A sand mold structure for a machine tool base casting

Abstract

The utility model discloses a sand mould structure is used in lathe base casting, aims at solving the problem that base blank is easy to deform and crack in the existing casting process, and the structure includes the base body made of foamed material, is provided with the tensile reinforcement structure between two vertical walls of base body, is provided with the bracing structure between two horizontal walls, is provided with the inclined strut structure between top triangle area and bottom front edge, these structures are constituted by foamed stick material, can solidify and form the internal framework first when cooling, and the deformation stress is resisted, the cooling structure is provided in the cavity of base body, and the cooling structure is constituted by the cooling pipe with spiral section, fixed plate and connecting rod, and the external connection air cooling system can actively accelerate sand core cooling, promotes its timely retreat, through the synergistic effect of structure strengthening and active cooling, the casting stress of casting is reduced, and the size precision and the yield of large -scale machine tool base blank are improved.

Description

Technical Field

[0001] This utility model relates to the technical field of lost foam casting, specifically a sand mold structure for casting machine tool bases. Background Technology

[0002] Large machine tools, especially the bases of vertical five-axis machining centers, typically employ an integrated frame structure to achieve extremely high static and dynamic rigidity and precision stability. These bases are characterized by large dimensions, uneven wall thickness, and complex internal cavities. Lost foam casting technology, due to its advantages of precise casting dimensions and small machining allowances, is considered an ideal process for producing such large and complex components. However, precisely because of its integrated frame design, the large distance between the two vertical walls and the presence of open triangular areas at the top lead to a significant deficiency in structural rigidity during the casting process. During pouring and cooling, the large sand core filling the cavity structure, due to its much slower cooling rate compared to the surrounding metal, cannot recede in time, generating continuous outward expansion stress on the two vertical walls, potentially causing internal stress or cracking in the casting. Simultaneously, weak areas of the structure are highly susceptible to deformation under uneven shrinkage stress. Existing technologies often attempt to improve this by adding external chills and optimizing risers and gating systems, but the effects are limited, failing to address the issues of heat insulation by the large sand core and the poor overall structural resistance to deformation. This results in a high risk of deformation and cracking in the finished castings, leading to a persistently high scrap rate and severely impacting production efficiency and cost control. Utility Model Content

[0003] The purpose of this invention is to provide a sand mold structure for casting machine tool bases. By setting up lost foam tie rods, support rods, diagonal braces, and sand core cooling structures, it effectively prevents cracking and deformation of large machine tool bases during the casting process, thereby improving the quality and stability of the castings.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a sand mold structure for casting machine tool bases, comprising a lost foam structure and a sand core structure. The lost foam structure includes a base body, which has two opposing vertical walls and two horizontal walls connecting the vertical walls, forming a frame structure with a cavity in the middle. The lost foam structure further includes: The tie structure, which is laterally connected between the two vertical walls, is configured to solidify before the vertical walls during the cooling process. The rib structure, vertically connected between the two transverse walls, is configured to solidify before the horizontal transverse walls during the cooling process; The diagonal bracing structure, connecting the protruding area of ​​the upper transverse wall of the base body and the leading edge of the lower transverse wall, is configured to solidify before the base body during the cooling process. The sand core structure includes a cooling structure, which is installed inside the sand core after the cavity is filled, to accelerate the cooling of the sand core, and is connected to an external air cooling system.

[0005] By incorporating tie rods, bracing rods, and diagonal bracing structures, stresses caused by uneven cooling and sand core obstruction can be effectively resisted and dispersed during the casting process, structurally preventing casting deformation. Simultaneously, the cooling structure within the cavity actively accelerates sand core cooling, causing it to recede promptly and reducing the risk of cracking at its source. These structural elements work synergistically to ensure the forming quality of large frame structure castings.

[0006] In a further technical solution, the cooling structure includes multiple cooling pipes, a fixing plate, a connecting rod, and a connecting plate. The cooling pipes have a spiral section and a connecting section. The fixing plate is used to fix the cooling pipes. The connecting rod and the connecting plate are used to connect the fixing plate to form an integral cooling structure.

[0007] The cooling pipes feature a spiral section design, increasing the contact area with the sand core and improving cooling efficiency. Multiple cooling pipes are assembled into an integral structure using fixing plates and connecting rods, ensuring the structural rigidity and stability of the cooling structure during sand filling and pouring, preventing displacement or deformation.

