Preheating assembly, additive manufacturing machine having same, and preheating method

Abstract

The present application relates to a preheating assembly (1) having a base plate (10) for carrying construction material, one or more heating sections (11) arranged around the base plate (10), and a heat collecting section (12), the one or more heating parts (11) are used for generating heat which can be transmitted to the substrate (10) to preheat the substrate (10) based on a heat radiation and / or heat conduction mode at least before the three-dimensional object is constructed, and the heat gathering part (12) is used for regulating and controlling a heat transmission path to uniformly gather the heat to a preset area of the substrate (10).

Description

Technical Field

[0001] The present application relates to the field of additive manufacturing, and more particularly to a preheating component, an additive manufacturing machine having the preheating component, and a preheating method. Background Art

[0002] In the field of additive manufacturing, especially in metal powder bed additive manufacturing technology, preheating of the substrate is a crucial link. Before officially building the part, the substrate needs to be heated to a certain temperature to improve the melting and solidification efficiency of the metal powder, reduce the temperature difference during the printing process, thereby reducing residual stress and ensuring the dimensional accuracy and surface quality of the printed part. If the preheating is insufficient or the temperature distribution of the substrate is uneven, it is easy to cause defects such as stress concentration, warping and cracking, which seriously affects the forming quality of the part.

[0003] At present, the preheating temperature of existing metal powder bed additive manufacturing machines is usually controlled within the range of 200°C to 500°C, while equipment that can raise the preheating temperature to above 500°C or even above 1000°C is extremely scarce. Achieving high-temperature preheating above 1000°C is a great technical challenge, and it is even more complicated when a narrow and wide substrate is required. On the one hand, the diffusion and accumulation of heat is very difficult, which makes temperature control more difficult; on the other hand, the uniformity of substrate preheating is often difficult to meet the requirements. In addition, the existing equipment has poor thermal insulation effect, and thermal radiation can easily affect other structures around the heating device, thereby damaging its performance or stability. Summary of the invention

[0004] One purpose of the present application is to provide a new preheating component to achieve efficient and uniform preheating effect on the substrate, avoid heat diffusion to the surrounding structure, and meet the higher requirements of metal powder bed additive manufacturing; another purpose is to provide a fastening component that can maintain stable performance in a high temperature environment, avoid melting and adhesion, failure and difficulty in disassembly.

[0005] In a first aspect, an embodiment of the present application provides a preheating assembly for an additive manufacturing machine, comprising: a substrate for carrying a building material; one or more heating parts, the one or more heating parts are arranged around the substrate, and are used to generate heat that can be transferred to the substrate in the form of thermal radiation and / or thermal conduction to preheat the substrate at least before building a three-dimensional object; and a heat convergence part, the heat convergence part is arranged around the substrate, and is used to regulate the transfer path of the heat so as to evenly converge the heat to a predetermined area of ​​the substrate.

[0006] Preferably, the heat converging portion comprises an optical element, which is arranged outside the substrate and is used to reflect and / or refract the waves of the thermal radiation to guide the heat to the predetermined area.

[0007] Preferably, the optical elements are provided in a plurality with the same or different focusing characteristics and are arranged along one or more sides of the substrate, wherein the focusing characteristics include a radius of curvature or a focal length.

[0008] Preferably, the optical element comprises a lens and / or a first coating.

[0009] Preferably, the heat converging portion comprises an enclosure, which at least surrounds the substrate, the optical element and one or more heating portions to limit the heat transfer path to the internal space of the enclosure.

[0010] Preferably, the first coating is distributed in the form of a single region or multiple regions on at least a portion of the inner wall of the enclosure.

[0011] Preferably, the preheating component also includes a posture adjustment part, which is arranged to be connected to the heat convergence part to drive the deflection and / or displacement of the heat convergence part relative to the substrate according to a predetermined temperature distribution, wherein the predetermined temperature distribution corresponds to the material of the building material and / or the process parameters used to construct the three-dimensional object.

[0012] Preferably, the preheating component also includes a plurality of temperature sensors and a temperature regulating part respectively connected to the plurality of temperature sensors, wherein the plurality of temperature sensors are distributed on one side or multiple sides of the substrate for temperature measurement, and the temperature regulating part is used to adjust the heating power of the one or more heating parts according to a predetermined temperature distribution and the temperature fed back by the plurality of temperature sensors.

[0013] Preferably, the heating part comprises an electric heating element made of any one of silicon carbide, molybdenum disilicide, tungsten and zirconium oxide.

[0014] Preferably, the preheating assembly further comprises a heat conducting part, which is arranged between the one or more heating parts and the substrate and in contact with the substrate and spaced apart from the one or more heating parts, and is used for transferring the received heat transferred based on the thermal radiation to the substrate in the form of heat conduction.

[0015] In a second aspect, an embodiment of the present application further provides an additive manufacturing machine comprising the preheating component described in any one of the first aspects.

[0016] Preferably, the additive manufacturing machine also includes: a mating portion, which is formed on the side wall of the substrate and has a first thermal expansion coefficient (γ1); a clamping portion, which is arranged on at least one side of the substrate and extends toward its side wall to form a clamping member for clamping the mating portion; wherein the clamping member has at least a second thermal expansion coefficient (γ2) different from the first thermal expansion coefficient (γ1), so that as the temperature increases during heating, one of the mating portion and the clamping member expands and applies pressure to the other side that remains relatively unchanged to gradually compress, and as the temperature decreases, the expanded side contracts and gradually loosens contact with the other side.

[0017] Preferably, at least a portion of the surface of the mating portion and / or the pressing member is coated with a second coating comprising any one of aluminum oxide (Al2O3), silicon nitride (Si3N4), silicon carbide (SiC), ceramics and nickel-based alloys.

[0018] Preferably, the clamping member comprises: a first layer, the first layer having the second thermal expansion coefficient (γ2); a second layer, the second layer being arranged outside the first layer and having a third thermal expansion coefficient (γ3), and satisfying γ1<γ3<γ2; wherein, when the temperature rises, the first layer expands and pushes the second layer to apply pressure to the mating part, and when the temperature drops, the first layer contracts so that the second layer gradually loosens contact with the mating part.

[0019] Preferably, the base plate is composed of a platform for carrying building materials and clamping plates respectively arranged at both ends of the platform, the matching portion is arranged on the side wall of the platform or the clamping plate, and the clamping portion extends to cover at least a portion of the side wall of the platform.

[0020] Preferably, the additive manufacturing machine also includes a tensioning part, which includes: one or more springs, one end of the spring is connected to the end of the clamping part away from the substrate, and the other end is connected to the fixed part; a pull pin, the pull pin is arranged in a limiting groove provided in the clamping part, and can drive the clamping part to be tensioned toward the fixed part under the push of external force to achieve the loosening of the matching part by the clamping member, and to achieve the tensioning of the matching part by the clamping member when the one or more springs rebound and reset.

[0021] In a third aspect, an embodiment of the present application also provides a preheating method for an additive manufacturing machine, wherein the additive manufacturing machine comprises: a substrate for carrying a building material; one or more heating parts and a heat convergence part arranged around the substrate; and a posture adjustment part arranged to be connected to the heat convergence part; wherein the preheating method comprises the following steps: at least before constructing a three-dimensional object, driving the one or more heating parts according to a predetermined temperature distribution to generate heat that can be transferred to the substrate in the form of thermal radiation and / or heat conduction to preheat the substrate, and controlling the heat convergence part to deflect and / or displace relative to the substrate so as to regulate the heat transfer path so that it is evenly converged to a predetermined area of ​​the substrate; wherein the predetermined temperature distribution corresponds to the material of the building material and / or the process parameters used to construct the three-dimensional object.

[0022] Preferably, the additive manufacturing machine further comprises a plurality of temperature sensors for measuring temperature distributed on one or more sides of the substrate, wherein the preheating method further comprises the following steps: adjusting the heating power of the one or more heating parts according to a predetermined temperature distribution and the temperatures fed back by the plurality of temperature sensors.

[0023] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate one or more embodiments of the present application and, together with the description, serve to explain the principles of the present application and to enable one of ordinary skill in the relevant art to make and use the present application.

