Lost foam casting model and forming method thereof

Abstract

The invention relates to the technical field of evanescent mode casting models, in particular to an evanescent mode casting model and a forming method thereof, and solves the problems of high production cost and low efficiency caused by slow drainage and low steam utilization rate of a traditional mold. The mold comprises an upper mold, a lower mold and a plurality of guide mechanisms, the upper die comprises an upper die frame and an upper die core; an upper mold air chamber is formed between the upper mold frame and the upper mold core; an included angle theta is formed between the inner surface of the bottom of the upper mold frame and the lower surface of the upper mold frame, and N first water outlets are formed in the side wall corresponding to the inclined downward direction of the included angle theta; the lower die comprises a lower die frame and a lower die core; a lower mold air chamber is formed between the lower mold frame and the lower mold core; the air inlet of the upper mold frame and the air inlet of the lower mold frame are respectively used for supplying steam to the upper mold air chamber, the lower mold air chamber and the mold cavity after being connected with a steam source, so that the EPS beads form a to-be-cast evanescent mold in the mold cavity. According to the method, the production efficiency can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lost foam casting models, and particularly relates to a lost foam casting model and a forming method thereof. Background Art

[0002] The essence of lost foam casting is to use a polystyrene foam plastic pattern instead of ordinary (wooden pattern, metal pattern). After molding, the polystyrene foam plastic pattern (commonly known as white pattern) is not taken out and molten metal is poured in. Under the thermal action of the hot molten metal, the polystyrene foam plastic pattern vaporizes and burns away, and the molten metal replaces the space originally occupied by the polystyrene foam plastic pattern. After cooling and solidifying, the required casting can be obtained. Since the polystyrene foam plastic pattern is an essential consumable in the lost foam casting process, and one pattern is consumed for each casting produced, the forming efficiency of the pattern is a key factor restricting the production efficiency of lost foam casting.

[0003] In lost foam casting, the manufacture of polystyrene foam plastic patterns is a key process. Its manufacturing process can be divided into mold foaming forming and machining forming with foam plastic sheets. Generally, for large and medium-sized patterns used in single-piece and small-batch production, machining forming is adopted; for patterns used in mass production, with complex shapes, and high requirements for casting dimensions and surface quality, mold foaming forming is used.

[0004] Traditional mold structures have the following disadvantages:

[0005] ① In the conventional design of the upper mold of the mold, only one drainage hole is reserved, and the drainage efficiency is slow;

[0006] ② The drainage area below the air chamber of the upper mold of the mold is in a horizontal state, resulting in slow drainage of cooling water during the molding process of the mold;

[0007] ③ The air chamber of the mold is surrounded by a mold frame, and the entire air chamber has a large volume, including other mold areas that do not participate in the forming surface, resulting in low steam utilization rate.

[0008] Chinese Patent CN106238673A discloses "A Forming Method for Low-Density EPS Patterns for Lost Foam Casting", which can obtain low-density modules, reduce the gas evolution amount of EPS patterns and reduce carbon defects in castings. Through multiple foaming, the content of the blowing agent is greatly reduced, and the size of the module is stable. After the secondary forming foaming process, high-quality EPS patterns can be obtained at a lower density, but it does not solve the problems of slow drainage of traditional molds and low steam utilization rate, resulting in high production costs and low efficiency. Summary of the Invention

[0009] The object of the present invention is to solve the problems of slow drainage and low steam utilization rate in traditional molds, which lead to high production costs and low efficiency, and to provide a lost foam casting model and its forming method.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] A lost foam casting model, characterized in that: it includes an upper mold, a lower mold, and a plurality of guiding mechanisms;

[0012] The upper mold includes an upper mold frame and an upper mold core nested inside the upper mold frame; an upper mold air chamber is formed between the upper mold frame and the upper mold core, and a first spraying device is arranged at the top of the upper mold core; an air inlet is arranged at the top of the upper mold frame, a feeding port and an upper water inlet are arranged on the side wall, the inner surface of the bottom forms an angle θ with its lower surface, θ≥5°, and N first drainage ports are arranged on the side wall corresponding to the downward direction of the angle θ, N≥2;

