Miniature die-casting sample preparation device and method

Abstract

The invention belongs to the technical field of metal casting, and discloses a miniature die-casting sample preparation device and method. The device comprises a mold assembly and a press machine. The die assembly comprises an upper die assembly and a lower die assembly; the upper die assembly comprises a connecting piece and a split upper die; the split surfaces of the split upper mold are assembled to form a plurality of upper mold inner cavities; the split upper die is connected and fixed with a pressing rod of a press machine through the connecting piece; the lower die assembly comprises a cylindrical die sleeve, a lower die support and a split lower die; the die sleeve is placed on a platform of a press machine, and a die sleeve lining is arranged at the bottom in the die sleeve; the split lower die is annularly arranged on the inner side wall of the die sleeve, the lower die support is placed on the die sleeve lining, and the split lower die and the lower die support are combined to form a lower die inner cavity; the transverse projection area of the lower die inner cavity is larger than the transverse projection area of all the upper die inner cavities. The mold filling speed and the die-casting solidification condition which are the same as or similar to those of actual die-casting can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of metal casting technology, and more specifically, relates to a micro die-casting sample preparation device and method. Background Technology

[0002] In the field of non-ferrous metal casting such as aluminum alloys and magnesium alloys, die casting accounts for a significant proportion of production. Especially in recent years, the rise of integrated casting technology has brought about a major revolution in the automotive manufacturing industry. At the same time, it has also brought enormous challenges and opportunities to the composition and process design of die-cast aluminum alloys. Among these, the research and application of heat-free aluminum alloys has received widespread attention. Since heat-free aluminum alloy castings do not undergo heat treatment after die casting, various high-alloying schemes are adopted to improve the mechanical properties of the castings. However, with the continuous optimization and adjustment of alloy composition design, research on the solidification process of new alloy die casting, especially the influence of die casting process parameters on solidification structure and casting properties, is increasingly attracting attention.

[0003] In the die casting process, the molten metal has an extremely high filling speed, and the alloy melt solidifies under pressure. Due to these characteristics of the die casting process, which differ significantly from conventional gravity casting, if it is necessary to study the solidification structure and properties of die-cast alloys, qualified samples can usually only be obtained by conducting die casting experiments using a specialized die casting machine.

[0004] However, most universities and research institutions lack the facilities for die casting experiments. Furthermore, the high cost and long cycle of die casting experiments severely restrict research and exploration into die casting alloy composition design and die casting processes. To obtain die casting samples, various solidification devices (such as vacuum strip casting devices) have been designed and manufactured in laboratories to simulate the sub-rapid solidification process during die casting. However, high-speed filling and pressure solidification are difficult to achieve during suction casting, resulting in more shrinkage defects in the suction-cast samples. Consequently, their strength and elongation are lower than actual die-cast samples, failing to accurately reflect the microstructure and mechanical properties of the die-cast alloy. Overall, although die casting research is gaining increasing attention, the lack of laboratory-level die casting sample preparation equipment hinders most related research institutions from conducting systematic and in-depth die casting research, significantly restricting research progress in the design of novel die-cast alloys and the optimization of die casting processes.

[0005] Therefore, in view of the current lack of laboratory-level die-casting experimental equipment, there is an urgent need to provide a micro die-casting sample preparation device and method. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a micro die-casting sample preparation device and method. This invention achieves filling speeds and solidification conditions similar to or comparable to actual die casting by adjusting the ratio of the lateral projected area of ​​the lower mold cavity to the lateral projected area of ​​all upper mold cavities, as well as the downward pressing speed of the upper mold assembly driven by the pressure rod.

[0007] To achieve the above objectives, the present invention provides a micro die-casting sample preparation device, the device comprising a mold assembly and a press;

[0008] The mold assembly includes an upper mold assembly and a lower mold assembly;

[0009] The upper mold assembly includes a connector and a split upper mold; the split surfaces of the split upper mold are assembled to form multiple upper mold cavities; the split upper mold is connected and fixed to the pressure rod of the press through the connector;

[0010] The lower die assembly includes a cylindrical die sleeve, a lower die support, and a split lower die; the die sleeve is placed on the platform of the press, and a die sleeve liner is provided at the bottom of the die sleeve; the split lower die is ringed on the inner side wall of the die sleeve, the lower die support is placed on the die sleeve liner, and the split lower die and the lower die support together form the lower die cavity;

[0011] Both the upper mold assembly and the lower mold assembly move along the height direction of the lower mold cavity, and the lateral projected area of ​​the lower mold cavity is greater than the lateral projected area of ​​all the upper mold cavities.

