Method for processing micro-castings based on embedded heat conductors and use thereof
By embedding a high thermal conductivity inlay heat conductor on the substrate to reconstruct the droplet temperature field, the problems of single droplet solidification morphology and shrinkage defects are solved, realizing precise control of multi-path solidification and complex morphology, which is suitable for the processing of micro castings of water-based, polymer and metal materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF SHANGHAI FOR SCI & TECH
- Filing Date
- 2026-05-25
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies have limited morphology control dimensions, lack universality and robustness during the solidification process of solidified droplets, making it difficult to achieve diverse topological structures, and materials with volume shrinkage are prone to forming shrinkage cavities.
By embedding a high thermal conductivity material into a heat conductor on the substrate, the internal temperature field of the droplet is reconstructed, forming a dual thermal gradient from the inside out and from the bottom up, which changes the solidification path and achieves multi-path solidification and morphological transformation.
It enables precise control of droplet morphology from a single tip to complex polygons, is applicable to a variety of materials, suppresses shrinkage defects, and improves the density and dimensional accuracy of products.
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Figure CN122298958A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of advanced manufacturing technology, specifically relating to a method for processing micro-cast parts based on embedded heat conductors and its application. Background Technology
[0002] The solidification process of a fixed droplet is a complex, unsteady physical process involving momentum transfer, energy exchange, and phase transition dynamics. This process is widely applied in many key technological fields, including cryogenic biomedical preservation, power battery thermal management, refrigeration engineering, metal additive manufacturing, and polymer microforming. In these applications, the geometry of the solidified droplet not only determines the surface roughness and fluid resistance but also directly affects the dimensional accuracy, mechanical properties, and functional characteristics of the subsequent products. Existing technologies have limited targeted research on the solidification process of fixed droplets, mainly focusing on theoretical studies. For example: Dang Q., Song M., Dang C., et al., Experimental Study on Solidification Characteristics of Sessile Urine Droplets on a Horizontal Cold Plate Surface under Natural Convection[J]. Langmuir: The ACS Journal of Surfaces and Colloids, 2022(25):38. This study investigated the natural convection solidification characteristics of fixed urine droplets on a horizontal cold plate; Kumar P., Subudhi S., Das AK, Understanding interfacial dynamics during freezing and melting of deposited and sessile water droplets[J]. Chemical Engineering Science, 2025, 307:121368. This study mainly focuses on the interfacial dynamics of contact line pinning and ice tip formation during the solidification / melting process; Mohammadipour OR, Duan X., A new lattice Boltzmann model. For liquid-solid phase transition and its application in the simulation of sessile droplet solidification-focusing on volume change[J].Journal of fluidmechanics, 2024, 978(000):33. Simulation of solidified droplet solidification process considering density change, etc.
[0003] Under traditional natural convection or conduction cooling conditions, the solidification of solidified droplets exhibits a high degree of path dependence. Since cold energy is typically transferred unidirectionally upwards from the substrate, a significant temperature gradient forms within the droplet, causing the solid-liquid interface to advance unidirectionally from the bottom up. Towards the end of solidification, due to the combined effects of volume change (expansion or contraction) and surface tension contraction, the residual liquid phase at the top of the droplet is often squeezed or drawn in and solidified, ultimately evolving into a characteristic "tip" structure (expanded material forms a pointed protrusion, while contracted material forms a pointed depression or crater). This singular evolutionary path results in extremely limited post-solidification morphology, making it difficult to meet the demands for diverse topologies in applications such as micro / nano optical device molding, precision casting, and polymer micromachining.
[0004] Currently, academia and industry often use substrate microstructure induction (such as the fabrication of micropillar arrays) or chemical coating modification (such as low surface energy coatings) to intervene in solidification behavior. However, existing technologies have revealed the following significant drawbacks in practical applications: First, the dimensions of morphological control are extremely limited.
[0005] Existing methods are mainly limited to static modification of the substrate boundary conditions, which are essentially two-dimensional inductions. Due to the lack of active programming capabilities for the overall three-dimensional temperature and flow fields of the droplet, the geometric evolution of the droplet tip still follows the natural laws of contraction or expansion, making it difficult to achieve a precise transformation from a single "point-like tip" to a "platform-like" or even more complex geometric structures.
