Injection molding device and method for plastic part

Abstract

The invention discloses an injection molding device and method for plastic parts, and belongs to the technical field of injection molding equipment, the injection molding device comprises a workbench, mold equipment and injection molding equipment, the injection molding equipment comprises an injection mechanism, a feeding mechanism and a ventilation mechanism, the injection mechanism comprises a moving seat and a spray head on the moving seat, and an ejection assembly is arranged in the spray head; by means of the injection molding device, after injection molding of each plastic part is completed, an air knife is formed on the inner wall of the front end of the spray head, drawn wires are cut off, backflow of extruded raw materials is blocked, meanwhile, an air film similar to an umbrella shape is formed on the inner wall of the front end of the spray head, and the air film is prevented from being blown out. And the molten raw material can be prevented from being attached to the abrasion trace, the situation that the raw material attached to the abrasion position for a long time is carbonized is prevented, flaws are avoided, and the quality and attractiveness of the product are improved.

Description

Technical Field

[0001] The present invention relates to intelligent manufacturing equipment, and more specifically to the technical field of injection molding equipment, and more specifically to an injection molding device and method for plastic parts. Background Art

[0002] Plastic injection molding, also known as an injection molding machine, is a specialized machine that melts thermoplastic or thermosetting plastic raw materials, injects them into a mold cavity under high pressure, and solidifies them after cooling to form plastic parts. It is widely used in a variety of fields, including automotive, electronics, medical, and packaging. Its structural design must meet the process requirements of plasticization, injection, mold closing, and cooling. The working principle can be summarized as follows: the raw materials are heated and plasticized → the screw / plunger pushes and injects → the mold is closed and pressurized → cooling and shaping → mold opening and part removal. Based on the structural form, injection molding machines can be divided into horizontal injection molding machines, vertical injection molding machines, and angle injection molding machines. Horizontal injection molding machines dominate the market due to their high stability and ease of operation.

[0003] The structure of injection molding equipment mainly includes the clamping system, injection system, hydraulic / electric system, temperature control system and control system. Through the mutual cooperation between these systems, efficient conversion from raw materials to finished products is achieved. Among them, the injection system heats and melts the plastic raw materials and injects them into the mold. It is the key part that determines the plasticization quality and injection accuracy. It mainly includes the screw, barrel, injection device and nozzle.

[0004] In existing injection molding systems, due to the inherent dead angles of the nozzle tip or after long-term use, the inner wall of the flow channel will show signs of wear, resulting in a decrease in smoothness. This can easily cause molten raw material to adhere to these worn areas. If the residual old material in these areas is not cleaned for a long time, after switching between different materials, this residual old material will cause a chemical reaction and thermal decomposition with the new material at high temperatures. The decomposition gases may corrode the inner wall of the nozzle, shortening the life of the components. At the same time, carbonization may also occur. These carbonized particles will be injected into the mold along with the subsequent melt, causing black spots and bubbles on the surface of the product, affecting the quality of the product. To avoid this, the inside of the nozzle is cleaned before each new raw material is injected into the barrel to eliminate the influence of previous residues. However, sometimes the raw material attached to the inner wall of the nozzle begins to carbonize before the same batch of raw material is processed (there is raw material in the barrel). At this time, the injection cavity is filled with molten raw material, and the equipment cannot be stopped for cleaning. This can easily lead to black spots (carbonized particles) and bubbles directly exposed on the surface or inside the products of the subsequent batch, forming obvious defects, reducing the quality and affecting the appearance. Summary of the Invention

[0005] The technical solution of the present invention addresses the technical problem that the existing technical solutions are too single, and provides a solution that is significantly different from the existing technology. The injection molding equipment of the present invention belongs to intelligent manufacturing equipment, and mainly provides an injection molding device and method for plastic parts, which is used to solve the technical problem raised in the above background technology that in the current existing plastic parts injection molding, before the processing of the same batch of raw materials is completed, sometimes part of the raw materials adhere to the wear position of the inner wall of the front end of the nozzle, forming carbonization. These carbonized particles will be injected into the mold along with the subsequent melt, resulting in black spots and bubbles on the surface of the product.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: A plastic part injection molding device includes a workbench, a mold device, and an injection molding device. The mold device includes a fixed mold and a movable mold. The movable mold moves linearly on the fixed mold to perform mold closing and demolding. The injection port of the fixed mold and the output end of the injection molding device are coaxial. The injection molding device includes an injection mechanism, a feeding mechanism, and a ventilation mechanism. The ventilation mechanism is connected to the injection mechanism and the feeding mechanism respectively through a hose. The injection mechanism includes a movable base and a nozzle on the movable base. The nozzle is provided with an ejection assembly. The ejection assembly includes a spiral structure and a sleeve. The sleeve is provided with an air injection structure that can form an "air knife" on the inner wall of the front end of the nozzle. The jet structure includes a mounting tube, an ejector head, an air inlet pipe and a spring. The mounting tube is located in the sleeve, and the mounting tube and the sleeve are connected by bolts. The air inlet pipe is connected to the interface on the mounting tube. The air inlet pipe passes through the sleeve and is inserted into the end of the spiral structure. The spring is sleeved on the ejector head for resetting the ejector head.

