A mineral casting and a method for producing and using the same

Abstract

The application discloses a mineral casting and a preparation method and application thereof, and belongs to the technical field of mineral casting. The mineral casting provided by the application is embedded with isotropic negative thermal expansion material. By embedding the isotropic negative thermal expansion material in the mineral casting, the thermal expansion coefficient of the mineral casting is reduced, the manufacturing precision is improved, and the isotropy of the obtained mineral casting is good, the deformation amount in each direction is uniform, and the mineral casting has wide application in machine tool manufacturing, building or transportation.

Description

Technical Field

[0001] This invention belongs to the field of mineral casting technology, and particularly relates to a mineral casting, its preparation method, and its application. Background Technology

[0002] Among the five key technologies of high-speed CNC machine tools, these are the structural design of the CNC machine tool, the high-speed electric spindle, the feed mechanism, the control system, and the safety protection system. A significant characteristic of high-speed machining CNC machine tools is their excellent dynamic characteristics, which need to be matched with the high machining accuracy and high-speed cutting of the machine tool. This places high demands on the local structural design of the machine tool body, requiring high precision, high rigidity, low inertia, low friction, high resonant frequency, and an appropriate damping ratio. To improve the structural rigidity and vibration resistance of the machine tool, and to reduce thermal deformation, the machine tool body is primarily constructed using welded structural components, employing cast iron (including Meehanite cast iron), natural granite, or mineral castings as the base components.

[0003] Cast iron has good fluidity, low volumetric and linear shrinkage, making it easy to obtain castings with complex shapes. Adding small amounts of alloying elements during casting can improve wear resistance. It has high internal friction and strong damping, resulting in good dynamic rigidity. Therefore, it is a commonly used machine tool body material for high-speed, high-precision CNC machine tools. Because of the high pouring temperature of cast iron, cast iron parts undergo significant shrinkage deformation during solidification. The accuracy after demolding is approximately 1–3 mm / m. To meet flatness requirements within 0.01 mm / m, the foundry needs to perform multiple stress-relief processes, milling, and grinding to achieve the required performance. Natural granite, due to millions of years of natural aging, has a relatively stable structure and is almost non-deformable. It is easy to process, achieving high and stable precision. It is not sensitive to temperature, has very low thermal conductivity and expansion coefficient, is non-conductive, non-magnetic, has good vibration absorption, does not rust, is corrosion-resistant, easy to use and maintain, and is low in cost.

[0004] With rapid economic development and the over-exploitation and use of resources, high-speed, high-precision CNC machine tools need to consider the environmental impact of their product lifecycle, maximizing the use of raw materials and energy, reducing hazardous waste and emissions of solids, liquids, and gases, improving operational safety, and eliminating environmental pollution. Since mineral castings are produced at room temperature, and compared to traditional cast iron, they offer advantages such as high damping coefficient, strong vibration resistance, good thermal stability, short production cycle, flexible design and manufacturing, low cost, and eco-friendliness and recyclability, gradually replacing cast iron and natural granite as the basic components of precision machine tools.

[0005] Generally, the crossbeam length of a high-speed, high-precision CNC machine tool is around 4 meters, with typical dimensions of 4 meters in length, 0.5 meters in width, and 0.5 meters in height. During the use of mineral castings, the coefficient of thermal expansion of the mineral castings is 11.5–14 × 10⁻⁶. -6 K -1 Compared to natural granite 4.61×10 -6 K -1 Due to the coefficient of thermal expansion, mineral castings exhibit greater variations in precision under the same temperature change, failing to meet the precision requirements of high-speed, high-precision CNC machine tools. Summary of the Invention

[0006] In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide a mineral casting with a low coefficient of thermal expansion, high manufacturing precision, good isotropy, and uniform deformation in all directions.

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned mineral castings.

[0008] A third objective of this invention is to provide an application of the above-mentioned mineral castings in the preparation of machine tools.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A first aspect of the present invention provides a mineral casting in which an isotropic negative thermal expansion material is embedded.

