Uniform preheating method and device for large-size substrate

Abstract

The invention belongs to the technical field of additive manufacturing, and particularly discloses a uniform preheating method and device for a large-size substrate, and the device comprises an infrared preheating unit which is used for projecting a preheating light spot with adjustable wavelength and range to the upper surface of the large-size substrate; the bottom preheating unit is used for forming a preheating area with an adjustable preheating range at the bottom of the large-size substrate; the side preheating unit is located on the side of the large-size substrate and used for preheating the large-size substrate and a printed object on the upper surface of the large-size substrate; and the detection unit is used for detecting real-time temperature information of the large-size substrate and the printed object. The preheating device can solve the problem that the temperature gradient of the molten pool in additive manufacturing is high.

Description

Technical Field

[0001] The present application belongs to the field of additive manufacturing technology, and more specifically, relates to a method and device for uniformly preheating a large-size substrate. Background Art

[0002] LDED (Laser Directed Energy Deposition) technology is an additive manufacturing technology that uses laser as an energy source to melt metal wire / powder and deposit it onto a substrate to build a three-dimensional object. This technology is applicable to all types of metal materials and is currently widely used in aerospace, automobiles, mold repair, medical equipment and other fields.

[0003] However, when applying LDED technology, after the laser heats the metal wire / powder, the temperature of the metal wire / powder quickly exceeds the melting point of the metal to form a molten pool and quickly cools down, resulting in a high temperature gradient and cooling rate in the molten pool. This makes it easy for the grains to grow in a columnar shape along the direction of the maximum temperature gradient, causing the mechanical properties of the additive manufacturing forming material to show anisotropy. In addition, the thermal stress generated by the temperature difference can easily cause the printed object to deform or even crack, resulting in a decrease in product qualification rate and an increase in cost. This situation is particularly evident in the integrated forming of large-size equipment based on large-size substrates, and it is urgently needed to be improved. Summary of the invention

[0004] In response to the defects of the prior art or the need for improvement, the present application provides a method and device for uniformly preheating a large-size substrate, aiming to improve the problem of high temperature gradient of the molten pool in additive manufacturing.

[0005] The present application provides a large-size substrate uniform preheating device, which specifically includes: Infrared preheating unit, used to project a preheating light spot with adjustable wavelength and range onto the upper surface of large-size substrates; A bottom preheating unit, used to form a preheating zone with an adjustable preheating range at the bottom of a large-size substrate; A side preheating unit, located on the side of the large-size substrate, is used to preheat the large-size substrate and the printed matter on the upper surface of the large-size substrate; The detection unit is used to detect the real-time temperature information of the upper surface of the substrate.

[0006] Through the above technical scheme conceived by the present application, compared with the prior art, the present scheme integrates multiple preheating units such as infrared preheating unit, bottom preheating unit, side preheating unit, etc., which can form all-round preheating for large-size substrates and printed objects, and the preheating mode is flexible and adjustable, which can significantly increase the overall temperature of the printed object, significantly reduce the temperature gradient in the LDED (laser directed energy deposition) additive manufacturing process, increase the width and single-layer height of the single-pass cladding in the manufacturing process, and the phase change process (such as melting and solidification) of the material will be more gentle, which can reduce the uneven crystal structure, reduce macro and micro defects, effectively improve the problems of deformation and cracking of the printed object, and improve the quality of the finished product of the printed object.

[0007] In addition, based on the detection results of the detection unit, by adjusting the size and shape of the projection spot generated by the infrared preheating unit, and adjusting the preheating area range of the bottom preheating unit, the device can have a full-surface preheating mode and a local preheating mode, providing a variety of preheating modes, and the side preheating unit can ensure that the printed objects on large-size substrates and their upper surfaces maintain a more uniform temperature during the printing process, reduce warping and deformation caused by uneven heat, and thus improve printing quality.

[0008] As further preferred, the preheating light spot includes a central light spot and an outer ring light spot distributed around the central light spot, and the temperature of the central light spot is greater than the temperature of the outer ring light spot.

[0009] As a further preference, the temperature ratio of the central light spot to the outer ring light spot is 1:0.8.

