Cooling device for additive manufacturing and cooling method thereof

Abstract

The present application relates to the technical field of additive manufacturing, and discloses a cooling device for additive manufacturing and a cooling method thereof, which comprises a cooling pipeline, a water pump, a liquid level sensor, a volume adjusting member, a controller and a water tank; the cooling pipeline is communicated with the water tank, the water pump is connected in series on the cooling pipeline, the water pump can drive the cooling medium to flow through the water tank along the cooling pipeline, the liquid level sensor is arranged in the water tank, the volume adjusting member is arranged in the water tank, and the controller is in communication connection with the volume adjusting member and the liquid level sensor; the controller can acquire real-time height information of a deposition layer in additive manufacturing, and calculate a target height of a liquid surface according to a preset target relative position relationship between the liquid surface and the deposition layer; the controller receives a feedback signal of the liquid level sensor, and adjusts the actual height of the liquid surface to the target height of the liquid surface by controlling the volume change of the volume adjusting member. The cooling device can maintain a constant flow rate, and the liquid level height of the cooling medium can be dynamically adjusted according to the height of the deposition layer.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a cooling device and cooling method for additive manufacturing. Background Technology

[0002] Additive manufacturing is a technology that shapes components by depositing materials layer by layer. In metal additive manufacturing, the continuous input of high-energy heat sources leads to significant heat accumulation inside the component. If heat dissipation is not timely or uniform, this heat accumulation can easily cause problems such as excessive residual stress, coarse grains, uneven microstructure and properties, and even component deformation and cracking, severely restricting the forming quality of high-performance complex components.

[0003] To control heat input and improve forming quality, existing technologies often employ methods such as air cooling and liquid nitrogen cooling. Among these, immersion liquid cooling has attracted widespread attention due to the high specific heat capacity and cooling efficiency of liquids. However, in the additive manufacturing process, as material is deposited layer by layer, the height of the deposited layer continuously increases, which places demands on the dynamic adjustment of the liquid level in immersion cooling.

[0004] Existing immersion coolant level adjustment technologies mainly fall into two categories: Mechanical lifting type: For example, Chinese patent document CN209077788U discloses a system that uses a lifting platform to move the workpiece to maintain the distance between its top and the liquid surface. However, this method has a complex mechanical structure, and the movement of the workpiece during the deposition process may introduce vibration or positioning errors, interfering with the high-precision additive manufacturing process. During additive manufacturing, this system requires coordinated control of the additive manufacturing equipment and the lifting platform, making operation complex and technically challenging. Furthermore, this method is difficult to adapt to contact additive manufacturing methods such as friction stir additive manufacturing.

[0005] Flow regulation type: For example, Chinese patent documents CN105081321A and CN110654024A disclose methods to change the liquid flow rate through the water tank or to inject / drain water into the tank by adjusting the opening of the inlet / outlet control valve or by adjusting the power of the inlet / drain pump, thereby changing the liquid level. However, this method causes fluctuations in the flow rate of the cooling medium in the water tank. Changes in flow rate directly lead to changes in the convective heat transfer coefficient, disrupting the steady-state environment of heat exchange. In addition, the control precision and response delay of the above methods are insufficient to meet the requirements for precise control of heat input.

[0006] In existing technologies, adjusting the liquid level and maintaining a constant flow rate are a difficult contradiction to reconcile. Furthermore, for ordinary water tanks with large cross-sections, raising the liquid level by pumping in liquid has a slow response speed and low control precision, making it difficult to meet the needs of fine, layer-by-layer deposition.

[0007] Therefore, how to achieve rapid, precise, and non-invasive adjustment of the liquid level in the working area without interrupting the additive manufacturing process or changing the circulation rate of the cooling medium is a technical challenge that urgently needs to be solved in the field of auxiliary cooling for additive manufacturing. Summary of the Invention

[0008] The purpose of this invention is to design a cooling device and cooling method for additive manufacturing that can maintain a constant flow rate and dynamically adjust the liquid level according to the deposition layer height.

