Vertical rubber and plastic foaming injection molding device

Abstract

The invention relates to a vertical rubber and plastic foaming injection molding device, and belongs to the technical field of injection molding. The injection molding device comprises a plasticizing material barrel, a mixing screw and a driving mechanism, the plasticizing material barrel is provided with a gas injection hole for injecting gas, the driving mechanism comprises an injection molding cylinder body and an injection molding piston, the plasticizing material barrel and the injection molding cylinder body are communicated, the axis of the injection molding cylinder body is perpendicular to the mold closing system, and the plasticizing material barrel is obliquely arranged on the injection molding cylinder body. The inclination angle is larger than or equal to 0 degree and smaller than 90 degrees; when the inclination angle is equal to 0 degree, the injection molding cylinder body and the plasticizing charging barrel are coaxially arranged, and the injection molding piston is connected with the mixing screw rod; when the inclination angle is larger than or equal to 0 degree and smaller than 90 degrees, the plasticizing material barrel becomes an extrusion system and is obliquely arranged on the side wall of the injection molding cylinder body. The rubber and plastic foaming forming device has the advantages that the equipment design cost and the occupied area are reduced, the overall design is simplified, operation is convenient, and the application universality and flexibility of the rubber and plastic foaming forming device are greatly improved.

Description

Technical Field

[0001] The present application relates to the technical field of injection molding, and in particular to a vertical rubber and plastic foaming injection molding device. Background Art

[0002] Foaming injection molding is an injection molding technology that adds chemical or physical foaming agents to plastics and performs injection molding through an injection molding machine, so that the plastics undergo chemical reactions or physical changes during the plasticization process to produce a large amount of gas, or directly inject gas to mix and diffuse with the melt, thereby achieving a foaming effect. Foaming injection molding machines are key equipment for realizing this technology.

[0003] Foam injection molding machines generally include an injection molding system, a heating system, a mold clamping system, a transmission system, and an electrical control system. Currently, the foam injection molding equipment used at home and abroad is a horizontal injection molding machine. The injection molding system structure includes a barrel, an injection screw arranged in the barrel, an injection cylinder for pushing the injection screw, and a nozzle arranged at the end of the barrel.

[0004] With respect to the above-mentioned related technologies, the injection molding system of a horizontal injection molding machine is generally arranged horizontally, which occupies a large area and is inconvenient to operate when used for insert molding. Summary of the invention

[0005] In order to solve the problem that the existing horizontal injection molding machine occupies a large area and is complicated to operate, the present application provides a vertical rubber and plastic foaming injection molding device.

[0006] The vertical rubber and plastic foam injection molding device provided in this application adopts the following technical solution: A vertical rubber and plastic foam injection molding device, comprising a plasticizing barrel, a mixing screw rotatably arranged in the plasticizing barrel, and a driving mechanism, wherein the plasticizing barrel is provided with a gas injection hole for injecting gas, characterized in that the driving mechanism comprises an injection cylinder and an injection piston slidably mounted on the injection cylinder and used to push the melt, the plasticizing barrel and the injection cylinder are connected and arranged, the axis of the injection cylinder is perpendicular to the clamping system, the plasticizing barrel is tiltedly arranged on the injection cylinder, and the tilt angle is greater than or equal to 0° and less than 90°; When the tilt angle is equal to 0°, the injection cylinder and the plasticizing barrel are coaxially arranged, the injection piston is connected to the mixing screw, and the driving mechanism further includes a rotation driving source for driving the injection piston to rotate circumferentially; When the inclination angle is greater than or equal to 0° and less than 90°, the plasticizing barrel becomes an extrusion system and is inclinedly arranged on the side wall of the injection cylinder.

[0007] By adopting the above technical scheme, the plasticizing barrel is tiltedly arranged on the injection cylinder, and the axis of the injection cylinder and the clamping system are vertically arranged, which reduces the equipment cost and floor space, simplifies the injection molding operation, and improves the injection molding accuracy. Compared with the horizontal injection molding machine in the prior art, the above-mentioned two combinations of the foaming device and the injection cylinder being arranged in one piece or in a separate piece make the injection molding machine suitable for small and medium-sized foamed parts and large parts respectively, thereby improving adaptability.