[0008] In a further technical solution, the cooling pipes are arranged in several rows, distributed from top to bottom, with several cooling pipes in each row.

[0009] The cooling pipes are arranged in multiple rows, which can cover different heights of the sand core in the vertical direction, achieving three-dimensional and uniform cooling of the sand core, avoiding local overheating or cooling blind spots, and further balancing the overall cooling and contraction process.

[0010] A further technical solution is that each of the cooling pipes is provided with a plurality of spiral segments.

[0011] Multiple spiral segments are set on each cooling pipe, which further extends the airflow path and heat dissipation surface, maximizing the heat exchange capacity of a single cooling pipe within a limited space and optimizing cooling efficiency.

[0012] In a further technical solution, the cooling structure also includes an air outlet pipe and an air inlet. The air outlet pipe is connected to the outlet of the cooling pipe, and the air inlet is located at the inlet of the cooling pipe for connecting to an external air-cooling system.

[0013] By setting up centralized air inlets and outlets, it is easy to connect quickly and reliably with external air-cooling systems, forming a closed forced convection cooling cycle, and realizing continuous heat exchange and discharge.

[0014] In a further technical solution, multiple fixing plates are provided, which are respectively fixed to both ends of each row of cooling pipes, and the fixing plates are fixedly connected to each other by connecting plates to increase the overall structural strength of the cooling structure.

[0015] Multiple fixing plates are fastened together by connecting plates, so that the entire cooling structure forms a high-strength integral skeleton, which enhances its resistance to pressure and impact in the loose casting sand environment and ensures the structural integrity and functional reliability throughout the casting process.

[0016] In a further technical solution, the reinforcing bar structure includes at least two first foam rods arranged in parallel, wherein the cross-section of the first foam rod is rectangular and its dimensions are 60mm×30mm to 80mm×40mm.

[0017] The tie rod structure uses parallel foam rods, which can form a stable and uniform tensile band between the two vertical walls. The specific size setting ensures that the foam rods can cool and solidify faster than the thick base vertical walls, so that they are formed before the main structure undergoes significant shrinkage deformation and play a rigid restraint role. At the same time, within this size range, it can also ensure stiffness and strength to bear tensile stress, effectively resist the tendency of the two vertical walls to open outward when the casting cools, and prevent deformation in the width direction of the casting.

[0018] In a further technical solution, the first foam rod material is provided in 4 groups, with 4 rods in each group, and they are evenly spaced along the length of the cavity.

[0019] The distribution of the first foam rod ensures that the base body receives almost equal rigidity support at any position along its entire length, thereby resisting the outward expansion stress caused by sand core obstruction and cooling contraction in all directions. This effectively prevents local deformation modes such as wave-like deformation or central bulging that may occur in the vertical wall. At the same time, the design of 16 foam rods provides sufficient structural rigidity while avoiding new shrinkage stress problems that may be caused by excessive metal volume. This achieves the best balance between rigidity and stress control, greatly improving the dimensional accuracy and consistency of large base castings.

[0020] In a further technical solution, the supporting structure includes at least two second foam rods arranged in parallel. The cross-sections of the second, third, and fourth foam rods are all rectangular, and their dimensions are all set to 30mm×30mm to 45mm×45mm.

[0021] The specific size range ensures that these ribs and diagonal braces have sufficient strength to effectively resist deformation stress, while avoiding the possibility of becoming new hot spots or generating excessive shrinkage stress due to excessively large cross-sections. The standardized size design of the second, third, and fourth foam rods simplifies the model preparation process, and it enables the rib structure and diagonal brace structure to work together to restrain the deformation trend of the base in the height direction and the protruding triangular area at the leading edge, enhancing the overall rigidity and dimensional stability of the entire frame structure during the cooling process, and effectively preventing shrinkage deformation of the casting in the vertical direction and twisting of the leading edge area.

[0022] In a further technical solution, the diagonal bracing structure includes two third foam rods and one fourth foam rod. One end of the third foam rod is connected to the protruding area of ​​the top horizontal wall of the base body, and the other end is connected to the edge of the bottom horizontal wall to form a triangular diagonal support. The fourth foam rod is laterally connected to the two third foam rods, and the two third foam rods are symmetrically arranged.