[0009] To achieve the above objectives, the present invention provides a cooling device for additive manufacturing, comprising: Cooling pipes, water pumps, level sensors, volume control components, controllers, and water tanks containing cooling media to provide an additive manufacturing working environment; The cooling pipe is connected to the water tank, the water pump is connected in series on the cooling pipe, the water pump can drive the cooling medium to flow through the water tank along the cooling pipe, the liquid level sensor is located in the water tank and can detect the liquid level height in the water tank, the volume adjustment component is located in the water tank, and the controller is communicatively connected to the volume adjustment component and the liquid level sensor respectively. The controller can acquire real-time height information of the deposited layer in additive manufacturing, and calculate the target height of the liquid surface according to the preset target relative position relationship between the liquid surface and the deposited layer; it receives the feedback signal from the liquid level sensor and adjusts the actual height of the liquid surface to the target height by controlling the volume change of the volume adjustment component.

[0010] Furthermore, the water tank includes a first chamber and a second chamber for providing an additive manufacturing working environment, which are connected sequentially from bottom to top. The minimum cross-sectional area of ​​the first chamber is greater than the maximum cross-sectional area of ​​the second chamber, and the volume adjustment member is located in the first chamber.

[0011] Furthermore, the longitudinal section of the water tank is convex, the first chamber defines a wide area in the lower half of the convex shape, and the second chamber defines a narrow and tall area in the upper half of the convex shape.

[0012] Furthermore, it also includes air pumps; The volume regulating component includes a housing and a pressure regulating chamber formed within the housing. The housing is a flexible bladder or a rigid cylinder with a piston. The air pump is connected to the pressure regulating chamber and can fill or discharge gas into the pressure regulating chamber. The air pump is communicatively connected to the controller.

[0013] Furthermore, it also includes a flow meter connected in series on the cooling pipe, and the flow meter is communicatively connected to the controller or the water pump.

[0014] Furthermore, it includes a support frame for supporting the additive manufacturing substrate, the support frame being disposed within the first cavity, and the maximum dimension of the support frame in the vertical direction being not less than the maximum dimension of the first cavity in the vertical direction, and the maximum cross-sectional area of ​​the support frame being less than the maximum cross-sectional area of ​​the second cavity, so as to allow for the flow of cooling medium.

[0015] Furthermore, the liquid level sensor is a non-contact ranging sensor or a contact liquid level sensor.

[0016] The present invention also provides a cooling method for additive manufacturing, comprising the following steps: S1 fixes the additively manufactured substrate in the water tank, starts the water pump, and injects cooling medium into the water tank to the initial liquid level. S2 sets the target relative position between the liquid surface and the deposition layer, and initiates additive manufacturing; During the additive manufacturing process, S3 acquires real-time height information of the deposited layer and calculates the target height of the liquid surface based on the relative position relationship of the target. It then compares the actual height of the liquid surface measured by the liquid level sensor with the target height of the liquid surface. S4 keeps the flow rate of the cooling medium flowing through the water tank constant, and changes its volume in the water tank by controlling the volume of the volume adjustment component, thereby driving the liquid level to rise or fall to the target liquid level height.

[0017] Furthermore, the relative positional relationship of the target includes a semi-immersion mode and a fully immersion mode: In semi-immersion mode, the liquid level is set below the lower surface of the deposition layer, and the height difference between the liquid level and the lower surface of the deposition layer remains constant; as the height of the deposition layer increases, the volume of the volume adjustment component is increased to actively raise the liquid level; In full immersion mode, the liquid level is set above the upper surface of the deposition layer, and the height difference between the liquid level and the upper surface of the deposition layer remains constant; when the volume of the deposition layer increases, causing the liquid level to rise passively above the target height, the volume adjustment component is controlled to decrease in volume to absorb the displaced liquid and thus lower the liquid level.

[0018] Furthermore, in step S3, the specific steps for obtaining the real-time height information of the deposition layer are as follows: Receive the layer height program signal from the additive manufacturing equipment; or It receives signals from visual sensors or ranging sensors that independently monitor the sediment layer.