[0011] Negative thermal expansion (NTE) materials are compounds whose average linear or volumetric expansion coefficient is negative within a certain temperature range. NTE materials can be combined with general positive thermal expansion materials to prepare materials with controllable or zero thermal expansion coefficients. Based on their negative thermal expansion properties, materials can be classified into anisotropic and isotropic negative thermal expansion materials. Isotropic negative thermal expansion materials are those whose crystals contract along all three axes with the same coefficient of contraction as temperature increases. The isotropic nature of thermal expansion properties requires the compound to have an isotropic structure, i.e., cubic symmetry.

[0012] This invention effectively reduces the linear expansion coefficient of mineral castings by embedding isotropic negative thermal expansion material inside the castings, balances the excessive deformation caused by thermal expansion and contraction, and improves the isotropy of the castings, making the deformation in all directions uniform. This effectively solves the problem of excessive deformation of mineral castings under temperature change conditions and improves the casting accuracy of mineral castings.

[0013] Preferably, in the mineral casting, the isotropic negative thermal expansion material includes ZrW2O8, ZrP2O7, ZrV2O7, or Y2W3O. 12At least one of the following; more preferably, in the mineral casting, the isotropic negative thermal expansion material includes at least one of ZrW2O8, ZrP2O7 or ZrV2O7; even more preferably, in the mineral casting, the isotropic negative thermal expansion material is selected from ZrW2O8.

[0014] ZrW₂O₈ exhibits a large negative coefficient of thermal expansion (-8.9 × 10⁻⁶ K) over a wide temperature range (0.3–1050 K). -6 K -1 In a specific embodiment of the present invention, ZrW2O8 is used as an isotropic negative thermal expansion material. By embedding it in mineral castings, the linear expansion coefficient of the mineral can be effectively reduced, and controlled within 2 × 10⁻⁶. -6 K -1 Within this range, it is superior to the current natural granite 4.61×10 -6 K -1 The coefficient of linear expansion is low enough to meet the requirements for stable use of high-speed, high-precision CNC machine tools.

[0015] Preferably, the isotropic negative thermal expansion material is uniformly dispersed and embedded in the mineral casting.

[0016] Preferably, the number of embedding sites in the mineral casting is 5 to 12; more preferably 6 to 10; and even more preferably 7 to 9.

[0017] In a specific embodiment of the present invention, the embedding sites are uniformly distributed within the mineral casting. For example, in a specific embodiment of the present invention, the mineral casting is cuboid in shape, and the embedding sites are equidistantly distributed along the length of the mineral casting. If the mineral casting has other shapes, the embedding sites need to be set according to the actual shape so that the isotropic negative thermal expansion material is uniformly dispersed and embedded within the mineral casting.

[0018] By uniformly dispersing and embedding the isotropic negative thermal expansion material in the mineral casting, the properties of various parts of the mineral casting are made more uniform, reducing the possibility of large local deformation of the casting due to temperature changes and improving the casting accuracy.

[0019] In a specific embodiment of the present invention, the coefficient of thermal expansion of the mineral casting is 1×10⁻⁶. -6 ~2×10 -6 K -1 In a more specific embodiment of the present invention, the coefficient of thermal expansion of the mineral casting is 1.2 × 10⁻⁶. -6 ~1.9×10 -6 K -1 In an embodiment of the present invention, the coefficient of thermal expansion of the mineral casting is 1.4 × 10⁻⁶. -6~1.8×10 -6 K -1 .

[0020] Preferably, the mineral casting has a cavity.

[0021] This invention uses topology optimization to create a reasonable cavity in mineral castings, thereby reducing the mass of the mineral castings and increasing their specific strength. Compared with the structure of mineral castings without cavities, the mineral castings with cavities in this invention have lower density and higher specific strength.

[0022] In this invention, the cavity setting method needs to be flexibly designed according to the shape of the workpiece, and therefore is not particularly limited.

[0023] In a specific embodiment of the present invention, the specific stiffness of the mineral casting with a cavity is 1.55 × 10⁻⁶. 7 ~2×10 7 N·m / kg; In a more specific embodiment of the invention, the specific stiffness of the mineral casting with a cavity is 1.6 × 10⁻⁶. 7 ~1.8×10 7 N·m / kg; In a specific embodiment of the present invention, the specific stiffness of the mineral casting with a cavity is 1.62 × 10⁻⁶. 7 ~1.7×10 7 N·m / kg.

