded blade rod (11). The outside of the fixing block (9) is fixedly connected to the inner wall of the second channel (2), and the inside of the fixing block (9) is rotatably connected to the outside of the rotating shaft (10). One end of the rotating shaft (10) is fixedly connected to the side of the second threaded blade rod (11), and the second threaded blade rod (11) is located at the top of one end of the connecting tube (7).

2. The supercritical injection molding mechanism according to claim 1, characterized in that: The conveying assembly includes a motor (3), the side of which is fixedly connected to the side of the first channel (1), and a first threaded blade rod (4) is fixedly connected to one end of the output shaft of the motor (3), the first threaded blade rod (4) being disposed inside the first channel (1).

3. The supercritical injection molding mechanism according to claim 1, characterized in that: The injection assembly includes a cylinder (12), the side of which is fixedly connected to the side of the second channel (2), and a push block (13) is fixedly connected to the telescopic end of the cylinder (12), and a sealing ring (14) is fixedly installed on the outside of the push block (13).

4. The supercritical injection molding mechanism according to claim 3, characterized in that: The telescopic end of the cylinder (12) and the push block (13) are both located inside the second channel (2), and the outside of the push block (13) is slidably connected to the inner wall of the second channel (2).

5. The supercritical injection molding mechanism according to claim 1, characterized in that: The second channel (2) is bolted to a connecting block (15), and an injection tube (16) is fixedly connected to the side of the connecting block (15). A discharge valve is fixedly installed on the outside of the injection tube (16).

6. The supercritical injection molding mechanism according to claim 1, characterized in that: The top of the first channel (1) is fixedly connected to a feed pipe (8).

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