[0007] Preferably, the ejector head includes a receiving portion and a guide portion, the high-pressure gas acts on the end of the receiving portion, and the guide portion is a hollow truncated cone structure; And / or, the guide portion has a conical structure with a hollow interior; And / or, the guide portion has a hemispherical structure with a hollow interior.

[0008] Preferably, the spiral structure and the sleeve are connected by threads, and a plurality of air inlet holes are arranged around the non-threaded portion of the spiral structure at equal intervals.

[0009] Preferably, the non-threaded part on the spiral structure is movably connected to the movable seat, and the protrusion at the bottom of the movable seat is slidably connected to a slide rail, and the slide rail is arranged on the upper surface of the workbench. A first hydraulic cylinder is arranged on the workbench, and the output end of the first hydraulic cylinder is connected to the interface on the movable seat. A second hydraulic cylinder and a movable plate are also arranged on the movable seat, and the second hydraulic cylinder drives the movable plate to move linearly on the movable seat. A motor is arranged on the movable plate, and the output end of the motor is connected to one end of the spiral structure.

[0010] Preferably, the feeding mechanism includes a barrel and a capping structure, the lower end of the barrel is connected to the interface on the upper side of the nozzle, a stirring shaft is provided in the barrel, the capping structure includes a top cover and a shell, the top cover and the shell are detachably connected, an impeller is provided in the shell, and the lower end of the impeller is connected to the upper end of the stirring shaft.

[0011] Preferably, the ventilation mechanism includes an air inlet cover plate, an air outlet cover plate, and a rotating drum between the two cover plates. The connection positions of the rotating drum and the two cover plates are each provided with a first shaft seal. An adjustment hole is provided in the rotating drum for respectively connecting the two hoses on the air outlet cover plate. One hose on the air outlet cover plate is connected to the air inlet interface at an eccentric position on the shell, and the other hose on the air outlet cover plate is connected to a ring-shaped docking structure.

[0012] Preferably, the annular docking structure includes an annular sleeve and two second shaft seals. The annular sleeve is connected to the non-threaded portion of the spiral structure through the two second shaft seals. The annular sleeve covers the air inlet holes that are distributed around the spiral structure at equal intervals.

[0013] Preferably, a gear ring is provided on the outer wall of the rotating drum, and the gear ring is meshedly connected with a rack, and the rack is mounted on the movable plate through a bracket.