[0008] Optionally, the plasticizing barrel is provided with a flow limiting element for preventing the injected gas from flowing back to the feeding port on the side of the gas injection hole away from the output end of the plasticizing barrel, and the end of the mixing screw is provided with a self-closing screw head for limiting the flow of fluid to the clamping system.

[0009] By adopting the above technical solution, during the injection molding process, a large pressure will be generated at the discharge port of the injection molding machine. By setting the current limiting element, the possibility of the molten material flowing back to the plasticizing barrel can be eliminated, thereby improving the quality and stability of the foaming injection molding product and protecting the various components in the plasticizing barrel from being damaged by the injection high pressure.

[0010] Optionally, the plasticizing barrel is provided with an aeration section and a mixing section in sequence between the flow limiting element and the self-closing screw head, the flow limiting element and the input port of the plasticizing barrel have a feeding and melting section, and the aeration section and the gas injection hole are correspondingly connected.

[0011] By adopting the above technical solution, the material is basically plasticized in the feeding and melting section of the screw, the molten material enters the gas adding section through the current limiting element, the gas enters the gas adding hole from the gas injection hole, and the material and gas are mixed to form a uniform gas-liquid mixed phase, which reduces the viscosity of the melt. After the gas is evenly mixed with the material melt in the mixing section, it becomes a single-phase fluid, making it easier for the melt to flow and fill the mold and generate microbubbles.

[0012] Optionally, a self-closing nozzle is provided at the output end of the injection cylinder.

[0013] By adopting the above technical solution and setting the self-closing nozzle, the pre-molded single-phase fluid can be temporarily stored in the injection cylinder, forming a certain back pressure in the injection cylinder to reduce the probability of pre-foaming.

[0014] Optionally, the advancement stroke of the mixing screw in a vertical position is less than or equal to twice the length of the diameter of the mixing screw.

[0015] By adopting the above technical solution, the advancement stroke of the injection molding screw in the vertical position is less than twice its outer diameter, which can make the plasticization and gas-liquid mixing of the screw in the injection molding barrel more efficient and help to evenly mix the gas and the melt. At the same time, the advancement stroke of the injection molding screw determines the volume during injection, and the short stroke helps to improve the dimensional accuracy and stability of the foamed injection molded parts.

[0016] Optionally, a side wall of the injection cylinder is provided with a connecting flange for the plasticizing barrel to be installed obliquely, and the connecting flange has a connecting chamber connecting the plasticizing barrel and the injection cylinder.

[0017] By adopting the above technical solution, the plasticizing barrel is fixedly connected to the injection cylinder through the connecting flange to form a stable connection structure, and at the same time a tight sealing structure is formed to reduce the leakage of single-phase fluid. The connecting flange is easy to disassemble, and parts can be disassembled and replaced relatively easily, reducing the difficulty and cost of maintenance.

[0018] Optionally, a one-way valve is provided at the output end of the plasticizing barrel, and the one-way valve includes a sealing valve core and a sealing spring connected to the sealing valve core, and the sealing valve core is located on the side facing the self-closing screw head. Through the one-way valve, the extruded material enters the injection cylinder from the plasticizing barrel, and the material in the injection cylinder is not allowed to flow back to the plasticizing barrel during injection.

[0019] By adopting the above technical solution, the one-way valve is set in the output end of the plunger barrel, so that when the injection piston moves, the one-way valve is in a closed state, so that the high pressure during injection will not be transmitted to the plasticizing barrel. Therefore, the pressure of the injection barrel is low, reducing the design and manufacturing costs.

[0020] Optionally, the injection cylinder has a pre-molding chamber for storing melt, and the pre-molding chamber is correspondingly connected to the connecting chamber.