[0013] The lower mold includes a lower mold frame and a lower mold core protruding from the top of the lower mold frame; a lower mold air chamber is formed between the lower mold frame and the lower mold core, and a second spraying device is arranged at the bottom of the lower mold core; an air inlet and a second drainage port are arranged at the bottom of the lower mold frame, and a lower water inlet is arranged on the side wall;

[0014] The upper mold frame and the lower mold frame are in contact through the guiding mechanism to form a closed space, and at the same time, a mold cavity is formed between the upper mold core and the lower mold core;

[0015] One end of the feeding port is communicated with the upper mold core, and the other end is used to connect with an external filling device to fill EPS beads into the mold cavity;

[0016] Air plugs are respectively arranged on the upper mold core and the lower mold core to discharge the air between the EPS beads in the mold cavity to avoid insufficient filling of the EPS beads;

[0017] The air inlets of the upper mold frame and the lower mold frame are respectively used to connect with a steam source to supply steam to the upper mold air chamber, the lower mold air chamber, and the mold cavity, so that the EPS beads form a lost foam to be cast in the mold cavity;

[0018] The outer ends of the upper water inlet of the upper mold frame and the lower water inlet of the lower mold frame are respectively used to connect with a cooling water source, and the inner ends of the upper water inlet of the upper mold frame and the lower water inlet of the lower mold frame are respectively connected with the inlets of the first spraying device and the second spraying device, and are used to spray water and cool the upper mold air chamber and the lower mold air chamber until the preset demolding temperature is reached.

[0019] Further, it further includes a demolding mechanism; the demolding mechanism includes a demolding plate and demolding columns; the demolding plate is a hollow structure and is movably nested between the top of the lower mold frame and the lower mold core. Its upper surface is connected to one end of the demolding columns, and its lower surface is used to be connected to the driving end of an external cylinder; through holes adapted to the demolding columns are provided on the lower mold core; the demolding columns are arranged perpendicular to the demolding plate, and the other ends thereof are inserted into the lower mold core through the through holes and are integrated with the outer surface of the lower mold core, for driving the demolding plate to drive the demolding columns to eject the casting-to-be lost mold upward along the height direction of the lower mold frame to demold it after the casting-to-be lost mold is formed.

[0020] Further, the guiding mechanism includes guiding columns and guiding sleeves; the guiding columns are arranged on the outer edge of the top of the lower mold frame; the guiding sleeves are arranged on the outer edge of the bottom of the upper mold frame corresponding to the positions of the guiding columns. Blind holes adapted to the guiding columns are provided in the guiding sleeves, and the openings face downward and are sleeved on the upper ends of the guiding columns for guiding the upper mold frame during mold opening or demolding.

[0021] Further, it further includes a conforming apron; the cross-sectional shape of the conforming apron is adapted to the outer edge of the bottom of the casting-to-be lost mold. Its upper end is connected to the lower surface of the lower mold core, and its lower end is flush with the inner surface of the bottom of the lower mold frame; the air inlet and the second drain port of the lower mold frame correspond to the positions of the conforming apron; the second spraying device is arranged at the bottom of the lower mold core inside the conforming apron.

[0022] Further, both the first drain port and the second drain port are used to be connected to a negative pressure water pumping device for efficient drainage.

[0023] Further, there are 4 sets of the guiding mechanisms. The effective height of each set of guiding mechanisms is 30 mm to 40 mm, and the material is tin bronze QSn4-3; θ = 5°, N = 2; the steam temperature range is 170 °C to 190 °C; the preset demolding temperature is below 40 °C; the diameter of the air plug is 4 mm or 6 mm or 8 mm, and the diameter of the pinhole on the air plug is 0.5 mm.

[0024] Further, the demolding columns include a plurality of arc-shaped protrusions, a plurality of cylinders and a plurality of cuboids.