[0010] As a further preference, a plurality of the side preheating units are provided, and the plurality of side preheating units are distributed at intervals along the circumference of the large-size substrate.

[0011] As further preferred, the bottom preheating unit has a plurality of sub-heating zones arranged side by side and capable of being independently switched on and off, and the plurality of sub-heating zones constitute the preheating zone.

[0012] As further preferred, the preheating device also includes a turntable, the large-size substrate and the bottom preheating unit are stacked and arranged at the center of the rotating surface of the turntable, and the side preheating unit is arranged at the edge of the rotating surface of the turntable.

[0013] As further preferred, the preheating device also includes a heat insulation structure, and the heat insulation structure is arranged at the bottom of the bottom preheating unit.

[0014] As further preferred, the preheating device further comprises a lens unit, and the preheating light spot generated by the infrared preheating unit is transmitted to the large-size substrate through the lens unit.

[0015] A preheating method provided in the second aspect of the present application adopts the following technical solution: A preheating method, based on any one of the large-size substrate uniform preheating devices described in the first aspect, comprises starting an infrared preheating unit, a bottom preheating unit and a side preheating unit to preheat the large-size substrate in the entire area before printing, until a detection unit detects that the real-time temperature of the large-size substrate reaches a preset temperature; During the printing process, the infrared preheating unit and the bottom preheating unit are adjusted to generate a real-time forming surface of the corresponding printed object, a designated feature part, or a preheating spot and a preheating area accompanying the movement of the printing laser beam, so that the infrared preheating unit and the bottom preheating unit are in a local preheating mode.

[0016] As further preferred, the preheating method further comprises: After each printing layer is finished, turn off the infrared preheating unit; Before printing the next printing layer, when the detection unit detects that the current molding surface has a low temperature area lower than the preset temperature range, the infrared preheating unit is started to preheat the low temperature area, so as to start the printing of the next printing layer after the temperature of the low temperature area reaches the preset temperature range, and the infrared preheating unit is adjusted to the local preheating mode when printing is started, and When the current molding surface does not have a low-temperature area below the preset temperature range, the next printing layer is directly printed, and the infrared preheating unit adopts a local preheating mode for preheating when printing starts.

[0017] In general, the above technical solutions conceived by this application have the following technical advantages compared with the prior art: 1. This solution integrates multiple preheating units such as infrared preheating unit, bottom preheating unit, side preheating unit, etc., which can form all-round preheating for large-size substrates and printed objects, and the preheating mode is flexible and adjustable, which can significantly increase the overall temperature of the printed object and reduce the temperature gradient in the LDED additive manufacturing process. The phase change process of the material will be more gentle, which can reduce the uneven crystal structure, reduce macro and micro defects, effectively improve the deformation and cracking of the printed object, improve the quality of the printed object, and facilitate the high-quality integrated forming of large-size equipment on large-size substrates.

[0018] 2. Based on the detection results of the detection unit, the device can adjust the size and shape of the projection spot generated by the infrared preheating unit, as well as the preheating area of ​​the bottom preheating unit, to achieve switching between the whole-surface preheating mode and the local preheating mode. The side preheating unit can ensure that the printed objects on the large-size substrate and its upper surface maintain a more uniform temperature during the printing process, reduce the warping and deformation caused by uneven heat, and thus improve the printing quality.

[0019] 3. During the layer-by-layer printing process, the infrared preheating unit of the device can provide heat to the molding surface in the form of a central light spot and an outer ring light spot. In particular, before printing the next layer, the light spot is used to preheat the low-temperature area at a fixed point, so that the temperature of the low-temperature area rises to the preset temperature range before the next printing layer can be started. When printing the next layer, the infrared preheating unit will be started and adjusted to the local preheating mode to preheat a specific area, thereby significantly reducing the temperature gradient and cooling speed during the printing operation and improving the printing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the principle of a large-size substrate uniform preheating device provided in an embodiment of the present application; Figure 2 is a schematic diagram of the optical path of the bottom preheating unit and the laser provided in an embodiment of the present application; Figure 3 It is a schematic diagram of a turntable, a bottom preheating unit and a large-size substrate provided in an embodiment of the present application; Figure 4 This is a schematic diagram of the zoned preheating principle of the crawler heater provided in an embodiment of the present application.