[0024] In a specific embodiment of the present invention, the mineral casting includes the following raw materials: an aggregate system and a resin system; the aggregate system includes coarse aggregate, fine aggregate and filler; the resin system includes organic resin, curing agent, diluent and toughening agent.

[0025] Furthermore, in the aggregate system, the coarse aggregate includes at least one of granite, pebbles, or limestone. This invention can use crushed stone such as granite, pebbles, or limestone as coarse aggregate, or other crushed stone; these are merely examples and are not intended to limit the material of the coarse aggregate. Similarly, it is understood that the specific types of fine aggregate, filler, organic resin, curing agent, diluent, and toughening agent described below are also examples and are not intended to limit the specific materials.

[0026] Furthermore, in the aggregate system, the fine aggregate includes silica sand, river sand, or a combination thereof.

[0027] In a specific embodiment of the present invention, the moisture content of the coarse aggregate and the fine aggregate is less than 0.5 wt%. The coarse aggregate and the fine aggregate should be fully dried.

[0028] Furthermore, in the aggregate system, the filler includes at least one of quartz powder, mica powder, calcium carbonate powder, or talc powder.

[0029] By adding the filler to mineral castings, not only can the amount of resin used be reduced and the cost lowered, but the physical and mechanical properties of the mineral castings can also be improved.

[0030] Furthermore, in the resin system, the organic resin includes at least one of epoxy resin, phenolic resin, or polyester resin; in a specific embodiment of the present invention, the organic resin is selected from epoxy resin; more specifically, it is bisphenol A type epoxy resin.

[0031] Furthermore, in the resin system, the curing agent is selected from aliphatic amine curing agents; in a specific embodiment of the present invention, the curing agent includes at least one of ethylenediamine, diethylenetriamine, or triethylenetetramine; in a specific embodiment of the present invention, the curing agent is selected from ethylenediamine.

[0032] Adding a curing agent can transform a linear thermoplastic material into a three-dimensional thermosetting material.

[0033] In a specific embodiment of the present invention, the diluent in the resin system includes organic solvents such as acetone, methyl ethyl ketone, cyclohexanone, benzene, or toluene; in a specific embodiment of the present invention, the diluent is selected from acetone.

[0034] In the resin system described in this invention, the diluent primarily reduces the viscosity of the organic resin and enhances its permeability. It also significantly improves the binder-encapsulating properties of the aggregate and effectively controls heat dissipation during the curing reaction. The effects are even more pronounced with a reasonable amount of diluent.

[0035] In a specific embodiment of the present invention, the toughening agent in the resin system is selected from rubber toughening agents; in a specific embodiment of the present invention, the toughening agent is selected from ethylene propylene rubber.

[0036] In the resin system described in this invention, the toughening agent can improve the toughness of the cured organic resin product, reduce heat loss during the curing reaction, and decrease the shrinkage rate of the material. The corresponding effects are even more significant with a reasonable amount of toughening agent.

[0037] Furthermore, the raw materials for preparing the mineral casting also include a reinforcement system. The reinforcement system further improves the strength and other properties of the mineral casting.

[0038] In a specific embodiment of the present invention, the reinforcement system may be added or not, depending on actual needs. Adding a reinforcement system can enhance the strength of mineral castings.

[0039] In a specific embodiment of the present invention, the reinforcing system includes at least one of steel fiber, glass fiber, or carbon fiber; in a specific embodiment of the present invention, the reinforcing system is selected from glass fiber.

[0040] A second aspect of the present invention provides a method for preparing the mineral casting described in the first aspect of the present invention, comprising the following steps: casting the raw material for preparing the mineral casting into a mold, embedding the isotropic negative thermal expansion material in the raw material, and obtaining the mineral casting after solidification.

[0041] In a specific embodiment of the present invention, the casting is carried out at room temperature; the room temperature described in the present invention is 20-30°C; more specifically, 24-26°C.