[0006] Second, the regulatory measures lack universality and robustness.
[0007] Substrate-modification-dependent methods are often extremely sensitive to droplet size, material properties (volume change rate, thermal conductivity, supercooling sensitivity), and cooling rate. Once the operating conditions change, the preset shape control effect will be greatly reduced. Different material systems (water-based, polymer, metal) have vastly different properties, and there is an urgent need for a universal control method that can be applied across different material systems.
[0008] Third, shrinkage defects in polymer and metal microforming are difficult to suppress.
[0009] For materials with volume shrinkage (such as polymers and metals), shrinkage cavities and porosity form in the final solidification region during the final solidification stage, severely affecting the mechanical properties and dimensional accuracy of the finished product. Traditional processes rely on pressure holding for feeding or gate design, but their effectiveness is limited at the microscale.
[0010] Therefore, the industry urgently needs a universal control method that can overcome substrate limitations and achieve precise programming of droplet morphology throughout the entire space. Summary of the Invention
[0011] The purpose of this invention is to provide a method for machining micro-casting parts based on an embedded heat conductor and its application, thereby overcoming the technical bottleneck of the single and uncontrollable solidification morphology of solidified droplets in the prior art. This solution achieves precise control from topological mapping to complex three-dimensional morphology, while effectively suppressing shrinkage defects in volume-shrinkage materials, and is applicable to the machining of micro-casting parts from various materials such as water-based systems, polymer systems, and molten metals.
[0012] The objective of this invention is achieved through the following technical solution: The first aspect of this invention discloses a method for machining micro-cast parts based on embedded heat conductors, comprising the following steps: S1: The embedded heat conductor is placed on the substrate and thermally coupled to the substrate; S2: Apply the molten molding material to the embedded heat conductor and the substrate, so that the molding material completely covers the embedded heat conductor and spreads on the surface of the substrate; S3: The molding material is cooled by the substrate and the embedded heat conductor to obtain a micro casting; during the cooling process, the embedded heat conductor acts as the internal priority heat dissipation channel, reconstructing the temperature field distribution inside the molding material; in, The embedded heat conductor is a high thermal conductivity material, and the thermal conductivity of the embedded heat conductor is greater than that of the molded material.
[0013] Preferably, the geometric dimensions of the embedded heat conductor are in the range of millimeters to micrometers. in, The millimeter range is 1.0 to 9.0 mm, excluding 1.0 mm; The range of micrometers is 1~1000 μm.
[0014] Preferably, the shape of the embedded heat conductor includes a spherical embedded heat conductor, a polygonal embedded heat conductor, and an embedded heat conductor with a complex cross-sectional shape.
[0015] Preferably, when the embedded heat conductor is a spherical embedded heat conductor: the embedded heat conductor is prepared by machining, microfluidic technology or self-assembly process; When the embedded heat conductor is a polygonal embedded heat conductor: the embedded heat conductor is prepared by extrusion process or thin film lamination process; When the embedded heat conductor is a complex cross-sectional shape, the embedded heat conductor is prepared by two-photon polymerization micro / nano 3D printing, electroforming, or precision machining.
[0016] Preferably, when the embedded heat conductor is a spherical embedded heat conductor, the particle size range is 10 μm to 5000 μm; When the embedded heat conductor is a polygonal embedded heat conductor, the cross-sectional side length is 50 μm to 5000 μm.
[0017] Preferably, the material of the embedded heat conductor is selected from one or more of metallic and organic materials; in, The metallic material is selected from one or more of copper, aluminum, silver, and gold; The organic material is selected from graphene.
[0018] Preferably, the surface of the embedded heat conductor is pretreated to make the surface of the embedded heat conductor completely hydrophilic or liquid-loving. The surface of the substrate undergoes surface energy modulation pretreatment to enhance the wettability and stability of droplets on the substrate.
[0019] Preferably, the molding material is selected from water-based systems, polymer systems, or metal melts.
[0020] Preferably, the thermal coupling method includes making the embedded thermal conductor in direct contact with the substrate, coating the embedded thermal conductor and the substrate with thermally conductive adhesive, or micro-welding the embedded thermal conductor and the substrate.
[0021] The second aspect of the present invention discloses the application of a micro casting machining method based on an embedded heat conductor as described above in the preparation of micro castings.