[0012] According to the present invention, preferably, the press is a vertical press.

[0013] According to the present invention, preferably, the split upper mold includes a first split mold core and a second split mold core, and the split surfaces of the first split mold core and the second split mold core are assembled by heat-resistant bolts to form the plurality of upper mold cavities.

[0014] According to the present invention, preferably, the split upper die and the connecting member are fixedly connected by heat-resistant bolts; the connecting member and the pressure rod of the press are fixedly connected by bolts.

[0015] According to the present invention, preferably, the number of cavities in the upper mold is 1 to 2.

[0016] According to the present invention, preferably, the shape of each upper mold cavity is a thin plate and / or a cylinder;

[0017] More preferably, the height of the inner cavity of the thin plate upper mold is 40-100 mm, the width is 5-20 mm, and the thickness is 1-5 mm;

[0018] More preferably, the height of the inner cavity of the cylindrical upper mold is 40-100 mm and the diameter is 2-8 mm.

[0019] In this invention, such as Figure 1 , 2 As shown in Figure 4, both the first and second split mold cores are provided with bolt through holes, allowing the split surfaces of the first and second split mold cores to be assembled using heat-resistant bolts to form the plurality of upper mold cavities. Additionally:

[0020] The formation of the inner cavity of the thin-plate upper mold is as follows: (e.g.) Figure 1-3 As shown, connecting grooves are machined on the opening surfaces of the first and second split mold cores using a milling machine. The depth of the connecting grooves is half the thickness of the thin-plate micro die-cast sample plus 0.05 to 0.1 mm as a shrinkage allowance. When the opening surfaces of the first and second split mold cores are assembled with heat-resistant bolts, the inner cavity of the thin-plate upper mold is obtained.

[0021] The inner cavity of the cylindrical upper mold is formed as follows: (e.g.) Figure 1-3 As shown, after the opening surfaces of the first split mold core and the second split mold core are assembled with heat-resistant bolts, holes are drilled. The hole diameter is the diameter of the cylindrical micro die-casting sample plus 0.05 to 0.2 mm as a shrinkage allowance, thus obtaining the cylindrical upper mold cavity.

[0022] In this invention, the inner cavity of each upper mold is shaped as a thin plate and / or a cylinder, so that the alloy melt fills the mold quickly under pressure to prepare a thin plate micro die-casting sample or a cylindrical micro die-casting sample.

[0023] According to the present invention, preferably, the ratio of the lateral projected area of ​​the lower mold cavity to the lateral projected area of ​​the entire upper mold cavity is (10000~22500): (2.3~60).

[0024] In this invention, the lateral projection area of ​​the lower mold cavity is greater than the lateral projection area of ​​all the upper mold cavities, thereby ensuring that the alloy melt in the lower mold cavity is injected into the upper mold cavity at high speed under pressure and solidifies under pressure, thereby obtaining the same or similar filling speed and die casting solidification conditions as in the actual die casting production process, and realizing the laboratory preparation of micro die casting samples.

[0025] According to the present invention, preferably, the lower mold cavity is U-shaped;

[0026] The cross-section of the part of the split upper mold that contacts the inner cavity of the lower mold is circular, and the diameter of the cross-section is equal to the diameter of the cross-section of the inner cavity of the lower mold, with a fit tolerance of 0.05 to 0.20 mm.

[0027] Another aspect of the present invention provides a method for preparing micro die-cast samples, the method employing the above-described system and comprising the following steps:

[0028] S1: Preheat the assembled mold assembly;

[0029] S2: Connect and fix the preheated upper die assembly to the press rod of the press through its connector; place the preheated lower die assembly on the platform of the press and place it correspondingly to the upper die assembly;

[0030] S3: The alloy melt that has reached the casting temperature is injected into the inner cavity of the lower mold in step S2; the press is started, and the pressure rod drives the upper mold assembly to press down, so that the alloy melt in the inner cavity of the lower mold is injected into the inner cavity of the upper mold under the action of the pressing upper mold assembly, realizing die casting filling and solidification under the pressure of the press to obtain the micro die casting sample.

[0031] According to the present invention, preferably, the preheating temperature is 200-300°C and the time is 1-2 hours.

[0032] According to the present invention, preferably, the pouring temperature is 680-750°C.