[0042] A third aspect of the present invention provides an application of the mineral castings described in the first aspect of the present invention in machine tool manufacturing, construction, or transportation.

[0043] Preferably, the machine tool is a CNC machine tool; more preferably, the CNC machine tool is a high-speed, high-precision CNC machine tool.

[0044] The beneficial effects of this invention are: by embedding isotropic negative thermal expansion material in mineral castings, this invention reduces the coefficient of thermal expansion of mineral castings, improves manufacturing precision, and the resulting mineral castings have good isotropy and uniform deformation in all directions, which has wide applications in machine tool manufacturing, construction or transportation.

[0045] Specifically, compared with the prior art, the present invention has the following advantages:

[0046] 1. This invention employs a specific isotropic negative thermal expansion material, combined with a specific embedding mass and number of embedding sites, to ensure that the isotropic negative thermal expansion material is uniformly and dispersedly distributed in the mineral casting, thereby significantly reducing the linear expansion coefficient of the mineral casting, down to as low as 2 × 10⁻⁶. -6 K -1 Within this range, it is superior to the current natural granite 4.61×10 -6 K -1 The coefficient of linear expansion is such that it meets the requirements for stable use of machine tools, especially high-speed and high-precision CNC machine tools.

[0047] 2. The present invention also uses topology optimization to set reasonable cavities in mineral castings, thereby reducing the mass of mineral castings and increasing their specific strength. Compared with the general mineral casting structure without cavities, the mineral castings with cavities in the present invention have lower density and higher specific strength.

[0048] 3. The mineral castings of this invention employ a room-temperature cold casting process. During the production of mineral castings, the heat generated during their own chemical reaction is generally utilized, without increasing additional energy consumption. Compared to cast iron parts, mineral castings can save approximately 30% of energy consumption during production. More environmentally friendly, mineral castings are fully recyclable and can therefore be used as building materials or road construction materials, reducing environmental impact, maximizing the utilization of raw materials and energy, reducing hazardous waste and emissions of solids, liquids, and gases, improving operational safety, and lowering environmental pollution. The mineral castings provided by this invention have wide applications in machine tool manufacturing, construction, and transportation. Attached Figure Description

[0049] Figure 1 This is a diagram showing the raw material composition for preparing the mineral casting according to a specific embodiment of the present invention.

[0050] Figure 2 The image shows a portion of the raw materials used in the preparation of the mineral castings according to a specific embodiment of the present invention.

[0051] Figure 3 The vibratory machine described in a specific embodiment of the present invention.

[0052] Figure 4 The steel casting mold coated with a release varnish is described in a specific embodiment of the present invention.

[0053] Figure 5 The image shows a physical sample of a mineral casting as described in a specific embodiment of the present invention.

[0054] Figure 6 The external structure 1 of the mineral casting described in a specific embodiment of the present invention.

[0055] Figure 7 The cavity structure 1 of the mineral casting described in a specific embodiment of the present invention.

[0056] Figure 8 The external structure 2 of the mineral casting described in a specific embodiment of the present invention.

[0057] Figure 9 The cavity structure 2 of the mineral casting described in a specific embodiment of the present invention.

[0058] Figure 10 This is a structural diagram of the mineral casting obtained in Embodiment 1 of the present invention.

[0059] Figure 11 This is a structural diagram of the mineral casting obtained in Comparative Example 1 of the present invention. Detailed Implementation

[0060] The following specific embodiments further illustrate the content of the present invention in detail. It should also be understood that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0061] It should be noted that the ZrW2O8 used in the embodiments of the present invention was purchased from Shanghai Gelin Technology Co., Ltd.

[0062] Compared with cast iron and natural granite, mineral castings have advantages such as high damping coefficient, strong vibration resistance, good thermal stability, short production cycle, flexible design and manufacturing, low cost, and environmental friendliness and recyclability. They are gradually replacing cast iron and natural granite as the basic components of precision machine tools. The mechanical properties of cast iron, mineral castings, and natural granite are shown in Table 1.