[0022] The working principle of this invention is as follows: During solidification, the highly thermally conductive embedded heat conductor serves as the internal priority heat dissipation channel, reconstructing the temperature field distribution inside the droplet. This changes the original isotherm that advances unidirectionally from the substrate upwards into a dual thermal gradient distribution that is both "from the inside out" and "from the bottom up," laying the thermal foundation for subsequent multi-path solidification.
[0023] During solidification, two competing solidification fronts exist within the system: (1) a substrate-driven front that grows from bottom to top; and (2) an embedded thermally conductive front that grows from the inside out and from bottom to top, induced by the reconstructed thermal gradient. The two fronts eventually converge and aggregate near the shoulder of the solidified droplet, redistributing the volume change effect (expansion or contraction) originally concentrated at the tip to the shoulder region, thus realizing the topological transformation of the solidification tip into a macroscopic platform or complex polygon.
[0024] Compared with the prior art, the present invention has the following beneficial effects: 1) Pioneering "thermal gradient reconstruction" driven morphology design: It overturns the traditional approach of relying solely on substrate modification. By embedding a heat conductor, it "programs" the internal temperature field of the droplet, giving the user more control over the design of the solidification morphology. This represents a technological leap from passive adaptation to active control, allowing for the customization of droplet morphology according to target requirements.
[0025] 2) Upgraded topological regulation morphology: The topological transformation from "0-dimensional point" to "2-dimensional platform" and "3-dimensional polyhedron" at the solidification end was successfully realized, which significantly improved the complexity of morphology control and provided a new path for the low-cost preparation of complex microstructures.
[0026] 3) Universality across material systems: This invention is applicable to both volume-expanding materials (such as water-based systems with a volume expansion rate of about 9%) and volume-shrinking materials (such as polymer systems with a volume shrinkage rate of up to 35%; and metal melts with a volume shrinkage rate of 4~13%). It achieves morphology control through a unified thermal gradient reconstruction mechanism, solving the problem of traditional methods being difficult to transfer across materials.
[0027] 4) Effectively suppresses shrinkage defects: For materials with volume shrinkage, this invention disperses or guides shrinkage defects to non-functional areas by transferring the final solidification area from the top to the shoulder annular area, significantly improving the density and dimensional accuracy of the product.
[0028] 5) Establish quantitative design criteria: By establishing the ratio between the volume of the solidified phase dominated by the embedded heat conductor and the volume of the solidified phase dominated by the substrate, the precise quantitative characterization of the phase transformation evolution path is achieved, which greatly improves the yield and consistency of processed products.
[0029] 6) Pioneering a new path for self-assembly additive manufacturing: This invention enables the forming and processing of complex shapes such as the Reuleaux triangle. Based on a self-assembly process driven by physical laws, it provides a simplified solution for preparing geometric objects with special mechanical or optical properties at the microscale without the need for expensive precision machining equipment.
[0030] 7) Flexibility and scalability of the embedded heat conductor fabrication process: This invention can fabricate the required embedded heat conductors using various micro-nano fabrication methods such as microfluidics, self-assembly, extrusion, and thin-film processes, enabling flexible manufacturing across scales and geometries, from micrometer to sub-millimeter scales and from spherical to complex prismatic shapes. This "designable and customizable" characteristic allows the invention to adapt to the varying requirements of morphology control precision in different application scenarios, while providing a low-cost, high-throughput technical path for large-scale production. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the dual curing path evolution of the copper ball embedded in the water droplet in Example 1.
[0032] Figure 2 This is a three-dimensional frustum structure and contour variation view of the copper sphere embedded in the water droplet in Example 1.
[0033] Figure 3 This is a three-dimensional "tent-like" structure and outline variation view of the copper triangular prism embedded in the water droplet in Example 3.
[0034] Figure 4 This is a top view of the changing contour of the droplet tip morphology of the water droplet with an embedded copper equilateral triangular prism in Example 4, and its mapping relationship. Detailed Implementation
[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0036] Unless otherwise specified in the following description, the reagents used are conventional commercial products, the methods used are well-known in the art, and any other matters not covered herein may be handled using existing technologies.