[0025] Meanwhile, the present invention also provides a forming method for the above-mentioned lost mold casting model, which is characterized in that it includes the following steps:

[0026] 1] Mold closing: Fix the lower mold on the fixed template of the molding machine and fix the upper mold on the moving template of the molding machine. Move the moving template of the molding machine to close the upper mold and the lower mold.

[0027] 2] Preheating: Preheat the upper mold and the lower mold simultaneously.

[0028] 3] Feeding: Fill EPS beads into the mold cavity through the feeding port.

[0029] 4】Steam heating: Open the steam source, supply steam to the upper mold chamber, lower mold chamber and mold cavity through the air inlet of the upper mold frame, the air inlet of the lower mold frame and the air plug, discharge the air between the EPS beads in the mold cavity until the closed space reaches the preset air pressure and maintains it, so that the EPS beads are heated and softened and expand again to bond with each other to form a lost mold to be cast, and then close the steam source;

[0030] 5】Water cooling: Open the cooling water source, and at the same time, pass the cooling water into the upper mold chamber, lower mold chamber and mold cavity through the upper water inlet of the upper mold frame, the lower water inlet of the lower mold frame, the first spraying device, the second spraying device and the air plug, spray and cool the lost mold to be cast until it reaches its preset demolding temperature, and then close the cooling water source to complete the casting of the lost mold casting model.

[0031] Further, step 3】 is specifically:

[0032] Use a compressed air feeder to blow the pre-expanded EPS beads into the mold cavity through the feeding port. After the EPS beads fill the entire mold cavity, immediately plug the feeding port with a feeding plug; in step 4】, the preset air pressure is 0.05MPa - 0.07MPa, and the holding time is 50s - 60s.

[0033] Further, it also includes 6】 Mold opening and demolding:

[0034] 6.1 Use the moving template of the molding machine to open the upper mold;

[0035] 6.2 Use the cylinder to drive the demolding template to drive the demolding column to push out the lost mold to be cast from bottom to top along the height direction of the lower mold frame to demold it, and complete the casting of the lost mold casting model.

[0036] Advantages of the present invention:

[0037] 1. For the lost mold casting model of the present invention, an included angle θ is formed between the inner surface of the bottom of the upper mold frame and its lower surface, θ≥5°, and N drain ports are provided on the side wall corresponding to the downward inclined direction of the included angle, which can quickly drain the water in the upper mold, thereby improving the molding efficiency. Compared with the existing mold, the drainage time is about 3 minutes, and a large amount of water will spray out when the mold is opened. The lost mold casting model of the present invention has the advantages of fast drainage time, about 1 minute, and no water spraying when the mold is opened, which not only saves the molding time, but also improves the on-site working environment.

[0038] 2. The lost foam casting model of the present invention isolates the mold area in the lower mold frame that does not participate in molding (i.e., the lower mold air chamber that does not participate in molding) with a conforming apron. Such an operation will reduce the volume of the lower mold air chamber, and the steam utilization rate can be increased by more than 20%, thus greatly saving resources. With the increase in the steam utilization rate, the heating time of EPS beads is also shortened, from about 90 s originally to about 60 s, and the molding efficiency is also improved; it solves the problem that the traditional mold air chamber is formed by enclosing the mold frame, which usually presents a regular rectangle, and the volume participating in molding in the air chamber is relatively small, while the volume of other areas not participating in molding is relatively large, resulting in a slow rise in steam pressure and a slow increase in the temperature of the mold and EPS beads during the molding process, seriously affecting the molding efficiency.

[0039] 3. The lost foam casting model of the present invention uses a demolding mechanism. After the lost foam to be cast is molded, the cylinder is used to drive the demolding plate to drive the demolding column to eject the lost foam to be cast upward along the height direction of the lower mold frame, making the force evenly distributed, enabling accurate demolding, improving production efficiency, and reducing unqualified products.