[0019] The cooling device and cooling method for additive manufacturing according to embodiments of the present invention have the following advantages compared with the prior art: The cooling device and method for additive manufacturing according to embodiments of the present invention achieve non-invasive, internally variable volume adjustment of the liquid level by setting a volume regulating component inside the water tank and cooperating with closed-loop control of the controller. During the process of adjusting the liquid level to follow the growth of the deposition layer, it is not necessary to change the total flow rate and velocity of the cooling medium in the external cooling pipes, thus solving the technical problem of flow field fluctuations caused by adjusting inlet and outlet valves or pump power in the prior art. The present invention can achieve precise liquid level tracking while ensuring that the flow velocity and turbulence of the cooling medium remain constant throughout the additive manufacturing process, thereby providing a highly stable and uniform thermal environment for component forming and effectively eliminating residual stress gradients and differences in microstructure properties caused by uneven heat dissipation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the cooling device for additive manufacturing according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the longitudinal section of a cooling device for additive manufacturing according to an embodiment of the present invention; Figure 3 This is a diagram of frictional additive manufacturing of a cooling device based on an embodiment of the present invention in a constant flow and constant volume semi-immersion cooling environment. Figure 4 This is a diagram of friction stir additive manufacturing in an air-cooled environment based on existing technology; Figure 5 It represents the hardness distribution along the thickness direction of the deposited component under different cooling environments.

[0021] In the figure, 1 is the cooling pipe; 2 is the water pump; 3 is the liquid level sensor; 4 is the volume adjustment component; 5 is the controller; 6 is the water tank; 61 is the first chamber; 62 is the second chamber; 7 is the flow meter; 8 is the support frame; 9 is the additive manufacturing device; 91 is the substrate; and 92 is the deposition layer. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention 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 this invention.

[0024] In the description of this invention, it should be understood that the terms "connected," "linked," and "fixed," etc., used in this invention 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 or a welded 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, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] In this invention, the terms "first," "second," etc., are used to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this invention, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information.

[0026] Reference Figure 1 A cooling device for additive manufacturing according to an embodiment of the present invention includes: Cooling pipes, water pumps, level sensors, volume control components, controllers, and water tanks containing cooling media to provide an additive manufacturing working environment; The cooling pipes are connected to the water tank, forming a circulation loop for the cooling medium. A water pump is connected in series with the cooling pipes to drive the cooling medium through the water tank. During this process, the water pump maintains a constant flow rate of the cooling medium in the water tank through flow control, such as in conjunction with a frequency converter or flow valve. A liquid level sensor is located inside the water tank and can detect the liquid level. A volume regulating component is located inside the water tank and immersed in the cooling medium. The controller is communicatively connected to both the volume regulating component and the liquid level sensor.

[0027] The controller is configured to execute the following core logic: acquire real-time height information of the deposited layer during additive manufacturing, and calculate the current target liquid level height based on a preset target relative position relationship between the liquid surface and the deposited layer; simultaneously, receive feedback signals from the liquid level sensor, and control the volume adjustment component to physically expand or contract, thereby changing the volume occupied by the liquid in the tank and accurately adjusting the actual liquid level to the target height. This process constitutes a complete closed-loop control system of "sensing-calculation-execution-feedback." Compared to open-loop control, closed-loop control can eliminate minor liquid level errors caused by evaporation or splashing of the cooling medium in real time, ensuring liquid level accuracy during long-term printing processes.

[0028] In this embodiment, an internal volume regulator is used as the actuator to simultaneously achieve constant flow of the cooling medium and follow-up of the liquid level. Different from the traditional method of changing the liquid level by adjusting the inlet and outlet valves or pump power, when adjusting the liquid level of this device, there is no need to change the flow rate and velocity of the external cooling pipeline, thus ensuring the absolute stability of the heat exchange boundary conditions, that is, the velocity field, during the additive manufacturing process, and avoiding inconsistent heating and uneven performance of the components caused by velocity fluctuations. In addition, this internal variable volume adjustment method belongs to "non-invasive" control, and there is no need to insert any robotic arm or lifting platform into the narrow processing area, avoiding spatial interference with the high-energy beam and powder feeding and wire feeding mechanisms.

[0029] In some improved solutions of the present application, the water tank structurally includes a first chamber and a second chamber for providing an additive manufacturing working environment, which are connected in sequence from bottom to top. Among them, the minimum cross-sectional area of the first chamber is larger than the maximum cross-sectional area of the second chamber, and the volume regulator is installed and located in the first chamber.

[0030] The first chamber serves as a liquid storage and buffer chamber, accommodating the volume regulator and most of the cooling medium; the second chamber serves as a working chamber, specifically for accommodating the substrate and the growing deposition layer of additive manufacturing. This sub-chamber design makes rational use of space. The large-volume first chamber provides sufficient space for the deformation of the volume regulator, avoiding interference with the processing process in the upper second chamber; while the small cross-section second chamber is conducive to improving the sensitivity of liquid level control. This design also further ensures that the effective heat exchange volume of the cooling medium is always in the upper narrow and high area, with high flow velocity and fast renewal, greatly improving the heat exchange efficiency.