[0021] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1. Infrared preheating unit; 2. Large-size substrate; 3. Bottom preheating unit; 3-1. Crawler heater; 3-2. Temperature control box; 4. Side preheating unit; 5. Detection unit; 6. Center light spot; 7. Outer ring light spot; 8. Lens unit; 9. Heat insulation structure; 10. Turntable; 11. Laser; 12. Feeding extrusion mechanism. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] The following is combined with Figure 1-Figure 4 This application is described in further detail.

[0024] The present application embodiment discloses a large-size substrate uniform preheating device. Figure 1-Figure 4The large-size substrate uniform preheating device comprises an infrared preheating unit 1, a bottom preheating unit 3, a side preheating unit 4 and a detection unit 5, wherein the infrared preheating unit 1 is used to project a preheating light spot with an adjustable wavelength and range onto the upper surface of the large-size substrate 2; the bottom preheating unit 3 is used to form a preheating zone with an adjustable preheating range at the bottom of the large-size substrate 2; the side preheating unit 4 is located on the side of the large-size substrate 2, and the side preheating unit 4 is used to preheat the large-size substrate 2 and the printed matter on the upper surface of the large-size substrate 2; the detection unit 5 is used to detect the real-time temperature information of the large-size substrate 2 and the printed matter.

[0025] Under this design, the device can adjust the size and shape of the projection spot generated by the infrared preheating unit 1 and the preheating area range of the bottom preheating unit 3 based on the detection results of the detection unit 5, so as to realize the switching between the whole surface preheating mode and the local preheating mode. The side preheating unit 4 can ensure that the large-size substrate 2 and the printed material on its upper surface maintain a more uniform temperature during the printing process, reduce the warping and deformation caused by uneven heat, and thus improve the printing quality.

[0026] In the full-surface preheating mode, the infrared preheating unit 1 generates a uniform solid projection pattern that fully covers the entire upper surface of the large-size substrate 2, and the bottom preheating unit 3 generates a preheating zone that preheats the entire bottom of the large-size substrate 2.

[0027] In the local preheating mode, the infrared preheating unit 1 generates a light spot pattern covering the current printing layer (or forming surface) of the printed object, the designated characteristic parts, or accompanying the movement of the laser beam (the range of the light spot pattern should cover and be larger than the range of the laser beam), and the bottom preheating unit 3 generates a preheating zone that changes with the position change of the laser beam (the range of the preheating zone should be larger than the range of the laser beam) for preheating the current printing layer (or forming surface) of the printed object, the designated characteristic parts, or accompanying the position adjustment of the laser beam. In actual application, the preheating forms such as preheating the current printing layer (or forming surface) of the printed object, preheating the designated specific parts, and adjusting the position of the laser beam position can be pre-set according to the needs, so that only one of the local preheating forms is executed when the local preheating mode is running.

[0028] Under the design of this scheme, this scheme integrates multiple preheating units such as infrared preheating unit 1, bottom preheating unit 3, side preheating unit 4, etc., which can form all-round preheating for large-size substrate 2 and printed objects, and the preheating mode is flexible and adjustable, which can significantly improve the overall temperature of the printed object, and the preheating accuracy is extremely high. It can significantly reduce the temperature gradient in the LDED (laser directed energy deposition) additive manufacturing process, increase the width and single-layer height of a single-pass cladding in the manufacturing process, and the phase change process (such as melting and solidification) of the material will be more gentle, which can reduce the uneven crystal structure, reduce macro and micro defects, and effectively improve the deformation and cracking problems of printed objects.

[0029] Specifically, in some embodiments, the infrared preheating unit 1 includes an infrared light machine, which can generate a projection light spot with adjustable size, shape and wavelength based on the principle of digital light processing to meet the preheating / heating requirements of different printing materials. Generally speaking, the preheating temperature can be adjusted by adjusting the output power of the infrared light machine. Among them, the principle of digital light processing is a prior art and will not be described in detail here.