[0063] Table 1 Mechanical property parameters of cast iron, mineral castings, and natural granite

[0064]

[0065] In a specific embodiment of the present invention, the raw material composition for preparing the mineral casting is as follows: Figure 1 As shown, it includes an aggregate system, a resin system, and a reinforcement system. The aggregate system includes coarse aggregate, fine aggregate, and filler. The resin system includes organic resin, curing agent, diluent, and toughening agent.

[0066] In a specific embodiment of the present invention, the coarse aggregate in the aggregate system includes at least one of granite, pebbles, or limestone; in a specific embodiment of the present invention, the coarse aggregate is selected from granite.

[0067] In a specific embodiment of the present invention, the fine aggregate in the aggregate system includes silica sand, river sand, or a combination thereof; in a specific embodiment of the present invention, the fine aggregate is selected from silica sand.

[0068] In a specific embodiment of the present invention, the moisture content of the coarse aggregate and the fine aggregate is less than 0.5 wt%.

[0069] In a specific embodiment of the present invention, the filler in the aggregate system includes at least one of quartz powder, mica powder, calcium carbonate powder, or talc powder; in a specific embodiment of the present invention, the filler is selected from quartz powder.

[0070] In a specific embodiment of the present invention, the organic resin in the resin system includes at least one of epoxy resin, phenolic resin, or polyester resin; in a specific embodiment of the present invention, the organic resin is selected from bisphenol A type epoxy resin, with a degree of polymerization n of 0 to 2 and a flash point of less than 50°C.

[0071] In a specific embodiment of the present invention, the curing agent in the resin system includes aliphatic amine curing agents such as ethylenediamine, diethylenetriamine, or triethylenetetramine; in a specific embodiment of the present invention, the curing agent is selected from ethylenediamine.

[0072] In a specific embodiment of the present invention, the diluent in the resin system includes organic solvents such as acetone, methyl ethyl ketone, cyclohexanone, benzene, or toluene; in a specific embodiment of the present invention, the diluent is selected from acetone.

[0073] In a specific embodiment of the present invention, the toughening agent in the resin system is selected from rubber toughening agents; in a specific embodiment of the present invention, the toughening agent is selected from ethylene propylene rubber.

[0074] In a specific embodiment of the present invention, the reinforcement system may be added or not, depending on actual needs. Adding a reinforcement system can enhance the strength of mineral castings.

[0075] In a specific embodiment of the present invention, the reinforcing system includes at least one of steel fiber, glass fiber, or carbon fiber; in a specific embodiment of the present invention, the reinforcing system is selected from glass fiber.

[0076] In a specific embodiment of the present invention, the method for preparing the mineral casting includes the following steps: pouring the raw materials for preparing the mineral casting into a mold, embedding the isotropic negative thermal expansion material in the raw materials, and obtaining the mineral casting after solidification.

[0077] In a specific embodiment of the present invention, the casting is carried out at room temperature; the room temperature described in the present invention is 20-30°C; more specifically, 24-26°C.

[0078] In a specific embodiment of the present invention, the method for preparing the mineral casting includes the following steps:

[0079] (1) Add the preparation raw materials to the mixing and batching equipment, some of which are such as Figure 2 As shown, the aggregate system is concentrated after being filtered to precise dimensions and then mixed with precisely measured amounts of resin system and quenching agent, in a manner similar to... Figure 3 The mixture is quenched in the vibratory machine shown to obtain the subsequent casting mixture.

[0080] (2) A release varnish is sprayed onto the steel casting mold to obtain the following result: Figure 4 The image shows a steel casting mold coated with a release varnish. This release varnish also serves as the base coat for the workpiece; with proper vibration and curing, the casting can be directly molded after demolding.

[0081] (3) The casting mixture from step (1) is filled into a steel casting mold coated with a release varnish, and an isotropic negative thermal expansion material is embedded in the mold. After reasonable vibration and curing, the casting is directly formed after demolding, resulting in the following: Figure 5 The mineral casting shown. The number of embedment sites in the mineral casting is 5 to 12.

[0082] Various equipment parts, precision components, and connectors can be cast in steel molds, such as various cooling water pipes, air and hydraulic pipes, electrical pipes, and even guide rails, bolt components, guide plates, seat plates, load-bearing hook components, and other parts.