[0014] A method for injection molding a plastic part comprises the following steps: S1 Preliminary preparation: First, align the adjustment hole on the rotating drum with the pipeline of the eccentric air inlet interface on the shell. After the high-pressure gas enters the shell, it drives the impeller to rotate, and then the impeller drives the stirring shaft to rotate. At the same time, the raw materials are introduced into the barrel and transported into the nozzle under the action of the stirring shaft, and the raw materials in the nozzle are melted; S2 injection molding: The motor drives the spiral structure in the ejector assembly to rotate rapidly, shearing and rubbing the raw material. At the same time, the first hydraulic cylinder is activated, pushing the movable seat toward the side of the mold equipment, so that the front end of the nozzle docks with the injection port of the fixed mold. Then the second hydraulic cylinder is activated, driving the movable plate toward the side of the mold equipment again. Then, the spiral structure squeezes out the molten raw material in the nozzle and injects the molten raw material into the mold cavity through the nozzle. The molten material fills every corner of the mold under high pressure, forming a prototype consistent with the shape of the mold cavity. After cooling, the movable mold leaves the fixed mold for demoulding; S3 pneumatic separation: After one injection is completed, the nozzle just leaves the fixed mold under the action of the first hydraulic cylinder. At this time, with the cooperation of the rack and the gear ring, the adjustment hole just rotates to the pipeline connected to the annular docking structure. Then the external high-pressure and high-temperature gas enters the air inlet pipe through the hose and the air inlet hole. Then the gas enters the installation cylinder through the air inlet pipe. The air pressure acts on the receiving part of the ejector head, the spring is compressed, and the ejector head is pushed out and moved to the front end of the nozzle, so that the guide part of the ejector head and the front end of the sleeve are separated, the high-pressure gas is released, the wire drawing is cut, and the raw material attached to the front end of the nozzle head is separated; S4 moves back and resets, and then with the cooperation of the first hydraulic cylinder and the second hydraulic cylinder, the nozzle and the ejection assembly are gradually reset. At the same time, with the cooperation of the gear ring and the rack, the adjustment hole is rotated again to the pipeline of the eccentric position air inlet interface on the shell, and the stirring shaft is driven to rotate again, and then the above injection molding steps are repeated in sequence.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention realizes injection molding into the mold equipment by setting a workbench, a movable seat, a nozzle, a movable plate, a motor, a hydraulic cylinder, a slide rail and an ejection assembly. After each plastic part is injected, the mutual cooperation between the mounting cylinder, the ejection head, the receiving part, the guide part, the air inlet pipe, the spring and the annular docking structure can form an "air knife" on the inner wall of the front end of the nozzle to cut off the wire drawing formed between the molten raw material inside the nozzle and the product in the mold, and block the backflow of the extruded raw material. Since the guide part is a truncated cone structure, a conical structure or a hemispherical structure, an umbrella-shaped air film can be formed on the inner wall of the front end of the nozzle. , blow away the raw materials at the worn parts to make them flow, avoid the molten raw materials from adhering to the worn marks for a long time, and prevent the raw materials that have been attached to the worn parts for a long time from carbonizing, thereby avoiding the carbonized particles and molten raw materials being squeezed out together during the processing, causing black spots and bubbles to form on the surface or inside the product, ensuring that the raw materials will not be carbonized at the front end of the nozzle during each processing, ensuring the uniformity and stability of the material density, improving the tensile strength, compressive strength and impact toughness of the product, and avoiding the situation where the product is unqualified due to defects in appearance, and needs to be reworked or scrapped.

[0016] (2) The present invention realizes that when the first hydraulic cylinder drives the nozzle to approach the injection port of the fixed mold, the impeller can be driven to rotate by high-pressure gas, which in turn drives the stirring shaft to stir and guide the raw materials. This can overcome the problem of "bridging" (raw materials piled up into an arch shape, hindering material discharge) or "dead corners" (local raw materials stagnate) when the granular raw materials enter the feed barrel due to uneven particle size, humidity or static electricity. The rotation of the stirring shaft can mechanically break the bridge and force the raw materials to fall evenly, thereby ensuring continuous and stable feeding. In addition, for high-viscosity plastics (such as polycarbonate PC) or raw materials with a large amount of fillers (such as calcium carbonate, glass fiber), the flow resistance can be well overcome, so that the molten material has good fluidity, avoiding the problem of insufficient filling or lack of material in the product.

[0017] (3) The present invention realizes that when the first hydraulic cylinder drives the nozzle to approach the injection port of the fixed mold and docks with the injection port, the ventilation structure is connected to the shell, ensuring that the impeller can drive the stirring shaft to rotate, so that the raw materials can enter the nozzle continuously and stably. When the second hydraulic cylinder drives the moving plate to move, the ejection assembly moves to the front end and squeezes out the molten raw materials. At this time, the rack drives the rotating drum to rotate through the gear ring, so that the adjustment hole moves to the pipeline on the annular docking structure to complete the switching, avoiding further material discharge. At the same time, an "air knife" is formed on the inner wall of the front end of the nozzle, which just matches the movement process of the nozzle at each stage in the existing injection molding equipment. It is orderly and improves the overall injection molding efficiency. The mutual cooperation between the annular docking structure, the annular shaft sleeve and the second shaft seal avoids the hose used for air intake from rotating synchronously with the ejection assembly, ensuring the stability and reliability of air intake.