[0033] According to the present invention, preferably, the alloy melt is an aluminum alloy melt or a magnesium alloy melt.

[0034] According to the present invention, preferably, the speed at which the pressure rod drives the upper mold assembly to press down is 200-250 mm / s.

[0035] According to the present invention, preferably, the filling speed ranges from 6.1 to 244.6 m / s.

[0036] According to the present invention, preferably, the cooling rate ranges from 100 to 10000 °C / s. The apparatus and method of the present invention essentially cover the range of filling and cooling rates under conventional die-casting process conditions.

[0037] According to the present invention, preferably, the pressure value of the pressure applied is 50 to 120 MPa.

[0038] According to the present invention, preferably, when the shape of the inner cavity of the upper mold is a thin plate, the micro die-cast sample is a thin plate, and the height of the thin plate micro die-cast sample is 40-100mm, the width is 5-20mm, and the thickness is 1-5mm.

[0039] According to the present invention, preferably, when the inner cavity of the upper mold is cylindrical, the micro die-cast sample is cylindrical, and the height of the cylindrical micro die-cast sample is 40-100 mm and the diameter is 2-8 mm.

[0040] In this invention, as a preferred embodiment, the specific steps of the micro die-casting sample preparation method of this invention to achieve high-speed filling and pressure solidification of the molten metal are as follows:

[0041] (i) Mold assembly: First, assemble the first split mold core and the second split mold core into a split upper mold using heat-resistant bolts, and fix the split upper mold to the connector using heat-resistant bolts to form an upper mold assembly; then, put the mold sleeve liner, the split lower mold and the lower mold support into the mold sleeve in sequence to form a lower mold assembly.

[0042] (ii) Mold preheating: Place the assembled upper mold assembly and lower mold assembly in an electric resistance furnace for preheating at a temperature of 230-300℃ and keep warm for 1-2 hours;

[0043] (III) Alloy melting: First, melt the alloy at the set temperature, then slowly lower the temperature of the alloy melt to the predetermined casting temperature and hold it for about 10 to 30 minutes;

[0044] (iv) Alloy casting: The preheated upper mold assembly is connected and fixed to the pressure rod of the press through its connecting parts using fastening bolts; then the lower mold assembly is placed on the platform of the press and aligned with the upper mold assembly; the alloy melt that has reached the casting temperature is injected into the inner cavity of the lower mold, and the press is quickly started so that the alloy melt is injected into the inner cavity of the upper mold under the action of the rapidly pressing upper mold assembly, realizing die casting filling and solidification under pressure;

[0045] (V) Sample Removal: First, invert the mold assembly and use a press to eject the split lower mold from the mold sleeve; then, use a screwdriver to loosen the heat-resistant bolts between the split upper mold and the connecting parts, as well as the heat-resistant bolts between the first split mold core and the second split mold core, to separate the split upper mold and expose the thin-plate micro die-cast sample or the cylindrical micro die-cast sample; finally, use a hand saw to cut and separate the thin-plate micro die-cast sample or the cylindrical micro die-cast sample from the ingot, and then process and prepare metallographic samples and mechanical tensile samples as needed.

[0046] The beneficial effects of the technical solution of the present invention are as follows:

[0047] 1) By adjusting the ratio of the lateral projected area of ​​the lower mold cavity to the lateral projected area of ​​all the upper mold cavities and the speed at which the pressure rod drives the upper mold assembly to press down, the present invention can obtain different melt filling speeds and obtain filling speeds that are the same as or similar to those of actual die casting.

[0048] 2) By setting different pressure values ​​of the press, the present invention can realize the solidification process under different pressures and obtain solidification pressure conditions that are the same as or similar to those of the die casting process.

[0049] 3) This invention can prepare micro die-casting samples of different thicknesses or diameters by changing the size of the inner cavity of the thin plate upper mold or the diameter of the inner cavity of the cylindrical upper mold; combined with changing the pouring temperature of the molten metal, a wider range of solidification rates can be obtained, enabling experimental research on different die-casting conditions.

[0050] 4) The die-casting specimens prepared by the device of the present invention can not only be used for solidification structure observation, but also for preparing mechanical tensile plate specimens (thin plate micro die-casting samples) or rod specimens (cylindrical micro die-casting samples), meeting the needs of solidification mechanical testing of die-casting specimens and for die-casting alloy composition design and process optimization research.