[0083] In a specific embodiment of the present invention, the coefficient of thermal expansion of the mineral casting is 1×10⁻⁶. -6 ~2×10 -6 K -1 .

[0084] In a specific embodiment of the present invention, the mineral casting is provided with a cavity.

[0085] The cavity configuration of this invention needs to be flexibly designed according to the shape of the workpiece, and therefore is not particularly limited.

[0086] In a specific embodiment of the present invention, the cavity can be configured as follows: Figures 6-9 As shown. Figure 6 A type of external structure 1 for mineral castings. Figure 7 for Figure 6 The cavity structure of the mineral casting shown is 1; Figure 8 2. A type of external structure for mineral castings. Figure 9 for Figure 8 The cavity structure of the mineral casting shown is 2.

[0087] Example 1

[0088] This example provides a mineral casting in which an isotropic negative thermal expansion material ZrW2O8 is embedded.

[0089] The raw materials for preparing the mineral casting are: an aggregate system comprising coarse aggregate, fine aggregate and filler; a resin system comprising organic resin, curing agent, diluent and toughening agent; and a reinforcement system.

[0090] The method for preparing the mineral casting described in this example includes the following steps:

[0091] (1) The raw materials are added to the mixing and batching equipment. The aggregate system is concentrated after being filtered through a precise size and mixed with a precisely measured amount of resin system and quenching agent. The mixture is then quenched in a vibratory machine to obtain the subsequent casting mixture.

[0092] (2) A release varnish is sprayed onto the steel casting mold to obtain a ready-to-use steel casting mold. The release varnish also serves as the base coat for the workpiece. After proper vibration and curing, the casting can be directly molded after demolding. In this example, the mold cavity is a cuboid structure with dimensions of 4 meters in length, 0.5 meters in width, and 0.5 meters in height.

[0093] (3) Fill the prepared steel casting mold with the casting mixture from step (1), and embed ZrW2O8 in the mold. After reasonable vibration and curing, the casting can be directly formed after demolding, resulting in the following: Figure 10 The mineral casting shown has eight embedding sites.

[0094] Example 2

[0095] The mineral casting provided in this example differs from that in Example 1 in that it also includes a cavity, the structure of which is as follows: Figure 9 As shown, it has a block-shaped hollow structure.

[0096] Comparative Example 1

[0097] The mineral casting provided in this example differs from that in Example 1 in that it does not contain an isotropic negative thermal expansion material. The mineral casting in Comparative Example 1 is as follows: Figure 11 As shown.

[0098] Comparative Example 2

[0099] The difference between the mineral casting provided in this example and Comparative Example 1 is that the mineral casting in this example does not have a cavity.

[0100] Performance testing

[0101] (1) Measure the density and specific stiffness of mineral castings.

[0102] (2) Measure the coefficient of linear expansion of mineral castings.

[0103] (3) Measure the deformation of the mineral casting in the X, Y, and Z directions; the X, Y, and Z directions are as follows: Figure 10 As shown, the length direction of the mineral casting is the X direction, the width direction is the Y direction, and the height direction is the Z direction.

[0104] The deformations of Example 1 and Comparative Example 1 in the X, Y, and Z directions are shown in Table 2.

[0105] Table 2 shows the deformation in the X, Y, and Z directions for Example 1 and Comparative Example 1.

[0106] X direction (μm) Y direction (μm) Z-direction (μm) Example 1 2.1 3.3 5.5 Comparative Example 1 9.1 8.1 17.3

[0107] As shown in Table 2, compared with Comparative Example 1 which did not embed isotropic negative thermal expansion material, Example 1, which embedded isotropic negative thermal expansion material in the mineral casting, resulted in mineral castings with similar deformation in the X, Y, and Z directions, more uniform performance in each direction, and good isotropy.

[0108] Furthermore, the coefficient of linear expansion of the mineral casting obtained in Example 1 is 2 × 10⁻⁶. -6 K -1 Within.

[0109] The density and specific stiffness of Example 2 and Comparative Example 2 are shown in Table 3.