[0025] Figure 1 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0026] Figure 2 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0027] Figure 3 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0028] Figure 4 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0029] Figure 5 A schematic diagram of area division of a substrate according to one embodiment of the present application is shown;

[0030] Figure 6 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0031] Figure 7 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0032] Figure 8 A schematic diagram showing the deflection and displacement of a heat converging portion relative to a substrate according to one embodiment of the present application is shown;

[0033] Fig. 9 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0034] Fig.10 A schematic structural diagram of a preheating assembly according to one embodiment of the present application is shown;

[0035] Fig.11 A schematic diagram of the installation structure of a fastening assembly and a substrate according to one embodiment of the present application is shown;

[0036] Fig.12 A schematic diagram of the installation structure of a fastening assembly and a substrate according to one embodiment of the present application is shown;

[0037] Fig.13 A schematic diagram showing the arrangement of a pressing member and a matching portion according to one embodiment of the present application is shown;

[0038] Fig.14 A schematic diagram showing the arrangement of a pressing member and a matching portion according to one embodiment of the present application is shown;

[0039] Fig.15 A schematic diagram showing the arrangement of a pressing member and a matching portion according to one embodiment of the present application is shown;

[0040] Fig.16 A schematic diagram of a model of a preheating system according to one embodiment of the present application is shown;

[0041] Fig.17 A schematic flow chart of a preheating method for an additive manufacturing machine according to one embodiment of the present application is shown. DETAILED DESCRIPTION

[0042] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments may be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; rather, the description of these embodiments is intended to make the present application more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a deeper understanding of the embodiments of the present application.

[0043] The "additive manufacturing" involved in this application includes additive manufacturing types such as LPBF (Laser Powder Bed Fusion), EBM (Electron Beam Melting), SLM (Selective Laser Melting) and SLS (Selective Laser Sintering). In particular, a preheating component for an additive manufacturing machine is proposed to perform a preheating treatment of a substrate, and the preheating component can be included as a part of the additive manufacturing machine.

[0044] The "building material" involved in this application is a raw material used to manufacture a three-dimensional object (part), and in terms of physical structure, for example, is a powder particle, and the powder particles can have different shapes, sizes and particle sizes. The "building material" herein is preferably made of metal, such as stainless steel, copper, copper alloy (such as copper-aluminum alloy), titanium, titanium alloy, aluminum, aluminum alloy and other usable metal materials. In addition, in an optional manner, powders of ceramics, plastics and composite materials can also be used to construct a three-dimensional object.

[0045] Figure 1 The figure shows a schematic diagram of the structure of a preheating assembly according to one embodiment of the present application. Figure 1 The preheating assembly 1 of the embodiment of the present application includes a substrate 10, a heating portion 11 (may be one or more) and a heat converging portion 12. Figure 1 In the example, the heating part 11 is arranged below the substrate 10, and the heat convergence part 12 is arranged between the substrate 10 and the heating part 11. The substrate 10 is used to carry the building materials (usually presented layer by layer in the form of powder layers) during the printing process, and provide a stable foundation for the manufactured parts to ensure that they are tightly combined with the substrate 10 to facilitate subsequent cutting and processing. The heating part 11 is arranged around the substrate 10. As a heat source, the heating part 11 can effectively generate heat and transfer the heat to the substrate 10 for heating in the form of thermal radiation and / or heat conduction. This heating process occurs in particular before constructing a three-dimensional object, that is, preheating the substrate 10. The heat convergence part 12 is also located around the substrate 10, and is used to regulate the heat transfer path generated by the heating part 11 so as to evenly converge the heat to a predetermined area of ​​the substrate 10. The predetermined area can be the entire area of ​​the substrate, or it can be a set local area to meet different construction requirements.

[0046] Figure 2 FIG. 1 shows a schematic diagram of the structure of a preheating assembly according to one embodiment of the present application. In this embodiment, the arrangement of the heating part 11 is similar to Figure 1 Different, that is, as Figure 1A variation of the example, Figure 2 The heating portion 11 is not only located around the substrate 10, but can also be arranged above the substrate 10 to more effectively utilize the heat of the heating portion 11, so that the heat is more concentrated when transferred to the upper surface of the substrate 10, thereby improving the preheating effect. The heat convergence portion 12 is also arranged between the substrate 10 and the heating portion 11 to enhance the efficiency of heat convergence and transfer. In order to avoid interference with the subsequent part construction process, a moving device can also be configured in the space above the substrate 10. The moving device can move the heating portion 11 and the heat convergence portion 12 together after the preheating is completed, thereby removing them from above the substrate 10, so that during the actual printing process, the top of the substrate 10 will not be blocked by any structure to avoid interference.

[0047] According to some embodiments, it is also possible to combine Figure 1 and Figure 2 The arrangement in the example preheats the substrate 10 from above and below the substrate 10 respectively. The two-way preheating configuration can not only more effectively accelerate the preheating process of the substrate 10, but also greatly reduce the loss of heat during the transfer process, ensuring that the substrate 10 can reach the set preheating temperature before building a three-dimensional object, further improving the preheating efficiency. In addition, two-way preheating can also better control the temperature distribution of the substrate 10, so that the heat can evenly penetrate into various areas of the substrate 10, thereby reducing stress concentration, reducing the risk of warping and cracking, and improving the dimensional accuracy and surface quality of the printed parts. Of course, in some possible implementations, the heating portion 11 and the heat convergence portion 12 can also be arranged on the left and / or right side of the substrate 10.

[0048] According to some embodiments, the heat converging portion 12 may be an optical element disposed outside the substrate 10 to reflect and / or refract the waves based on the thermal radiation of the heating portion 11 to guide the heat to a predetermined area of ​​the substrate 10 .

[0049] Reference Figure 1 or Figure 2For example, in one implementation, the optical elements 12a to 12d can be an optical lens. Specifically, the optical elements 12a and 12b arranged on both sides of the substrate 10 and the heating part 11 are used as reflectors, and the optical elements 12c and 12d arranged between the substrate 10 and the heating part 11 are used as refractors. Among them, the main function of the reflector is to receive the thermal radiation waves emitted from the heating part 11 and guide them to the substrate 10 by reflection. This process relies on the principle of optical reflection, that is, when the thermal radiation waves (electromagnetic waves) encounter the surface of the reflector, part of the radiation will be reflected at a specific angle. In order to improve the reflection efficiency, the surface of the reflector can be coated with a material with high reflectivity, such as aluminum or silver, to ensure that the heat can be reflected as much as possible to the substrate 10. In addition, the shape and angle design of the reflector will also affect the reflection path to optimize the concentration and distribution of heat. The function of the refractor is to use the principle of optical refraction to change the propagation direction of the thermal radiation wave when passing through the refractor, so as to more accurately guide it to a specific area of ​​the substrate 10. The material of the refractor has high light transmittance and thermal stability, such as silicon dioxide or other high temperature resistant materials. The design of the refractor includes not only the choice of material but also its geometry to ensure that heat is directed evenly and efficiently.

[0050] In another implementation, the optical elements 12a to 12d may be in the form of a coating (first coating). The optical elements 12a and 12b arranged on both sides of the substrate 10 and the heating portion 11 may be coatings with a light reflection function, which can effectively reflect the heat radiation waves from the heating portion 11 and concentrate them in a predetermined area of ​​the substrate 10. The optical elements 12c and 12d arranged between the substrate 10 and the heating portion 11 may be, for example, coatings with a refractive function, which change the direction of the heat radiation waves by refraction to achieve precise heat guidance.

[0051] Figure 3 and Figure 4 The schematic diagrams of the structure of the preheating assembly according to one embodiment of the present application are shown respectively. Figure 3 and Figure 4 In one implementation, the optical elements 12a to 12d may all be configured as reflectors or coatings with a light-reflecting function, or may all be configured as refractors or coatings with a light-refracting function. Figure 3 and Figure 4 In the example, the optical elements 12 a - 12 d may be configured in different shapes and angles to ensure that heat is concentrated in a specific area of ​​the substrate 10 , thereby promoting uniform preheating of the substrate 10 .

[0052] In general, whether in the form of optical lenses or coatings, the design and configuration of the optical elements 12a~12d are intended to improve the efficiency of heat utilization and ensure that heat can be evenly and concentratedly transferred to a predetermined area of ​​the substrate 10, thereby providing the necessary thermal environment for the additive manufacturing process, thereby improving the preheating efficiency while reducing potential defects caused by uneven temperature and ensuring the quality and performance of the printed parts.

[0053] In one implementation, the optical elements 12a-12d may be configured to have the same or different focusing characteristics, such as a curvature radius or a focal length.