[0040] 4. The lost foam casting model of the present invention sets the guide posts on the outer edge of the top of the lower mold frame and the guide sleeves on the outer edge of the bottom of the upper mold frame. Four sets of guiding mechanisms are set on the mold, and their effective height is 30 mm - 40 mm, which can accurately position and guide the mold to prevent damage to the mold during mold closing.

[0041] 5. The lost foam casting model of the present invention. Both the first drain port and the second drain port are used to connect to a negative pressure water pumping device, and thus the cooling water can be drained faster.

[0042] 6. The molding method of the lost foam casting model of the present invention can accurately control the closing of the upper mold and the lower mold, shorten the time of the cooling and molding links in the production process, and greatly improve production efficiency. Brief Description of the Drawings

[0043] Figure 1 is a schematic structural diagram of an embodiment of a lost foam casting model of the present invention;

[0044] Figure 2 is a schematic structural diagram of the top of the upper mold frame and the upper mold core in an embodiment of a lost foam casting model of the present invention;

[0045] Figure 3 is a schematic structural diagram of the upper mold frame, the upper mold core and the first spraying device in an embodiment of a lost foam casting model of the present invention;

[0046] Figure 4 is a schematic structural diagram of the bottom of the upper mold frame, the upper mold core and the guide sleeve in an embodiment of a lost foam casting model of the present invention;

[0047] Figure 5 It is a schematic structural diagram of a lower die frame, a lower die core and a guide post in an embodiment of a lost foam casting model of the present invention;

[0048] Figure 6 It is a schematic structural diagram of a lower die frame, a lower die core and a second spraying device in an embodiment of a lost foam casting model of the present invention;

[0049] Figure 7 It is a schematic structural diagram of a demoulding mechanism in an embodiment of a lost foam casting model of the present invention.

[0050] Explanation of reference numerals: 1 - upper die, 11 - upper die frame, 12 - upper die core, 13 - first spraying device, 14 - feeding port, 2 - lower die, 21 - lower die frame, 22 - lower die core, 23 - second spraying device, 24 - contoured fence, 3 - guiding mechanism, 31 - guide post, 32 - guide sleeve, 4 - air inlet, 51 - upper water inlet, 52 - lower water inlet, 6 - first drain port, 7 - demoulding mechanism, 71 - demoulding plate, 72 - demoulding post. Detailed implementation manners

[0051] As Figures 1 to 4 shown, a lost foam casting model includes an upper die 1 fixed on a movable template of a molding machine, a lower die 2 fixed on a fixed template of the molding machine, multiple sets of guiding mechanisms 3, a contoured fence 24 and a demoulding mechanism 7; the upper die 1 includes an upper die frame 11 and an upper die core 12 nested inside the upper die frame 11; an upper die air chamber is formed between the upper die frame 11 and the upper die core 12, and a first spraying device 13 is arranged at the top of the upper die core 12; an air inlet 4 is arranged at the top of the upper die frame 11, a feeding port 14 and an upper water inlet 51 are arranged on the side wall, an included angle θ is formed between the inner surface of the bottom and its lower surface, θ≥5°, and two first drain ports 6 are arranged on the side wall corresponding to the downward direction of the included angle θ.

[0052] As Figure 5 , Figure 6 shown, the lower die 2 includes a lower die frame 21 and a lower die core 22 protruding from the top of the lower die frame 21; a lower die air chamber is formed between the lower die frame 21 and the lower die core 22, and a second spraying device 23 located inside the contoured fence 24 is arranged at the bottom of the lower die core 22; the cross-sectional shape of the contoured fence 24 is adapted to the outer edge of the bottom of the lost foam to be cast, its upper end is connected to the lower surface of the lower die core 22, and its lower end is flush with the inner surface of the bottom of the lower die frame 21; an air inlet and a second drain port are arranged at the position of the bottom of the lower die frame 21 corresponding to the contoured fence 24, and a lower water inlet 52 is arranged on the side wall; both the first drain port 6 and the second drain port are used to be connected to a negative pressure water pumping device, and can drain water efficiently.

