A high-throughput material additive processing method and apparatus

Abstract

The application relates to a high-flux material additive processing method, belonging to the field of additive manufacturing, which comprises the following steps: wire feeding to an additive area, energy supply for the wire; a plurality of lasers are shot into a molten pool area around the wire, and the plurality of lasers are aggregated in the molten pool; the powder is delivered in multiple ways, and each way of powder delivery is coaxial delivery around a laser. The application has the effects of improving the preparation efficiency, flexibility and forming quality of high-flux materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing, in particular to a high-throughput material additive processing method and device. BACKGROUND

[0002] In the field of material science, high-throughput material preparation is of great significance for rapid screening and development of new materials. Traditional material preparation methods are often time-consuming and inefficient, making it difficult to meet the needs of high-throughput preparation. With the development of additive manufacturing technology, it has shown unique advantages in material preparation, but the existing additive manufacturing process still has some limitations in preparing high-throughput materials. For example, traditional additive manufacturing technology usually relies on a single energy source, which cannot achieve the best material heat treatment effect in some cases for different types of materials and different forming needs. Moreover, the uniform distribution of powder and melting efficiency are difficult to guarantee when the powder is transported from the laser off-axis to the molten pool area, resulting in directional anisotropy of the formed material. At the same time, different powders have large differences in laser absorption rate, which may lead to insufficient energy utilization, increasing processing time and reducing efficiency. SUMMARY

[0003] In order to improve the preparation efficiency, flexibility and forming quality of high-throughput materials, the present application provides a high-throughput material additive processing method and device.

[0004] The high-throughput material additive processing method provided by the present application adopts the following technical scheme:

[0005] A high-throughput material additive processing method, comprising the following steps:

[0006] Feeding wire to the additive area to provide energy for the wire;

[0007] Surrounding the wire with multiple lasers to shoot into the molten pool area, and the multiple lasers are aggregated in the molten pool.

[0008] The powder is transported in multiple ways, and each way of powder is transported coaxially around a laser.

[0009] By adopting the technical scheme, the power supply for the wire current can be a hot wire power supply or a fuse power supply. When a high-flux material is prepared by using a multi-laser processing technology, the hot wire power supply can preheat the wire. When the high-flux material is prepared by using an arc-laser composite technology, the arc and the multi-laser act simultaneously to provide multi-source energy and quickly melt the material, thereby significantly improving the processing efficiency and the stability of the molten pool. In addition, the multi-laser can be set to different wavelengths to adapt to the light absorption characteristics of different powders, enhance the melting efficiency of the powder, further improve the processing efficiency, and ensure the optimal energy absorption of different materials. When each powder feeding nozzle feeds the same mixed material, the mixed material is uniformly distributed around the laser spot regardless of the moving direction of the deposition head, thereby reducing the problem of material anisotropy and ensuring the uniformity of the deposited material.

[0010] When each powder feeding nozzle feeds different single powders, the arc action can enhance the stirring of the molten pool, promote the uniform distribution of the powder in the molten pool, improve the microstructure of the material by refining the grains, reduce the directional difference, and improve the deposition quality. Compared with the traditional single-side powder feeding mode, the powder is uniformly fed around the laser, which enables more powder to directly contact the high-temperature area, fully absorbs the laser energy, and improves the melting efficiency and material utilization rate.

[0011] The powder feeding amount of each powder feeding nozzle can be independently adjusted to support the manufacturing of variable-component gradient materials, meet the diversified demand for different material performance requirements, and improve the flexibility and adaptability of additive manufacturing.

[0012] Optionally, before the arc is introduced, an inner layer of protective gas is fed to the current additive area, and an outer layer of protective gas is fed to the surroundings of the additive area, and the outer layer of protective gas is sprayed from the rear of the moving direction of the deposition head.

[0013] By adopting the technical scheme, the inner layer of protective gas mainly acts on the current additive area, protects the atmosphere of the molten pool area, ensures the stability and purity of the molten pool, avoids the entry of oxygen or moisture in the air into the molten pool, thereby reducing the oxidation reaction of the material, significantly improving the deposition quality and material performance, and ensuring the purity of the material during the additive process.

