Die casting machine

Abstract

The utility model relates to the technical field of die-casting, and discloses a die-casting machine, which comprises a pulping part, a die-casting part and a die-casting part, the pulp storage chamber is communicated with the discharge hole of the pulping cylinder; the injection part comprises an injection barrel, a feed port of the injection barrel is communicated with the pulp storage chamber, and the pulping part, the pulp storage chamber and the injection part are connected in a closed mode. All components of the die-casting machine are arranged in a closed mode, inert gas protection does not need to be additionally arranged when active metal is die-cast, and the die-casting machine is more environmentally friendly, safer and more economical.

Description

[0001] This application claims priority and benefits to Chinese Patent Application No. 202411001023.4, filed on July 25, 2024, entitled “Semi-solid die casting machine and die casting method”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This utility model relates to the field of die casting technology, specifically to a die casting machine. Background Art

[0003] Semi-solid die casting technology is a die casting technology suitable for complex alloy materials. In the traditional semi-solid die casting process, a screw is used to shear the heated chip-like or granular alloy material into a molten slurry containing solid components, which is then stored at the front end of the die casting machine barrel. During the injection process, a hydraulic cylinder pushes the entire screw forward, extruding the molten metal into the mold for shaping.

[0004] There are certain drawbacks to processing metal in this way:

[0005] 1. The storage and injection processes of molten metal are both carried out at the end of the die-casting machine barrel. At the same time, the screw as a whole needs to move and its position is not fixed. Therefore, it is difficult to add a heating device to the barrel for temperature control.

[0006] 2. During the injection process, when the screw moves as a whole, there are too many contact points with the wall of the die-casting machine cylinder, making sealing difficult and prone to leakage. In the die-casting process of magnesium and aluminum alloys, there is a risk of fire and other safety hazards.

[0007] 3. The screw structure has limited load-bearing capacity, which limits the speed and pressure of the injection process. The semi-solid die casting process range is small, and therefore it is not possible to flexibly switch between conventional die casting and semi-solid die casting, resulting in low equipment flexibility.

[0008] In addition, during the die casting of magnesium alloys, magnesium is highly reactive and easily reacts with air and water to cause oxidation or even explosion. Therefore, strict protective measures are required during the die casting production process. Magnesium alloy raw materials and molten metal also need to be strictly controlled to avoid contact with water.

[0009] However, in existing magnesium alloy die-casting equipment, the die-casting machine and the metal supply systems such as melting, holding, and molten metal supply are separate systems. The transportation process between these systems requires additional protection, such as using a closed quantitative pump molten metal supply system and using inert gas to protect the injection chamber and mold environment of the die-casting machine. This results in higher die-casting production costs and still carries certain safety risks. Utility Model Content

[0010] This utility model was made to solve the above-mentioned technical problems. One of its objectives is to provide a die-casting machine that does not require inert gas protection when die-casting reactive metals, making it more environmentally friendly, safe, and economical.

[0011] Another objective of this invention is to provide a die-casting machine that can stably supply semi-solid slurry, reduce leakage problems in traditional screw injection, expand the process range of semi-solid die casting, and support greater injection speed and pressure.

[0012] Another objective of this invention is to provide a die-casting machine that allows for more precise temperature control when preparing semi-solid slurry.

[0013] According to one embodiment of the present invention, a die casting machine is provided, comprising: a slurry preparation section including a slurry preparation cylinder; a slurry storage chamber connected to the outlet of the slurry preparation cylinder; and an injection section including an injection cylinder, wherein the inlet of the injection cylinder is connected to the slurry storage chamber; wherein the slurry preparation section, the slurry storage chamber, and the injection section are connected in a sealed manner.

[0014] As one embodiment, a first heating structure is provided on the slurry storage chamber.

[0015] As one embodiment, the die-casting machine further includes a feeding structure disposed between the slurry storage chamber and the injection cylinder, for conveying the material in the slurry storage chamber to the injection cylinder.

[0016] In one embodiment, the pulping section further includes a screw, which is rotatably disposed in the pulping cylinder and has helical blades on its outer periphery.

[0017] As one embodiment, the pulping cylinder is provided with a second heating structure and a third heating structure along the material flow direction; the screw is provided with a fourth heating structure.

[0018] In one embodiment, the fourth heating structure is slidably disposed within the screw.

[0019] In one embodiment, two of the fourth heating structures are provided inside the screw.

[0020] As one embodiment, a fifth heating structure is provided on the pulping cylinder at a position opposite to the discharge port.

[0021] In one embodiment, the second, third, and fifth heating structures are induction coils disposed on the outer periphery of the pulping cylinder; the fourth heating structure is a heating rod or heating wire.