[0053] The upper die frame 11 and the lower die frame 21 are in contact with each other through the guiding mechanism 3 to form a sealed space, and at the same time, a die cavity is formed between the upper die core 12 and the lower die core 22. One end of the feeding port 14 is communicated with the upper die core 12, and the other end is used to be connected with an external filling device to fill EPS beads into the die cavity; air plugs are respectively arranged on the upper die core 12 and the lower die core 22 to discharge the air between the EPS beads in the die cavity to avoid insufficient filling of the EPS beads; the air inlet 4 of the upper die frame 11 and the air inlet of the lower die frame 21 are respectively used to be connected with a steam source to supply steam to the upper die air chamber, the lower die air chamber and the die cavity so that the EPS beads form a lost foam to be cast in the die cavity; the outer ends of the upper water inlet 51 of the upper die frame 11 and the lower water inlet 52 of the lower die frame 21 are respectively used to be connected with a cooling water source, and the inner ends of the upper water inlet 51 of the upper die frame 11 and the lower water inlet 52 of the lower die frame 21 are respectively connected with the inlet of the first spraying device 13 and the inlet of the second spraying device 23. The outlet of the first spraying device 13 is used to spray water from top to bottom on the upper die air chamber, and the outlet of the second spraying device 23 is used to spray water from bottom to top on the lower die air chamber for cooling until the preset demoulding temperature is reached.

[0054] As Figure 5 , Figure 7 shown, the demoulding mechanism 7 includes a demoulding plate 71 and demoulding columns 72; the demoulding plate 71 is a hollow structure and is movably nested between the top of the lower die frame 21 and the lower die core 22. Its upper surface is connected with one end of the demoulding columns 72, and its lower surface is used to be connected with the driving end of an external cylinder; through holes adapted to the demoulding columns 72 are arranged on the lower die core 22; the demoulding columns 72 are arranged perpendicular to the demoulding plate 71, and the other ends thereof are inserted into the lower die core 22 through the through holes and are integrated with the outer surface of the lower die core 22, and are used to push out the lost foam to be cast from bottom to top along the height direction of the lower die frame 21 by driving the demoulding plate 71 with a cylinder after the lost foam to be cast is formed so as to demould it. In order to make the lost foam to be cast be stressed evenly during demoulding, the demoulding columns 72 include a plurality of arc-shaped protrusions, a plurality of cylinders and a plurality of cuboids.

[0055] As Figure 4 , Figure 5 shown, the guiding mechanism 3 includes a guiding column 31 and a guiding sleeve 32; the lower end of the guiding column 31 is arranged on the outer edge of the top of the lower die frame 21; the guiding sleeve 32 is arranged on the outer edge of the bottom of the upper die frame 11 corresponding to the position of the guiding column 31. A blind hole adapted to the guiding column 31 is arranged in the guiding sleeve 32, and its opening faces downwards and is sleeved on the upper end of the guiding column 31 for guiding the upper die frame 11 during mold opening or demoulding.

[0056] In this embodiment, there are 4 sets of guiding mechanisms 3. The effective height of each set of guiding mechanism 3 is 30 mm to 40 mm, and the material is tin bronze QSn4-3; the steam temperature range is 170°C to 190°C; the preset demolding temperature is below 40°C; the diameter of the air plug is 4 mm or 6 mm or 8 mm, and the diameter of the pinhole on the air plug is 0.5 mm.

[0057] In the existing process for mold forming, mold forming is to fill the mold cavity with an air chamber with pre-expanded and matured EPS beads through a material gun. The mold is horizontally divided into two parts: the upper mold 1 and the lower mold 2. In a lost foam casting model of the present invention, superheated steam enters the mold cavity through the air plugs on the upper mold core 12 and the lower mold core 22, passes through the gaps between the EPS beads, drives out the air and condensed water therein, and quickly fills the space between the EPS beads and penetrates into the foam cells of the EPS beads. When the pressure in the foam cells, that is, the sum of the vapor pressure of the blowing agent, the saturated vapor pressure at the forming temperature, and the expansion pressure of the air, is much greater than the external pressure on the EPS beads, and the EPS beads are softened by heat, the EPS beads expand and foam again to form an integrated lost foam pattern to be cast. Subsequently, the upper water inlet 51 of the upper mold frame 11 and the lower water inlet 52 of the lower mold frame 21 are used to spray and cool the upper mold air chamber and the lower mold air chamber through the first spraying device 13 and the second spraying device 23 to the demolding temperature, cool and shape the lost foam pattern to be cast, and finally use the demolding mechanism 7 to demold to obtain the required foam plastic pattern.