[0021] By adopting the above technical solution, the single-phase fluid is transported to the pre-molding chamber under the extrusion pressure of the screw, and the single-phase fluid is stored in the pre-molding chamber and the plunger provides appropriate back pressure to prevent pre-foaming. When the pre-molding chamber has a capacity for one injection, the drive mechanism is started to inject the single-phase fluid into the mold. The one-way valve seals the injection pressure formed in the pre-molding chamber, thereby reducing the probability of reflux of the single-phase fluid.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: The present invention reduces the floor space by tilting the plasticizing barrel on the injection molding cylinder, facilitates the molding of complex and precise parts, and is conducive to efficient injection molding operations; The present application adopts the split tilting arrangement of the plasticizing barrel and the injection molding cylinder, so that the mixing screw does not have the action of retreating for pre-plasticization and advancing for injection, and the position of gas injection is constant, thereby improving the uniformity of gas and melt mixing and diffusion, and shortening the effective length of the screw; By setting up the pre-molding chamber, the present application can enable the single-phase fluid to complete a precise pre-molding volume in the pre-molding chamber and provide a constant set back pressure by the plunger, while the pressure and speed during injection can be accurately controlled by the plunger to improve the molding quality of the injection molded foam parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a cross-sectional schematic diagram of Example 1.

[0024] Figure 2 It is a cross-sectional schematic diagram of Example 2.

[0025] Figure 3 yes Figure 2 A local enlarged schematic diagram of point A in the middle.

[0026] Explanation of the reference numerals: 1. plasticizing barrel; 2. mixing screw; 3. driving mechanism; 4. heating element; 5. air injection hole; 6. injection cylinder; 7. injection piston; 8. rotation driving source; 9. hopper; 10. opening; 11. conveying section; 12. current limiting element; 13. self-closing nozzle; 14. aeration section; 15. mixing section; 16. feeding and melting section; 17. self-closing screw head; 18. connecting flange; 19. connecting chamber; 20. one-way valve; 21. sealing chamber; 22. sealing valve core; 23. sealing spring; 24. mounting ring; 25. barrel chamber; 26. pre-plastic chamber. DETAILED DESCRIPTION

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present invention can be set in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

[0028] The following is combined with Figure 1-3 This application is described in further detail.

[0029] The embodiment of the present application discloses a vertical rubber and plastic foaming injection molding device. Example

[0030] Reference Figure 1The vertical rubber and plastic foam injection molding device comprises a plasticizing barrel 1, a mixing screw 2 rotatably mounted on the plasticizing barrel 1, and a driving mechanism 3 for injecting melt. The plasticizing barrel 1 can use the same components as a standard injection molding machine, and the outer wall of the plasticizing barrel 1 is sleeved with a plurality of heating elements 4 along the axial direction. The side wall of the plasticizing barrel 1 has a gas injection hole 5 connected to the inner cavity and used for injecting gas.

[0031] The driving mechanism 3 includes an injection cylinder 6 and an injection piston 7 which is slidably mounted on the injection cylinder 6 and is used to push the fluid. In the present embodiment, the injection piston 7 is pushed vertically by a hydraulic cylinder. The injection cylinder 6 and the clamping system of the injection molding machine are arranged vertically. In the present embodiment, the injection cylinder 6 is arranged vertically. One end of the plasticizing barrel 1 is fixed to the side wall of the injection cylinder 6, and the other end extends upward at an angle. A hopper 9 for adding materials is provided at the top of the plasticizing barrel 1. The inclination angle between the plasticizing barrel 1 and the injection cylinder 6 is defined as α. α is greater than or equal to 0° and less than 90°.

[0032] If the equipment floor space is limited but the workshop height is not limited, α can be zero, that is, the plasticizing barrel 1 and the injection molding cylinder 6 are parallel; if the workshop height is limited, α can be set according to actual needs. In this embodiment, the angle of α is equal to 0°, the plasticizing barrel 1 and the injection molding cylinder 6 are coaxially arranged, and the injection and plasticizing of the injection molding device are integrated, and injection, plasticization, gas injection and mixing are performed in the plasticizing barrel 1.

[0033] The plunger head of the injection piston 7 is fixedly connected to the end of the mixing screw 2. A rotation drive source 8 for driving the injection piston 7 to rotate is also provided at the top of the injection piston 7. The rotation drive source 8 can be a hydraulic motor or an electric motor. In this embodiment, the advancement stroke of the mixing screw 2 is within 2D (D is the outer diameter of the mixing screw 2), and the aspect ratio of the mixing screw 2 is greater than or equal to 24:1.