[0018] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the overall model structure of the present invention Figure 2 It is a schematic diagram of the overall structure of the present invention; Figure 3 It is a schematic structural diagram of the injection mechanism of the present invention; Figure 4 This is an exploded schematic diagram of the injection mechanism of the present invention; Figure 5 This is an exploded schematic diagram of the ejection assembly of the present invention; Figure 6 It is an exploded schematic diagram of the feeding mechanism of the present invention; Figure 7 This is an exploded schematic diagram of the ventilation mechanism of the present invention; Figure 8 It is a schematic cross-sectional view of the cover plate and the rotating drum of the present invention.

[0020] In the figure: 1. Workbench; 2. Injection mechanism; 21. Moving seat; 22. Nozzle; 23. Moving plate; 24. Motor; 25. First hydraulic cylinder; 26. Slide rail; 27. Second hydraulic cylinder; 28. Rack; 3. Feeding mechanism; 31. Barrel; 32. Housing; 33. Top cover; 34. Impeller; 35. Stirring shaft; 4. Ventilation mechanism; 41. Inlet cover plate; 42. Outlet cover plate; 43. Rotating drum; 431. Adjustment hole; 432. Gear ring; 44. First shaft seal; 45. Annular docking structure; 451. Annular sleeve; 452. Second shaft seal; 5. Mould equipment; 51. Fixed mould; 52. Moving mould; 6. Ejector assembly; 61. Spiral structure; 611. Air inlet; 62. Sleeve; 7. Jet structure; 71. Mounting tube; 72. Ejector head; 721. Receiving part; 722. Guide part; 73. Inlet pipe; 74. Spring. DETAILED DESCRIPTION

[0021] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0022] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly used by those skilled in the art to which the present invention pertains. The terminology used in the specification of the present invention is for the purpose of describing specific embodiments and is not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0024] Example 1, please refer to the attached Figure 1-8As shown, a plastic part injection molding device includes a workbench 1, a mold device 5 and an injection molding device. The mold device 5 includes a fixed mold 51 and a movable mold 52. The movable mold 52 moves linearly on the fixed mold 51 to perform mold closing and demolding, and the injection port of the fixed mold 51 and the output end of the injection molding device are on the same axis. The injection molding device includes an injection mechanism 2, a feeding mechanism 3 and a ventilation mechanism 4. The ventilation mechanism 4 is connected to the injection mechanism 2 and the feeding mechanism 3 respectively through a hose. The injection mechanism 2 includes a movable seat 21 and a nozzle 22 on the movable seat 21. The nozzle 22 is provided with a top The ejection assembly 6 includes a spiral structure 61 and a sleeve 62. The sleeve 62 is provided with an injection structure 7 that can form an "air knife" on the inner wall of the front end of the nozzle 22; the injection structure 7 includes a mounting cylinder 71, an ejection head 72, an air inlet pipe 73 and a spring 74. The mounting cylinder 71 is located in the sleeve 62, and the mounting cylinder 71 and the sleeve 62 are connected by bolts. The air inlet pipe 73 is connected to the interface on the mounting cylinder 71, the air inlet pipe 73 passes through the sleeve 62 and is inserted into the end of the spiral structure 61. The spring 74 is sleeved on the ejection head 72 for resetting the ejection head 72.

[0025] Through the above structure, after each plastic part is injection molded, an "air knife" will be formed on the inner wall of the front end of the nozzle 22 to cut off the wire drawing formed between the molten raw material inside the nozzle 22 and the product in the mold, and block the backflow of the extruded raw material. At the same time, an umbrella-shaped air film is formed on the inner wall of the front end of the nozzle 22, which can prevent the molten raw material from adhering to the wear marks and prevent the raw material that has been attached to the wear position for a long time from carbonizing. In this way, it is avoided that during the processing, carbonized particles and molten raw materials are extruded together, so that black spots and bubbles are formed on the surface or inside of the product, thereby ensuring that the raw material will not be carbonized at the front end of the nozzle 22 during each processing process, thereby ensuring the uniformity and stability of the material density, improving the tensile strength, compressive strength and impact toughness of the product, and avoiding the situation where the product is unqualified due to defects in appearance and needs to be reworked or scrapped.