[0054] Specifically, when the optical elements 12a~12d have the same focusing characteristics, their radius of curvature or focal length is consistent, and a uniform heat concentration area can be formed. By evenly arranging these optical elements on one or more sides of the substrate 10, the heat can be effectively concentrated in a specific area of ​​the substrate 10, thereby achieving uniform preheating. This configuration is particularly suitable for scenarios with high requirements for uniform heat distribution, ensuring that the substrate 10 will not have defects such as warping or cracking due to uneven temperature during the additive manufacturing process. When the optical elements 12a~12d have different focusing characteristics, the radius of curvature or focal length of each optical element can be adjusted according to specific needs to achieve heat distribution in different areas. This configuration can apply higher heat to certain specific areas of the substrate 10, while maintaining a lower heat level in other areas. In this way, the different preheating requirements of different building materials or parts can be precisely controlled to improve the melting and solidification efficiency of the material. For example, when printing complex geometries, some parts require higher temperatures to ensure good interlayer bonding, while other parts can maintain a lower preheating temperature to avoid unnecessary energy consumption.

[0055] In addition, the arrangement of the optical elements 12a-12d can also take a variety of forms, such as linear arrangement, symmetrical arrangement or asymmetrical arrangement. The heat focusing path can be further optimized through reasonable layout. For example, if the optical elements are arranged along one side of the substrate 10, the straight-line propagation characteristics of light can be used to concentrate the heat more quickly to the edge area of ​​the substrate, thereby improving the overall preheating efficiency. When arranged on multiple sides of the substrate 10, more comprehensive heat coverage can be achieved, further ensuring the overall temperature uniformity of the substrate 10.

[0056] In addition, by configuring the optical elements 12a to 12d to use different radii of curvature or focal lengths, the gradient preparation of the part in the XY plane can be better achieved, that is, using building materials of different materials on a layer section to give the formed part unique functions and performance characteristics. For example, in the central area of ​​a particular layer, a high-strength metal material is required to carry the mechanical load, while a lighter material can be selected in the edge area to reduce weight. This selection of different materials can be achieved by adjusting the focusing characteristics of the optical elements. For example, some optical elements focus on heating a specific area so that the metal powder in the area melts and solidifies quickly, while other areas use different focusing methods to achieve the melting requirements of different materials.

[0057] Figure 5 FIG. 1 shows a schematic diagram of the region division of a substrate according to one embodiment of the present application. Figures 1 to 5 , for example, the convergence area of ​​the optical element 12a corresponds to the central area P1 of the substrate 10, the convergence area of ​​the optical element 12b corresponds to the middle area P2 of the substrate 10, the convergence area of ​​the optical element 12c corresponds to the edge area P3 of the substrate 10, and the convergence area of ​​the optical element 12d corresponds to the middle area P4 of the substrate 10. Specifically, the optical element 12a can be set to have a smaller radius of curvature (e.g., R1) or a shorter focal length (e.g., f1) to generate concentrated and intense heat to ensure that high-strength metals (such as titanium alloys) melt quickly in this area and form a dense structure. The optical element 12b can be configured with a medium radius of curvature (e.g., R2) or focal length (e.g., f2) to achieve uniform heat distribution, and a lower-strength but lighter metal (e.g., aluminum alloy) can be used in this area to reduce the weight of the entire structure while maintaining a certain strength. Optical element 12c is set to have a larger radius of curvature (such as R3) or a longer focal length (such as f3) to make the heat distribution more dispersed, which is suitable for using lighter composite materials in the edge area to reduce weight and improve corrosion resistance. Optical element 12d can be set to have a medium focusing characteristic (such as R2 or f2) to ensure that there is enough heat in the transition area between the stronger material and the lighter material to achieve a good bonding effect and avoid cracks or weaknesses caused by differences in material properties. Among them, R1 < R2 < R3 or f1 < f2 < f3.

[0058] Figure 6 The figure shows a schematic diagram of the structure of a preheating assembly according to one embodiment of the present application. Figure 6In some embodiments, the heat convergence portion 12 further includes a baffle 121, which at least surrounds the substrate 10, the optical element 12 and the heating portion 11, and its main function is to limit the heat transfer path and ensure that the heat can be effectively concentrated in the predetermined area of ​​the substrate 10. The baffle 121 forms a closed heat conduction environment, which reduces the heat loss in the surrounding environment, thereby improving the preheating efficiency. The baffle 121 can be made of high-temperature insulating material with good heat insulation performance to prevent heat from radiating outward to maintain the high temperature environment inside the baffle 121, while also protecting the surrounding equipment and structures from excessive temperature and avoiding potential damage or performance degradation caused by thermal radiation. In addition, the structure of the baffle 121 can also be set to be adjustable so that its height and shape can be adjusted according to different manufacturing requirements and process parameters. For example, under different printing materials or printing conditions, the degree of closure of the baffle 121 can be appropriately adjusted to achieve the best heat convergence effect. In addition, in a possible implementation, a larger volume of heat-insulating parts made of heat-insulating materials can be formed outside the enclosure 121 to further reduce the loss of heat inside the enclosure 121 to the surrounding environment. In addition to setting the enclosure 121 and / or the heat-insulating part to prevent heat from being transferred to unnecessary areas, other parts of the machine can be protected from high temperatures. A forced cooling system, such as an air cooling or liquid cooling system, can also be set up to quickly reduce the temperature of unnecessary areas and improve the safety of the overall equipment.

[0059] Figure 7 The figure shows a schematic diagram of the structure of a preheating assembly according to one embodiment of the present application. Figure 7 In some embodiments, when the optical elements 12a~12d are in the form of a coating (first coating), the optical elements 12a~12d are distributed on the inner wall of the enclosure 121 in the form of a single area (an integral coating) or multiple areas.

[0060] Figure 7 Taking the optical elements 12a~12d using a coating with a reflective function as an example, the inner wall of the enclosure 121 is not set vertically, but is set to be bent sections (straight lines or curves) with different angles. For example, the optical elements 12a and 12b are set on the two bent sections of the left inner wall of the enclosure 121, and the optical elements 12c and 12d are set on the two bent sections of the right inner wall of the enclosure 121. This setting can effectively guide the heat to be reflected to a specific area of ​​the substrate 10, thereby achieving a more uniform heat distribution.

[0061] The number and angle of the bending sections of the inner wall of the enclosure 121 are not limited to Figure 7The example in the figure can be flexibly set according to the specific heat reflection requirements. For example, in some cases, more bending segments are needed to increase the heat focusing ability, or the angle of the bending segment is adjusted to optimize the heat transfer path, so that the enclosure 121 can adapt to different types of materials and process requirements, and improve the performance of the preheating component 1.

[0062] In addition, in some embodiments, the inner wall of the enclosure 121 can also extend toward the center of the enclosure 121 to form an extension section. The extension section can be provided with a coating having a refractive function to further optimize the focusing and distribution of heat. In this way, a multi-level thermal management system can be created inside the enclosure 121, which not only improves the heat concentration efficiency, but also reduces the heat loss in the entire system.

[0063] Figure 8 FIG. 1 shows a schematic diagram of the deflection and displacement of the heat converging portion relative to the substrate 10 according to one embodiment of the present application. Figure 8 The preheating assembly 1 also includes a posture adjustment portion 13, which is arranged to be connected to the heat convergence portion 12 to drive the deflection and / or displacement of the heat convergence portion 12 relative to the substrate 10 according to a predetermined temperature distribution, wherein the predetermined temperature distribution corresponds to the material of the building material and / or the process parameters for constructing the three-dimensional object.

[0064] In some embodiments, the posture adjustment unit 13 may use a pneumatic drive device to achieve long-distance transmission. The pneumatic drive device uses compressed air as a transmission medium and drives the deflection and / or displacement of the optical element 12e by controlling the action of the cylinder.

[0065] Reference Figure 8 The pneumatic drive device mainly includes components such as an air source 130, solenoid valves 131a and 131b, and cylinders 132a and 132b. Cylinders 132a and 132b are equipped with pistons, which can push piston rods 133a and 133b to perform telescopic movements according to the input direction of compressed air. The solenoid valves 131a and 131b are opened and closed by the control system 200 to control the airflow direction and pressure so that the cylinders 132a and 132b can move at a predetermined telescopic degree.

[0066] One end of the solenoid valves 131a and 131b are respectively connected to the air source 130, and are also respectively connected to the control system 200. The other end of the solenoid valve 131a is connected to the cylinder 132a, and the other end of the solenoid valve 131b is connected to the cylinder 132b. The cylinders 132a and 132b are arranged on one side of the optical element 12e, wherein the piston rod 133a of the cylinder 132a is connected to one end of the optical element 12e, and the piston rod 133b of the cylinder 132b is connected to the other end of the optical element 12e. The preheating assembly 1 of the present application also has a telescopic rod 134, one end of which is connected to the middle of the optical element 12e, and the other end is fixedly arranged, for example, fixed to the side wall of the enclosure 12, to serve as a fulcrum for the optical element 12e.