[0110] Table 2. Density and specific stiffness of Example 2 and Comparative Example 2

[0111] <![CDATA[Density (kg / m 3 )]]> Specific stiffness (N·m / kg) Example 2 2450 16326531 Comparative Example 2 2825 15068493

[0112] As shown in Table 3, compared with Comparative Example 2 which did not have a cavity, Example 2, which had a cavity in the mineral casting, resulted in a mineral with a gradually lower density and a higher specific stiffness.

[0113] This invention reduces the coefficient of thermal expansion of mineral castings by embedding isotropic negative thermal expansion materials in the castings, thereby improving manufacturing precision. The resulting mineral castings exhibit good isotropy and uniform deformation in all directions, making them widely applicable in machine tool manufacturing, construction, and transportation.

[0114] This invention employs a specific isotropic negative thermal expansion material, combined with a specific embedding mass and number of embedding sites, to ensure that the isotropic negative thermal expansion material is uniformly and dispersedly distributed in the mineral casting. This significantly reduces the linear expansion coefficient of the mineral casting, potentially lowering it to as low as 2 × 10⁻⁶. -6 K -1 Within this range, it is superior to the current natural granite 4.61×10 -6 K -1 The coefficient of linear expansion is such that it meets the requirements for stable use of machine tools, especially high-speed and high-precision CNC machine tools.

[0115] This invention also uses topology optimization to set reasonable cavities in mineral castings, thereby reducing the mass of mineral castings and increasing their specific strength. Compared with the structure of mineral castings without cavities, the mineral castings with cavities in this invention have lower density and higher specific strength.

[0116] The mineral castings of this invention employ a room-temperature cold casting process. During production, the heat generated by the minerals' own chemical reactions is generally utilized, eliminating additional energy consumption. Compared to cast iron, mineral castings can save approximately 30% of energy consumption during production. More environmentally friendly, mineral castings are fully recyclable and can therefore be used as building materials or road construction materials, reducing environmental impact, maximizing the use of raw materials and energy, reducing hazardous waste and emissions of solids, liquids, and gases, improving operational safety, and lowering environmental pollution. The mineral castings provided by this invention have wide applications in machine tool manufacturing, construction, and transportation.

Claims

1. A mineral casting, characterized in that, An isotropic negative thermal expansion material is embedded in the mineral casting; the isotropic negative thermal expansion material is dispersedly embedded in the mineral casting, and the number of embedding sites in the mineral casting is 5 to 12. The mineral casting is cuboid in shape, and the embedding sites are equidistantly distributed along the length direction of the mineral casting.

2. The mineral casting according to claim 1, characterized in that, The isotropic negative thermal expansion material includes ZrW2O8, ZrP2O7, ZrV2O7, or Y2W3O. 12 At least one of them.

3. The mineral casting according to claim 2, characterized in that, The isotropic negative thermal expansion material is selected from ZrW2O8.

4. The mineral casting according to claim 1, characterized in that, The coefficient of thermal expansion of the mineral casting is 1×10⁻⁶. -6 ~2×10 -6 K -1 .

5. The mineral casting according to claim 1, characterized in that, The mineral casting has a cavity.

6. The mineral casting according to claim 5, characterized in that, The specific stiffness of the mineral casting is 1.55 × 10⁻⁶. 7 ~2×10 7 N·m / kg.

7. The mineral casting according to claim 1, characterized in that, The mineral casting comprises the following raw materials: an aggregate system and a resin system; the aggregate system comprises coarse aggregate, fine aggregate and filler, the filler comprising at least one of quartz powder, mica powder, calcium carbonate powder or talc powder; the resin system comprises organic resin, curing agent, diluent and toughening agent.

8. The method for preparing the mineral casting according to any one of claims 1 to 7, characterized in that, Includes the following steps: The raw materials for preparing mineral castings are poured into a mold, and the isotropic negative thermal expansion material is embedded in the raw materials. After solidification, the mineral castings are obtained.

9. The application of the mineral castings according to any one of claims 1 to 7 in machine tool manufacturing, construction or transportation.

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