[0022] As one embodiment, the outer periphery of the injection cylinder is provided with a sixth heating structure.

[0023] Based on the above description and practice, it can be seen that the die casting machine of this utility model has a storage chamber between the slurry cylinder and the injection cylinder, which can stably supply die casting slurry. Furthermore, the slurry cylinder, the storage chamber, and the injection cylinder are sealed together, so there is no need to use inert gas protection when die casting reactive metals, making it more environmentally friendly, safe, and economical.

[0024] Furthermore, the injection section and slurry preparation section of the die-casting machine of this invention are separate structures, forming a composite injection system. The injection section can utilize existing injection systems, reducing costs. When semi-solid die casting is not required, it can be switched to conventional die casting for production. Additionally, this split structure, compared to the traditional structure where the screw and injection cylinder are integrated, eliminates the need for the slurry preparation section to withstand significant pressure during die casting, reducing or even eliminating leakage problems within the slurry cylinder. This expands the process range of semi-solid die casting, supporting greater injection speed and pressure, and correspondingly improving control precision. It is applicable to complex semi-solid die casting processes such as liquid forging.

[0025] Furthermore, the die-casting machine of this invention features a second heating structure and a third heating structure on the outer periphery of the slurry preparation cylinder. The second heating structure preheats the material entering the cylinder, while the third heating structure, combined with the screw rotation, processes the material into the desired semi-solid slurry with low energy consumption. During the slurry preparation process, a fourth heating structure located within the screw ensures more uniform temperature distribution within the cylinder, enabling precise temperature control and ultimately supplying qualified semi-solid slurry. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a die-casting machine involved in one embodiment of the present invention.

[0027] The attached figures are labeled as follows:

[0028] 11. Pulping cylinder; 12. Screw; 13. Hopper; 14. Pulping storage chamber; 15. Feeding structure; 21. First heating structure; 22. Second heating structure; 23. Third heating structure; 24. Fourth heating structure; 25. Fifth heating structure; 26. Sixth heating structure; 31. Injection cylinder; 32. Injection rod; 33. Injection punch; 34. Feeding cylinder; 35. Energy storage device; 36. Mold. DETAILED DESCRIPTION

[0029] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0030] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. It should be noted that in this disclosure, the terms "comprising," "configured with," and "set in" are used to indicate an open-ended inclusion, meaning that additional elements / components / etc. may exist besides those listed; the terms "first," "second," etc., are used only as labels and are not intended to limit the number or order of objects; the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0031] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] According to one embodiment of this utility model, a die-casting machine is provided. Please refer to [reference needed]. Figure 1 The die-casting machine includes a slurry preparation section, a slurry storage chamber, and an injection section. The slurry preparation section includes a slurry preparation cylinder 11, which is a cylindrical structure with an inlet at one end and an outlet at the other. Material enters the slurry preparation cylinder 11 through the inlet, is processed to generate die-casting slurry, and is output through the outlet. A hopper 13 is provided at the inlet to hold the material and facilitate the feeding of material into the slurry preparation cylinder 11. The injection section includes an injection cylinder 31, whose inlet is connected to the slurry storage chamber 11. Furthermore, the slurry preparation section, the slurry storage chamber 14, and the injection section of the die-casting machine are sealed together. Specifically, the inlet of the slurry storage chamber 14 is sealed to the outlet of the slurry preparation cylinder 11, and the outlet of the slurry storage chamber 14 is sealed to the inlet of the injection cylinder.

[0033] Slurry storage chamber 14 is used for temporary storage of the generated die casting slurry, such as... Figure 1 As shown, the slurry storage chamber 14 is located at the outlet of the slurry preparation cylinder 11. By providing this slurry storage chamber 14, a portion of the die-casting slurry can be temporarily stored, ensuring a stable supply of slurry for subsequent injection operations. For example, if the slurry storage chamber 14 contains the slurry required for one injection operation, then during that operation, the slurry preparation rate of the preparation section need not be considered. The injection operation can be performed simply by transferring the slurry from the storage chamber 14 to the injection cylinder 31 in the required quantity and rate, ensuring continuous operation of multiple injection operations and thus improving the overall efficiency of die casting. Furthermore, the separately located slurry storage chamber 14 facilitates cleaning and allows for precise control of the slurry flow rate from the storage chamber 14 to the injection cylinder 31, ensuring a stable injection volume.