[0031] In a specific embodiment, the cooling pipeline includes an inlet pipe and an outlet pipe. The outlet end of the inlet pipe and the inlet end of the outlet pipe are both arranged on the side wall of the second chamber, so that the cooling medium forms a horizontal flow field flowing through the additive manufacturing working area in the second chamber. A heat exchanger or a heating and cooling integrated machine is also connected in series on the cooling pipeline. The heat exchanger or the heating and cooling integrated machine is communicatively connected to the controller and is used to maintain the temperature of the cooling medium in the cooling pipeline constant.

[0032] In some improved solutions of the present application, the longitudinal section of the water tank has a "convex" shape structure. The first chamber defines the wide lower part of the "convex" shape, and the second chamber defines the narrow and high upper part of the "convex" shape.

[0033] This structure creates a significant difference in cross-sectional area. In a specific embodiment, the upper cross-sectional area can be set to be 1 / 3 to 1 / 5 of the lower cross-sectional area, thus forming a "hydraulic amplifier" effect. This allows the volume change of the volume regulating component to amplify the height change within the second chamber. Due to the smaller cross-sectional area of ​​the upper region, a slight volume expansion of the lower volume regulating component forces liquid into the upper region, resulting in a significant and rapid rise in the liquid level. This not only improves the liquid level response speed but also reduces the stroke requirements of the volume regulating component, enhancing control precision. This means that a wider range of liquid level adjustment can be achieved using a smaller power air pump or a smaller airbag, reducing system energy consumption and cost.

[0034] In some improvements to this application, the device further includes an air pump or a hydraulic pump. The volume regulating component includes a housing and a pressure regulating chamber formed within the housing. The housing can be designed as a flexible bladder such as a rubber airbag, or a rigid cylinder with a piston. The air pump is connected to the pressure regulating chamber via an air pipe and is capable of inflating the pressure regulating chamber by filling it with gas or deflating it by expelling gas. The air pump is communicatively connected to the controller and receives control commands. In a specific embodiment, the initial state of the pressure regulating chamber is preferably a semi-inflated state to allow for bidirectional adjustment of inflation or deflation at any time.

[0035] The volume regulating component is driven by pneumatic or hydraulic means to achieve non-invasive liquid level regulation. The flexible bladder or piston structure is simple and reliable, with good sealing performance, and can raise or lower the liquid level solely through internal volume displacement without introducing external cooling medium, thus maintaining a constant total amount of cooling medium.

[0036] In some improvements to this application, the device further includes a flow meter. The flow meter is connected in series on the cooling pipe and is communicatively connected to the controller or the water pump. The flow meter monitors the flow rate in real time and feeds it back to the controller, which adjusts the water pump speed using an algorithm to form a closed-loop flow rate control.

[0037] To ensure that when the movement of the volume adjustment component causes local pressure changes in the water tank, the flow rate of the entire circulation system can still resist the disturbance and remain constant, thus ensuring consistent cooling.

[0038] In some improvements of this application, the apparatus includes a support frame for supporting the additive manufacturing substrate. The support frame is disposed within the first chamber, and its maximum dimension in the vertical direction is not less than the height of the first chamber in the vertical direction; that is, the support frame supports the substrate to the bottom or interior of the second chamber. The maximum cross-sectional area of ​​the support frame is smaller than the maximum cross-sectional area of ​​the second chamber to allow for the flow of cooling medium. In other improvements of this application, the support frame may also employ a mesh or perforated structure.

[0039] The support frame not only serves to fix the substrate, but its hollow or small cross-section design can ensure that the cooling medium in the first chamber can flow smoothly to the second chamber, preventing liquid surface fluctuations or local overheating caused by flow obstruction.

[0040] In some improvements of this application, the liquid level sensor is a non-contact ranging sensor such as a laser displacement sensor and an ultrasonic sensor, or it can be a contact liquid level sensor such as a magnetostrictive liquid level gauge or a hydrostatic liquid level gauge.