[0037] This invention belongs to the fields of phase change heat transfer, interface science and advanced manufacturing technology. It aims to provide a method to reconstruct the internal temperature gradient of droplets during the cooling stage by introducing an embedded heat conductor with high thermal conductivity, thereby solving the technical bottleneck of single and uncontrollable droplet solidification morphology. Specifically, it involves a method to achieve the transformation of droplet solidification morphology from tip to plateau and complex polygon topology by embedding a high thermal conductivity embedded heat conductor inside the droplet and reconstructing the thermal gradient. This method is applicable to the high-precision forming and processing of micro castings of various materials such as water-based systems, polymer systems and metal melts.
[0038] A method for machining micro-cast parts based on embedded heat conductors includes the following steps: S1. Preparation and surface pretreatment of embedded heat conductor: S1.1 Preparation of embedded heat conductor: The embedded thermal conductor is a micro-nano-scale structure made of highly thermally conductive material, with geometric dimensions ranging from millimeter (1.0~9.0 mm, excluding 1.0 mm) to micrometer (1~1000 μm).
[0039] The fabrication method of the embedded heat conductor is selected based on the target geometry as follows: 1) Spherical Embedded Thermal Conductors: Millimeter-sized spheres can be fabricated using conventional machining methods. Smaller spheres are fabricated using microfluidic technology or self-assembly processes. Microfluidic methods utilize coaxial microchannels or flow-focusing structures to emulsify molten high thermal conductivity materials (such as low-melting-point metals or metal precursor solutions) in a continuous phase, followed by cooling and solidification to form monodisperse microspheres with precisely controllable particle sizes ranging from 10 to 500 μm. Self-assembly methods utilize surface tension to drive the formation of regularly arranged microsphere arrays under template guidance, which are then separated for use.
[0040] 2) Polygonal embedded heat conductors (equilateral triangular pillars, square pillars, etc.): These are prepared using extrusion or thin-film lamination processes. The extrusion process uses a micro-mold to extrude high thermal conductivity materials (such as metals like copper, aluminum, and silver, or graphene composite slurries), which are then cut to obtain micro-strip structures with specific cross-sectional shapes. The side length of the cross-section can be controlled within the range of 50–5000 μm. The thin-film lamination process involves forming micro-pillars of the desired cross-sectional shape from a high thermal conductivity material film through photolithography, etching, or laser processing, followed by peeling or cutting to obtain discrete embedded heat conductors.
[0041] 3) Other complex cross-sectional shapes of embedded heat conductors: These are prepared by two-photon polymerization micro / nano 3D printing, electroforming, or precision machining to meet specific topological morphology induction requirements.
[0042] S1.2 Surface pretreatment: The prepared embedded heat conductor and the substrate are respectively subjected to surface pretreatment: the surface pretreatment of the embedded heat conductor makes the surface of the embedded heat conductor reach a completely hydrophilic or liquid-philic state, ensuring that the molding material can be closely attached to it and eliminating the interfacial air gap thermal resistance; the surface energy regulation treatment of the substrate surface enhances the wettability and stability of the droplets (i.e., the molten molding material) on the substrate and prevents unexpected contact line desorption during solidification.
[0043] S2. Embedded heat conductor placement and thermal coupling: A pretreated, high thermal conductivity embedded heat conductor is embedded on the substrate surface at the expected central axis of the droplet, ensuring good thermal coupling between the bottom of the embedded heat conductor and the cold substrate (this can be achieved through thermally conductive adhesive, direct contact, or micro-welding). Then, a droplet is added to completely encapsulate the embedded heat conductor and spread it on the substrate surface, thereby creating additional directional heat dissipation channels inside the droplet.
[0044] S3. Thermal gradient reconstruction during the cooling phase: The substrate is cooled by an external cooling system, and the highly thermally conductive embedded heat conductor serves as the internal priority heat dissipation channel, reconstructing the temperature field distribution inside the droplet. This changes the original isotherm that advances unidirectionally from the substrate upwards into a dual thermal gradient distribution that is both "from the inside out" and "from the bottom up," laying the thermal foundation for subsequent multi-path curing.
[0045] During the cooling and solidification process: 1. Multipath induction and topological transformation during solidification: After the solidification process is initiated, two competing solidification fronts exist within the system: (1) a substrate-driven front that grows from bottom to top; and (2) an embedded thermally conductive front that grows from the inside out and from top to bottom under the influence of the reconstructed thermal gradient. The two fronts eventually converge and aggregate near the shoulder of the droplet, redistributing the volume change effect (expansion or contraction) that was originally concentrated at the tip to the shoulder region, thus realizing the topological transformation of the solidification tip into a macroscopic platform or complex polygon.