[0030] Further, such as Figure 2 As shown, in some embodiments, the projection light spot generated by the infrared preheating unit 1 includes a central light spot 6 and an outer ring light spot 7 distributed around the central light spot 6, wherein the temperature of the central light spot 6 is greater than the temperature of the outer ring light spot 7, and the temperature ratio of the central light spot 6 to the outer ring light spot 7 is preferably 1:0.8.

[0031] In this design, when the infrared preheating unit 1 is working, the central light spot 6 generated by it preferably plays the role of central heating and temperature rise, which can provide sufficient energy to maintain the stability of the molten pool, and the outer ring light spot 7 is preferably used for preheating and heat preservation, especially suitable for preheating and heat preservation in the local preheating mode. This temperature distribution of the central light spot 6 and the outer ring light spot 7 can provide better energy flowability and fusion during the cladding or filling process, which is conducive to forming a smoother surface.

[0032] In actual use, by adjusting the temperature and size corresponding to the central light spot 6 and the outer ring light spot 7, the temperature can be adaptively adjusted to the uneven temperature field, and the temperature difference in the thermal imbalance area can be adjusted to avoid the phenomenon that the temperature difference generates thermal stress and causes deformation or even cracking of the printed matter.

[0033] In actual use, the infrared preheating unit 1 can also be made to generate only the central light spot 6 when working. Generally speaking, before the printing job, the infrared preheating unit 1 is enabled to be in the whole surface preheating mode of generating only the central light spot 6, so as to generate a uniform solid projection pattern that fully covers the entire upper surface of the large-size substrate 2. After the printing job is started, the infrared preheating unit 1 is enabled to be in the local preheating mode of generating the central light spot 6 and the outer ring light spot 7.

[0034] Furthermore, in some embodiments, the device also includes a lens unit 8, and the preheating light spot generated by the infrared preheating unit 1 is transmitted and deflected to the upper surface of the large-size substrate 2 through the lens unit 8. The lens unit 8 usually includes lenses such as a beam combiner and a reflector, which are used to deflect and transmit the preheating light spot.

[0035] In some embodiments, the lens unit 8 further includes an automatic adjustment mechanism for adjusting the lens posture and spatial position, so as to adjust the position, size and other characteristics of the preheating spot by adjusting the lens posture and spatial position. The adjustment mechanism is prior art and will not be described in detail here.

[0036] In some preferred embodiments, the lens unit 8 can also be used in printing of printed objects. For example, it is used to deflect the laser light generated by the laser 11 to the surface of the large-sized substrate 2 for deposition printing. Taking the metal wire deposition solution as an example, Figure 2 As shown, the feeding mechanism 12 works to feed the metal wire to the large-size substrate 2, and the laser beam generated by the laser 11 passes through the lens unit 8 and is superimposed with the infrared light path generated by the infrared preheating unit to act on the surface of the raw material, and deposition begins. Among them, the feeding mechanism 12 and the metal wire are both in a misaligned state with the lens unit 8 in space.

[0037] Furthermore, in some embodiments, the bottom preheating unit 3 has a plurality of sub-heating zones arranged side by side and capable of being independently switched on and off, and the plurality of sub-heating zones constitute a preheating zone.

[0038] Specifically, if Figure 2 and Figure 3 The bottom preheating unit 3 preferably adopts a crawler heating system, which includes a crawler heater 3-1 and a temperature control box 3-2, wherein the crawler heater 3-1 is connected to a digital display regulator in the temperature control box 3-2 through an AC contactor, and the temperature digital display regulator sets the preheating temperature. The large-sized substrate 2 is placed on the crawler heater 3-1 and can be preheated by the crawler heater 3-1.

[0039] Furthermore, in some specific embodiments, the track heater 3-1 generates heat energy in the form of resistance wire heating. Figure 4 As shown, the resistance heating wire forms a "bow"-shaped circuitous sub-heating zone in the heater to ensure that the heating efficiency is maximized within the heating area. The resistance wire is protected by a high-temperature resistant and insulating ceramic sheet. The size of the crawler heater 3-1 can be customized according to the needs of specific working conditions. The heating area can be adjusted by selecting different sub-heating zones (i.e. Figure 4 In other embodiments, the bottom preheating unit 3 may also adopt a heating mechanism / component / device of other heating forms.