[0026] The specific operation is as follows: first, the adjustment hole 431 on the rotating drum 43 is aligned with the pipeline of the eccentric position air inlet interface on the shell 32, so that after the high-pressure gas enters the shell 32, it drives the impeller 34 to rotate, and then the impeller 34 can drive the stirring shaft 35 to rotate, and at the same time, the raw material is introduced into the barrel 31, and is transported to the nozzle 22 under the action of the stirring shaft 35, and the raw material in the nozzle 22 is melted; the motor 24 drives the spiral structure 61 in the ejection assembly 6 to rotate rapidly, shearing and rubbing the raw material, and at the same time the first hydraulic cylinder 25 starts The movable base 21 moves to the side of the mold device 5, so that the front end of the nozzle 22 docks with the injection port of the fixed mold 51. Then the second hydraulic cylinder 27 is started, driving the movable plate 23 to move closer to the side of the mold device 5 again. Then, the molten raw material in the nozzle 22 is squeezed out through the spiral structure 61, and the molten raw material is injected into the mold cavity through the nozzle 22. The molten material fills every corner of the mold under high pressure to form a prototype consistent with the shape of the mold cavity. After cooling, the movable mold 52 leaves the fixed mold 51 for demoulding. After one injection molding, as the nozzle 22 just leaves the fixed mold 51 under the action of the first hydraulic cylinder 25, the adjustment hole 431 is just rotated to the pipeline connected to the annular docking structure 45 under the cooperation of the rack 28 and the gear ring 432. Then the external high-pressure and high-temperature gas enters the intake pipe 73 through the hose and the intake hole 611, and then the gas enters the installation cylinder 71 through the intake pipe 73. The air pressure acts on the receiving portion 721 of the ejector head 72, the spring 74 is compressed, and the ejector head 72 is pushed out, moving to the nozzle. The front end of the nozzle 22 is moved away from the guide portion 722 of the ejector head 72 and the front end of the sleeve 62, thereby releasing the high-pressure gas, cutting the wire drawing, and separating the raw material attached to the front end of the nozzle 22; subsequently, with the cooperation of the first hydraulic cylinder 25 and the second hydraulic cylinder 27, the nozzle 22 and the ejector assembly 6 are gradually reset, and at the same time, with the cooperation of the gear ring 432 and the rack 28, the adjustment hole 431 is rotated again to the pipeline of the eccentric position air inlet interface on the shell 32, and the stirring shaft 35 is driven to rotate again, and then the above injection molding steps are repeated in sequence.

[0027] Example 2, please refer to the attached Figure 3 、 4As shown in Figure 5, the ejector head 72 includes a receiving portion 721 and a guide portion 722. The high-pressure gas acts on the end of the receiving portion 721. The structure of the guide portion 722 is an internal hollow frustum structure; and / or, the structure of the guide portion 722 is an internal hollow conical structure; and / or, the structure of the guide portion 722 is an internal hollow hemispherical structure. Through the structural design of the guide portion 722, the flow of high-pressure and high-temperature gas is guided to form an "umbrella-shaped" structure so as to better fit with the front end of the inner wall of the nozzle 22 for cutting and anti-sticking. The spiral structure 61 and the sleeve 62 are threadedly connected, and the non-threaded part on the spiral structure 61 is equidistantly surrounded by a plurality of air inlet holes 611. Through the air inlet holes 611, the high-temperature High-pressure gas is introduced into the ejection assembly 6, and the non-threaded part on the spiral structure 61 is movably connected to the moving seat 21. The protrusion at the bottom of the moving seat 21 is slidably connected to the slide rail 26, and the slide rail 26 is arranged on the upper surface of the workbench 1. The workbench 1 is provided with a first hydraulic cylinder 25, and the output end of the first hydraulic cylinder 25 is connected to the interface on the moving seat 21. The moving seat 21 is also provided with a second hydraulic cylinder 27 and a moving plate 23. The second hydraulic cylinder 27 drives the moving plate 23 to move linearly on the moving seat 21. The moving plate 23 is provided with a motor 24, and the output end of the motor 24 is connected to one end of the spiral structure 61. Through the first hydraulic cylinder 25 and the second hydraulic cylinder 27, the linear movement of the moving seat 21 and the moving plate 23 is realized, providing driving force.