[0034] The hopper 9 is mounted on the side wall of the plasticizing barrel 1. The hopper 9 includes an opening portion 10 facing upward and a conveying portion 11 arranged obliquely. The conveying portion 11 and the inner cavity of the plasticizing barrel 1 A limiting flow element 12 is installed in the middle of the inner cavity of the plasticizing barrel 1. The limiting flow element 12 can be a one-way check valve or a flange or other flow limiting structure, which is used to prevent the injected gas from flowing back to the feeding port. In this embodiment, the limiting flow element 12 is a one-way check valve. A self-closing nozzle 13 is installed at the bottom of the plasticizing barrel 1. The principle of the self-closing nozzle 13 is consistent with the structure of the one-way valve body, which is used to reduce the probability of the single-phase fluid in the connecting chamber 19 entering the mold clamping system before the injection piston 7 is started.

[0035] The plasticizing barrel 1 has a barrel chamber 25 for material conveying, and the barrel chamber 25 is formed with an aeration section 14 and a mixing section 15 between the flow limiting element 12 and the self-closing nozzle 13, and the aeration section 14 is correspondingly connected to the gas injection hole 5. There is a feeding and melting section 16 between the flow limiting element 12 and the hopper 9. The material is heated and initially plasticized in the feeding and melting section 16, and then mixed with gas in the aeration section 14 through the flow limiting element 12. With the conveying of the mixing screw 2, the material and the gas are evenly mixed to form a single-phase fluid.

[0036] The output end of the mixing screw 2 also has a self-closing screw head 17. The front end of the self-closing screw head 17 has a pre-molding chamber 26 and is connected to the connecting hole of the self-closing nozzle 13. When the single-phase fluid in the mixing section 15 accumulates to a certain capacity in the self-closing screw head, the mixing screw 2 stops rotating and the self-closing screw head 17 automatically closes.

[0037] The vertical rubber and plastic foaming injection molding device of this embodiment is suitable for the molding of small and medium-sized parts, and the specific process is as follows: the material is added from the hopper 9, the rotating drive source 8 is started, and the material is transported downward in the feeding and melting section 16 under its own gravity and the rotation of the mixing screw 2. The material is basically plasticized after being heated in the feeding and melting section 16; then the fluid enters the gas adding section 14 through the flow limiting element 12, the material is evenly mixed with the gas in the mixing section 15 to form a single-phase fluid, and enters the self-closing screw head 17, and the single-phase fluid is stored in the front end pre-plasticizing chamber 26 of the self-closing screw head 17.

[0038] Since the self-closing nozzle 13 is in a closed state, the driving mechanism 3 can apply a certain pressure to the mixing screw 2, so that the pre-molding chamber 26 has a certain back pressure, and the single-phase fluid will not be pre-foamed; the single-phase fluid gradually accumulates in front of the self-closing screw head 17, and under the preset back pressure of the piston of the driving mechanism 3, the mixing screw 2 retreats until the preset pre-molding volume and stops rotating; After the mold filling begins, the self-closing nozzle 13 is completely closed and acts as a plunger, and the single-phase fluid is injected into the mold flow channel under the action of the driving mechanism 3. After the mold filling is completed, the part foams and cools in the mold, the mixing screw 2 starts to rotate, and the next mold filling cycle begins. Example

[0039] Compared with the first embodiment, the present embodiment is different in that the plasticizing barrel and the driving mechanism are two devices. The plasticizing barrel becomes an extruder for plasticizing, gasifying and mixing without reciprocating injection action. The injection action is completed by the driving mechanism.

[0040] In this embodiment, the angle α is greater than 0° and less than 90°, and the plasticizing barrel 1 and the injection cylinder 6 are arranged obliquely. Plasticizing, gas injection and mixing are performed in the plasticizing barrel 1.

