Magnesium alloy semi-solid thixotropic injection molding device and molding method thereof

Abstract

The application provides a magnesium alloy semi-solid thixotropic injection molding device and a molding method thereof, and particularly relates to the field of magnesium alloy processing. The magnesium alloy semi-solid thixotropic injection molding device and the molding method thereof comprise a processing table, a barrel fixedly connected to the processing table, a nozzle arranged at the tail end of the barrel, a mold connected to the nozzle, and a receiving box arranged below the mold. The magnesium alloy semi-solid thixotropic injection molding device and the molding method thereof further comprise a preheating barrel in communication with the barrel, a first afterheat treatment assembly, and a second afterheat treatment assembly. A spiral stirring rod is rotatably connected in the preheating barrel. The magnesium alloy semi-solid thixotropic injection molding device and the molding method thereof provided by the application utilize the waste gas afterheat of the barrel and the workpiece afterheat to preheat and dehumidify the magnesium alloy particles through the arrangement of the first afterheat treatment assembly and the second afterheat treatment assembly, thereby reducing the energy consumption. The structure of the whole device is very compact, the afterheat utilization rate is high, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of magnesium alloy processing technology, specifically to a magnesium alloy semi-solid thixotropic injection molding apparatus and its molding method. Background Technology

[0002] Magnesium alloy semi-solid thixotropic injection molding is a molding process in which magnesium alloy granules are heated to a semi-solid state in a barrel, sheared by a screw, and then injected into a mold. Due to its advantages such as high molding precision, dense structure, and high production efficiency, it is widely used in automotive lightweighting, 3C electronics and other fields.

[0003] In existing magnesium alloy semi-solid thixotropic injection molding equipment, the granules need to be preheated and dehumidified before entering the barrel. Usually, an independent oven is used to remove the surface-adsorbed moisture to prevent the decomposition of water at high temperature and the generation of hydrogen gas, which would cause porosity in the casting. However, the independent oven not only occupies a large area and consumes a lot of energy, but the preheated granules will also absorb moisture again during the transfer to the hopper, affecting the dehumidification effect. At the same time, the high-temperature exhaust gas continuously emitted from the barrel exhaust port and the residual heat of the workpiece after mold opening are not effectively utilized and are directly discharged into the workshop, resulting in energy waste.

[0004] Therefore, it is necessary to provide a magnesium alloy semi-solid thixotropic injection molding apparatus and molding method to solve the above-mentioned technical problems. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the high energy consumption and waste heat in the preheating of granules in existing semi-solid thixotropic injection molding of magnesium alloys, and to provide a semi-solid thixotropic injection molding device and molding method for magnesium alloys. This device, through the cooperation of a first waste heat treatment component and a second waste heat treatment component, utilizes a first annular jacket to introduce waste gas heat and a second annular jacket to introduce workpiece waste heat within a rotating preheating cylinder, thereby realizing waste heat recovery and rotational preheating of the granule processing, improving preheating efficiency and energy utilization.

[0006] To solve the above-mentioned technical problems, the present invention provides a magnesium alloy semi-solid thixotropic injection molding apparatus and molding method, including a processing table, a barrel fixedly connected to the processing table, a nozzle disposed at the end of the barrel, a mold connected to the nozzle, and a receiving box disposed below the mold. It also includes a preheating cylinder communicating with the barrel, a first waste heat treatment component, and a second waste heat treatment component. A spiral stirring rod is rotatably connected inside the preheating cylinder. A first annular jacket and a second annular jacket are respectively sleeved on both sides of the preheating cylinder. The first waste heat treatment component is used to recover the waste heat of the barrel exhaust gas, and the second waste heat treatment component is used to recover the waste heat of the workpiece.

[0007] Preferably, the first waste heat treatment component includes an air inlet pipe and an exhaust port. One end of the air inlet pipe is connected to the exhaust port of the material cylinder, and the other end of the air inlet pipe is connected to a first annular jacket. An air outlet is provided at the top of the first annular jacket.