[0028] Example 3, please refer to the attached Figure 4 、 6As shown in Figure 7, the feeding mechanism 3 includes a barrel 31 and a capping structure. The lower end of the barrel 31 is connected to the interface on the upper side of the nozzle 22. A stirring shaft 35 is provided in the barrel 31. The capping structure includes a top cover 33 and a shell 32. The top cover 33 and the shell 32 are detachably connected. An impeller 34 is provided in the shell 32, and the lower end of the impeller 34 is connected to the upper end of the stirring shaft 35. Through the impeller 34, the high-pressure gas is utilized to drive the stirring shaft 35 to rotate, so that The raw materials in the barrel 31 flow stably. The ventilation mechanism 4 includes an air inlet cover plate 41, an air outlet cover plate 42, and a rotating drum 43 between the two cover plates. The two cover plates are mounted on the movable seat 21 through a bracket. The connecting position of the rotating drum 43 and the two cover plates is provided with a first shaft seal 44. The rotating drum 43 is provided with an adjustment hole 431 for connecting the two hoses on the air outlet cover plate 42 respectively. A hose on the air outlet cover plate 42 is connected to the air inlet interface at the eccentric position on the shell 32. , another hose on the air outlet cover plate 42 is connected to an annular docking structure 45, and the ventilation mechanism 4 is used to switch the direction of the gas introduced into the feeding mechanism 3 and the ejection assembly 6. The annular docking structure 45 includes an annular sleeve 451 and two second shaft seals 452. The annular sleeve 451 is connected to the non-threaded part on the spiral structure 61 through the two second shaft seals 452. The annular sleeve 451 covers the air inlet holes 611 distributed around the same interval. The annular docking structure 45 is used to prevent the hose used for air intake from rotating synchronously with the ejection assembly 6, thereby ensuring the stability and reliability of air intake. A gear ring 432 is provided on the outer wall of the rotating cylinder 43, and the gear ring 432 is meshed with a rack 28. The rack 28 is mounted on the movable plate 23 through a bracket. The rack 28 and the gear ring 432 are in the same horizontal plane, which can drive the adjusting hole 431 on the rotating cylinder 43 to rotate 180 degrees, so that the adjusting hole 431 is connected to the pipeline of the annular docking structure 45.

[0029] The above description of the present invention is exemplified in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A plastic part injection molding device, comprising a workbench (1), a mold device (5) and an injection molding device, wherein the mold device (5) comprises a fixed mold (51) and a movable mold (52), the movable mold (52) moves linearly on the fixed mold (51) to perform mold closing and demolding, and the injection port of the fixed mold (51) and the output end of the injection molding device are on the same axis, characterized in that The injection molding device includes an injection mechanism (2), a feeding mechanism (3) and a ventilation mechanism (4), the ventilation mechanism (4) being connected to the injection mechanism (2) and the feeding mechanism (3) respectively through a hose, the injection mechanism (2) including a movable seat (21) and a nozzle (22) on the movable seat (21), an ejection assembly (6) being provided in the nozzle (22), the ejection assembly (6) including a spiral structure (61) and a sleeve (62), an air jet structure (7) being provided in the sleeve (62) for forming an "air knife" on the inner wall of the front end of the nozzle (22); The jet structure (7) includes a mounting cylinder (71), an ejection head (72), an air inlet pipe (73) and a spring (74). The mounting cylinder (71) is located in the sleeve (62), and the mounting cylinder (71) and the sleeve (62) are connected by bolts. The air inlet pipe (73) is connected to an interface on the mounting cylinder (71). The air inlet pipe (73) passes through the sleeve (62) and is inserted into the end of the spiral structure (61). The spring (74) is sleeved on the ejection head (72) and is used to reset the ejection head (72).

2. The plastic part injection molding device according to claim 1, characterized in that: The ejector head (72) comprises a receiving portion (721) and a guide portion (722), high-pressure gas acts on the end of the receiving portion (721), and the guide portion (722) has a hollow truncated cone structure. And / or, the guide portion (722) has a structure of a conical structure with a hollow interior; And / or, the structure of the guide portion (722) is a hemispherical structure with a hollow interior.

3. The plastic part injection molding device according to claim 1, characterized in that: The spiral structure (61) and the sleeve (62) are connected by a thread, and a plurality of air inlet holes (611) are arranged around the non-threaded portion of the spiral structure (61) at equal intervals.

4. The plastic part injection molding device according to claim 3, characterized in that: The non-threaded portion on the spiral structure (61) is movably connected to the movable seat (21), and the protrusion at the bottom of the movable seat (21) is slidably connected to a slide rail (26), which is arranged on the upper surface of the workbench (1). A first hydraulic cylinder (25) is provided on the workbench (1), and the output end of the first hydraulic cylinder (25) is connected to the interface on the movable seat (21). A second hydraulic cylinder (27) and a movable plate (23) are also provided on the movable seat (21). The second hydraulic cylinder (27) drives the movable plate (23) to move linearly on the movable seat (21). A motor (24) is provided on the movable plate (23), and the output end of the motor (24) is connected to one end of the spiral structure (61).