[0058] An included angle θ is formed between the inner surface of the bottom of the upper mold frame 11 and its lower surface, θ = 5°, and 2 first drain ports 6 are provided on the side wall corresponding to the inclination direction of the included angle. First, the addition of the drain ports speeds up the drainage during the forming process of the lost foam pattern to be cast, improves the efficiency, and the drain ports can be connected to a negative pressure pumping device (negative pressure system) to accelerate the discharge of the cooling water during the forming process; second, a 5° slope is reserved in the drainage area of the upper mold 1, making the area near the drain port lower and the inner surface side of the upper mold frame higher than the other side, which is beneficial to the discharge of the cooling water during the forming process; finally, a follow-up apron 24 is added to the bottom of the lower mold core 22, and the follow-up apron 24 separates the mold cavity area from the area not participating in the forming, which will reduce the volume of the lower mold air chamber, increase the heating speed, improve the forming efficiency, improve the steam utilization rate, and save energy.

[0059] Through the above solutions, the daily output of a lost foam casting mold for a certain transmission housing can be increased from the original 84 molds per shift to 105 molds per shift, the production efficiency is increased by 25%, and the steam utilization rate is also improved, saving energy and reducing the production cost of the enterprise. Therefore, a lost foam casting model of the present invention has considerable economic benefits and promotional significance and is worthy of continued promotion and application in subsequent molds.

[0060] The specific steps of a forming method of the present invention based on the above lost foam casting model are as follows:

[0061] 1] Mold closing: Fix the lower mold 2 on the fixed template of the molding machine, fix the upper mold 1 on the moving template of the molding machine, move the moving template of the molding machine, and lower the upper mold 1 to close it with the lower mold 2;

[0062] 2] Preheating: Preheat the upper mold 1 and the lower mold 2 simultaneously. Preheating the upper mold 1 and the lower mold 2 before feeding can reduce the condensation of steam during the foaming and molding of EPS beads and shorten the foaming and molding time;

[0063] 3] Feeding: Fill the mold cavity with EPS beads through the feeding port 14;

[0064] Use a compressed air feeder to blow pre-expanded EPS beads into the mold cavity through the feeding port 14. After the EPS beads fill the entire mold cavity, immediately plug the feeding port 14 with a feeding plug;

[0065] 4] Steam heating: Open the steam source, supply steam to the upper mold chamber, the lower mold chamber and the mold cavity through the air inlet 4 of the upper mold frame 11, the air inlet 4 of the lower mold frame 21, and the air plug to discharge the air between the EPS beads in the mold cavity; Then, supply steam to the upper mold frame 11 and the lower mold frame 21 simultaneously until the closed space reaches a preset air pressure of 0.05 MPa to 0.07 MPa, and maintain it for 50 s to 60 s. Then close the steam source, so that the EPS beads are heated and softened and expand again to bond with each other to form a lost foam for casting;

[0066] 5] Water cooling: Open the cooling water source, and at the same time pass cooling water into the upper mold chamber, the lower mold chamber and the mold cavity through the upper water inlet 51 of the upper mold frame 11, the lower water inlet 52 of the lower mold frame 21, the first spraying device 13, the second spraying device 23 and the air plug, and spray and cool the lost foam for casting until it reaches its preset demolding temperature. Then close the cooling water source to complete the casting of the lost foam casting model;

[0067] 6] Mold opening and demolding:

[0068] 6.1 Open the upper mold 1 by using the moving template of the molding machine;

[0069] 6.2 Use the cylinder to drive the demolding plate 71 to drive the demolding column 72 to eject the lost foam for casting upward along the height direction of the lower mold frame 21 to demold it, ensure that the model of the lost foam for casting is separated from the lower mold core 22, and take it out to complete the casting of the lost foam casting model.