[0067] When it is necessary to control the angle deflection of the optical element 12e, the control system 200 transmits different control signals to the solenoid valves 131a and 131b to open the corresponding solenoid valves. For example, the control system 200 sends a signal to the solenoid valve 131a to allow compressed air to enter the cylinder 132a, pushing the piston rod 133a to extend, and at the same time controls the cylinder 132b through the solenoid valve 131b to retract the piston rod 133b synchronously. Similarly, when the piston rod 133b is pushed out, the piston rod 133a is controlled to retract synchronously. Through this relative telescopic operation, one end of the optical element 12e rises and the other end falls, thereby achieving angle deflection. Since the cylinders 132a and 132b act in opposite directions, the optical element 12e can be accurately adjusted to the desired angle around the support point (telescopic rod 134).

[0068] When the optical element 12e needs to be displaced in parallel as a whole, the control system 200 will synchronously operate the solenoid valves 131a and 131b to make the piston rods 133a and 133b of the cylinders 132a and 132b extend or retract in the same direction. Since the two piston rods act at the same time, the optical element 12e can be translated as a whole without changing the angle, and the telescopic rod 134 also follows the action to ensure that the moving direction of the optical element 12e is stable.

[0069] It should be understood that the cylinder drive can achieve a longer distance transmission to avoid the influence of high temperature. For example, the gas source 130, solenoid valves 131a and 131b and other components can be arranged at a position away from the heating area, or outside the additive manufacturing machine. The cylinders 132a and 132b can be arranged inside the enclosure 121, or arranged in an insulating part made of heat-insulating material formed outside the enclosure 121. The pipeline for transmitting compressed gas can be made of high-temperature resistant material.

[0070] It should be understood that by adopting a cylinder drive device, the posture adjustment unit 13 can achieve long-distance driving of the optical element 12e and avoid the adverse effects caused by the high temperature area. For example, components such as the gas source 130, solenoid valves 131a and 131b can be arranged in a cooling area away from the heating area, or even directly placed outside the additive manufacturing machine to ensure system stability. The cylinders 132a and 132b are arranged in a position close to the optical element, and can be installed on the side of the enclosure 121 away from the optical element 12e, or placed in the insulation part outside the enclosure 121. In addition, the pipeline for transmitting compressed gas is made of high temperature resistant material to maintain its structural stability in the heating area and ensure that the action response of the cylinder is not affected by the ambient temperature.

[0071] In some other implementations, the posture adjustment unit 13 can also use a hydraulic drive device to achieve long-distance transmission. The hydraulic drive uses the incompressibility of the liquid to transmit pressure and torque through a liquid medium (such as hydraulic oil) to drive the deflection and / or displacement of the optical element 12e. The hydraulic drive device includes components such as a hydraulic pump, a hydraulic pipeline, and a hydraulic cylinder. The hydraulic pump can be set at a location away from the high temperature area, while the hydraulic cylinder is arranged in the insulation part or inside the enclosure 121 close to the optical element. The hydraulic drive system can achieve precise control by adjusting the hydraulic valve, which can not only withstand high temperature environments, but also provide stable driving force to meet the needs of long-term work under high temperature conditions.

[0072] Combined with the deflection and displacement adjustment, the posture adjustment unit 13 can realize the free configuration of the optical element 12e, further optimize the heat concentration and distribution effect, so that the preheating assembly 1 can adapt to various building materials and process parameters. For example, when printing high-strength titanium alloy, stronger heat concentration is required, while when using lighter aluminum alloy, the heat concentration can be reduced to avoid overheating and deformation of the material.

[0073] Fig. 9 The figure shows a schematic diagram of the structure of a preheating assembly according to one embodiment of the present application. Fig. 9 The preheating component 1 also includes temperature sensors 14a, 14b, 14c and a temperature regulating part 15 respectively connected to the temperature sensors 14a, 14b, 14c. The temperature sensors 14a, 14b, 14c are distributed around or inside (one side or multiple sides) of the substrate 10 for temperature measurement. The temperature regulating part 15 selects the temperature according to the predetermined temperature distribution and the temperature feedback from the temperature sensors 14a, 14b, 14c to adjust the heating power of the heating part 11.

[0074] In one implementation, the temperature sensors 14a, 14b, and 14c can be sensors made of high-temperature resistant materials such as thermocouples, thermistors, or infrared temperature sensors. Through real-time feedback from the sensors, the temperature regulating unit 15 can monitor the temperature changes of the substrate 10 and identify possible temperature unevenness or abnormalities. The temperature regulating unit 15 is, for example, a control unit electrically connected to the temperature sensors 14a, 14b, and 14c, which receives temperature data from each temperature sensor and analyzes it according to a preset temperature distribution scheme. If the sensor detects that the temperature of a certain area of ​​the substrate 10 is lower than the set value, the temperature regulating unit 15 will adjust the heating power of the heating unit 11 to increase the temperature of the area; conversely, if the temperature of a certain area is too high, the heating power can be appropriately reduced to avoid deformation or damage of the material caused by overheating. In this way, during the additive manufacturing process, the substrate 10 is always kept within the ideal temperature range to improve the forming quality of the printed parts.

[0075] In addition, the temperature adjustment unit 15 can also be integrated with other control systems to form an intelligent control network. For example, before printing begins, the system can preset the temperature distribution according to the characteristics of different materials and adjust it in real time during the entire printing process. The preset function can provide personalized thermal management solutions for different materials to ensure that the temperature uniformity of the substrate 10 reaches the optimal state when printing each layer.

[0076] According to some embodiments, the heating part 11 can be selected as an electric heating element (such as an infrared heater, an electrode heater, an electromagnetic heater, etc.) made of any one of silicon carbide, molybdenum disilicide (for example, a silicon molybdenum rod can be used), tungsten and zirconium oxide to achieve high-temperature preheating of the substrate 10, for example, achieving a preheating temperature greater than 1000°C or even up to 1600°C.

[0077] According to some embodiments, the heating portion 11 can adopt a variety of high-performance electric heating elements (such as infrared heaters, electrode heaters, electromagnetic heaters, etc.) to meet the high-temperature preheating requirements of the substrate 10, including but not limited to silicon carbide, molybdenum disilicide (such as silicon molybdenum rods), tungsten and zirconium oxide and other materials, all of which have good high temperature tolerance and thermal stability, and are suitable for additive manufacturing applications that require high temperature preheating.

[0078] Specifically, silicon carbide (SiC) is an excellent high-temperature electric heating material with extremely high thermal conductivity and good chemical stability. The silicon carbide heater can work stably at a temperature of up to 1600°C. It can not only heat up quickly, but also evenly distribute heat to ensure the preheating effect of the substrate 10. In addition, its anti-oxidation property also makes it perform well in an oxidizing environment, reducing the risk of material aging and failure. Molybdenum silicide (MoSi2) is also an efficient high-temperature heating material, especially with excellent electrical and thermal conductivity at high temperatures. When using silicon molybdenum rods as heating elements, they can maintain stable electrical and mechanical properties under high temperature conditions of 1200°C to 1600°C, and are suitable for occasions that require long-term continuous high-temperature preheating. In addition, the corrosion resistance of molybdenum disilicide also makes it perform well in the fierce additive manufacturing environment. Tungsten is another material suitable for high-temperature heating, with a melting point of up to 3422°C, making it an ideal choice for high-temperature applications. Tungsten heaters can withstand extreme temperatures and high load conditions, provide stable heat output, and ensure uniform heating of the substrate 10 during the printing process. Zirconia (ZrO2) is a high-temperature insulating material that can also be used in the manufacture of electric heating elements. Zirconia's high melting point and excellent insulating properties allow it to withstand extremely high temperatures without losing its insulating ability. In specific settings, zirconia heaters can be combined with other materials to form a composite heating system, thereby achieving more efficient thermal management and energy utilization.

[0079] Fig.10 The figure shows a schematic diagram of the structure of a preheating assembly according to one embodiment of the present application. Fig.10 According to some embodiments of the present application, the preheating assembly 1 further includes a heat conducting portion 16, which is arranged between the heating portion 11 and the substrate 10 and in contact with the substrate 10 and separated from the heating portion 11, and is used to transfer the received heat based on thermal radiation transfer to a predetermined area of ​​the substrate 10 in the form of heat conduction.