[0051] 5) The device of the present invention has a simple structure, low cost, easy operation and high preparation efficiency, which is conducive to its promotion and use in a wide range of universities and research institutions. It can be used for the preparation of die casting research samples of metal materials such as aluminum alloys and magnesium alloys, and solves the problems of complex equipment structure, high cost, cumbersome operation and long test cycle in the existing die casting sample preparation.

[0052] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0053] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0054] Figure 1 The image shown is a physical picture of the split upper mold (the inner cavity of the upper mold is cylindrical) of the micro die-casting sample preparation device provided by the present invention before assembly.

[0055] Figure 2 The image shows a physical picture of the assembled split upper mold (the inner cavity of the upper mold is cylindrical) of the micro die-casting sample preparation device provided by the present invention.

[0056] Figure 3 The image shows a physical picture of the assembled split upper mold (the inner cavity of the upper mold is in the shape of a thin plate) of the micro die-casting sample preparation device provided by the present invention.

[0057] Figure 4 A schematic diagram of the structure of a micro die-casting sample preparation device provided by the present invention is shown.

[0058] Figure 5 The image shown is a physical photograph (before hand sawing) of a thin-plate micro-die-cast sample obtained by a micro-die-cast sample preparation method provided by the present invention.

[0059] The annotations in the attached figures are explained as follows:

[0060] 1. Connecting parts; 2. Split upper mold; 3. Melt; 4. Split lower mold; 5. Lower mold support; 6. Mold sleeve; 7. Mold sleeve liner;

[0061] 2-1. First split mold core; 2-2. Second split mold core; 2-3. Bolt through hole; 2-4. Upper mold inner cavity. Detailed Implementation

[0062] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0063] Example 1

[0064] This embodiment provides a micro die-casting sample preparation device, such as... Figure 1-5 As shown, the device includes a mold assembly and a press;

[0065] The press is a vertical press;

[0066] The mold assembly includes an upper mold assembly and a lower mold assembly;

[0067] The upper mold assembly includes a connector 1 and a split upper mold 2; the split upper mold includes a first split mold core 2-1 and a second split mold core 2-2, both of which are provided with bolt through holes 2-3, so that the split surfaces of the first split mold core 2-1 and the second split mold core 2-2 can be assembled by M8 heat-resistant bolts to form the two thin plate-shaped upper mold cavities 2-4, each thin plate-shaped upper mold cavity 2-4 having a width of 14mm, a thickness of 2.1mm, and a height of 60mm; the split upper mold 2 is fixedly connected to the connector 1 by M8 heat-resistant bolts (not shown); the connector 1 is fixedly connected to the pressure rod of the press by M6 fastening bolts.

[0068] The lower die assembly includes a cylindrical die sleeve 6, a lower die support 5, and a split lower die 4; the die sleeve 6 is placed on the platform of the press, and a die sleeve liner 7 is provided at the bottom of the die sleeve 6; the split lower die 4 is arranged around the inner sidewall of the die sleeve 6, the lower die support 5 is placed on the die sleeve liner 7, and the split lower die 4 and the lower die support 5 combine to form the lower die cavity, as shown below. Figure 4As shown, the cross-section of the part of the split upper mold 2 that contacts the inner cavity of the lower mold is circular, and the diameter of the cross-section is equal to the diameter of the cross-section of the inner cavity of the lower mold (120mm), with a fit tolerance of 0.05 to 0.20mm.

[0069] In this embodiment, the movement is along the height direction of the lower mold cavity. The lateral projection area of ​​the lower mold cavity is greater than the lateral projection area of ​​the two thin plate-shaped upper mold cavities. That is, the ratio of the lateral projection area of ​​the lower mold cavity to the lateral projection area of ​​the two thin plate-shaped upper mold cavities is 11309.73:58.8.

[0070] This embodiment also provides a method for preparing micro die-cast samples, wherein the alloy melt material is an AlMgSiMn aluminum alloy, and the method uses the above-described system and includes the following steps:

[0071] S1: Place the assembled upper mold assembly and lower mold assembly in a resistance furnace for preheating at a temperature of 240℃ and keep warm for 1.5 hours.