[0014] The outer layer of protective gas acts on the surroundings of the additive area, especially the area just completed by additive. Since the temperature of the area after additive is still high, the risk of oxidation is large, and therefore the outer layer of protective gas can effectively avoid the oxidation of the material, ensure that there is no excessive oxidation reaction during the additive process, and maintain the ideal chemical environment of the additive area. In addition, the outer layer of protective gas can also accelerate the cooling of the area after the additive is completed, thereby avoiding overheating and reducing the performance of the material.

[0015] Meanwhile, the outer protective gas can also reduce the temperature between the additive layers, reduce the thermal gradient, and prevent excessive grain growth caused by overheating between the layers. By reducing the temperature fluctuations in the additive area, the outer protective gas helps to refine the grains, thereby improving the strength and durability of the material, and providing better structural performance for the finished product in the additive manufacturing process.

[0016] Optionally, the preset laser parameters, arc parameters, protective gas parameters, powder feeding parameters, and wire feeding parameters;

[0017] During the deposition process, the molten pool state is monitored in real time, the molten pool information is obtained, and the laser parameters, arc parameters, protective gas parameters, powder feeding parameters, and wire feeding parameters are automatically corrected by the system according to the equipment conditions.

[0018] By adopting the above technical solutions, the laser parameters, arc parameters, protective gas parameters, powder feeding parameters, and wire feeding parameters are dynamically corrected according to the molten pool information by real-time monitoring of the molten pool state, and the system can automatically adapt to changes in actual processing. This real-time adjustment ensures the stability of the molten pool and the uniformity of the material deposition process, and the process parameters are corrected according to the actual situation, which can effectively control the microstructure of the material and improve the processing precision. Especially in complex additive processes, different materials and different processing environments may cause fluctuations in the molten pool state. This adaptive adjustment can effectively cope with these fluctuations, reduce human operation errors, ensure the high quality of the final product, and ensure the repeatability and reliability of high-throughput material preparation;

[0019] The energy input of laser and arc, the feeding amount of powder and wire, and the flow rate of protective gas all directly affect the energy utilization efficiency in the additive process. By automatically adjusting these parameters according to real-time molten pool information, the system can accurately control energy input and avoid unnecessary energy waste.

[0020] Optionally, the method for setting and correcting the laser parameters is:

[0021] The laser parameter value is preset according to the type of material and the target performance;

[0022] During the deposition process, the laser power is corrected according to the formula where P is the laser power, m is the mass of the material melted per unit time, C p is the specific heat capacity of the material, △T is the temperature change of the material from room temperature to the melting point, L f is the latent heat of fusion of the material, t is the laser action time, and η is the laser energy utilization rate. The laser action time is adjusted in combination with process factors, and then the laser power is corrected.

[0023] By adopting the above technical scheme, according to the experience, the laser processing power is preset, in the manufacturing process of high-throughput materials, the laser action time depends on multiple factors, such as material type, processing area, process parameters and part geometry, etc., and the system re-corrects the laser power according to the adjusted laser action time. By synchronously adjusting the laser power and action time, the utilization rate of laser energy can be effectively improved, the molten pool temperature and melting process can be accurately controlled, the deformation and residual stress in the processing process can be reduced, and the quality and performance of the material can be improved.

[0024] Optionally, when using composite laser for deposition, according to the absorption characteristics of different wavelength lasers in the material, according to the formula: And P1: P2: P3...p n = α (λ1) × η1: α (λ2) × η2: α (λ3) × η3... α (λ n ) × η n , the power parameters of each laser are adjusted and distributed, wherein A and n are constants related to the material, λ is the wavelength, η is the laser energy utilization rate, and P is the laser power.

[0025] By adopting the above technical scheme, in the multi-wavelength laser composite process, the power distribution of different wavelength lasers also needs to consider the absorption characteristics of each wavelength in the material, and the above method can fine-tune the adjusted laser power again to achieve the best energy coupling effect and further improve the deposition quality.

[0026] Optionally, the setting and correction method of the arc parameter is:

[0027] According to the type and target performance of the material, preset the arc current and wire feeding speed parameter values, that is, the preset parameter values of the arc voltage and arc power can be obtained;

[0028] In the deposition process, the arc power is adjusted according to the formula Q arc = μv s (C wire (T m -T0)+L melt ), wherein Q arc is the heat input of the arc, μ is the arc efficiency, Vs is the wire feeding speed, L melt is the latent heat of fusion of the wire material, C wire is the specific heat capacity of the wire material, T m is the melting point of the wire material, and T0 is the room temperature.