[0080] The location and material selection of the heat-conducting part 16 directly affect the efficiency of heat transfer. Ideally, the heat-conducting part 16 can be made of a material with high thermal conductivity, such as copper, aluminum or some composite materials. These materials can quickly transfer heat to ensure that the substrate 10 can reach a predetermined temperature in the shortest possible time. During operation, the heating part 11 first releases heat through thermal radiation. The heat-conducting part 16 uses its excellent thermal conductivity to quickly transfer the heat to the substrate 10 through heat conduction. Since the heat-conducting part 16 is in close contact with the substrate 10, this heat transfer path reduces heat loss and improves the overall thermal efficiency. In addition, the structural setting of the heat-conducting part 16 may also include an appropriate geometric shape to increase its contact area with the substrate 10, thereby further enhancing the heat conduction effect.

[0081] In a possible implementation, the heat conducting part 16 may also have a certain heat storage capacity to cope with instantaneous load changes. In practical applications, the heat conducting part 16 can store part of the heat. When the heat output of the heating part 11 changes instantaneously, the heat conducting part 16 can release the stored heat to maintain the temperature of the substrate 10 stable. Because the temperature required for the substrate 10 will be different at different stages of printing. In addition, the material and structural setting of the heat conducting part 16 must also take into account thermal isolation from the heating part 11 to avoid excessively high temperatures affecting other components. The heat conducting part 16 can be configured to have certain insulation properties to prevent heat from being lost to the surrounding environment and ensure that the heat is concentrated in a predetermined area of ​​the substrate 10 as much as possible.

[0082] Fig.16 A schematic diagram of a preheating system according to one embodiment of the present application is shown. A preheating component is arranged in the preheating system. Fig.16 According to some embodiments, the substrate 10 can be set to a narrower width, such as about 2 mm, for use in X-ray synchrotron diffraction (XRD) experiments during additive manufacturing. X-ray synchrotron diffraction monitors the diffraction data of the material at different stages of additive manufacturing in real time, allowing researchers to obtain information about the material phase change, crystal structure change, and stress state for optimizing subsequent additive manufacturing parameters. The narrow width of the substrate 10 can provide a concentrated and consistent diffraction signal for the X-rays. When the width of the substrate 10 is reduced, the width of the material is also reduced, thereby reducing the absorption and scattering of the X-rays during the penetration process, allowing more rays to effectively participate in the diffraction reaction. In addition, the narrow width of the substrate 10 is also convenient for controlling the conduction and dissipation of heat during the additive manufacturing process. Since the area of ​​the substrate 10 is relatively small, its heat diffusion rate increases, making the temperature control in the preheating and subsequent part construction stages more precise.

[0083] According to some embodiments, the preheating system may be configured as a part of the additive manufacturing machine of the present application. In addition to the preheating component disclosed above, the preheating system further has a fastening component.

[0084] It should be understood that in a high-temperature preheating environment (e.g., a preheating temperature exceeding 1000°C), the substrate of the metal powder bed additive manufacturing equipment and the fasteners around it (such as screws, bolts, etc.) will be exposed to extreme temperatures, leading to the following problems: (1) Melting and adhesion: Ordinary metal fasteners tend to soften or even melt at high temperatures, and adhere to the substrate or other components. (2) Degradation of mechanical properties: High temperatures can cause the strength and hardness of the fastener material to drop significantly, resulting in looseness or lack of fastening force. (3) Difficulty in disassembly: Due to adhesion and material deformation, fasteners are easily unable to be disassembled smoothly, increasing the complexity of equipment maintenance.

[0085] In order to solve the above problems, a fastening assembly is provided that can maintain stable performance in a high temperature environment to avoid melting, adhesion, failure and difficulty in disassembly. The present application also provides a preheating assembly. Figure 11~Figure 16 The fastening assembly is described in detail.

[0086] Fig.11 FIG. 1 shows a schematic diagram of the installation structure of a fastening assembly and a substrate according to one embodiment of the present application. Fig.11 The fastening assembly 3 has a matching portion 30 and a clamping portion 31. The matching portion 30 is arranged on the side wall of the substrate 10, and the clamping portion 31 is arranged on the left side of the substrate 10 and extends toward the substrate 10 to form a pressing member 310 in the extended area, and the pressing member 310 is used to press the matching portion 30.

[0087] The present application does not limit the specific form (shape and size) of the substrate 10. Its shape can be set to, for example, a square or a circle, and its size can be set to, for example, the size of a conventional substrate, such as a common width in the range of 100 to 1000 mm. It can also be set to a smaller width. For example, in some embodiments, the substrate 10 can be set to a narrower width, such as about 2 mm, for use in X-ray synchrotron diffraction (XRD) experiments in the additive manufacturing process.

[0088] In addition, in some embodiments, the clamping portion 31 may also be disposed on the right side, front side, rear side, or bottom side of the substrate 10, and may also be disposed on multiple sides, for example Fig.12 In the installation structure shown, the clamping portion 31 is respectively arranged on the left and right sides of the substrate 10, namely the clamping portion 31a and 31b. The clamping portion 31a is arranged on the left side of the substrate 10 and extends toward the substrate 10 to form a clamping member 310a in the extended area, while the clamping portion 31b is arranged on the right side of the substrate 10 and extends toward the substrate 10 to form a clamping member 310b in the extended area. The matching portions 30a and 30b are respectively arranged on the side walls of the substrate 10.

[0089] In order to achieve the fastening of the substrate 10, especially the fastening in a temperature environment such as greater than 1000°C or even higher, according to an embodiment of the present application, the mating part 30 is configured to have a first thermal expansion coefficient (γ1), and the pressing member 310 is configured to have a second thermal expansion coefficient (γ2), γ2≠γ1. By setting these two different expansion coefficients, as the temperature increases during heating, one of the mating part 30 and the pressing member 310 expands and applies pressure to the other side that remains relatively unchanged to gradually tighten, and as the temperature decreases, the expanded side contracts and gradually loosens contact with the other side.

[0090] The “heating” described here mainly refers to the stage of preheating the substrate 10 before building a three-dimensional object.

[0091] In one implementation, the pressing member 310 is used as the expanding side, and the matching portion 30 is used as the other side that remains relatively unchanged (unless otherwise specified, the following description will use this as an example). In another implementation, the matching portion 30 can be used as the expanding side and the pressing member 310 can be used as the other side that remains relatively unchanged. The above-mentioned opposite setting mode can also be understood as male-female matching.

[0092] Taking the clamp 310 as an example of the expanding party, when the temperature rises to the predetermined temperature of the substrate 10, the clamp 310 begins to expand due to its higher thermal expansion coefficient (γ2). According to the principle of thermal expansion, when the material is heated, the atomic or molecular activity inside it intensifies, resulting in an increase in the volume of the material. This process causes the clamp 310 to expand outward and exert force on the mating portion 30. Since the thermal expansion coefficient (γ1) of the mating portion 30 is relatively low, the volume change of the mating portion 30 is relatively small when the temperature rises, so the mating portion 30 maintains a relatively unchanged shape and size. Specifically, the expansion of the clamp 310 will push the contact area between it and the mating portion 30 to gradually increase, forming a tight locking effect. This locking can not only effectively prevent the loosening of the material due to thermal stress under high temperature conditions, but also avoid the loosening or detachment of the contact point due to the cooling of the material in the subsequent additive manufacturing process. When the temperature drops, the volume of the clamp 310 will shrink and return to its original size. At this time, the mating part 30 will gradually loosen as the pressing part shrinks because it remains relatively unchanged, so that during the cooling stage of the machine, the fastening component 3 can effectively release the pressure between the mating part 30 to ensure that it will not get stuck or damaged during operation. In addition, the interaction of expansion and contraction not only improves the stability of the fastening component 3 in a high temperature environment, but also enables it to quickly respond to environmental changes during the alternation of high and low temperatures to maintain good fastening performance.

[0093] According to the embodiment of the present application, the material of the pressing member 310 is selected from nickel-based alloys, titanium alloys, polymer composite materials, and materials having a second thermal expansion coefficient (γ2) greater than 15 × 10 -6 / K; the material of the mating portion 30 is selected from stainless steel, molybdenum alloy and having a first thermal expansion coefficient (γ1) less than 15 × 10 -6 / K any of the materials.