[0034] This die-casting machine features a storage chamber between the slurry preparation cylinder and the injection cylinder, ensuring a stable supply of die-casting slurry. Furthermore, the sealed design between the slurry preparation cylinder, storage chamber, and injection cylinder eliminates the need for inert gas protection when die-casting reactive metals (such as magnesium alloys), making it more environmentally friendly, safer, and more economical. Compared to traditional die-casting systems, this machine combines the injection equipment, melting and holding furnace, and slurry feeder in a single design, resulting in a smaller footprint and greater cost-effectiveness.

[0035] In one implementation, the slurry preparation section and the storage chamber are located above the injection section, and the die casting slurry can be transferred to the injection section by gravity, making the die casting machine more economical.

[0036] As one implementation, a first heating structure 21 is provided on the upper part of the slurry storage chamber 14 to maintain the slurry therein in a better state. The first heating structure 21 can be located in the cylinder wall, inside the cylinder wall, or on the outer periphery of the slurry storage chamber 14. It can also be in the form of an induction coil, heating wire, heating rod, or heating plate to heat the slurry in the slurry storage chamber 14. All of these methods can achieve the technical effect of precise temperature control in the slurry storage chamber 14.

[0037] As one implementation, a feeding structure 15 is also provided between the slurry storage chamber 14 and the injection cylinder 31. For example... Figure 1 As shown, the end of the slurry storage chamber 14 is connected to the feed port of the injection cylinder 31 via the feeding structure 15, which allows the user to accurately control the flow rate of the slurry entering the injection cylinder 31 through the feeding structure 15. Specifically, the feeding structure 15 can be a servo valve, a screw feeder, or other feeding equipment that facilitates flow control.

[0038] In one implementation, this die-casting machine is used in semi-solid die-casting operations, and correspondingly, the slurry preparation section also includes a screw 12. For example... Figure 1As shown, the screw 12 is rotatably mounted in the pulping cylinder 11. Both ends of the screw 12 are rotatably connected to the cylinder walls at both ends of the pulping cylinder 11 and are sealed to the cylinder walls to prevent slurry leakage. Helical blades are provided on the outer periphery of the screw 12. When the screw 12 rotates, the blades can agitate the material in the pulping cylinder 11, shearing it to form a semi-solid slurry. For example, heated, shaving-like or granular alloy material can be fed into the pulping cylinder 11, and then sheared by the blades on the screw 12 to form a semi-solid slurry.

[0039] Accordingly, in this embodiment, the injection section also includes an injection rod 32 and a mold 36. The upper side of the left end of the injection cylinder 31 has a feed hole communicating with the slurry storage chamber 14. The left end of the injection rod 32 is connected to the feeding cylinder 34 and the accumulator 35, and the right end forms an injection punch 33 slidably connected to the injection cylinder 31. The mold 36 is connected to the right end of the injection cylinder 31. With the power provided by the accumulator 35, the injection rod 32 can press the semi-solid slurry entering the injection cylinder 31 into the mold 36 on the right side, maintaining a certain pressure to form the semi-solid slurry in the mold 36, thus forming the desired die-cast product.

[0040] In this type of die-casting machine, the injection section and the slurry preparation section are separate structures, forming a composite injection system. The injection section can utilize existing injection systems, reducing costs. When semi-solid die casting is not required, it can be switched to conventional die casting for production. Furthermore, compared to the traditional structure where the screw 12 and injection cylinder 31 are integrated, this split structure means that the slurry preparation section does not need to withstand significant pressure during die casting, preventing leakage within the slurry cylinder 11. This expands the process range for semi-solid die casting, supporting higher injection speeds and pressures, and correspondingly improving control precision. It is suitable for complex semi-solid die casting processes such as liquid forging.

[0041] In one embodiment, a second heating structure 22 and a third heating structure 23 are provided on the pulping cylinder 11 along the material flow direction, and a fourth heating structure 24 is provided inside the screw 12. Figure 1 As shown, in this embodiment, the second heating structure 22 and the third heating structure 23 employ induction coils to heat the material. The second heating structure 22 is located near the feed inlet of the pulping cylinder 11 to preheat the material entering the cylinder. The third heating structure 23 is located in the middle region of the pulping cylinder 11 and serves as the main heating structure. For example, it uses a high-frequency induction coil to heat the material to the required temperature and, in conjunction with the rotation of the screw 12, processes the material into a semi-solid slurry.

[0042] The fourth heating structure 24 is disposed within the screw 12. Its main function is to assist in heating, ensuring that the temperature of the middle part of the pulping cylinder 11, especially the area where the material contacts the center of the screw 12, reaches the required temperature. This results in a more uniform temperature distribution throughout the pulping cylinder 11 from the center outwards, ultimately achieving precise temperature control within the pulping cylinder 11. The fourth heating structure 24 can be an electric heating rod or an electric heating wire, which facilitates its placement within the screw 12 and allows for precise control of the heating power.