[0008] Preferably, the intake pipe is provided with a filter unit, the filter unit including a filter cylinder fixedly connected to the intake pipe and a filter screen fixedly connected inside the filter cylinder.

[0009] Preferably, the second waste heat treatment component includes a first heat exchange tube and a second heat exchange tube, the receiving box is filled with heat transfer oil, the first heat exchange tube connects one end of the receiving box to the second annular jacket, and the second heat exchange tube connects the other end of the receiving box to the second annular jacket.

[0010] Preferably, the preheating cylinder is rotatably connected to the processing table, a first motor is fixedly connected to the processing table, a drive gear is fixedly connected to the output end of the first motor, a follower gear is fixedly connected to the preheating cylinder, and the drive gear meshes with the follower gear.

[0011] Preferably, a second motor is fixedly connected to the preheating cylinder, and the output end of the second motor is fixedly connected to the spiral stirring rod.

[0012] Preferably, the preheating cylinder and the material cylinder are connected by a connecting pipe, an electric push rod is fixedly connected to the connecting pipe, and a sealing plate is fixedly connected to the extended end of the electric push rod.

[0013] A method for semi-solid thixotropic injection molding of magnesium alloys includes the following steps: S1: Pour the magnesium alloy raw material into the preheating cylinder, start the first motor and the second motor, so that the preheating cylinder rotates and drives the internal granules to tumble, and the spiral stirring rod stirs the raw material. S2: The first waste heat treatment component introduces the high-temperature waste gas discharged from the exhaust port of the material cylinder into the first annular jacket to dehumidify and preheat the granules at one end of the preheating cylinder. S3: The second waste heat treatment component introduces the waste heat of the workpiece in the receiving box into the second annular jacket through heat transfer oil to dehumidify and preheat the granules at the other end of the preheating cylinder. S4: The electric push rod retracts, opening the connecting pipe to allow the dehumidified and preheated granules to enter the barrel for subsequent heating and injection molding.

[0014] Preferably, in step S1, the first motor and the second motor rotate in opposite directions to ensure the stirring effect.

[0015] Preferably, in step S3, the heat transfer oil flows in from the bottom of the second annular jacket and flows out from the top of the second annular jacket to ensure the heat exchange effect.

[0016] By adopting the above technical solution, the beneficial effects achieved by the present invention are as follows: The magnesium alloy semi-solid thixotropic injection molding device and molding method proposed in this invention utilize the waste heat from the barrel exhaust gas and the workpiece to preheat and dehumidify the magnesium alloy granules through the setting of the first waste heat treatment component and the second waste heat treatment component, thereby reducing energy consumption. The entire device has a very compact structure, high waste heat utilization rate, and reduced production costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a magnesium alloy semi-solid thixotropic injection molding device according to the present invention. Figure 2 This is a schematic diagram of the structure of a magnesium alloy semi-solid thixotropic injection molding device from another angle. Figure 3 This is a diagram showing the positional relationship between the preheating cylinder and the annular jacket of a magnesium alloy semi-solid thixotropic injection molding apparatus according to the present invention. Figure 4 This is a schematic diagram of the internal structure of the preheating cylinder of a magnesium alloy semi-solid thixotropic injection molding apparatus according to the present invention. Figure 5 This is a diagram showing the positional relationship between the sealing plate and the electric push rod of a magnesium alloy semi-solid thixotropic injection molding device according to the present invention. Figure 6 This is a schematic diagram of the structure of the filter unit of a magnesium alloy semi-solid thixotropic injection molding device according to the present invention; Figure 7 This is a schematic diagram of the structure of the second waste heat treatment component of a magnesium alloy semi-solid thixotropic injection molding apparatus according to the present invention.