[0094] On the one hand, the thermal expansion coefficient of nickel-based high-temperature alloys (such as typical nickel-based alloys Inconel 625 and Inconel 718) is usually 15-20 × 10 -6 / K range, and has excellent high temperature strength, suitable for use as a clamping piece 310. Titanium alloys also show good performance in high temperature environments, especially in terms of heat resistance and strength. Although the thermal expansion coefficient of titanium alloys is generally 8-10 × 10 -6 / K, but the thermal expansion coefficient of some special titanium alloys can reach 15× 10 -6 / K or above, such as Ti-6Al-4, Ti-5Al-2.5Sn, Ti-6Al-2Sn-4Zr-6Mo and Ti-3Al-8V-6Cr-4Zr. Therefore, in certain applications, titanium alloys can be used as the material of the clamping member 310, especially in high temperature and high load environments. Some high-performance polymer composites (such as polyimide or polytetrafluoroethylene) can increase their thermal expansion coefficient through special fillers. After proper design, these materials can maintain a certain strength and elasticity at high temperatures and have a high thermal expansion coefficient (up to 20-50 × 10 -6 / K). In addition, any material having a second thermal expansion coefficient (γ2) greater than 15 × 10 -6 Materials of 1000A and 1000B may also be selected as the pressing member 310. For example, some high-performance ceramic materials may also meet such requirements, especially under extreme temperatures.

[0095] On the other hand, in terms of the material selection of the mating portion 30, tantalum alloy and molybdenum alloy have relatively low thermal expansion coefficients, which makes them relatively less likely to expand significantly under high temperature conditions. In addition to tantalum alloy and molybdenum alloy, any material having a first thermal expansion coefficient (γ1) less than 15 × 10 -6 Materials of 100 % or higher and 100 % or higher may be considered as options for the mating portion 30 so as to be able to maintain its shape at high temperatures and resist external thermal stress.

[0096] It should be understood that, through the above material selection, a mutual cooperation mechanism is formed between the matching portion 30 and the pressing member 310. When the temperature rises, the expansion of the pressing member 310 increases the pressure exerted on the matching portion 30, thereby achieving effective fastening and being able to effectively resist the influence of the high temperature environment, avoiding the risk of adhesion and failure caused by softening or melting of the material.

[0097] In some embodiments, the matching portion 30 and the pressing member 310 may also be made of the same material and have different thermal expansion coefficients. For example, if titanium alloy is selected as the material of the two components, different thermal expansion coefficients can be obtained by adjusting the alloy composition or processing method, thereby achieving the best matching and fastening effect.

[0098] According to an embodiment of the present application, at least a portion of the surface of the mating part 30 and / or the clamping member 310 is coated with a first coating of any material selected from the group consisting of aluminum oxide (Al2O3), silicon nitride (Si3N4), silicon carbide (SiC), ceramics, and a nickel-based alloy to reduce the risk of oxidation and adhesion.

[0099] Al2O3 has excellent wear resistance and corrosion resistance, and can prevent oxidation reactions of metal substrates at high temperatures. In addition, Al2O3 has a low thermal conductivity, which can effectively isolate heat and reduce temperature changes in the heat-affected zone. Si3N4 has extremely high heat resistance and strength, can withstand high temperatures and their transient changes, and reduce material fatigue caused by temperature changes. At the same time, Si3N4 has excellent oxidation resistance at high temperatures and can effectively prevent adhesion. SiC has a relatively low thermal expansion coefficient, and its stability and oxidation resistance at high temperatures make it an excellent protective coating that can resist chemical corrosion in high-temperature environments and reduce the risk of wear and adhesion. The high melting point and excellent thermal stability of ceramics make it suitable for coating high-temperature components, which can prevent oxidation and adhesion of metal substrates. Nickel-based alloy coatings also exhibit good oxidation resistance and corrosion resistance at high temperatures, which allows them to effectively protect the base material in extreme environments and reduce the difficulty of disassembly caused by adhesion.

[0100] It should be understood that when the surface of the mating part 30 and / or the pressing part 310 is coated with the above-mentioned first coating, the material selection range of the mating part 30 and / or the pressing part 310 becomes larger, that is, the presence of the coating provides additional protection for the substrate, reduces the strict requirements for high melting point materials, and enables more materials to be safely used under high temperature conditions. Generally, high temperature environments impose strict restrictions on the selection of materials because conventional materials tend to soften, melt or undergo oxidation reactions at extreme temperatures. However, the use of coatings provides an effective barrier that can significantly reduce the direct contact between the substrate and the high temperature environment. In this way, certain materials with lower melting points (such as certain polymer composites or alloys) can still maintain good performance in high temperature environments under the protection of the coating. For example, certain low melting point alloys can effectively prevent oxidation and adhesion at high temperatures after being treated with specific coatings, and can still meet structural and functional requirements.

[0101] Fig.13 FIG. 1 shows a schematic diagram of the arrangement of a pressing member and a matching portion according to one embodiment of the present application. Fig.13 The matching portion 30 may be a groove formed on the side wall of the substrate 10 , and the pressing member 310 may be inserted into the groove, thereby achieving fastening of the substrate 10 .

[0102] The groove can provide a physical space for the clamp 310 to be embedded and can have a special geometric shape to enhance the locking effect. For example, the shape of the groove can be U-shaped, V-shaped or other complex shapes to adapt to the outer contour of the clamp 310. The inner wall of the groove can be surface treated, such as increasing the roughness or coating an anti-oxidation material, to increase the friction and prevent the clamp from sliding or loosening in a high temperature environment. In addition, the mating portion 30 should have a first thermal expansion coefficient (γ1) at least in the portion close to the groove, which is relatively stable in a high temperature environment and maintains its shape and structural integrity. The clamp 310 has a second thermal expansion coefficient (γ2). During the heating process, the expansion of the clamp 310 will apply pressure to the groove to achieve a tightening effect. The outer edge of the clamp 310 can be set to a specific texture structure, such as a thread, corrugation or other interlocking design, to provide additional locking force. The texture structure can effectively increase the contact area when subjected to force, thereby increasing the friction and preventing the clamp 310 from loosening during use.

[0103] In actual use, when the substrate 10 is heated to a high temperature (such as over 1000°C), the clamp 310 will expand due to the temperature increase, and the degree of expansion depends on its thermal expansion coefficient (γ2). Since the thermal expansion coefficient (γ1) of the mating part 30 is relatively low, the geometric shape of the groove remains relatively stable, and the mismatch in thermal expansion causes the clamp 310 to apply additional pressure to the groove, thereby achieving a tightening effect. As the temperature rises, the outer edge of the clamp 310 fits tightly to the inner wall of the groove through its texture structure, so that the clamp 310 can be effectively locked in the groove, forming a strong mechanical connection to prevent loosening under high temperature conditions. When the temperature drops, the clamp 310 will shrink, while the groove maintains its shape, so that the clamp 310 automatically releases contact with the groove during the cooling process, facilitating disassembly and reducing the complexity of equipment maintenance.

[0104] In some embodiments, the mating portion 30 may be a flat plate structure in addition to being a groove formed on the side wall of the substrate 10. For example, the mating portion 30 may be configured as the side wall of the substrate 10 itself, and is no longer limited to the need to dig a groove. In this case, the clamping member 310 may act directly on the side wall of the substrate 10 through surface contact, without the need to machine a groove on the side wall of the substrate 10, to provide a clamping effect different from that of the groove. Since the clamping member 310 is in direct contact with the side wall, the applied pressure can be directly and evenly distributed on the side wall of the substrate 10, forming a reliable clamping effect.

[0105] In the implementation of the mating part 30 using a flat plate structure (e.g., with distributed tiny concave points), the main function of the clamping member 310 is to apply pressure to the side wall of the substrate 10 to achieve the clamping function. Since the clamping member 310 directly applies pressure to the side wall, the magnitude of the clamping force can be freely adjusted by the thermal expansion of its material or mechanical force. The clamping member 310 will undergo thermal expansion under high temperature conditions, thereby applying greater pressure to the mating part 30 (i.e., the side wall of the substrate 10), further enhancing the clamping force. In this way, the effect of automatic pressurization can be achieved in a high temperature environment, and a reliable clamping state can be maintained under different temperature conditions. When the temperature drops, the contraction effect of the clamping member 310 gradually loosens its contact with the side wall of the substrate 10, achieving the unlocking function. Automatic clamping and loosening can be repeatedly achieved in the temperature cycle.

[0106] Fig.14 FIG. 1 shows a schematic diagram of the arrangement of a pressing member and a matching portion according to one embodiment of the present application. Figure 3 A variation of the implementation method, referring to Fig.14 The pressing member 310 is composed of a first layer 311 and a second layer 312. The first layer 311 is the inner layer of the pressing member 310, and the second layer 312 is the outer layer of the pressing member 310. There is a gap between the first layer 311 and the second layer 312. The first layer 311 has a second thermal expansion coefficient (γ2); the second layer 312 has a third thermal expansion coefficient (γ3), and satisfies γ1<γ3<γ2. In actual use, when the temperature rises, the first layer 311 expands and pushes the second layer 312 to apply pressure to the groove wall of the matching part 30 to achieve locking, and when the temperature drops, the first layer 311 contracts so that the second layer 312 gradually loosens contact with the groove wall of the matching part 30.