[0046] 2. Precise mapping of geometric shapes and fabrication of complex structures: By changing the cross-sectional geometry of the embedded heat conductor (such as equilateral triangular prism, square prism, cross shape, etc.), the continuous axisymmetry is broken, and the solidification interface is discretized into a specific number of topological features, so as to achieve precise control of the morphology after solidification and complete the forming and processing of micro castings.
[0047] Example 1 Water-based system – Spherical high thermal conductivity embedded material induces “freeze-loop” morphology construction: This embodiment demonstrates the dynamic process of reconstructing the internal thermal field of a water droplet using a high thermal conductivity copper sphere, thereby breaking the conventional sharp-cornered shape and generating a ring-shaped solidification platform. Water's solidification volume expansion rate is approximately 9%, forming a pointed protrusion under conventional conditions (horizontal cold plate). This embodiment achieves the morphological transformation through thermal gradient reconstruction.
[0048] S1. Surface pretreatment of the embedded material: A high-purity copper ball with a diameter of 2.0 mm was selected as the embedded heat conductor and ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 10 min each to remove surface oil.
[0049] After cleaning, the copper balls were treated with an oxygen plasma device for 5 minutes at a power of 100 W to make the surface of the copper balls completely hydrophilic (contact angle less than 10°).
[0050] After standardized cleaning, the substrate (silicon wafer) undergoes silanization treatment to regulate surface energy and ensure that droplets have a stable initial contact angle on its surface.
[0051] S2. Embedded heat conductor placement and thermal coupling: The pretreated copper spheres and silicon wafers were precisely placed in the center of a semiconductor cooling stage with a temperature control accuracy of 0.1℃, with the bottom of the copper spheres in direct contact with the substrate to achieve thermal coupling. Using a micropipette, 20 μL of deionized water was slowly added dropwise to the top of the copper spheres, allowing the droplets to completely coat the copper spheres and spread onto the substrate.
[0052] S3. Cooling and solidification process control: The external cooling system is activated, and its built-in PID controller stabilizes the cold stage temperature at -5℃. The ambient temperature is controlled at 25℃, and the relative humidity is below 50%. The copper spheres have a thermal conductivity of approximately 400 W / m·K, which is much higher than that of water (approximately 0.6 W / m·K). As a priority internal heat dissipation channel, they reconstruct the internal temperature field of the water droplets, forming a dual thermal gradient from the inside out and from the bottom up.
[0053] Morphological evolution and results: During the solidification stage, the substrate-driven upward ice front and the copper sphere-induced outward ice front compete and converge. Under conventional single-substrate cooling conditions, the ice front advances unidirectionally from bottom to top, and the volume expansion effect squeezes the residual liquid phase to the top, forming a tip. In this embodiment, as... Figure 1 , Figure 2 As shown, due to the reconstruction of the internal thermal gradient by the copper sphere, the two ice fronts converge near the droplet shoulder, guiding the volume expansion effect to the shoulder region to form a ring-shaped bulge (the topology of the frozen tip transforms into a macroscopic frozen platform). After solidification, the droplet shoulder forms a broad, flat platform, exhibiting clear and symmetrical axisymmetric solidification ring features when viewed from above. Simultaneously, due to... Figure 1 As can be seen from the structural schematic diagram reflecting the completion of solidification, this scheme achieves accurate quantitative characterization of the phase transformation evolution path by using the ratio of the volume of the solidified phase dominated by the embedded heat conductor to the volume of the solidified phase dominated by the substrate, thereby effectively improving the yield and consistency of processed products.
[0054] in conclusion: This embodiment verifies that by reconstructing the internal temperature field of a water droplet through an embedded high thermal conductivity object (copper ball), the traditional single pointed morphology can be transformed into a platform-like structure, proving the effectiveness of the present invention in water-based volume expansion material systems.