[0041] A specific embodiment of the present invention also provides a cooling method for additive manufacturing, based on the above-described apparatus, comprising the following steps: S1: Fix the additively manufactured substrate onto the support frame inside the water tank, start the water pump, and inject cooling medium into the water tank to the initial liquid level. At the same time, adjust the water pump through the flow meter feedback to establish and maintain a constant flow rate of the cooling medium.

[0042] S2: Set the target relative position between the liquid surface and the deposition layer in the controller, and start the additive manufacturing equipment.

[0043] S3: During the additive manufacturing process, real-time height information of the deposited layer is acquired, and the target liquid level height is calculated based on the relative position of the target. Simultaneously, the controller reads the actual liquid level height measured by the liquid level sensor in real time and compares the actual height with the target height. The height difference between the liquid level and the deposited layer is calculated by the controller based on the difference between the liquid level height measured by the liquid level sensor and the real-time height information of the deposited layer.

[0044] S4: Keep the flow rate of the cooling medium flowing through the water tank constant, and change its volume in the water tank by controlling the volume of the volume adjustment component, thereby driving the liquid level to rise or fall to the target liquid level height.

[0045] This method enables fully automated closed-loop control. Regardless of how the deposited layer grows, the liquid surface follows closely behind, maintaining a constant flow rate to flush the workpiece surface, ensuring a highly consistent solidification thermal environment for each metal layer. This high consistency is crucial for large and complex components, fundamentally suppressing microstructure and residual stress gradients caused by variations in heat dissipation conditions with height.

[0046] In some improvements of this application, the target relative positional relationship includes a semi-immersion mode and a fully immersion mode: In semi-submerged mode: the liquid level is set below the lower surface of the deposition layer, and the height difference between the liquid level and the lower surface of the deposition layer remains constant. As the deposition layer height increases, the controller controls the air pump to inflate the volume regulating component, increasing its volume and forcing the lower liquid into the upper region to actively raise the liquid level. In this mode, the real-time height information of the deposition layer is based on its lower surface.

[0047] In full immersion mode: the liquid level is set above the upper surface of the deposition layer, and the height difference between the liquid level and the upper surface of the deposition layer remains constant. In this mode, the newly added deposition material displaces the liquid, causing the liquid level to passively rise. At this time, the controller controls the air pump to vent air from the volume regulating component, reducing its volume to absorb the liquid displaced by the material accumulation, thereby actively lowering the liquid level and maintaining a constant immersion depth. In this mode, the real-time height information of the deposition layer is based on its upper surface.

[0048] This embodiment offers flexible process options. In particular, the reverse adjustment logic in the full immersion mode cleverly utilizes Archimedes' principle to solve the problem of uncontrollable liquid level rise as the workpiece volume increases in traditional immersion printing.

[0049] In some improvements of this application, the specific steps for obtaining the real-time height information of the deposition layer in step S3 are as follows: Receive the layer height program signal from the additive manufacturing equipment; or It receives signals from visual sensors or ranging sensors that independently monitor the sediment layer.

[0050] The former is simple and low-cost to implement, requiring no additional expensive measurement hardware; the latter can handle actual deviations during the printing process and provides more precise control.

[0051] To further illustrate the practical application effect of the present invention, a specific experimental embodiment based on friction stir additive manufacturing of 7075-T6 aluminum alloy is provided below: Experimental conditions: The cooling device described in this invention is used for friction stir additive manufacturing of 7075-T6 aluminum alloy particles.

[0052] Device configuration: The water tank is a stainless steel U-shaped structure. The upper second chamber has a cross-section of 320mm × 120mm and a height of 300mm; the lower first chamber has a cross-section of 320mm × 350mm and a height of 200mm. The volume adjustment component uses a corrosion-resistant rubber airbag and is placed in the lower first chamber. The liquid level sensor is a laser rangefinder sensor, vertically installed directly above the water tank. The controller communicates with the CNC system of the friction stir additive manufacturing equipment, receiving real-time data on the lower surface height of the deposition layer calculated based on a preset single-layer thickness of 3mm and the number of deposition layers.

[0053] Cooling parameters: The cooling medium is deionized water, the flow rate is set to a constant 12L / min, and the water temperature is controlled at 25±2℃.

[0054] Control mode: Select semi-immersion mode, and set the target relative position relationship as follows: the liquid level is always 3mm lower than the current deposition layer lower surface.