[0107] Fig.14 The pressing member 310 is a multi-layer structure consisting of two layers (in other embodiments, it may be more than two layers): the inner layer is the first layer 311, and the outer layer is the second layer 312. A certain gap is left between the two layers to achieve a tightening effect of layered expansion.

[0108] Specifically, the first layer 311 is the inner layer of the clamp 310, and its material is selected to have a higher thermal expansion coefficient, such as the second thermal expansion coefficient (γ2). The first layer 311 will expand significantly when the temperature rises, thereby pushing the second layer 312 outward to achieve a locking effect. The second layer 312 is the outer layer of the clamp 310, and the thermal expansion coefficient of the material is relatively small, such as the third thermal expansion coefficient (γ3), and satisfies γ1<γ3<γ2 (where γ1 is the thermal expansion coefficient of the mating part 30). When selecting the material of the second layer 312, it is considered that it not only needs to have a certain thermal expansion, but also needs to maintain structural strength at high temperatures, so as to apply a uniform locking force to the mating part 30 when subjected to the pressure of the first layer 311. A gap is provided between the first layer 311 and the second layer 312, and the gap acts as a buffer space, allowing the expansion of the first layer 311 under high temperature conditions without directly applying excessive radial pressure, but gradually pushing the second layer 312 to expand outward, so that the clamping member 310 is gradually locked during the heating process, avoiding sudden stress caused by thermal expansion.

[0109] In actual use, as the temperature rises, the first layer 311 begins to expand. Due to its high expansion coefficient, the expansion amplitude will be much greater than the outer second layer 312, thereby pushing the second layer 312 to apply pressure to the groove wall of the matching part 30, so that the clamping member 310 is firmly fixed on the groove wall of the matching part. Because the thermal expansion coefficient (γ1) of the matching part 30 is smaller than the expansion coefficients of the second layer 312 and the first layer 311, its groove wall remains basically unchanged at high temperature, so it can withstand the expansion pressure from the clamping member 310 and achieve a reliable mechanical locking effect. When the device stops heating and the temperature gradually decreases, the first layer 311 will shrink as the temperature drops. Due to its high expansion characteristics, the shrinkage amplitude is also large. Under its shrinkage, the pressure between the second layer 312 and the groove wall of the matching part 30 gradually decreases to produce looseness, so that the clamping member 310 can be easily separated from the matching part 30 when cooling.

[0110] By setting Fig.14 The gap between the first layer 311 and the second layer 312 of the double-layered pressing member 310 acts as a buffer, preventing the first layer 311 with a high expansion coefficient from directly exerting excessive pressure on the second layer 312 under high temperature conditions, thereby extending the service life of the device. In addition, through the combination of materials with different expansion coefficients, the locking force of the pressing member 310 can change with the change of temperature, so that it has a significant locking effect at high temperatures, and automatically loosens after cooling, ensuring the reusability of the device.

[0111] Fig.15 FIG. 1 shows a schematic diagram of the arrangement of a pressing member and a matching portion according to one embodiment of the present application. Fig.13 or Fig.14In a variation of the embodiment, the fastening assembly 3 further includes a cooling channel 32 for realizing rapid cooling of the mating portion 30 and / or the pressing member 310 during the waiting process for the temperature change of the substrate when the substrate is disassembled. The cooling channel 32 may be as follows: Figure 5 As shown, it is arranged inside the matching part 30, and can also be arranged around the matching part 30 and / or inside or around the clamping member 31 in other embodiments, and is used to reduce the temperature of the matching part 30 and / or the clamping member 310 by flowing cooling medium during the contraction stage to achieve a stable and controllable expansion and contraction effect.

[0112] Fig.15 In the illustrated embodiment, the cooling channel 32 is disposed inside the mating portion 30. By constructing the cooling channel inside the material of the mating portion 30, the heat can be directly taken away by a flowing cooling medium (such as water, cooling oil or inert gas), thereby effectively reducing the temperature of the mating portion 30, so that the temperature of the mating portion 30 drops rapidly, which is beneficial to quickly reduce the temperature in the cooling stage after the high-temperature operation is completed, so as to accelerate the contraction process of the expansion part.

[0113] In other embodiments, the cooling channel 32 may also be arranged along the periphery of the mating portion 30 to form a surround cooling effect, and effective cooling may be achieved without affecting the overall structure of the mating portion 30. If it is necessary to more directly control the cooling speed of the pressing member 310, the cooling channel 32 may also be arranged inside or around the pressing member 310, and by appropriately improving the internal structure of the material of the pressing member 310, the cooling medium may directly contact or closely affect the pressing member 310, thereby achieving a precise temperature control effect.

[0114] By properly arranging the position and path of the cooling channel 32, the temperature of the mating part 30 and the pressing part 310 can be uniformly controlled, avoiding the thermal stress problem caused by excessive local cooling in the traditional cooling method. The flow rate, temperature and flow rate of the cooling medium can be adjusted to achieve a gradual change in temperature during the cooling process, so that the shrinkage process proceeds smoothly and orderly, reducing the thermal shock to the fastening component 3.

[0115] In some embodiments, the pressing member 310 may include any one or more structures of a square block, a wedge block, a lock, a screw, and a metal spring.

[0116] For example, in one implementation, the clamping member 310 includes a combination of a metal spring and a wedge block, wherein the metal spring can produce a gradual displacement as the temperature increases to push the wedge block to slide and clamp the mating portion 30, and as the temperature decreases, the metal spring applies a reverse force to the wedge block to cause it to gradually loosen contact with the mating portion 30.

[0117] Specifically, the metal spring piece, as an elastic structural element, can be, for example, bow-shaped or wavy, and can undergo elastic deformation when the temperature rises, resulting in a gradual displacement. The displacement is caused by the thermal expansion of the metal material under high temperature conditions. The special shape of the spring piece allows it to gradually stretch within a specific temperature range, thereby achieving continuous and controllable force output during temperature changes. The wedge block has a slidable structure. Under the thrust applied by the metal spring piece, the wedge block gradually slides into the groove of the mating portion 30, so that the clamping effect is gradually enhanced.

[0118] During the temperature rise process, the metal spring first produces thermal expansion, and gradually bends or stretches, causing the spring to produce a continuous and uniform thrust, pushing the wedge block to slide toward the groove of the matching part 30. Under the push of the metal spring, the wedge block enters the groove of the matching part 30. The geometric shape of the wedge block (such as the slope angle) can achieve sufficient pressing force within a limited displacement range. The wedge block gradually fills the space of the groove, making its contact with the matching part 30 closer, achieving a locking effect. When the temperature gradually decreases, the metal spring shrinks due to the temperature change, and its bending or wavy displacement gradually returns to its original state, exerting a reverse force on the wedge block, causing the wedge block to slide outward from the groove, thereby achieving loosening. Specifically, as the temperature gradually decreases, the metal spring gradually returns to its original shape and shrinks to produce a reverse displacement. This reverse force in turn acts on the wedge block, causing it to gradually move outward, reducing the squeezing force on the inner wall of the groove. Under the push of the reverse force of the metal spring, the wedge-shaped block gradually withdraws from the groove until the contact with the matching portion 30 is completely released, thereby achieving loosening. This process is gradual and does not require additional external force intervention.

[0119] The fastening assembly 3 is arranged in the preheating system. Fig.16 The base plate 10 is composed of a platform 101 for carrying building materials and clamping plates 102a and 102b respectively arranged at both ends of the platform 101, the matching portion 30 is arranged on the side wall of the clamping plates 102a and / or 102b (in other embodiments, it can also be arranged on the side wall of the platform 101), and the clamping portion 31 extends to cover at least a part of the side wall of the platform 101. The clamping plates 102a and 102b fix the platform 101 in the structure of the preheating system through the side wall.

[0120] The substrate 10 described here may be the substrate 10 disclosed above that is configured to have a narrower width (eg, about 2 mm) for use in an X-ray synchrotron diffraction (XRD) experiment in an additive manufacturing process.