[0041] A connecting flange 18 is provided between the bottom end of the plasticizing barrel 1 and the injection cylinder 6, and the opposite sides of the connecting flange 18 are respectively fixed to the plasticizing barrel 1 and the injection cylinder 6 by bolts. The connecting flange 18 has a connecting chamber 19 that penetrates the two side end surfaces in the horizontal direction and connects the injection cylinder 6 and the plasticizing barrel 1.

[0042] A one-way valve 20 is also provided at one end of the plasticizing barrel 1 close to the connection chamber 19, and the barrel chamber 25 has a sealing chamber 21 that cooperates with the one-way valve 20. The one-way valve 20 includes a sealing valve core 22 and a sealing spring 23 connected to the sealing valve core 22. A fixed mounting ring 24 for the end of the sealing spring 23 is provided in the sealing chamber 21. The sealing valve core 22 is located on the side of the sealing spring 23 away from the connection chamber 19. When the sealing spring 23 is in a normal state, the sealing valve core 22 closes the outlet of the sealing chamber.

[0043] The plasticizing barrel 1 has a barrel chamber 25 for rotating the mixing screw 2. A rotation drive source 8 ( Figure 2 The rotation driving source 8 may be a hydraulic motor or an electric motor.

[0044] A pre-molding chamber 26 for temporarily storing the single-phase fluid is provided between the plunger head of the injection piston 7 and the inner cavity outlet of the injection cylinder 6. The pre-molding chamber 26 is connected to the connection chamber 19 of the connection flange 18. The bottom of the injection cylinder 6 is provided with a self-closing nozzle 13 connected to the mold clamping system. The principle of the self-closing nozzle 13 is consistent with the structure of the one-way valve 20, and is used to reduce the probability of the single-phase fluid in the connection chamber 19 entering the mold clamping system before the injection piston 7 is started.

[0045] The vertical rubber and plastic foam injection molding device of this embodiment is widely applicable to the molding of various parts, especially large parts. The specific process is as follows: the material is poured from the hopper 9, the material is heated and pre-plasticized in the feeding and melting section 16, the pre-plasticized material enters the gas adding section 14 through the current limiting element 12, and the material and the gas are fully mixed in the mixing section 15 to form a single-phase fluid; the pressure of the single-phase fluid is continuously increased under the strong push of the extrusion screw until it reaches the preset back pressure, and this back pressure is high enough to open the self-closing screw head 17 and the one-way valve 20, and the single-phase fluid enters the pre-plasticizing chamber 26 along the sealing chamber 21 and the connecting chamber 19; when the fluid in the pre-plasticizing chamber 26 is stored to the pre-plasticizing amount that can be injected once, the pushing drive source is started so that the fluid is pressed into the clamping system.

[0046] Compared with Example 1, the mixing screw 2 of this embodiment does not have the action of retreating for pre-plasticization and advancing for injection, so the length of the gas-injection section 14 of this embodiment is smaller than that of Example 1. The gas-injection section 14 only needs to correspond to the gas injection hole.

[0047] The setting of the one-way valve 20 in the plasticizing barrel 1 allows the single-phase fluid to freely enter the pre-molding chamber 26, but cannot flow back to the plasticizing barrel 1. After the pre-molding of the fluid in the pre-molding chamber 26 is completed, the injection piston 7 pushes the injection, and the one-way valve 20 automatically closes under the action of pressure, and the high pressure of the injection will not be transmitted to the plasticizing barrel 1. Therefore, the design cost of the plasticizing barrel 1 and the mixing screw 2 of this embodiment is relatively low. The principle of this embodiment to become a single-phase fluid is consistent with that of embodiment 1, but the screw of this embodiment has no axial displacement, and the uniformity and solubility of the gas injection are better than those of embodiment 1.