[0040] In order to avoid the potential safety hazard caused by the powder being deposited on the crawler heater 3-1 during the LDED printing process, in this embodiment, Figure 3 As shown, the track heater 3-1 is completely hidden under the large-size substrate 2 and is sealed all around.

[0041] In order to transfer heat to the large-size substrate 2 to the maximum extent, the preheating device also includes a heat insulation structure 9, which is arranged at the bottom of the crawler heater 3-1. The heat insulation structure 9 is preferably made of aluminum silicate fiber.

[0042] Furthermore, the side preheating unit 4 is arranged in a direction perpendicular to the large-size substrate 2, and the side preheating unit 4 can remain in an open state throughout the whole process and can set the temperature; the side preheating unit 4 includes but is not limited to using a heater.

[0043] In some embodiments, to improve the preheating effect, multiple side preheating units 4 are provided, and the multiple side preheating units 4 are distributed at intervals along the circumference of the large-size substrate 2. For example, two side preheating units 4 are provided, and the two side preheating units 4 are mirror-imaged at both ends of the radial direction of the large-size substrate 2.

[0044] Furthermore, in some embodiments, the preheating device further comprises a turntable 10, which is preferably a large-size servo turntable, wherein the large-size substrate 2, the bottom preheating unit 3 and the heat insulation structure 9 are stacked from top to bottom at the center of the rotating surface of the turntable 10, and the side preheating unit 4 is arranged at the edge of the rotating surface of the turntable 10.

[0045] Under this design, on the one hand, as the turntable 10 rotates, the relative position between the preheated part (such as a large-size substrate 2, a printed object) and the laser and infrared preheating unit 1 can be adjusted to ensure that the material is melted or deposited at the optimal temperature during the printing process, thereby improving the printing quality. On the other hand, after printing is completed, the rotation can accelerate the dissipation of heat and improve the cooling efficiency. This is very beneficial for maintaining the structural integrity of the material and preventing defects (such as cracks) caused by uneven cooling.

[0046] It should be noted that, in order to facilitate the display of the temperature control box 3-2, Figure 2 and Figure 3 In the figure, the temperature control box 3 - 2 of the bottom preheating unit 3 is shown outside the turntable 10 . Actually, the temperature control box 3 - 2 is also installed in the turntable.

[0047] Furthermore, the detection unit 5 includes but is not limited to a thermal imaging thermometer, which is used to detect the temperature field and preheating effect of the molding surface in real time.

[0048] In some embodiments, the device also includes a controller (not shown in the figure), which is electrically connected to the infrared preheating unit 1, the bottom preheating unit 3, the side preheating unit 4, the detection unit 5, the lens unit, the turntable and other structures. The controller is used to control the start and stop of each structure and the adjustment of operating parameters and modes based on the detection results of the detection unit 5, and the controller can manually adjust parameters, modes, etc. to improve the preheating efficiency while ensuring the safety of the heating process. It is suitable for large components and engineering site applications; among them, the control principle of the controller is the existing technology and will not be elaborated here.

[0049] The present application also discloses a preheating method based on any of the above-mentioned large-size substrate uniform preheating devices. The preheating method includes: S1: Before the printing job starts, the infrared preheating unit 1 and the bottom preheating unit 3 are started in the full-surface preheating mode, and the side preheating unit 4 is started to preheat the large-size substrate 2 in the entire area until the detection unit 5 detects that the real-time temperature of the large-size substrate 2 reaches the preset temperature to complete the preheating before printing.

[0050] During this process, the user can set the preheating temperature according to needs and adjust the power of the infrared preheating unit 1, the bottom preheating unit 3 and the side preheating unit 4.