[0043] Furthermore, since the slurry preparation section is not directly located within the injection cylinder 31 of the die-casting machine, the placement of the various heating structures on the slurry preparation section is more convenient and will not significantly affect the placement of other structures. For example, as one embodiment, the second heating structure 22 and the third heating structure 23 can also be located within or inside the cylinder wall of the slurry preparation cylinder 11, achieving the same heating function. Additionally, the second heating structure 22 and the third heating structure 23 can also employ heating wires, heating rods, or heating plates to heat the material in the slurry preparation cylinder 11, all achieving the aforementioned precise temperature control effect.

[0044] In one implementation, the fourth heating structure 24 is slidably disposed within the screw 12. During pulping operations, the specific position of the fourth heating structure 24 can be adjusted to precisely control the temperature of a specific area within the pulping cylinder 11. For example, by moving the fourth heating structure 24 to the area where the third heating structure 23 is located, the temperature of that area can be precisely controlled within the required temperature range, thereby making the semi-solid pulp more uniformly formed.

[0045] As one implementation, two fourth heating structures 24 are provided inside the screw 12, which makes it more convenient for users to adjust the area of ​​precise temperature control inside the pulping cylinder 11, so that different areas can reach different temperature ranges. For example, one fourth heating structure 24 is located in the area where the second heating structure 22 is located, and the other fourth heating structure 24 is located in the area where the third heating structure 23 is located, which can respectively achieve precise control of the temperature of the preheating section and the semi-solid pulp generation section, making the pulping process more precise and efficient.

[0046] As one implementation method, a fifth heating structure 25 is also provided on the pulping cylinder 11 at a position opposite to the discharge port. Its main function is to maintain the tail of the pulping cylinder 11 at a preset temperature, so as to achieve precise temperature control of the entire pulping cylinder 11, so that the generated semi-solid slurry will not undergo property changes at this point, and ensure that the subsequent injection operation can proceed normally.

[0047] Similar to the second heating structure 22 and the third heating structure 23, the fifth heating structure 25 can also be located in the cylinder wall of the pulping cylinder 11, inside the cylinder wall, or on the outer periphery. It can also be used in the form of heating wire, heating rod, or heating plate to heat the material in the pulping cylinder 11, all of which can achieve the above-mentioned precise temperature control effect.

[0048] As one implementation, the lengths of the second heating structure 22, the third heating structure 23, and the fifth heating structure 25 can be set within the following ranges to process a semi-solid slurry in an optimal state. For example... Figure 1 As shown, along the length of the pulping cylinder 11, i.e. the left-right direction in the figure, the length of the second heating structure 22 is L2, the length of the third heating structure 23 is L3, the length of the fifth heating structure 25 is L5, and the length of the pulping cylinder 11 is L0.

[0049] in At the same time, L2+L3+L5≤L0.

[0050] This range of values ​​can cover the processing of a wide variety of metal materials into semi-solid slurries. Specifically, the lengths of the heating structures can be adjusted according to the type of material to produce the best semi-solid slurry.

[0051] As one embodiment, the injection cylinder 31 in the die-casting machine is provided with a sixth heating structure 26 on its outer periphery, which covers the injection cylinder 31. For example, an induction coil, heating wire, or heating plate can be used to maintain the injection cylinder 31 at a preset temperature, ensuring that the slurry can be stably in a semi-solid state before entering the mold 36, thereby indirectly improving the quality of the die-casting product.

[0052] In one specific embodiment, using AZ91D magnesium alloy as raw material, the operation process of this die-casting machine when applied to semi-solid die casting is described in detail. The particle density of this magnesium alloy is 1.81 g / cm³. 3 The melting point is 598℃. During the slurry preparation process, based on product process requirements, the heating structure involved in this invention is used for multi-stage temperature control of the screw section and precise temperature control of the slurry storage chamber; the slurry supply speed is controlled by adjusting the screw speed and the opening of the feeding structure. During the injection process, semi-solid slurry is injected using conventional die-casting injection technology. Compared to traditional screw injection molding, the injection speed, casting pressure, and control precision are significantly improved.

[0053] Specifically, the die-casting method includes the following steps:

[0054] Step S1: Inject material into the pulping cylinder 11 and start the screw 12 to produce semi-solid slurry.