[0048] In Example 1 and the prior art, the back pressure of the single-phase fluid during plasticization is directly provided by the driving mechanism 3, while in this embodiment, the pre-plasticization back pressure of the mixing screw 2 is converted into a pressure similar to the head pressure of the extruder plus the pressure of the injection piston 7, thereby reducing the pressure control requirements for the mixing screw 2 during pre-plasticization, so the self-sealing ability requirements of the flow-limiting element 12 and the self-closing screw head 17 do not need to be very high. Under certain conditions, after the mixing screw 2 completes the pre-plasticization, it can maintain a low speed rotation and maintain the minimum pressure to prevent the pre-foaming of the gas-containing melt between the middle of the mixing screw 2 and the self-closing screw head 17. The self-closing screw head 17 and the flow-limiting element do not need to be completely self-closed, or the above-mentioned two one-way valves (self-closing screw head 17, flow-limiting element) structure design can be cancelled under appropriate low-speed rotation conditions, thereby simplifying the overall design.

[0049] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A vertical rubber and plastic foam injection molding device, comprising a plasticizing barrel (1), a mixing screw (2) rotatably arranged in the plasticizing barrel (1), and a driving mechanism (3), wherein the plasticizing barrel (1) is provided with a gas injection hole (5) for injecting gas, characterized in that: The driving mechanism (3) comprises an injection cylinder (6) and an injection piston (7) slidably mounted on the injection cylinder (6) and used to push the melt, the plasticizing barrel (1) and the injection cylinder (6) are connected, the axis of the injection cylinder (6) is perpendicular to the mold clamping system, and the plasticizing barrel (1) is tilted on the injection cylinder (6), and the tilt angle is greater than or equal to 0° and less than 90°; When the tilt angle is equal to 0°, the injection cylinder (6) and the plasticizing barrel (1) are coaxially arranged, the injection piston (7) is connected to the mixing screw (2), and the driving mechanism (3) further comprises a rotation driving source (8) for driving the injection piston (7) to rotate circumferentially; When the inclination angle is greater than or equal to 0° and less than 90°, the plasticizing barrel (1) becomes an extrusion system and is arranged obliquely on the side wall of the injection cylinder (6).

2. A vertical rubber and plastic foaming injection molding device according to claim 1, characterized in that: The plasticizing barrel (1) is provided with a flow limiting element (12) for preventing the injected gas from flowing back to the feeding port on the side of the gas injection hole (5) away from the output end of the plasticizing barrel (1), and the end of the mixing screw (2) is provided with a self-closing screw head (17) for limiting the flow of fluid to the clamping system.

3. A vertical rubber and plastic foam injection molding device according to claim 2, characterized in that: The plasticizing barrel (1) is provided with an aeration section (14) and a mixing section (15) in sequence between the flow limiting element (12) and the self-closing screw head (17); the flow limiting element (12) and the input port of the plasticizing barrel (1) are provided with a feeding and melting section (16); and the aeration section (14) and the gas injection hole (5) are correspondingly connected.

4. A vertical rubber and plastic foam injection molding device according to claim 1, characterized in that: The output end of the injection cylinder (6) is provided with a self-closing nozzle (13).

5. A vertical rubber and plastic foam injection molding device according to claim 1, characterized in that: The advancement stroke of the mixing screw (2) in a vertical position is less than or equal to twice the length of the diameter of the mixing screw (2).

6. A vertical rubber and plastic foam injection molding device according to claim 2, characterized in that: The side wall of the injection cylinder (6) is provided with a connecting flange (18) for the plasticizing barrel (1) to be installed obliquely, and the connecting flange (18) has a connecting chamber (19) that communicates with the plasticizing barrel (1) and the injection cylinder (6).

7. A vertical rubber and plastic foam injection molding device according to claim 6, characterized in that: A one-way valve (20) is provided at the output end of the plasticizing barrel (1), the one-way valve (20) comprising a sealing valve core (22) and a sealing spring (23) connected to the sealing valve core (22), the sealing valve core (22) being located on the side facing the self-closing screw head (17), and the one-way valve (20) allows the extruded material to enter the injection molding cylinder (6) from the plasticizing barrel (1), while the material in the injection molding cylinder (6) is not allowed to flow back to the plasticizing barrel (1) during injection.

8. A vertical rubber and plastic foam injection molding device according to claim 7, characterized in that: The injection cylinder (6) has a pre-molding chamber (26) for storing melt, and the pre-molding chamber (26) and the chamber of the plasticizing barrel (1) are connected to each other via a one-way valve (20).

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