[0051] S2: During the printing operation, the infrared preheating unit 1 and the bottom preheating unit 3 are adjusted to the local preheating mode. The infrared preheating unit 1 generates a preheating spot corresponding to the current printing layer of the printed object, the specified characteristic part, or the range of movement of the laser beam, which covers the laser beam (the spot pattern range generally covers and is larger than the laser beam range). The bottom preheating unit 3 generates a preheating zone corresponding to the current printing layer of the printed object, the specified characteristic part, or the range of movement of the laser beam accompanying printing, which is not less than the laser beam range, so as to adjust the preheating temperature.

[0052] In this process, the controller can be adjusted according to demand to pre-select a specific preheating scheme for the local preheating mode, that is, the local preheating mode can be pre-selected as any one of the schemes of preheating the current printing layer of the printed object, preheating a designated feature portion, preheating with the movement of the laser beam, etc., and then the preheating device can be operated according to this scheme during the printing operation.

[0053] S3: After the printing job is completed, the side preheating unit 4, the infrared preheating unit 1, the bottom preheating unit 3 and the detection unit 5 are closed in sequence.

[0054] In some embodiments, the shutdown sequence of the units can be adjusted or they can be shut down simultaneously.

[0055] Furthermore, in some embodiments, step S2 also includes the following specific process: In the printing operation, after each printing layer is printed, the infrared preheating unit 1 is immediately turned off or delayed for a certain period of time to allow the printing layer to cool down and set.

[0056] The delay time is set according to the demand. Generally speaking, the higher the number of printing layers, the shorter the delay closing time; and the closing time can be set, preferably controlled or determined according to the detection situation of the detection unit 5.

[0057] When the cooling reaches the specified time, or the detection unit 5 detects that the temperature of the current molding surface of the printed object basically reaches the temperature requirement for printing the next layer, if the detection unit 5 detects that the current molding surface of the printed object has a low-temperature area lower than the preset temperature range, the infrared preheating unit 1 is started to preheat the low-temperature area. The printing of the next printing layer can be started only after the temperature of the low-temperature area rises back to the preset temperature range. When starting the printing of the next printing layer, the infrared preheating unit 1 is adjusted to the local preheating mode.

[0058] The basic condition for detecting that the current molding surface temperature of the printed object has basically reached the temperature requirement for the next layer of printing is that the highest point of the current real-time temperature of the molding surface is not higher than the upper limit of the preset temperature range. Generally speaking, the preset temperature range is usually determined based on the material properties. Printing within this set temperature range can avoid overheating of the printed material. Of course, the preset temperature range can be preset and adjusted by personnel.

[0059] For example, taking TiAl material as an example, the preset temperature range of the material is set to 800℃-900℃. When the detection unit 5 detects that the current molding surface of the printed object has a low-temperature area below 800℃, the infrared preheating unit 1 is started to preheat the low-temperature area. After the temperature of the low-temperature area rises to 800℃, the printing of the next printing layer can be started.

[0060] When the current molding surface does not have a low-temperature area below the preset temperature range, the next printing layer is directly printed, and the infrared preheating unit 1 is started as a local preheating mode.

[0061] Example: This scheme takes titanium aluminum alloy (Ti6Al4V) additive manufacturing as an example, and its specific implementation process is as follows: S1: Turn on the whole surface preheating mode to preheat the entire surface of the large-size substrate 2, and set the crawler heater 3-1, infrared light machine and heater power according to the preheating temperature requirements.

[0062] S2: After preheating for 5-10 seconds, turn on the laser 11 to perform the first layer deposition printing, and adjust the crawler heater 3-1 and the infrared light machine to the local preheating mode. After the first layer deposition printing is completed, immediately turn off or delay turning off the infrared light machine.

[0063] S3: Use a thermal imaging thermometer to monitor the temperature field of the current molding surface. If the temperature of all areas of the current molding surface is within the set temperature setting value range, the next layer of deposition printing is directly started; if the temperature of an area is lower than the set value range, the infrared light machine is started based on the detection result of the thermal imaging thermometer to perform local preheating on the specific low-temperature area. After the temperature of the low-temperature area reaches the temperature setting value range, the next layer of deposition printing is performed, and the infrared light machine is adjusted to the local preheating mode. After the deposition printing of the printing layer is completed, the infrared light machine is immediately turned off or delayed.