[0023] The diagonal bracing structure uses symmetrical third foam rods and connected fourth foam rods to form a stable triangular support frame in the weak triangular protrusion area, which enhances the rigidity of the area and effectively prevents the front wall from tilting or twisting during the cooling process.

[0024] In a further technical solution, the air-cooled system includes a compressor, a heat exchanger, a throttling expansion valve, and a fan.

[0025] It utilizes a mature and reliable air-cooling system to provide a cooling source, which is cost-effective and easy to maintain. Its forced convection heat exchange method is highly efficient and can quickly remove heat from the inside of the sand core, ensuring that the cooling structure continues to perform effectively.

[0026] In summary, this invention has the following beneficial effects: By combining internal reinforcing ribs with active cooling, it solves the technical problem of easy deformation and cracking of large machine tool bases in lost foam casting; the tie ribs, bracing ribs, and diagonal bracing structures are formed in the early stage of metal solidification, which is like building a prestressed skeleton inside the casting, actively resisting and guiding shrinkage stress, and suppressing deformation from a structural level; at the same time, the built-in cooling structure actively intervenes in the cooling process of the sand core through forced air cooling, so that it can shrink synchronously with the casting body, reducing the expansion stress that leads to cracking from the root; finally, this invention can significantly improve the dimensional accuracy and internal quality of the casting blank, reduce the scrap rate, reduce the allowance and correction time of subsequent machining, and has high practical and economic value. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a three-dimensional structural diagram of this application; Figure 2 This is a schematic diagram of the flipped three-dimensional structure of this application; Figure 3 This is a first side view of the present application; Figure 4 This is a schematic diagram of the second side view of Ben Shen; Figure 5 This is a three-dimensional structural diagram of the cooling structure of this application.

[0028] In the diagram: 10. Base body; 11. Tie structure; 12. Support structure; 13. Diagonal brace structure; 14. Cooling pipe; 15. Connecting rod; 16. Fixing plate; 17. Air outlet pipe; 18. Air inlet; 19. Connecting plate; 101. Protruding area; 111. First foam rod material; 121. Second foam rod material; 131. Third foam rod material; 132. Fourth foam rod material; 141. Spiral section; 142. Connecting section. Detailed Implementation

[0029] To more clearly illustrate the overall concept of this application, a detailed explanation is provided below with reference to the accompanying drawings.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0031] Furthermore, it should be understood in the description of this application that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", 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 application and simplifying the description, and are not intended to 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 the present invention.

[0032] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0034] like Figures 1-5 As shown, a sand mold structure for casting machine tool bases includes a lost foam structure and a sand core structure. The lost foam structure includes a base body 10, which is made of paraffin wax or foam material. The base body 10 is manufactured into the outline shape of a large machining center base, and its surface is coated with refractory material. After the model is buried in the sand box with casting sand, molten metal is poured into the model, causing the paraffin wax or foam constituting the model to vaporize. The molten metal occupies the position of the model in the sand mold. After cooling and solidification, the refractory material on the surface of the casting is removed. The resulting casting product has accurate dimensions, high surface finish, and small machining allowance, making it suitable for casting large machine tool bases.

[0035] In one embodiment, such as Figures 1 to 4 As shown, the base body 10 has two opposing vertical walls and two opposing horizontal walls, forming a frame structure with a cavity in the middle. A tie structure 11 is provided between the two vertical walls. The tie structure 11 is arranged horizontally and includes at least two first foam rods 111, with the two first foam rods 111 arranged in parallel. A support structure 12 is provided between the two horizontal walls. The support structure 12 is arranged vertically and includes at least two second foam rods 121, with the two second foam rods 121 arranged in parallel.

[0036] Specifically, the dimensions of the first foam rod should be such that its cooling rate is higher than that of the two vertical walls, allowing it to solidify first during the cooling process and form a reinforcing rib. In this embodiment, the cross-sectional area of ​​the first foam rod 111 is 60mm×30mm to 80mm×40mm, and it can be arranged in two to four vertical rows, with two to four rods per row, preferably in groups of four, evenly spaced along the front-to-back direction of the machine tool base, i.e., the length direction. The cooling structure is arranged between adjacent vertical rows of the first foam rod 111, and the number of cooling structures can be adjusted according to the number of rows of the first foam rod 111. For example, if there are two rows of the first foam rod 111, then there can be one cooling structure located between the two rows of the first foam rod 111. The dimensions of the second foam rod 121 should be such that its cooling rate is higher than that of the horizontal wall of the base body 10, allowing it to solidify first during the cooling process and form a supporting rib.