[0029] By adopting the technical scheme, the laser processing power is preset according to experience, in the manufacturing process of high-throughput materials, especially in the variable composition gradient material, the composition proportion of the wire material will also change, therefore, according to the change of the wire feeding speed, the change of the room temperature detected at the same time (which can usually be ignored), the system also timely corrects the arc power. The change of the material concentration can be adapted, the adjustment of the arc power can ensure that the appropriate melting condition is maintained at all times, the energy waste or deficiency caused by the excessively high or low heat input is avoided, the energy efficient transmission is realized, the deposition efficiency is improved, the defects caused by the heat fluctuation are reduced, and the performance of the gradient material is ensured to meet the expectation.

[0030] Optionally, the method for setting and correcting the protective gas is as follows:

[0031] The inner layer protective gas flow rate and the outer layer protective gas flow rate are preset;

[0032] During the deposition process, the inner layer protective gas flow rate and the outer layer protective gas flow rate are adjusted according to the formula Q=vAa, wherein Q is the protective gas flow rate, v is the flow rate of the protective gas on the surface of the molten pool, A is the surface area of the molten pool, and a is the flow rate coefficient, which is valued according to the actual situation;

[0033] At the same time, the inner layer protective gas pressure P g ≥ p l gh , wherein P g is the inner layer protective gas pressure, h is the depth of the molten pool, p l is the metal density, and g is the acceleration of gravity.

[0034] By adopting the technical scheme, the protective gas flow rate is preset according to experience, during the deposition process, the surface area of the molten pool and other factors will change under the action of different laser arcs, and then the flow rate coefficient also needs to be adjusted, at the same time, the inner layer protective gas also needs to have a corresponding gas pressure for preventing the molten pool metal from overflowing, therefore, after the protective gas flow rate is adjusted once, the inner layer protective gas pressure can be adjusted again.

[0035] In combination with the above method, the flow rates of the outer layer protective gas and the inner layer protective gas can be adjusted in real time, the covering effect of the protective gas is accurately controlled, and the stability of the molten pool is ensured. The appropriate inner layer protective gas pressure can provide sufficient support force, avoid excessive expansion or spatter of the metal, reduce the risk of molten pool overflow, enhance the stability of the gas flow and avoid turbulence, optimize the surface atmosphere of the molten pool, and effectively optimize the deposition quality. At the same time, the utilization efficiency of the protective gas can be improved, and the waste of excessive protective gas is reduced.

[0036] Optionally, the method for setting and correcting the powder feeding and wire feeding parameters is as follows:

[0037] According to the material composition and structure requirements, the wire / powder feeding speed of each layer is preset;

[0038] In the deposition process, according to the formula F = K * V * A / p ρVAC , and according to the equipment situation, the proportional coefficient K is set to adjust the powder / silk rate, F is the powder / silk rate, p is the powder / silk material density, V is the deposition speed, A is the cross-sectional area of the molten pool, and C is the proportion of the powder / silk material in the target composition;

[0039] When the composition gradient material of the multi-layer structure is formed, a mathematical model of the change of the material composition with time and space is established for control, according to the formula: Where C is the composition concentration, t is the time, and D is the diffusion coefficient, so as to preset the time point t of the composition concentration switching;

[0040] In the deposition process, according to the formula: Where D0 is the diffusion constant, Q is the diffusion activation energy, R is the gas constant, and T is the molten pool temperature. By monitoring the molten pool temperature in real time, the time t of the composition concentration switching is corrected.

[0041] By adopting the above technical scheme, the silk rate and powder rate are preset according to experience, and in the process of manufacturing high-throughput materials, especially in the deposition process of variable component gradient materials and parts with complex geometry, the silk rate and powder rate are corrected in time according to the actual cross-sectional area of the molten pool. And the powder and silk concentration switching process of each layer of material also needs to accurately control the switching time and transition area to avoid composition mutation affecting the material performance. By establishing a mathematical model to preset the time point of completing the switching of the corresponding material concentration, and then adjusting according to the detected molten pool temperature in the actual deposition process, the composition is accurately controlled, which is beneficial to improve the quality of variable component gradient materials.