[0121] The fastening assembly 3 also includes a tensioning portion 33, which includes springs 331a, 331b and a pull pin 332. One end of the springs 331a, 331b is connected to the end of the clamping portion 31 away from the substrate 10, and the other end is connected to the fixing portion 333; the pull pin 332 is arranged in the limiting groove 313 provided in the clamping portion 31, and can drive the clamping portion 31 to be tensioned in the direction of the fixing portion 333 under the push of external force to realize the loosening of the pressing member 310 on the matching portion 30, and realize the tensioning of the pressing member 310 on the matching portion 30 when the springs 331a, 331b rebound and reset. The springs 331a, 331b are in a natural state when not acted upon by external force, and provide tensioning force through elasticity to press the pressing member 310 tightly against the matching portion 30 to ensure the stability of the substrate 10. When an external force is applied, the pull pin 332 pushes the clamping portion 31 to move toward the fixing portion 333, thereby driving the pressing member 310 to disengage from the mating portion 30 to achieve a loosening effect. Conversely, when the external force is removed, the springs 331a and 331b are reset and generate a rebound force, bringing the clamping portion 31 back to its original position and restoring the tension on the mating portion 30. Through the action of the pull pin 332, the pressing member 310 can effectively control the mating portion 30 and achieve automatic adjustment.

[0122] It should be understood that the various processes and steps in the preheating assembly mentioned above can be used as the improved method of the present disclosure and constitute, for example, a preheating method for controlling an additive manufacturing machine. Although the specific content of this method has been described in detail above, in order to more clearly understand the core of the method involved in the present disclosure, the following reference Fig.17 (The structure and function of the components can be found in Figure 1-10 The main steps are briefly introduced in any of the attached drawings.

[0123] Fig.17 A schematic flow chart of a preheating method for an additive manufacturing machine according to one embodiment of the present application is shown.

[0124] The method 20 involved in the embodiment of the present application mainly includes the following steps 201 and 202.

[0125] 201. At least before constructing the three-dimensional object, drive the one or more heating units according to a predetermined temperature distribution to generate heat that can be transferred to the substrate in the form of thermal radiation and / or thermal conduction to preheat the substrate;

[0126] 202. Control the heat convergence portion to deflect and / or displace relative to the substrate to regulate the heat transfer path so that it is evenly converged to a predetermined area of ​​the substrate; wherein the predetermined temperature distribution corresponds to the material of the building material and / or the process parameters used to construct the three-dimensional object.

[0127] In some embodiments, the preheating method further comprises the following step: adjusting the heating power of the one or more heating parts according to a predetermined temperature distribution and the temperatures fed back by the plurality of temperature sensors.

[0128] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the contents disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art that are not disclosed in the present application. The specification and embodiments are to be regarded as exemplary only, and the present application is not limited to the precise structures described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof.

Claims

1. A preheating assembly for an additive manufacturing machine, comprising: a base plate for supporting building materials; One or more heating parts, the one or more heating parts are arranged around the substrate, and are used to generate heat that can be transferred to the substrate in the form of thermal radiation and / or thermal conduction to preheat the substrate at least before building the three-dimensional object; as well as A heat converging portion is arranged at the periphery of the substrate and is used to regulate the heat transfer path so as to uniformly converge the heat to a predetermined area of ​​the substrate. 2 . The preheating assembly according to claim 1 , wherein the heat converging portion comprises an optical element, which is arranged on the outside of the substrate and is used to reflect and / or refract the waves of the thermal radiation to guide the heat to the predetermined area.

3. The preheating assembly according to claim 2, wherein the optical elements are arranged in a plurality of configurations having the same or different focusing characteristics and arranged along one or more sides of the substrate, wherein the focusing characteristics include a radius of curvature or a focal length.

4. The preheating assembly according to claim 2 or 3, wherein the optical element comprises a lens and / or a first coating.

5. The preheating assembly according to claim 4, wherein the heat converging portion comprises an enclosure, the enclosure at least surrounding the substrate, the optical element and the one or more heating portions to limit the heat transfer path to the internal space of the enclosure. 6 . The preheating assembly according to claim 5 , wherein the first coating is distributed in the form of a single region or multiple regions on at least a portion of the inner wall of the enclosure.

7. The preheating assembly according to claim 1 further includes a posture adjustment unit, which is arranged to be connected to the heat convergence unit to drive the deflection and / or displacement of the heat convergence unit relative to the substrate according to a predetermined temperature distribution, wherein the predetermined temperature distribution corresponds to the material of the building material and / or the process parameters used to construct the three-dimensional object.

8. The preheating assembly according to claim 1 or 7, further comprising a plurality of temperature sensors and a temperature regulating part respectively connected to the plurality of temperature sensors, wherein the plurality of temperature sensors are distributed on one side or multiple sides of the substrate for temperature measurement, and the temperature regulating part is used to adjust the heating power of the one or more heating parts according to a predetermined temperature distribution and the temperature fed back by the plurality of temperature sensors.

9. The preheating assembly according to claim 1, wherein the heating portion comprises an electric heating element selected from any one of silicon carbide, molybdenum disilicide, tungsten and zirconium oxide.

10. The preheating assembly according to claim 1 further comprises a heat conducting portion, which is arranged between the one or more heating portions and the substrate and in contact with the substrate and spaced apart from the one or more heating portions, and is used for transferring the received heat transferred based on the thermal radiation to the substrate in the form of heat conduction.

11. An additive manufacturing machine comprising the preheating assembly according to any one of claims 1 to 10.

12. The additive manufacturing machine of claim 11, further comprising: A mating portion, the mating portion being formed on a side wall of the substrate and having a first thermal expansion coefficient (γ1); A clamping portion, the clamping portion is disposed on at least one side of the substrate and extends toward a side wall thereof to form a clamping member for clamping the matching portion; Wherein, the clamping member has at least a second thermal expansion coefficient (γ2) different from the first thermal expansion coefficient (γ1), so that as the temperature increases during heating, one of the mating part and the clamping member expands and applies pressure to the other side that remains relatively unchanged to gradually compress, and as the temperature decreases, the expanded side contracts and gradually loosens contact with the other side.

13. The additive manufacturing machine according to claim 12, wherein at least a portion of the surface of the mating part and / or the pressing part is coated with a second coating comprising any one of aluminum oxide (Al2O3), silicon nitride (Si3N4), silicon carbide (SiC), ceramics and nickel-based alloys.

14. The additive manufacturing machine according to claim 12, wherein the pressing member has: a first layer having the second coefficient of thermal expansion (γ2); a second layer, the second layer being disposed outside the first layer and having a third thermal expansion coefficient (γ3) and satisfying γ1<γ3<γ2; in, When the temperature rises, the first layer expands and pushes the second layer to apply pressure to the matching portion, while when the temperature drops, the first layer contracts to make the second layer gradually release contact with the matching portion.

15. The additive manufacturing machine according to claim 12, wherein the base plate is composed of a platform for carrying building materials and clamping plates respectively arranged at both ends of the platform, the matching portion is arranged on the side wall of the platform or the clamping plate, and the clamping portion extends to cover at least a portion of the side wall of the platform.

16. The additive manufacturing machine according to claim 15, further comprising a tensioning portion, the tensioning portion comprising: One or more springs, one end of each spring being connected to an end of the clamping portion away from the substrate, and the other end of each spring being connected to the fixing portion; A pull pin is arranged in a limiting groove provided in the clamping portion, and can drive the clamping portion to be tensioned toward the fixing portion under the push of an external force so as to realize the loosening of the matching portion by the clamping member, and realize the tensioning of the matching portion by the clamping member when the one or more springs rebound and reset.

17. A preheating method for an additive manufacturing machine, wherein the additive manufacturing machine comprises: a base plate for supporting building materials; One or more heating parts and heat converging parts arranged around the substrate; as well as a posture adjustment portion arranged to be connected to the heat converging portion; The preheating method comprises the following steps: At least before constructing the three-dimensional object, the one or more heating parts are driven to generate heat that can be transferred to the substrate in the form of thermal radiation and / or thermal conduction to preheat the substrate according to a predetermined temperature distribution, and the heat converging part is controlled to deflect and / or displace relative to the substrate to regulate the transfer path of the heat so that the heat is uniformly converged to a predetermined area of ​​the substrate; The predetermined temperature distribution corresponds to the material of the building material and / or the process parameters used to construct the three-dimensional object.

18. The preheating method according to claim 17, wherein the additive manufacturing machine further comprises a plurality of temperature sensors distributed on one or more sides of the substrate for measuring the temperature, wherein the preheating method further comprises the following steps: The heating power of the one or more heating parts is adjusted according to the predetermined temperature distribution and the temperatures fed back by the plurality of temperature sensors.

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