[0037] The horizontal wall at the top of the base body 10 protrudes outward, forming a protruding area 101. The protruding area 101 can be a triangular area. A diagonal bracing structure 13 is provided between the protruding area 101 and the leading edge of the bottom horizontal wall. The diagonal bracing structure 13 includes two third foam rods 131 and one fourth foam rod 132. One end of the third foam rod 131 is connected to the protruding area 101 of the horizontal wall, and the other end is connected to the edge of the bottom horizontal wall. The fourth foam rod 132 is laterally connected to the two third foam rods 131.

[0038] The dimensions of the second foam rod 121 to the fourth foam rod 132 are set to 30mm×30mm to 45mm×45mm. The number of the second foam rod 121 can be set to 4 to 8. The third foam rod 131 can be set to two. The fourth foam rod 132 can be set to one to two. The cooling rate of the third foam rod 131 and the fourth foam rod 132 is higher than the cooling rate of the base body.

[0039] The tie structure 11, the support structure 12, and the diagonal brace structure 13 are all integrally connected to the base body 10. Specifically, the first foam rod 111, the second foam rod 121, the third foam rod 131, and the fourth foam rod 132 are all pre-set on the base body 10, forming an integral foam model with the base body 10, and are integrally formed through an integral processing molding method.

[0040] The central cavity of the base body 10 needs to be filled with clay sand, which forms a large sand core. Because the sand core is too large, during the cooling process after pouring, the cooling rate of the sand core is lower than that of the molten iron. During cooling, the core does not retreat in time, which generates an outward expansion force on the two side walls of the base. In addition, the casting blank has a large casting stress and a high risk of cracking. Therefore, the sand mold structure also includes a sand core structure. The sand core structure includes a cooling structure installed in the sand core. The cooling structure is placed into the central cavity of the base body 10 and connected to the ventilation and cooling system through external pipelines. Then, clay sand is filled until the central cavity of the base body 10 is completely filled.

[0041] Specifically, refer to Figure 5 The cooling structure includes a cooling pipe 14, a connecting rod 15, and a fixing plate 16. The cooling pipe 14 is provided with a spiral section 141 and a connecting section 142. The spiral section 141 is used to increase the heat dissipation area. The fixing plate 16 is used to fix the cooling pipe 14. The connecting rod 15 is used to connect the fixing plate 16. The cooling structure includes multiple rows of cooling pipes 14. The cooling pipes 14 are connected to a ventilation and cooling system through pipes to form an airflow channel for heat dissipation.

[0042] The cooling pipe 14 is made of metal and can be coated with a fire-resistant coating to withstand high-temperature environments.

[0043] In one embodiment, the cooling pipes 14 are arranged in three rows from top to bottom, with three cooling pipes 14 in each row. Each cooling pipe 14 is provided with three spiral segments 141, which are connected and communicated through connecting segments 142. The cooling structure also includes an exhaust pipe 17 and an air inlet 18. The exhaust pipe 17 is connected to the outlet of the cooling pipe 14, and the air inlet 18 is provided at the inlet of the cooling pipe 14 for connecting to an external air-cooling system.

[0044] In one embodiment, the cooling pipes 14 are arranged in three rows from top to bottom, with three cooling pipes 14 in each row. Each cooling pipe 14 has three spiral segments 141. The rear end of the first cooling pipe 14 in the first row is connected and communicates with the rear end of the first cooling pipe 14 in the second row. The front end of the first cooling pipe 14 in the second row is connected and communicates with the front end of the first cooling pipe 14 in the third row. The rear ends of the three cooling pipes 14 in the third row are connected and communicated together through an air outlet pipe 17 for air outlet. Each cooling pipe 14 in the first row has an air inlet 18 at its front end for air intake. Two fixing plates 16 are provided at both ends of each row of cooling pipes 14 for fixing the cooling pipes 14. In this embodiment, a total of six fixing plates 16 are provided, which are respectively fixed to both ends of each row of cooling pipes 14.