[0018] Figure label: 1. Processing table; 11. Material cylinder; 12. Nozzle; 13. Mold; 14. Preheating cylinder; 2. First waste heat treatment component; 21. First annular jacket; 22. Air inlet pipe; 23. Air outlet; 24. Filter unit; 241. Filter cylinder; 242. Filter screen; 3. Second waste heat treatment component; 31. Second annular jacket; 32. Receiving box; 33. First heat exchange tube; 34. Second heat exchange tube; 41. First motor; 42. Second motor; 43. Drive gear; 44. Follower gear; 45. Spiral stirring rod; 46. Connecting pipe; 47. Electric push rod; 48. Sealing plate. Detailed Implementation

[0019] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] Please see Figures 1 to 7As shown in the figure, an embodiment of the present invention provides a magnesium alloy semi-solid thixotropic injection molding device and its molding method, including a processing table 1, a barrel 11 fixedly connected to the processing table 1, a nozzle 12 disposed at the end of the barrel 11, a mold 13 connected to the nozzle 12, and a receiving box 32 disposed below the mold 13. It also includes a preheating cylinder 14 communicating with the barrel 11, a first waste heat treatment component 2, and a second waste heat treatment component 3. The barrel 11 is fixedly installed on the processing table 1, and has a screw inside, with the nozzle 12 connected to its end. The nozzle 12 is connected to the gate of the mold 13. A receiving box 32 is disposed below the mold 13 to receive the castings falling after mold opening. The preheating cylinder 14 is installed on the barrel 11, and has a spiral stirring rod 45 inside. First annular sleeves 21 are respectively fitted on the left and right sides of the outer wall of the preheating cylinder 14. The first waste heat treatment component 2 is connected to the exhaust port of the material box 32 and the first annular jacket 21 through a pipe. The high-temperature waste gas discharged from the material cylinder 11 is introduced into the first annular jacket 21 to heat the granules on one side of the preheating cylinder 14. The second waste heat treatment component 3 is connected to the receiving box 32 and the second annular jacket 31 through a pipe. The waste heat of the workpiece in the receiving box 32 is introduced into the second annular jacket 31 through heat transfer oil to heat the granules on the other side of the preheating cylinder 14. The preheating cylinder 14 uses the two streams of waste heat generated by the device itself to preheat and dehumidify the magnesium alloy granules. There is no need to set up an additional drying oven, which reduces energy consumption. The spiral stirring rod 45 continuously stirs the granules in the preheating cylinder 14 to prevent uneven heating of the raw materials in different positions in the preheating cylinder 14.

[0023] The exhaust port of the material cylinder 11 is located at the rear section of the material cylinder 11, and the air outlet 23 is located at the top of the first annular jacket 21. The exhaust gas is directly introduced into the first annular jacket 21 from the exhaust port of the material cylinder 11. The air outlet 23 is located at the top of the jacket, which is conducive to the hot air forming a bottom-up flow in the jacket, ensuring uniform temperature distribution in the jacket, and also making it easier to discharge the exhaust gas after heat exchange in a timely manner.

[0024] The filter cartridge 241 is a cylindrical shell with a metal wire mesh installed inside as a filter screen 242. The filter unit 24 can trap trace amounts of magnesium dust and other solid particles carried in the exhaust gas of the material cylinder 11, preventing dust from entering the first annular jacket 21 and depositing on the inner wall of the jacket, thus affecting the heat exchange efficiency. It can also prevent dust from entering the preheating cylinder 14 with the hot air and contaminating the granules, ensuring the purity of the granules.

[0025] In addition, the receiving box 32 is a metal container filled with heat transfer oil. After the high-temperature casting falls after the mold is opened, it is immersed in the heat transfer oil and transfers heat to the heat transfer oil. The first heat exchange pipe 33 is connected to the bottom of the receiving box 32 and the bottom of the second annular jacket 31. The second heat exchange pipe 34 is connected to the top of the receiving box 32 and the top of the second annular jacket 31. In specific implementation, an oil pump can be installed on the first heat exchange pipe 33 to drive the heat transfer oil to be drawn out from the bottom of the receiving box 32 and sent to the bottom of the second annular jacket 31. The heat transfer oil flows from bottom to top in the second annular jacket 31. After exchanging heat with the preheating cylinder 14, it flows back from the top of the second annular jacket 31 through the second heat exchange pipe 34 to the receiving box 32 to form a cycle.