[0055] Process parameters: stirring head speed 500 rpm, traveling speed 100 mm / min, feeding rate 24 g / min.

[0056] Experimental procedure: After the system starts, the water pump maintains a constant flow of 12 L / min. As the stirring head carries particles and deposits layer by layer, after each layer (approximately 3 mm thick), the controller receives a signal indicating an increase in layer height and immediately drives the air pump to inflate a measured amount of gas into the rubber bladder. The bladder expands, forcing water from the first chamber into the second chamber, causing the liquid level to rise rapidly by 3 mm before returning to a position 3 mm below the bottom surface of the deposited layer. The water flow is smooth throughout the entire process, without any surging.

[0057] Experimental Results and Comparison: Shape and morphology (e.g.) Figure 3 and Figure 4 As shown): Under the constant current and constant volume semi-immersion cooling environment provided by this invention, the prepared 34mm high straight wall has a uniform side morphology and no collapse. In contrast, in the conventional air natural cooling environment, when deposited to the 6th layer (approximately 19mm high), severe softening occurs due to heat accumulation, resulting in collapse and flash.

[0058] Hardness distribution (e.g.) Figure 5 (as shown) This invention employs a semi-immersion mode, resulting in a flat Vickers hardness distribution curve along the height direction of the sample with minimal fluctuations (89-98 HV) and an average hardness as high as 94 HV. Furthermore, the hardness at the bottom and top is consistent, indicating excellent thermal history control.

[0059] Control group: Air cooling was used, and the hardness of the sample fluctuated greatly. The bottom was softened by aging due to repeated thermal cycling (about 74 HV), which was much lower than the hardness of the top (about 97 HV). The average hardness was only 83 HV.

[0060] in conclusion: This embodiment strongly demonstrates that the device and method of the present invention can provide a stable, uniform and controllable cooling environment for additive manufacturing, effectively suppress the negative effects of heat accumulation, and significantly improve the mechanical properties and microstructure uniformity of the formed components.

[0061] In summary, the embodiments of the present invention provide a cooling device and cooling method for additive manufacturing, which have the following advantages: 1) Achieving non-interference between constant flow and constant volume and fluid level movement, ensuring thermal field stability: An internal volume regulating component is used as the fluid level driving source. Without changing the total fluid volume of the circulation system or interfering with the constant flow rate of the water pump, the fluid level rises and falls solely through internal volume displacement. This design solves the flow field fluctuation problem caused by adjusting valves or changing pump power in existing solutions, ensuring that the flow rate and turbulence of the cooling medium remain constant throughout the additive manufacturing process, creating an extremely stable cooling environment for high-quality forming.

[0062] 2) Utilizing a convex-shaped water tank to achieve hydraulic amplification effect, significantly improving control accuracy and response speed: Through an irregularly shaped water tank structure that is narrower at the top and wider at the bottom, the lower large-section chamber accommodates the volume adjustment components, while the upper small-section chamber performs the operation. A small volume change in the lower part can be converted into a significant liquid level displacement in the upper part. This hydraulic amplification mechanism reduces the stroke requirements of the actuator, improves the agility and positioning accuracy of liquid level adjustment, and adapts to the rapid deposition process requirements in additive manufacturing.

[0063] 3) Eliminates heat accumulation effect, significantly improving component forming quality and uniformity of mechanical properties: By employing closed-loop servo control with either "semi-immersion" or "full immersion," the coolant surface can follow the growth of the deposited layer like a shadow, ensuring that every layer of the component experiences a completely consistent thermal history from bottom to top. Experimental data shows that this method effectively suppresses bottom over-aging softening and top grain coarsening caused by heat accumulation, achieving extremely high uniformity of hardness distribution along the height direction and a significant improvement in overall mechanical properties.