[0055] Based on the temperature-solid fraction distribution of AZ91D magnesium alloy shown in Table 1, and considering the control process requirements, the temperature from the inlet to the outlet is set in multiple segments using the multiple heating structures in the slurry preparation cylinder 11. With a screw speed of 105 rev / min, the desired semi-solid slurry can be generated. The monitoring positions corresponding to each temperature segment are evenly distributed between the inlet and outlet. In other words, by utilizing the multiple heating structures on the slurry preparation cylinder 11 and the screw 12, precise temperature control along the material movement direction in the slurry preparation cylinder 11 can be achieved, which is beneficial for producing high-quality semi-solid slurry that meets the requirements of injection molding operations.

[0056] Table 1:

[0057] Temperature / ℃ 565 575 585 595 605 Solid fraction / % 55 35 20 3 ＜1

[0058] Step S2: Store the generated semi-solid slurry in the slurry storage chamber 14.

[0059] In this step, in order to maintain the semi-solid slurry in a better state, the first heating structure 21 is used to keep the slurry storage chamber 14 at 570°C, so that the semi-solid slurry is in a better heat preservation environment.

[0060] Step S3: Input a preset amount of semi-solid slurry from the slurry storage chamber 14 into the injection cylinder 31.

[0061] Specifically, in this step, the semi-solid slurry is fed into the injection cylinder 31 by the feeding structure 15 according to the parameters of 5.7 seconds per mold feeding time and 1750g per mold weight, so as to ensure the stability of the injection volume.

[0062] Step S4: Start the injection rod 32 to press the semi-solid slurry in the injection cylinder 31 into the mold 36.

[0063] Specifically, the injection process is controlled in two stages: low speed and high speed. The low speed is 0.6 m / s, and the high speed is 5.38 m / s, with a maximum air injection speed of ≥8 m / s. In the high-speed stage, the energy storage pressure of the accumulator is 145 bar, the hammer diameter is 80 mm, corresponding to an injection force of 430 kN and a casting pressure of 85 MPa.

[0064] Testing revealed the following physical properties of the final semi-solid die-cast product: tensile strength 299 MPa, yield strength 169 MPa, and elongation 10%. In contrast, using the same material and conventional die-casting methods, the resulting die-cast product exhibited a tensile strength of 230 MPa, a yield strength of 150 MPa, and an elongation of 3%. This demonstrates that the die-casting machine described in this invention significantly improves the tensile strength, yield strength, and elongation of semi-solid die-cast parts compared to conventional die-cast parts, effectively combining the power advantages of conventional die-casting with the performance advantages of semi-solid slurry.

[0065] In another specific embodiment, using the die-casting machine involved in this invention to perform semi-solid die casting of aluminum alloy of material A356.2, after adjusting the aforementioned slurry preparation parameters and injection parameters accordingly, the physical properties of the resulting semi-solid die-cast product are: tensile strength 284 MPa, yield strength 215 MPa, and elongation 9%. However, using the same material and conventional die-casting methods, the physical properties of the resulting die-cast product are: tensile strength 210 MPa, yield strength 190 MPa, and elongation 5%.

[0066] Therefore, using this die-casting machine to produce magnesium and aluminum alloy products can significantly improve the physical properties of the die-cast products.

[0067] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A die-casting machine, characterized in that, include: The pulping section includes a pulping cylinder; A slurry storage chamber is connected to the discharge port of the slurry preparation cylinder; The injection section includes an injection cylinder, the inlet of which is connected to the slurry storage chamber: wherein The pulping section, pulp storage chamber, and injection section are connected in a sealed manner.

2. The die-casting machine as described in claim 1, characterized in that, A first heating structure is provided on the slurry storage chamber.

3. The die-casting machine as described in claim 1, characterized in that, Also includes: A feeding structure is provided between the slurry storage chamber and the injection cylinder, for conveying the material in the slurry storage chamber to the injection cylinder.

4. The die-casting machine as described in claim 1, characterized in that, The pulping section also includes: The screw is rotatably mounted in the pulping cylinder and has helical blades on its outer circumference.

5. The die-casting machine as described in claim 4, characterized in that, The pulping cylinder is provided with a second heating structure and a third heating structure along the material flow direction; The screw is equipped with a fourth heating structure.

6. The die-casting machine as described in claim 5, characterized in that, The fourth heating structure is slidably disposed within the screw.

7. The die-casting machine as described in claim 5, characterized in that, The screw is equipped with two of the fourth heating structures.

8. The die-casting machine as described in claim 5, characterized in that, A fifth heating structure is provided on the pulping cylinder at a position opposite to the discharge port.

9. The die-casting machine as described in claim 8, characterized in that, The second heating structure, the third heating structure, and the fifth heating structure are induction coils disposed on the outer periphery of the pulping cylinder; The fourth heating structure is a heating rod or a heating wire.

10. The die-casting machine as described in claim 1, characterized in that, The outer periphery of the injection cylinder is provided with a sixth heating structure.

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