[0026] Secondly, the two ends of the preheating cylinder 14 are rotatably connected to the processing table 1. A follower gear 44 is fixed on the preheating cylinder 14. The first motor 41 is fixedly installed on the processing table 1, and its output shaft is fixed with a drive gear 43. The drive gear 43 meshes with the follower gear 44. When the first motor 41 starts, it drives the preheating cylinder 14 to rotate through gear transmission, ensuring that the preheating cylinder 14 rotates stably. When the preheating cylinder 14 rotates, the granules inside tumble, so that the granules are in full contact with the wall of the preheating cylinder 14 after heating, thereby improving the heat exchange efficiency.

[0027] Secondly, the second motor 42 is fixedly installed at one end of the preheating cylinder 14, and its output shaft is fixedly connected to the spiral stirring rod 45. The spiral stirring rod 45 is located inside the preheating cylinder 14. When the second motor 42 is started, it drives the spiral stirring rod 45 to rotate and stir the granules in the preheating cylinder 14. The stirring action of the spiral stirring rod 45 can make the granules more evenly distributed in the preheating cylinder 14, avoid local overheating of the granules, and at the same time, the stirring accelerates the evaporation of moisture on the surface of the granules and improves the dehumidification effect.

[0028] The connecting pipe 46 is a vertical pipe, with its upper end connected to the discharge port of the preheating cylinder 14 and its lower end connected to the material cylinder 11. The electric push rod 47 is fixedly installed on the outer wall of the connecting pipe 46, and its end is fixed with a sealing plate 48. The shape of the sealing plate 48 matches the inner diameter of the connecting pipe 46. When the electric push rod 47 extends, the sealing plate 48 closes the channel of the connecting pipe 46 to prevent the granules from falling. When the electric push rod 47 retracts, the sealing plate 48 moves out of the channel, and the granules fall from the preheating cylinder 14 into the material cylinder 11 under the action of gravity. During the preheating process, the sealing plate 48 is closed, so that the granules have sufficient residence time in the preheating cylinder 14 for preheating and dehumidification. After the preheating is completed, the sealing plate 48 is opened, so that the granules enter the material cylinder 11.

[0029] Working principle: When using this device, magnesium alloy granules are poured into the preheating cylinder 14, and the first motor 41 and the second motor 42 are started. The first motor 41 drives the preheating cylinder 14 to rotate through gear transmission. The granules inside the preheating cylinder 14 rotate under the action of centrifugal force and the spiral guide plate. At the same time, the second motor 42 drives the spiral stirring rod 45 to rotate in the opposite direction to stir the granules and ensure the stirring effect. The first waste heat treatment component 2 introduces the high-temperature waste gas discharged from the exhaust port of the material cylinder 11 into the first annular jacket 21 through the air inlet pipe 22 and the filter unit 24. The granules on one side of the preheating cylinder 14 are heated and dehumidified. The second waste heat treatment component 3 introduces the waste heat of the workpiece in the receiving box 32 into the second annular jacket 31 through heat transfer oil circulation to assist in heating the granules on the other side of the preheating cylinder 14. The granules are fully stirred and heated in the preheating cylinder 14, and the moisture adsorbed on the surface is evaporated and removed, and the temperature rises. After preheating is completed, the electric push rod 47 retracts, the sealing plate 48 opens, and the preheated granules enter the material cylinder 11 through the connecting pipe 46 for subsequent heating and injection molding.

[0030] The present invention also provides a method for semi-solid thixotropic injection molding of magnesium alloys, comprising the following steps: S1: Pour the magnesium alloy raw material into the preheating cylinder 14, start the first motor 41 and the second motor 42, so that the preheating cylinder 14 rotates and drives the internal granules to tumble, and the spiral stirring rod 45 stirs the raw material. S2: The first waste heat treatment component 2 introduces the high-temperature waste gas discharged from the exhaust port of the material cylinder 11 into the first annular jacket 21 to dehumidify and preheat the granules at one end of the preheating cylinder 14. S3: The second waste heat treatment component 3 introduces the waste heat of the workpiece in the receiving box 32 into the second annular jacket 31 through heat transfer oil to dehumidify and preheat the granules at the other end of the preheating cylinder 14. S4: The electric push rod 47 retracts, opening the connecting pipe 46, allowing the dehumidified and preheated granules to enter the material barrel 11 for subsequent heating and injection molding.