[0064] 4) Compact structure, easy to integrate and promote: This device eliminates the need for complex mechanical lifting platforms or external liquid injection systems in the work area. The volume adjustment components are concealed at the bottom of the water tank, ensuring no spatial interference with additive manufacturing heat sources and motion mechanisms such as stirring friction, lasers, electric arcs, and electron beams. Its modular design allows for easy integration into existing additive manufacturing equipment, giving it significant engineering application value and broad applicability.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A cooling device for additive manufacturing, characterized in that, Comprising: A cooling pipeline, a water pump, a liquid level sensor, a volume adjusting member, a controller, and a water tank containing a cooling medium and used for providing an additive manufacturing working environment; The cooling pipeline is communicated with the water tank, the water pump is connected in series on the cooling pipeline, the water pump can drive the cooling medium to flow through the water tank along the cooling pipeline, the liquid level sensor is arranged in the water tank and can detect the liquid level height in the water tank, the volume adjusting member is arranged in the water tank, and the controller is respectively in communication connection with the volume adjusting member and the liquid level sensor; The controller can obtain the real-time height information of the deposition layer in additive manufacturing, and calculate the target liquid level height according to the preset target relative position relationship between the liquid level and the deposition layer; Receive the feedback signal of the liquid level sensor, and adjust the actual liquid level height to the target liquid level height by controlling the volume change of the volume adjusting member.

2. The cooling apparatus for additive manufacturing as described in claim 1, characterized in that, The water tank includes a first chamber and a second chamber for providing an additive manufacturing working environment that are communicated in sequence from bottom to top. The minimum cross-sectional area of the first chamber is larger than the maximum cross-sectional area of the second chamber, and the volume adjusting member is located in the first chamber.

3. The cooling apparatus for additive manufacturing as described in claim 2, characterized in that, The longitudinal section of the water tank is in a "convex" shape. The first chamber defines the wide lower half region of the "convex" shape, and the second chamber defines the narrow upper half region of the "convex" shape.

4. The cooling apparatus for additive manufacturing as described in claim 1, characterized in that, It further includes an air pump; The volume adjusting member includes a housing and a pressure regulating chamber formed inside the housing. The housing is a flexible bladder or a rigid cylinder with a piston. The air pump is communicated with the pressure regulating chamber and can fill or discharge gas into the pressure regulating chamber. The air pump is in communication connection with the controller.

5. The cooling apparatus for additive manufacturing as described in claim 1, characterized in that, It further includes a flow meter. The flow meter is connected in series on the cooling pipeline, and the flow meter is in communication connection with the controller or the water pump.

6. The cooling apparatus for additive manufacturing as described in claim 2, characterized in that, It includes a support frame for carrying an additive manufacturing substrate. The support frame is arranged in the first chamber, and the maximum dimension of the support frame in the up and down direction is not less than the maximum dimension of the first chamber in the up and down direction. The maximum cross-sectional area of the support frame is smaller than the maximum cross-sectional area of the second chamber for the cooling medium to flow through.

7. The cooling apparatus for additive manufacturing as claimed in claim 1, characterized in that, The liquid level sensor is a non-contact ranging sensor or a contact liquid level sensor.

8. A cooling method for additive manufacturing, characterized in that, Including the following steps: S1 Fix the substrate for additive manufacturing in the water tank, start the water pump, and inject the cooling medium into the water tank to the initial liquid level height; S2 Set the target relative position relationship between the liquid level and the deposition layer, and start additive manufacturing; S3 During the additive manufacturing process, obtain the real-time height information of the deposition layer, calculate the target liquid level height in combination with the target relative position relationship, and compare the actual liquid level height measured by the liquid level sensor with the target liquid level height; S4 Keep the flow rate of the cooling medium flowing through the water tank set unchanged, and drive the liquid level to rise or fall to the target liquid level height by controlling the volume of the volume adjusting member to change its occupied volume in the water tank.

9. The cooling method for additive manufacturing as described in claim 8, characterized in that, The target relative position relationship includes a semi-immersion mode and a full-immersion mode: In semi-immersion mode, the liquid level is set below the lower surface of the deposition layer, and the height difference between the liquid level and the lower surface of the deposition layer remains constant; as the height of the deposition layer increases, the volume of the volume adjustment component is increased to actively raise the liquid level; In full immersion mode, the liquid level is set above the upper surface of the deposition layer, and the height difference between the liquid level and the upper surface of the deposition layer remains constant; when the volume of the deposition layer increases, causing the liquid level to rise passively above the target height, the volume adjustment component is controlled to decrease in volume to absorb the displaced liquid and thus lower the liquid level.

10. The cooling method for additive manufacturing as described in claim 8, characterized in that, In step S3, the specific steps for obtaining the real-time height information of the deposition layer are as follows: Receive the layer height program signal from the additive manufacturing equipment; or It receives signals from visual sensors or ranging sensors that independently monitor the sediment layer.

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