[0070] Using the forming method of the lost foam casting model of the present invention, there is no water spraying during mold opening after improvement. Compared with a large amount of cooling water spraying during mold opening before improvement, the on-site operation environment is greatly improved.

Claims

1. A lost foam casting model, characterized in that: It comprises an upper die (1), a lower die (2), and multiple sets of guide mechanisms (3); The upper mold (1) comprises an upper mold frame (11) and an upper mold core (12) nested in the upper mold frame (11); an upper mold air chamber is formed between the upper mold frame (11) and the upper mold core (12), and a first spray device (13) is arranged on the top of the upper mold core (12); an air inlet (4) is arranged on the top of the upper mold frame (11), a feed port (14) and an upper water inlet (51) are arranged on the side wall, an angle θ is formed between the inner surface of the bottom and its lower surface, θ≥5°, ​​and N first drain ports (6) are arranged on the side wall corresponding to the downward direction of the angle θ, N≥2; The lower mold (2) comprises a lower mold frame (21) and a lower mold core (22) protruding from the top of the lower mold frame (21); a lower mold air chamber is formed between the lower mold frame (21) and the lower mold core (22), and a second spray device (23) is provided at the bottom of the lower mold core (22); an air inlet (4) and a second water outlet are provided at the bottom of the lower mold frame (21), and a lower water inlet (52) is provided on the side wall; The upper mold frame (11) and the lower mold frame (21) are abutted against each other through the guide mechanism (3) to form a closed space, and a mold cavity is formed between the upper mold core (12) and the lower mold core (22); One end of the feeding port (14) is connected to the upper mold core (12), and the other end is used to connect to an external filling device to fill the mold cavity with EPS beads; The upper mold core (12) and the lower mold core (22) are respectively provided with air plugs for discharging air between the EPS beads in the mold cavity to avoid insufficient filling of the EPS beads; The air inlet (4) of the upper mold frame (11) and the air inlet (4) of the lower mold frame (21) are respectively used to supply steam to the upper mold air chamber, the lower mold air chamber and the mold cavity after being connected to a steam source so that the EPS beads form a lost mold to be cast in the mold cavity; The outer ends of the upper water inlet (51) of the upper mold frame (11) and the lower water inlet (52) of the lower mold frame (21) are respectively used to be connected to a cooling water source, and the inner ends of the upper water inlet (51) of the upper mold frame (11) and the lower water inlet (52) of the lower mold frame (21) are respectively connected to the inlet of the first spray device (13) and the inlet of the second spray device (23), so as to spray water to cool the upper mold air chamber and the lower mold air chamber until a preset demoulding temperature is reached.

2. The lost foam casting model according to claim 1, characterized in that: Also includes a demoulding mechanism (7); The demoulding mechanism (7) comprises a demoulding plate (71) and a demoulding column (72); The stripping plate (71) is a hollow structure and can be movably nested between the top of the lower mold frame (21) and the lower mold core (22), with its upper surface connected to one end of the stripping column (72) and its lower surface used to connect to the driving end of the external cylinder; The lower mold core (22) is provided with a through hole adapted to the demoulding column (72); The demoulding column (72) is arranged perpendicular to the demoulding plate (71), and the other end thereof is inserted into the lower mold core (22) through a through hole and is integrated with the outer surface of the lower mold core (22). It is used to drive the demoulding plate (71) with a cylinder to drive the demoulding column (72) to eject the lost mold to be cast from bottom to top along the height direction of the lower mold frame (21) to demould the lost mold to be cast.