[0042] Optionally, in the deposition process, the laser power and arc power should also be corrected according to the molten pool temperature detection data, according to the formula: P new = P old + K p (T ref -T actual ), where P new is the adjusted power, P old is the current power, K p is the proportional coefficient, T ref is the reference temperature, and T actual is the actual molten pool temperature.

[0043] By adopting the above technical scheme, according to the monitored molten pool temperature, the laser power and arc power are corrected again by using the above method, which is beneficial to further enhance the stability of the molten pool, improve the energy utilization rate and adapt to the dynamic change of the molten pool, thereby further improving the molten pool shape and material properties.

[0044] The high-throughput material additive manufacturing device provided by the application adopts the technical scheme as follows:

[0045] A high-throughput material additive manufacturing device for realizing the high-throughput material additive manufacturing method described above, comprising a wire feeding assembly and a mounting seat, wherein a plurality of coaxial powder feeding nozzles and a plurality of mirror module are arranged on the mounting seat, the mirror module corresponds to the coaxial powder feeding nozzle one by one, the mirror module is connected with a fiber plug, and a plurality of coaxial powder feeding nozzles are arranged around the wire feeding assembly, and the wire feeding assembly is provided with an electrified tube;

[0046] The wire material passes through the electrified tube and is conveyed through the wire feeding assembly, and the laser is emitted along the central axis of the coaxial powder feeding nozzle, the coaxial powder feeding nozzle is provided with an annular powder feeding channel around its own central axis, so that the powder is fed around the laser, and a plurality of lasers intersect with the central axis of the wire material at the same point;

[0047] The mirror module is provided with an air inlet, the air inlet is communicated with the laser conveying channel of the coaxial powder feeding nozzle, the side of the coaxial powder feeding nozzle away from the wire feeding assembly is provided with an air inlet pipe, the air inlet is used for conveying inner protective gas, the air inlet pipe is used for conveying outer protective gas, and the coaxial powder feeding nozzle is provided with a powder feeding pipe communicated with the annular powder feeding channel.

[0048] By adopting the above technical scheme, each fiber plug can emit different types of laser independently and realize independent real-time adjustment, a plurality of coaxial powder feeding nozzles can also realize independent powder adjustment, the electrified tube is electrified to realize the arc additive function, the cooperation of the air inlet and the air inlet pipe realizes the conveying of the inner protective gas and the outer protective gas, and the powder can be uniformly distributed around the laser, so that the powder uniformly absorbs the laser energy. Therefore, the above device can realize arc wire additive manufacturing, laser wire additive manufacturing, laser powder additive manufacturing, laser-arc composite wire additive manufacturing, laser-arc composite wire-powder additive manufacturing and other additive manufacturing methods, so as to realize the above-mentioned manufacturing method and improve the manufacturing efficiency and quality of high-throughput materials.

[0049] In summary, the present application has at least one of the following beneficial technical effects:

[0050] 1. The method realizes the synergistic effect of multiple energy sources and raw materials, greatly improves the efficiency and flexibility of material preparation, and is especially suitable for the preparation of high-throughput materials. The multi-wavelength laser composite can select the optimal wavelength combination according to the material characteristics to improve the energy absorption efficiency; the laser-arc composite can enhance the stirring of the molten pool, refine the grains and improve the material performance; the double-path protective gas composite ensures the stability and purity of the molten pool; and the wire-powder composite realizes the diversification control of ingredients.

[0051] 2. By precisely controlling process parameters such as multi-wavelength laser, laser arc, dual-path protective gas, and wire powder, element quantification can be achieved accurately, composition segregation can be effectively avoided, and high-quality variable composition gradient materials, in-situ alloyed materials, and high-entropy alloys can be prepared. The forming complexity and size range are greatly expanded. Complex process parameter calculation formulas and control strategies ensure accurate regulation of material composition and structure during preparation, meeting the requirements of high-throughput materials for composition diversity and performance uniformity;

[0052] 3. The parameters in the preparation process can be adjusted in real time, improving the stability and accuracy of the preparation process, and ensuring the repeatability and reliability of high-throughput material preparation. The closed-loop control system and model-based parameter optimization method enable the device to dynamically adjust the process parameters according to the actual situation, adapting to changes in different materials and process conditions. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a flowchart of the high-throughput material manufacturing method according to an embodiment of the present application.