[0055] Example 2 Polymer System – Spherical High Thermal Conductivity Embedded Elements Inducing the Construction of a “Plateau” Morphology in Polymers: This embodiment demonstrates the kinetic process of reconstructing the internal thermal field of polyethylene glycol (PEG) melt using high thermal conductivity silver spheres, thereby breaking the conventional shrinkage tip morphology and generating a plateau-shaped solidification morphology. PEG 600 has a volume shrinkage rate of approximately 35%, which is much higher than that of water-based systems. Under conventional conditions, it forms significant tip depressions or shrinkage cavities. This embodiment achieves defect suppression and morphology transformation through thermal gradient reconstruction.
[0056] S1. Embedded object preparation and surface pretreatment: Embedded object preprocessing: High-purity silver microspheres with a diameter of approximately 2.0 mm were selected and prepared using a self-assembly process. The silver microspheres prepared by this method have a density greater than 96% and a surface roughness Ra < 0.3 μm. The silver microspheres were treated with oxygen plasma for 5 min at a power of 100 W to achieve a completely hydrophilic state on the surface. A copper sheet was used as the substrate, and surface energy modulation treatment was performed to ensure stable wettability of the polymer melt on its surface.
[0057] S2. Selection of experimental fluid: Polyethylene glycol (PEG) 600 was selected as the experimental fluid. PEG 600 is liquid at room temperature, with a molecular weight of 570–630 g / mol, a melting point range of 10–20 °C, and a solid density of approximately 1.12–1.13 g / cm³. 3 The liquid density is approximately 1.09 g / cm³. 3 (60~80℃), volume shrinkage rate is about 35%.
[0058] S3. Embedded object setup and thermal coupling: The pretreated silver spheres and copper substrate were precisely placed in the center of a semiconductor cooling stage with a temperature control accuracy of 0.1℃, with the bottom of the silver spheres in direct contact with the substrate to achieve thermal coupling. PEG 600 was heated to 60℃ to completely melt it, and 20 μL of the PEG melt was slowly added dropwise to the top of the silver spheres using a micropipette, so that the droplets completely enveloped the silver spheres and spread on the substrate.
[0059] S4. Cooling and solidification process control: The cooling system is activated, and the PID controller stabilizes the cold stage temperature at 0℃. The ambient temperature is maintained at 25℃. The thermal conductivity of the silver spheres is approximately 429 W / m·K, which is much higher than that of the PEG melt (approximately 0.3 W / m·K). As a priority internal heat dissipation channel, it reconstructs the internal temperature field of the PEG melt, forming a dual thermal gradient from the inside out and from the bottom up.
[0060] Morphological evolution and results: During the solidification stage, the substrate-driven upward solidification front and the silver sphere-induced outward solidification front compete and converge. PEG 600 has a volume shrinkage rate of approximately 35%. Under conventional single-substrate cooling conditions, the solidification front advances unidirectionally from bottom to top, and the volume shrinkage effect causes the residual liquid phase at the top to be drawn away, forming tip depressions or shrinkage cavities. In this embodiment, because the silver sphere reconstructs the internal thermal gradient, the two solidification fronts converge near the droplet shoulder, dispersing and guiding the volume shrinkage effect to the annular region of the shoulder, avoiding concentrated collapse in the central region. After solidification, a wide, flat platform forms at the top of the droplet, rather than the traditional tip depression morphology, significantly suppressing shrinkage cavities.
[0061] in conclusion: This embodiment verifies that by reconstructing the internal temperature field of a polymer melt using an embedded high thermal conductivity object (silver sphere), the traditional single-point shrinkage morphology can be transformed into a plateau-like structure. Since the volume shrinkage rate of polymer systems is much greater than that of water-based systems, the control effect of this invention has more significant technical value in polymer microforming, effectively suppressing casting defects such as shrinkage cavities and porosity.
[0062] Example 3 This embodiment is basically the same as Embodiment 1, the main difference being that the embedded heat conductor is a horizontally placed copper triangular prism; such as Figure 3 As shown, it yields a three-dimensional "tent" structure.
[0063] in conclusion: This embodiment verifies that by reconstructing the internal temperature field of a water droplet through an embedded high thermal conductivity object (horizontal copper triangular prism), the traditional single tip shape can be transformed into a three-dimensional "tent" structure, proving the effectiveness of the present invention in water-based volume expansion material systems.
[0064] Example 4 This embodiment is basically the same as Embodiment 1, the main difference being: the copper triangular prism with the embedded heat conductor placed vertically; such as Figure 4 As shown, it yields a Reuleaux triangle structure.