3. The lost foam casting model according to claim 2, characterized in that: The guide mechanism (3) comprises a guide column (31) and a guide sleeve (32); the guide column (31) is arranged on the top outer edge of the lower mold frame (21); The guide sleeve (32) is arranged on the outer edge of the bottom of the upper mold frame (11) corresponding to the position of the guide column (31). A blind hole matched with the guide column (31) is arranged in the guide sleeve (32). The opening of the blind hole is sleeved on the upper end of the guide column (31) downward, and is used to guide the upper mold frame (11) when opening or demoulding.

4. The lost foam casting model according to claim 3, characterized in that: It also includes a form-fitting enclosure (24); the cross-sectional shape of the form-fitting enclosure (24) is adapted to the bottom outer edge of the lost foam to be cast, the upper end of the form-fitting enclosure (24) is connected to the lower surface of the lower mold core (22), and the lower end is flush with the bottom inner surface of the lower mold frame (21); The air inlet (4) and the second water outlet of the lower mold frame (21) correspond to the positions of the conformable enclosure plate (24); The second spray device (23) is arranged at the bottom of the lower mold core (22) inside the conformable enclosure (24).

5. The lost foam casting model according to claim 4, characterized in that: The first drain port (6) and the second drain port are both used to be connected to a negative pressure pumping device, so as to efficiently drain water.

6. The lost foam casting model according to claim 1, characterized in that: There are four sets of guide mechanisms (3), each set of guide mechanisms (3) has an effective height of 30 mm to 40 mm, and is made of tin bronze QSn4-3; The θ=5°, N=2; The steam temperature range is 170°C to 190°C; The preset demoulding temperature is below 40°C; The diameter of the air plug is 4 mm, 6 mm or 8 mm, and the diameter of the pinhole on the air plug is 0.5 mm.

7. The lost foam casting model according to claim 5, characterized in that: The demoulding column (72) comprises a plurality of arc-shaped protrusions, a plurality of cylinders and a plurality of cuboids.

8. A method for forming a lost foam casting model according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1] Mold closing: fix the lower mold (2) on the fixed template of the molding machine, fix the upper mold (1) on the movable template of the molding machine, move the movable template of the molding machine, and close the upper mold (1) and the lower mold (2); 2] Preheating: preheat the upper mold (1) and the lower mold (2) at the same time; 3] Feeding: Filling the mold cavity with EPS beads through the feeding port (14); 4] Steam heating: Turn on the steam source, supply steam to the upper mold air chamber, the lower mold air chamber and the mold cavity through the air inlet (4) of the upper mold frame (11), the air inlet (4) of the lower mold frame (21) and the air plug, and discharge the air between the EPS beads in the mold cavity until the enclosed space reaches a preset air pressure and maintains it, so that the EPS beads are softened by heat and expand again to bond to each other to form a lost mold to be cast, and then turn off the steam source; 5] Water cooling: Turn on the cooling water source, and at the same time, pass the cooling water into the upper mold air chamber, the lower mold air chamber and the mold cavity through the upper water inlet (51) of the upper mold frame (11), the lower water inlet (52) of the lower mold frame (21), the first spray device (13), the second spray device (23) and the air plug, spray and cool the lost foam to be cast until it reaches its preset demoulding temperature, and then turn off the cooling water source to complete the casting of the lost foam casting model.

9. The method for forming a lost foam casting model according to claim 8, characterized in that: Step 3] Specifically: Using a compressed air feeder to blow pre-foamed EPS beads into the mold cavity through a feeding port (14), and after the EPS beads fill the entire mold cavity, immediately plugging the feeding port (14) with a feeding plug; In step 4], the preset air pressure is 0.05MPa to 0.07MPa, and the holding time is 50s to 60s.

10. The method for forming a lost foam casting model according to claim 8, characterized in that: Also includes 6】Mold opening and demoulding: 6.

1. Use the molding machine to move the template and open the upper mold (1); 6.

2. The stripping plate (71) is driven by a cylinder to drive the stripping column (72) to push out the lost foam to be cast from bottom to top along the height direction of the lower mold frame (21) to demould the lost foam casting model, thereby completing the casting of the lost foam casting model.

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