[0054] Figure 2 is a schematic diagram of the overall structure of embodiment 3 of the present application.

[0055] Figure 3 is a schematic diagram of the structure of the ring-shaped powder feeding channel and laser output channel according to embodiment 3 of the present application.

[0056] BRIEF DESCRIPTION OF DRAWINGS 1, wire feeding assembly; 2, mounting seat; 3, coaxial powder feeding nozzle; 31, ring-shaped powder feeding channel; 32, laser delivery channel; 33, powder feeding pipe; 34, gas inlet pipe; 4, mirror module; 41, gas inlet; 5, fiber plug; 6, power supply pipe. DETAILED DESCRIPTION

[0057] The following will be described in detail in combination with the accompanying Figures 1-3 Further detailed description of the present application.

[0058] The present application discloses a high-throughput material additive processing method.

[0059] As Figure 1 , the high-throughput material additive processing method comprises the following steps:

[0060] S1, according to the characteristics and requirements of the required prepared material, select the appropriate equipment configuration, accurately prepare a plurality of metal powder or wire raw materials according to the designed composition of the high-throughput material, and the particle size, purity and other parameters of the raw materials meet the requirements of the equipment. Pre-set process parameters such as laser parameters, arc parameters, protective gas parameters, powder feeding parameters and wire feeding parameters;

[0061] S2, turn on the inner and outer protective gas;

[0062] S3, vertically feeding the wire to the additive area, and connecting the power supply to the wire;

[0063] S4, surrounding the wire with multiple lasers into the molten pool area, the multiple lasers are aggregated in the molten pool, so that the multiple lasers intersect with the central axis of the wire at the same point, and the multiple lasers are asymmetric about the central axis of the wire;

[0064] S5, the powder is delivered in multiple paths, and each path of the powder is coaxially delivered around a laser;

[0065] S6, starting the equipment, controlling the robot to move the deposition head according to the preset slice path planning, and performing layer-by-layer deposition of the material;

[0066] S7, during the deposition process, using the Tardis IGNIS MP200 molten pool camera and picture acquisition software (including dry elongation recognition) in the extended configuration to monitor the molten pool state in real time, obtaining information such as molten pool size and temperature distribution. At the same time, based on the dry elongation recognition data, the process intelligent collaborative optimization plug-in automatically optimizes the wire feeding rate, powder feeding rate, laser power, arc power, inner protective gas flow rate, outer protective gas flow rate, and robot movement speed, and corrects the layer height;

[0067] S8, after the preparation is completed, the necessary post-processing is performed on the formed piece, the support structure (if any) is removed, heat treatment is performed to eliminate residual stress, surface polishing is performed, etc., to improve the performance and surface quality of the material. The selection of heat treatment process parameters (temperature, time, heating rate and cooling rate, etc.) needs to be determined according to the material type, the residual stress state in the forming process and the target performance, which can be predicted and optimized through thermal simulation analysis software;

[0068] The prepared high-throughput material is subjected to performance testing and analysis, such as using X-ray diffraction (XRD), scanning electron microscope (SEM), mechanical property testing, etc., to evaluate the material's organizational structure, composition uniformity and mechanical properties, etc., to verify the effectiveness of the preparation method and whether the material performance meets the expectations.

[0069] In step S1, according to the type of material and the target performance, the power, frequency, scanning speed, etc. of the multi-wavelength laser are preset. For example, for some refractory metal materials, the laser power can be appropriately increased (such as the total power can reach 1500W or more) and the scanning speed can be reduced to ensure that the material is fully melted and fused; for materials sensitive to heat, the laser power can be reduced and the scanning speed can be increased to reduce the heat effect.

[0070] In step S7, during the deposition process, the formula Where P is the laser power, m is the mass of the material melted per unit time, Cp is the specific heat capacity of the material, △T is the temperature change of the material from room temperature to the melting point, Lf is the latent heat of fusion of the material, t is the laser action time, η is the laser energy utilization rate, the laser action time is adjusted in combination with the process factors, and the laser power is then corrected.