[0072] S2: Use M6 fastening bolts to connect and fix the preheated upper die assembly to the press rod of the press through its connector 1; place the preheated lower die assembly on the platform of the press and place it correspondingly to the upper die assembly;

[0073] S3: Melt the aluminum alloy at a set temperature of 750℃, then slowly reduce the temperature of the alloy melt to the predetermined pouring temperature of 700℃ and hold it at that temperature for about 12 minutes; inject the alloy melt that has reached the pouring temperature into the inner cavity of the lower mold in step S2; start the press, causing the pressure rod to drive the upper mold assembly to press down (at a speed of 200mm / s), thereby causing the alloy melt in the inner cavity of the lower mold to be injected into the inner cavity 2-4 of the upper mold under the squeezing action of the pressing upper mold assembly, realizing die casting filling and solidification under the pressure of the press (pressure value 100MPa), wherein the filling speed range is 38. The cooling rate is 840℃ / s, with a speed of 5m / s. After the die casting solidifies, the mold assembly is inverted, and the lower mold 4 is ejected from the mold sleeve 6 using a press. Then, the M8 heat-resistant bolts between the upper mold 2 and the connecting piece 1, as well as the M8 heat-resistant bolts between the first and second mold cores 2-1 and 2-2, are loosened with a screwdriver to separate the upper mold 2 and expose the thin-plate micro die casting sample. Finally, the thin-plate micro die casting sample is separated from the ingot by a hand saw. The thickness of the thin-plate (plate-shaped) micro die casting sample in this embodiment is 2.1mm.

[0074] In this embodiment, a cross-section along the thickness direction of a thin-plate micro-die-cast sample was cut for metallographic observation, and sheet-like tensile specimens were prepared for room temperature tensile testing (GB / T 228.1-2021). Macroscopic and microscopic observation results show:

[0075] The thin-plate micro die-cast sample of this embodiment has complete mold filling, and the sample surface is free of oxidation or inclusions. Metallographic analysis shows that the grain structure is fine and uniform, with a grain size of about 35-45 μm. The thin-plate micro die-cast sample of this embodiment has excellent room temperature performance, with a cast tensile strength of 302.7 MPa, a yield strength of 158.4 MPa, and an elongation of 9.7%, which is comparable to the microstructure and cast tensile properties of aluminum alloy die-casting of the same composition produced by industrial die casting.

[0076] Example 2

[0077] This embodiment provides a micro die-casting sample preparation device. The only difference between this device and Embodiment 1 is that:

[0078] The width of the inner cavity 2-4 of each thin plate mold is 14mm, the thickness is 1.7mm, and the height is 60mm;

[0079] In this embodiment, the movement is along the height direction of the lower mold cavity. The lateral projection area of ​​the lower mold cavity is greater than the lateral projection area of ​​the two thin plate-shaped upper mold cavities. That is, the ratio of the lateral projection area of ​​the lower mold cavity to the lateral projection area of ​​the two thin plate-shaped upper mold cavities is 11309.73:47.6.

[0080] This embodiment also provides a method for preparing micro die-cast samples. The only difference between this method and Example 1 is that:

[0081] The alloy melt in this embodiment is made of ZL205A aluminum alloy;

[0082] In S1, the preheating temperature is 280℃, and the temperature is maintained for 1.0 hour;

[0083] In step S3, the aluminum alloy of this embodiment is melted at a set temperature of 760°C. Then, the temperature of the alloy melt is slowly reduced to the predetermined pouring temperature of 710°C and held for about 15 minutes. The alloy melt that has reached the pouring temperature is injected into the inner cavity of the lower mold in step S2. The press is started, and the pressure rod drives the upper mold assembly to press down (at a speed of 220 mm / s). The alloy melt in the inner cavity of the lower mold is then injected into the inner cavity 2-4 of the upper mold under the squeezing action of the pressing upper mold assembly, thus realizing die casting filling and solidification under the pressure of the press (pressure value 115 MPa). The filling speed range is 52.3 m / s, and the cooling speed range is 1160°C / s.

[0084] The thickness of the thin-plate (plate-shaped) micro die-cast sample in this embodiment is 1.7 mm.

[0085] In this embodiment, a cross-section along the thickness direction of a thin-plate micro-die-cast sample was cut for metallographic observation, and sheet-like tensile specimens were prepared for room temperature tensile testing (GB / T 228.1-2021). Macroscopic and microscopic observation results show:

[0086] The thin-plate micro die-cast sample of this embodiment has complete mold filling, and the sample surface is free of oxidation or inclusions. Metallographic analysis shows that the grain structure is fine and uniform, with a grain size of about 30-36 μm. The thin-plate micro die-cast sample of this embodiment has excellent room temperature performance, with a cast tensile strength of 355.7 MPa, a yield strength of 282.5 MPa, and an elongation of 10.7%, which is comparable to the microstructure and cast tensile properties of aluminum alloy die-casting of the same composition produced by industrial die casting.