5. The plastic part injection molding device according to claim 1, characterized in that: The feeding mechanism (3) includes a barrel (31) and a capping structure. The lower end of the barrel (31) is connected to the interface on the upper side of the nozzle (22). A stirring shaft (35) is provided in the barrel (31). The capping structure includes a top cover (33) and a shell (32). The top cover (33) and the shell (32) are detachably connected. An impeller (34) is provided in the shell (32), and the lower end of the impeller (34) is connected to the upper end of the stirring shaft (35).

6. The plastic part injection molding device according to claim 1, characterized in that: The ventilation mechanism (4) comprises an air inlet cover plate (41), an air outlet cover plate (42), and a rotating drum (43) between the two cover plates. The connecting positions of the rotating drum (43) and the two cover plates are both provided with a first shaft seal (44). An adjusting hole (431) is provided in the rotating drum (43) for respectively connecting two hoses on the air outlet cover plate (42). One hose on the air outlet cover plate (42) is connected to an air inlet interface at an eccentric position on the housing (32), and the other hose on the air outlet cover plate (42) is connected to an annular docking structure (45).

7. The plastic part injection molding device according to claim 6, characterized in that: The annular docking structure (45) comprises an annular shaft sleeve (451) and two second shaft seals (452). The annular shaft sleeve (451) is connected to the non-threaded portion of the spiral structure (61) via the two second shaft seals (452). The annular shaft sleeve (451) covers the air inlet holes (611) that are distributed around the spiral structure at equal intervals.

8. The plastic part injection molding device according to claim 7, characterized in that: A gear ring (432) is provided on the outer wall of the rotating drum (43), and the gear ring (432) is meshedly connected with a rack (28), and the rack (28) is mounted on the movable plate (23) through a bracket.

9. A method for injection molding a plastic part, using the injection molding device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1 Preliminary preparation: First, align the adjustment hole (431) on the rotating drum (43) with the pipeline of the eccentric position air inlet interface on the shell (32), so that the high-pressure gas enters the shell (32) and drives the impeller (34) to rotate, and then the impeller (34) can drive the stirring shaft (35) to rotate, and at the same time, the raw material is introduced into the barrel (31), and is transported to the nozzle (22) under the action of the stirring shaft (35), and the raw material in the nozzle (22) is melted; S2 injection molding: the motor (24) drives the spiral structure (61) in the ejection assembly (6) to rotate rapidly, shearing and rubbing the raw material, and at the same time the first hydraulic cylinder (25) is started to push the movable seat (21) toward the side of the mold device (5), so that the front end of the nozzle (22) docks with the injection port of the fixed mold (51), and then the second hydraulic cylinder (27) is started to drive the movable plate (23) to approach the side of the mold device (5) again, and then the molten raw material in the nozzle (22) is squeezed out through the spiral structure (61), and the molten raw material is injected into the mold cavity through the nozzle (22). The molten material fills every corner of the mold under high pressure to form a prototype consistent with the shape of the mold cavity. After cooling, the movable mold (52) leaves the fixed mold 51 for demoulding; S3 pneumatic separation: After one injection molding is completed, the nozzle (22) just separates from the fixed mold (51) under the action of the first hydraulic cylinder (25). At this time, under the cooperation of the rack (28) and the gear ring (432), the adjustment hole (431) just rotates to the pipeline connected to the annular docking structure (45), and the external high-pressure and high-temperature gas enters the intake pipe (73) through the hose and the intake hole (611). Then the gas enters the installation cylinder (71) through the intake pipe (73). The air pressure acts on the receiving portion (721) of the ejector head (72), and the spring (74) is compressed and pushes the ejector head (72) out and moves it to the front end of the nozzle (22), so that the guide portion (722) of the ejector head (72) and the front end of the sleeve (62) are separated, the high-pressure gas is released, the wire drawing is cut, and the raw material attached to the front end of the nozzle (22) is separated; S4 moves back and resets, and then, with the cooperation of the first hydraulic cylinder (25) and the second hydraulic cylinder (27), the nozzle (22) and the ejection assembly (6) are gradually reset. At the same time, with the cooperation of the gear ring (432) and the rack (28), the adjustment hole (431) is rotated again to the pipeline of the eccentric position air inlet interface on the shell (32), and the stirring shaft (35) is driven to rotate again, and then the above injection molding steps are repeated in sequence.

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