[0045] In one embodiment, the three rows of fixed plates 16 are fixedly connected together by connecting plates 19, and the connecting plates 19 and fixed plates 16 are fixed by bolts, thereby increasing the structural strength of the entire cooling structure.

[0046] In this embodiment, the air-cooling system dissipates heat into the atmosphere through forced convection. The air-cooling system connects the air outlet 17 and the air inlet 18. When the air-cooling system is working, the fan accelerates the airflow and blows cold air into the cooling pipe 14 of the cooling structure, thereby improving the heat exchange efficiency, accelerating the cooling of the sand core, and preventing the cooling rate of the sand core from being lower than that of the molten iron. If the cooling is not timely, it will generate an outward expansion force on the two vertical walls of the base, causing the casting blank to deform and crack.

[0047] The working principle of a sand mold structure for casting machine tool bases is as follows: This deformation- and crack-resistant sand mold structure is achieved through the synergistic effect of the following two aspects: 1) Structural reinforcement and synchronous solidification: In key weak points of the base body, such as between the two vertical walls, between the horizontal walls, and the protruding triangular area 101 at the front, pre-installed tie rod structures 11, support rod structures 12, and diagonal bracing structures 13 made of foam rods of specific dimensions. These structures are all made of foam rods, which vaporize after casting and are filled by the molten metal. Because the cross-sectional dimensions of these rib structures are designed to cool and solidify much faster than the thicker base walls they connect to, these metal rib structures have already solidified and possessed sufficient strength while the base body is still shrinking. This provides strong tensile resistance and support to the shrinkage deformation of the main body wall, effectively resisting the casting stress caused by sand core obstruction and structural unevenness, and preventing deformation and hot cracking.

[0048] 2) Internal forced cooling accelerates sand core retreat: A cooling structure is embedded inside the cavity forming the huge sand core. This cooling structure, through an external air-cooling system, continuously supplies cooling airflow into the cooling pipe 14 after pouring, achieving active and forced heat dissipation of the sand core. This significantly accelerates the cooling speed of the sand core, enabling it to cool and shrink almost synchronously with the external casting body. The timely and uniform "retreat" of the sand core reduces its outward expansion force on the two vertical walls of the base, reducing the risk of casting cracking due to untimely cooling of the sand core.

[0049] Structural ribs are responsible for resisting and guiding stress, while internal cooling is responsible for reducing stress at the source, together ensuring the dimensional stability and integrity of large base castings during solidification and cooling.

[0050] The specific steps for using this sand mold structure in casting large machine tool bases are as follows: Step 1: Create a lost foam model: The basic outline of the base body 10 is made using foam material, including two vertical walls, two horizontal walls, and a protruding area 101 at the top.

[0051] Install foam rods at designated locations inside the model using methods such as gluing. Multiple first foam rods 111 are installed between the two vertical walls to form a tie structure 11.

[0052] Multiple second foam rods 121 are installed between the two transverse walls to form a rib structure 12.

[0053] A third foam rod 131 and a fourth foam rod 132 are installed between the top triangular protrusion area 101 and the bottom leading edge to form a diagonal bracing structure 13.

[0054] Step 2: Assemble the cooling system. Multiple cooling pipes 14 are assembled into a rigid cooling structure by means of a fixing plate 16 and a connecting plate 19, ensuring that the air inlet 18 and the air outlet 17 of each cooling pipe are correctly and unobstructed.

[0055] A fire-resistant coating is applied to the outer surface of the cooling pipe 14 to protect it so that it can work normally in a high-temperature molten metal environment.

[0056] Step 3: Shaping and Embedding the Box A fire-resistant coating is applied to the outer surface of the foam model of the base body 10 and then dried.

[0057] Place the prepared model into the sand box and begin filling it with clay sand.

[0058] When the clay sand is filled to a certain height, enough to fix the position of the cooling structure, the assembled cooling structure is placed smoothly in the predetermined position of the central cavity of the base model, that is, between the two adjacent rows of tie rod structures 11.

[0059] The air inlet 18 and air outlet 17 of the cooling structure are led to the outside of the sand box through pipelines and connected to the air cooling system.