[0031] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made under the concept of the present invention using the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A magnesium alloy semi-solid thixotropic injection molding apparatus, comprising a processing table (1), a barrel (11) fixedly connected to the processing table (1), a nozzle (12) disposed at the end of the barrel (11), a mold (13) connected to the nozzle (12), and a receiving box (32) disposed below the mold (13), characterized in that: It also includes a preheating cylinder (14) connected to the material cylinder (11), a first waste heat treatment component (2) and a second waste heat treatment component (3). A spiral stirring rod (45) is rotatably connected inside the preheating cylinder (14). A first annular jacket (21) and a second annular jacket (31) are respectively fitted on both sides of the preheating cylinder (14). The first waste heat treatment component (2) is used to recover the waste heat of the exhaust gas of the material cylinder (11), and the second waste heat treatment component (3) is used to recover the waste heat of the workpiece.

2. The magnesium alloy semi-solid thixotropic injection molding apparatus according to claim 1, characterized in that: The first waste heat treatment component (2) includes an air inlet pipe (22) and an exhaust port. One end of the air inlet pipe (22) is connected to the exhaust port of the material cylinder (11), and the other end of the air inlet pipe (22) is connected to the first annular jacket (21). An air outlet (23) is provided at the top of the first annular jacket (21).

3. The magnesium alloy semi-solid thixotropic injection molding apparatus according to claim 2, characterized in that: The intake pipe (22) is provided with a filter unit (24), which includes a filter cylinder (241) fixedly connected to the intake pipe (22) and a filter screen (242) fixedly connected inside the filter cylinder (241).

4. The magnesium alloy semi-solid thixotropic injection molding apparatus according to claim 1, characterized in that: The second waste heat treatment component (3) includes a first heat exchange tube (33) and a second heat exchange tube (34). The receiving box (32) is filled with heat transfer oil. The first heat exchange tube (33) is connected to one end of the receiving box (32) and the second annular jacket (31). The second heat exchange tube (34) is connected to the other end of the receiving box (32) and the second annular jacket (31).

5. The magnesium alloy semi-solid thixotropic injection molding apparatus according to claim 4, characterized in that: The preheating cylinder (14) is rotatably connected to the processing table (1).

6. The magnesium alloy semi-solid thixotropic injection molding apparatus according to claim 1, characterized in that: The preheating cylinder (14) and the material cylinder (11) are connected by a connecting pipe (46), and an electric push rod (47) is fixedly connected to the connecting pipe (46). A sealing plate (48) is fixedly connected to the extended end of the electric push rod (47).

7. A method for semi-solid thixotropic injection molding of magnesium alloy, using the magnesium alloy semi-solid thixotropic injection molding apparatus according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Pour the magnesium alloy raw material into the preheating cylinder (14), start the first motor (41) and the second motor (42) to make the preheating cylinder (14) rotate and drive the internal granules to tumble, and the spiral stirring rod (45) stirs the raw material. S2: The first waste heat treatment component (2) introduces the high-temperature waste gas discharged from the exhaust port of the material cylinder (11) into the first annular jacket (21) to dehumidify and preheat the granules at one end of the preheating cylinder (14); S3: The second waste heat treatment component (3) introduces the waste heat of the workpiece in the receiving box (32) into the second annular jacket (31) through heat transfer oil to dehumidify and preheat the granules at the other end of the preheating cylinder (14); S4: The electric push rod (47) retracts and opens the connecting pipe (46), allowing the dehumidified and preheated granules to enter the barrel (11) for subsequent heating and injection molding.

8. The method for semi-solid thixotropic injection molding of magnesium alloy according to claim 7, characterized in that: In S1, the first motor (41) and the second motor (42) rotate in opposite directions.

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