[0087] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A micro die-casting sample preparation device, characterized in that, The device includes a mold assembly and a press; The mold assembly includes an upper mold assembly and a lower mold assembly; The upper mold assembly includes a connector and a split upper mold; the split surfaces of the split upper mold are assembled to form multiple upper mold cavities; the split upper mold is connected and fixed to the pressure rod of the press through the connector; The lower die assembly includes a cylindrical die sleeve, a lower die support, and a split lower die; the die sleeve is placed on the platform of the press, and a die sleeve liner is provided at the bottom of the die sleeve; the split lower die is ringed on the inner side wall of the die sleeve, the lower die support is placed on the die sleeve liner, and the split lower die and the lower die support together form the lower die cavity; Both the upper mold assembly and the lower mold assembly move along the height direction of the lower mold cavity, and the lateral projected area of ​​the lower mold cavity is greater than the lateral projected area of ​​all the upper mold cavities.

2. The micro die-casting sample preparation device according to claim 1, wherein, The press is a vertical press; The split upper mold includes a first split mold core and a second split mold core. The split surfaces of the first split mold core and the second split mold core are assembled by heat-resistant bolts to form the plurality of upper mold cavities. The split upper die is fixedly connected to the connecting piece by heat-resistant bolts; the connecting piece is fixedly connected to the pressure rod of the press by bolts.

3. The micro die-casting sample preparation apparatus according to claim 1, wherein, The number of cavities in the upper mold is 1 to 2; The inner cavity of each upper mold is in the shape of a thin plate and / or a cylinder; Preferably, the height of the inner cavity of the thin plate upper mold is 40-100mm, the width is 5-20mm, and the thickness is 1-5mm; Preferably, the height of the inner cavity of the cylindrical upper mold is 40-100 mm, and the diameter is 2-8 mm.

4. The micro die-casting sample preparation apparatus according to claim 3, wherein, The ratio of the lateral projected area of ​​the lower mold cavity to the lateral projected area of ​​all the upper mold cavities is (10000~22500):(2.3~60).

5. The micro die-casting sample preparation device according to claim 1, wherein, The inner cavity of the lower mold is U-shaped; The cross-section of the part of the split upper mold that contacts the inner cavity of the lower mold is circular, and the diameter of the cross-section is equal to the diameter of the cross-section of the inner cavity of the lower mold, with a fit tolerance of 0.05 to 0.20 mm.

6. A method for preparing a micro die-cast sample, characterized in that, The method employs the system described in any one of claims 1-5 and includes the following steps: S1: Preheat the assembled mold assembly; S2: Connect and fix the preheated upper die assembly to the press rod of the press through its connector; place the preheated lower die assembly on the platform of the press and place it correspondingly to the upper die assembly; S3: The alloy melt that has reached the casting temperature is injected into the inner cavity of the lower mold in step S2; the press is started, and the pressure rod drives the upper mold assembly to press down, so that the alloy melt in the inner cavity of the lower mold is injected into the inner cavity of the upper mold under the action of the pressing upper mold assembly, realizing die casting filling and cooling and solidification under the pressure of the press to obtain the micro die casting sample.

7. The method for preparing micro die-cast samples according to claim 6, wherein, The preheating temperature is 200-300℃, and the time is 1-2 hours.

8. The method for preparing micro die-cast samples according to claim 6, wherein, The pouring temperature is 680–750℃; The alloy melt is an aluminum alloy melt or a magnesium alloy melt.

9. The method for preparing micro die-cast samples according to claim 6, wherein, The pressure rod drives the upper mold assembly to press down at a speed of 200-250 mm / s; The filling speed ranges from 6.1 to 244.6 m / s; Cooling rate range is 100–10000℃ / s; The pressure applied is 50–120 MPa.

10. The method for preparing micro die-cast samples according to claim 6, wherein, When the inner cavity of the upper mold is in the shape of a thin plate, the micro die-casting sample is in the shape of a thin plate. The height of the thin plate micro die-casting sample is 40-100mm, the width is 5-20mm, and the thickness is 1-5mm. When the inner cavity of the upper mold is cylindrical, the micro die-cast sample is cylindrical, with a height of 40–100 mm and a diameter of 2–8 mm.

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