[0060] Continue filling with clay sand until the entire model and cooling structure are completely buried, filled, and compacted.

[0061] Step 4: Pouring and Cooling Molten metal is poured into the model in the sand box. The high temperature of the molten metal causes the foam model, including the base body and all foam rods, to rapidly vaporize, and the molten metal takes its place.

[0062] The air-cooling system is started simultaneously, continuously supplying cooling airflow into the cooling structure. The airflow passes through the spiral section 141 of the cooling pipe 14, absorbs the heat of the sand core in the cavity and carries it away, forcibly accelerating the cooling of the sand core.

[0063] During this process, the thin-walled rib structure formed by the gasification of foam rod material solidifies first, playing a reinforcing role; at the same time, the internal sand core recoils rapidly under the action of the cooling structure, jointly preventing the casting from deforming and cracking.

[0064] Step 5: Unpacking and Cleaning After the casting has cooled to a temperature below 290°C in the sand box, it is opened from the box. This lower opening temperature helps the casting to complete more stress relief within the box.

[0065] Remove the casting, and remove the process ribs formed by tie rods, struts, and diagonal braces on the casting by cutting and other methods. Then, perform subsequent treatments such as sand removal and polishing on the casting to obtain a high-quality large machine tool base blank.

[0066] For any parts not mentioned in this application, existing technologies may be used or referenced.

[0067] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0068] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A sand mold structure for casting a machine tool base, comprising a lost foam structure and a sand core structure, wherein the lost foam structure includes a base body (10), the base body (10) having two opposing vertical walls and two horizontal transverse walls connecting the upper and lower vertical walls, forming a frame structure with a cavity in the middle, characterized in that, The lost foam structure also includes: A tie structure (11) is laterally connected between the two vertical walls; The bracing structure (12) is vertically connected between the two transverse walls; A diagonal bracing structure (13) connects the upper transverse wall protrusion area (101) of the base body (10) to the front edge of the lower transverse wall; The sand core structure includes a cooling structure, which is disposed inside the sand core after the cavity is filled, and is used to accelerate the cooling of the sand core.

2. The sand mold structure according to claim 1, characterized in that, The cooling structure includes multiple cooling pipes (14), a fixing plate (16), a connecting rod (15), and a connecting plate (19). The cooling pipes (14) have a spiral section (141) and a connecting section (142). The fixing plate (16) is used to fix the cooling pipes (14). The connecting rod (15) and the connecting plate (19) are used to connect the fixing plate (16).

3. The sand mold structure according to claim 2, characterized in that, The cooling pipes (14) are arranged in several rows, distributed from top to bottom, with several cooling pipes (14) in each row.

4. The sand mold structure according to claim 2, characterized in that, The cooling structure also includes an air outlet (17) and an air inlet (18). The air outlet (17) is connected to the outlet of the cooling pipe (14), and the air inlet (18) is located at the inlet of the cooling pipe (14) for connecting to an external air-cooling system.

5. The sand mold structure according to claim 1, characterized in that, The tie structure (11) includes at least two first foam rods (111), and the first foam rods (111) are arranged in parallel. The cross-section of the first foam rods (111) is rectangular, and its size is 60mm×30mm to 80mm×40mm.

6. The sand mold structure according to claim 5, characterized in that, The first foam rod (111) is provided in 4 groups, with 4 rods in each group, and is evenly spaced along the length of the cavity.

7. The sand mold structure according to claim 1, characterized in that, The rib structure (12) includes at least two second foam rods (121), and the second foam rods (121) are arranged in parallel.

8. The sand mold structure according to claim 7, characterized in that, The diagonal bracing structure (13) includes two third foam rods (131) and one fourth foam rod (132). One end of the third foam rod (131) is connected to the protruding area (101) of the top horizontal wall of the base body (10), and the other end is connected to the edge of the bottom horizontal wall to form a triangular diagonal bracing. The fourth foam rod (132) is horizontally connected to the two third foam rods (131), and the two third foam rods (131) are symmetrically arranged.

9. The sand mold structure according to claim 8, characterized in that, The cross-sections of the second foam rod (121), the third foam rod (131), and the fourth foam rod (132) are all rectangular, and their dimensions are all set to 30mm×30mm to 45mm×45mm.

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