[0064] S4: Repeat step S3 to preheat the printed material layer by layer.

[0065] S5: After completing all printing jobs, turn off the side preheating unit 4, infrared light machine and crawler heater 3-1 and other components in sequence.

[0066] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations or constituent elements, and do not limit one or more additional functions, operations and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components or combinations thereof.

[0067] It should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0068] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0069] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0070] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A large-size substrate uniform preheating device, characterized in that: include: An infrared preheating unit (1) is used to project a preheating light spot with adjustable wavelength and range onto the upper surface of a large-sized substrate (2); A bottom preheating unit (3) is used to form a preheating zone with an adjustable preheating range at the bottom of the large-sized substrate (2); A side preheating unit (4), located on the side of the large-size substrate (2), and used for preheating the large-size substrate (2) and the printed matter on the upper surface of the large-size substrate (2); The detection unit (5) is used to detect real-time temperature information of the large-size substrate (2) and the printed matter.

2. The large-size substrate uniform preheating device according to claim 1, characterized in that: The preheating light spot comprises a central light spot (6) and an outer ring light spot (7) distributed around the central light spot (6), and the temperature of the central light spot (6) is greater than the temperature of the outer ring light spot (7).

3. The large-size substrate uniform preheating device according to claim 2, characterized in that: The temperature ratio between the central light spot (6) and the outer ring light spot (7) is 1:0.

8.

4. The large-size substrate uniform preheating device according to claim 1, characterized in that: A plurality of the side preheating units (4) are provided, and the plurality of side preheating units (4) are distributed at intervals along the circumference of the large-size substrate (2).

5. The large-size substrate uniform preheating device according to claim 1, characterized in that: The bottom preheating unit (3) has a plurality of sub-heating zones arranged side by side and capable of being independently switched on and off, and the plurality of sub-heating zones constitute the preheating zone.

6. The large-size substrate uniform preheating device according to any one of claims 1 to 5, characterized in that: The preheating device also includes a turntable (10), the large-size substrate (2) and the bottom preheating unit (3) are stacked and arranged at the center of the rotating surface of the turntable (10), and the side preheating unit (4) is arranged at the edge of the rotating surface of the turntable (10).

7. The large-size substrate uniform preheating device according to any one of claims 1 to 5, characterized in that: The preheating device further comprises a heat insulation structure (9), wherein the heat insulation structure (9) is arranged at the bottom of the bottom preheating unit (3).

8. The large-size substrate uniform preheating device according to any one of claims 1 to 5, characterized in that: The preheating device also includes a lens unit (8), and the preheating light spot generated by the infrared preheating unit (1) is transmitted to the large-size substrate (2) through the lens unit (8).

9. A preheating method, based on a large-size substrate uniform preheating device as claimed in any one of claims 1 to 8, characterized in that: include: Before the printing operation, the infrared preheating unit (1), the bottom preheating unit (3) and the side preheating unit (4) are started to preheat the entire area of ​​the large-size substrate (2) until the detection unit (5) detects that the real-time temperature of the large-size substrate (2) reaches a preset temperature; During the printing process, the infrared preheating unit (1) and the bottom preheating unit (3) are adjusted to generate a real-time forming surface of a corresponding printed object, a designated characteristic part, or a preheating spot and a preheating area accompanying the movement of a printing laser beam, so that the infrared preheating unit (1) and the bottom preheating unit (3) are in a local preheating mode.

10. The preheating method according to claim 9, characterized in that: The preheating method also includes: After each printing layer is printed, the infrared preheating unit (1) is turned off; Before printing the next printing layer, when the detection unit (5) detects that the current molding surface has a low temperature area below a preset temperature range, the infrared preheating unit (1) is started to preheat the low temperature area, so as to start printing the next printing layer after the temperature of the low temperature area reaches the preset temperature range, and the infrared preheating unit (1) is adjusted to a local preheating mode when printing is started, and When the current molding surface does not have a low-temperature area below the preset temperature range, the next printing layer is directly printed, and the infrared preheating unit (1) adopts a local preheating mode for preheating when printing starts.

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