[0065] in conclusion: This embodiment verifies that by reconstructing the internal temperature field of a water droplet through an embedded high thermal conductivity object (vertical copper triangular prism), the traditional single tip shape can be transformed into a Reuleaux triangle structure. This demonstrates the effectiveness of the present invention in water-based volume expansion material systems and the feasibility of preparing geometries with special mechanical or optical properties at the microscale.
[0066] In summary, the solidification morphology control method based on embedded heat conductors proposed in this invention has the following industrial application potential: 1. Application in water-based systems: Ice crystal morphology control in cryobiomedicine (to reduce cell damage) and microstructure shaping in microfluidic chips.
[0067] 2. Applications of polymer systems: Suppression of shrinkage and improvement of dimensional accuracy in precision micro-injection molding, optimization of interlayer bonding and warpage control in 3D printing, defect-free molding of precision parts such as optical lenses, and encapsulation molding of phase change energy storage materials.
[0068] 3. Applications of molten metal: Shrinkage control in microcasting, melt pool morphology control in additive manufacturing, and forming and processing of micro-precision parts.
[0069] 4. Application of composite systems: The embedded material itself can be retained in the casting as a functional component (such as conductive, thermally conductive, or magnetic particles), achieving integrated structural-functional molding.
[0070] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A method for processing a micro casting based on an embedded heat conductor, characterized by, Includes the following steps: S1: The embedded heat conductor is placed on the substrate and thermally coupled to the substrate; S2: Apply the molten molding material to the embedded heat conductor and the substrate, so that the molding material completely covers the embedded heat conductor and spreads on the surface of the substrate; S3: The molding material is cooled by the substrate and the embedded heat conductor to obtain a micro casting; during the cooling process, the embedded heat conductor acts as the internal priority heat dissipation channel, reconstructing the temperature field distribution inside the molding material; in, The embedded heat conductor is a high thermal conductivity material, and the thermal conductivity of the embedded heat conductor is greater than that of the molded material.
2. The method of claim 1, wherein the method further comprises: The geometric dimensions of the embedded heat conductor are in the range of millimeters to micrometers. in, The millimeter range is 1.0 to 9.0 mm, excluding 1.0 mm; The range of micrometers is 1~1000 μm.
3. The method of claim 1, wherein the method further comprises: The shape of the embedded heat conductor includes a spherical embedded heat conductor, a polygonal embedded heat conductor, and an embedded heat conductor with a complex cross-sectional shape.
4. The method of claim 3, wherein the method further comprises: When the embedded heat conductor is a spherical embedded heat conductor: the embedded heat conductor is prepared by machining methods, microfluidic technology or self-assembly process; When the embedded heat conductor is a polygonal embedded heat conductor: the embedded heat conductor is prepared by extrusion process or thin film lamination process; When the embedded heat conductor is a complex cross-sectional shape, the embedded heat conductor is prepared by two-photon polymerization micro / nano 3D printing, electroforming, or precision machining.
5. The method of claim 4, wherein the method further comprises: When the embedded heat conductor is a spherical embedded heat conductor: the particle size range is 10 μm to 5000 μm; When the embedded heat conductor is a polygonal embedded heat conductor, the cross-sectional side length is 50 μm to 5000 μm.
6. The method of claim 1, wherein the method further comprises: The material of the embedded heat conductor is selected from one or more of metallic and organic materials; in, The metallic material is selected from one or more of copper, aluminum, silver, and gold; The organic material is selected from graphene.
7. The method of claim 1, wherein the method further comprises: The surface of the embedded heat conductor is pretreated to make it completely hydrophilic or liquid-loving. The surface of the substrate undergoes surface energy modulation pretreatment to enhance the wettability and stability of droplets on the substrate.
8. The method of claim 1, wherein the method further comprises: The molding material is selected from water-based systems, polymer systems, or metal melts.
9. The method of claim 1, wherein the method further comprises: The thermal coupling methods include direct contact between the embedded thermal conductor and the substrate, coating the embedded thermal conductor and the substrate with thermally conductive adhesive, or micro-welding the embedded thermal conductor and the substrate.
10. The application of the micro casting machining method based on embedded heat conductor as described in any one of claims 1 to 9 in the preparation of micro castings.