[0071] If there are multiple types of lasers and powder, multiple lasers need to be corrected again. When using composite lasers for deposition, according to the absorption characteristics of different wavelengths of laser in the material, according to the formula:

[0072] And P1: P2: P3...P n = α (λ1) × η1: α (λ2) × η2: α (λ3) × η3... α (λ n ) × η n , the power parameters of each laser are adjusted and distributed, where A and n are constants related to the material, λ is the wavelength, η is the laser energy utilization rate, and P is the laser power.

[0073] At the same time, after the laser power is corrected as described above, it should also be finally corrected according to the detected molten pool temperature. According to the formula: P new = P old + K p (T ref -T actual ), where P new is the adjusted power, P old is the current power, K p is the proportionality coefficient, T ref is the reference temperature, and T actual is the actual molten pool temperature. Therefore, through the above method, the laser power can be adjusted in time during the deposition process, effectively improving the utilization rate of laser energy, accurately controlling the molten pool temperature and the melting process, reducing the deformation and residual stress in the processing process, and improving the quality and performance of the material.

[0074] In step S1, in the composite laser-arc deposition process, the preset of the arc power is determined according to the type of the material, the target performance and the heat input requirement in the deposition process. First, the arc current, voltage and wire feeding rate are preset to calculate the preliminary value of the arc power. The following empirical formula can be referred to for specific calculation: Where I is the arc current, k is a coefficient related to the material, P arc is the arc power, and V is the arc voltage.

[0075] For refractory metal materials such as tungsten and molybdenum, the arc power can be appropriately increased (e.g., the arc power can be set to 200-400 W) to enhance the material melting capacity; while for heat-sensitive materials such as aluminum and magnesium, the arc power can be reduced (e.g., 50-150 W) and the wire feeding rate can be adjusted to control the heat input to avoid high temperature causing thermal damage.

[0076] In step S7, during the deposition process, the arc power is adjusted according to the formula Q arc = μv s (C wire (T m -T0) + L melt , where Q arc is the heat input of the arc, μ is the arc efficiency, Vs is the wire feeding speed, L melt is the latent heat of the wire material, C wire is the specific heat capacity of the wire material, T m is the melting point of the wire material, and T0 is the room temperature.

[0077] In the variable composition gradient material, the composition ratio of the wire material also changes, so according to the change of the wire feeding speed, the room temperature change (which can usually be ignored) is detected at the same time, and the arc power is timely corrected by the system.

[0078] Meanwhile, after the above correction of the arc power, the detected molten pool temperature should also be used for the final correction. According to the formula: P new = P old + K p (T ref -T actual ), where P new is the adjusted power, P old is the current power, K p is the proportional coefficient, T ref is the reference temperature, and T actual is the actual molten pool temperature. Therefore, through the above method, the arc power can be timely adjusted during the deposition process, effectively improving the utilization rate of laser energy, accurately controlling the molten pool temperature and melting process, reducing the deformation and residual stress in the processing process, and improving the quality and performance of the material.

[0079] In step S1, the flow rate of the protective gas is preset based on the type of material, the heat input during the deposition process, and the stability requirements of the molten pool. First, the flow rates of the inner and outer protective gases are preset to ensure the protection of the molten pool and prevent material oxidation. For high-melting-point metals, such as titanium alloys and stainless steel, the inner protective gas flow rate is typically set relatively high (e.g., 10-20 L / min) to provide sufficient atmosphere protection and prevent oxidation and contamination. The outer protective gas flow rate is set to 5-10 L / min depending on the actual situation to effectively avoid the influence of ambient gases on the additive manufacturing area, while rapidly cooling the newly deposited area to prevent material oxidation at high temperatures. For heat-sensitive materials (such as aluminum alloys), the outer protective gas flow rate can be increased to quickly remove excess heat and improve the forming quality of the material.

[0080] In step S7, during the deposition process, changes in factors such as the surface of the molten pool are detected, and the flow rates of the inner and outer protective gas are adjusted according to the formula Q = vAα, where Q is the flow rate of the protective gas, v is the velocity of the protective gas on the surface of the molten pool, A is the surface area of ​​the molten pool, and α is the flow coefficient, which is selected according to the actual situation, such as the temperature of the molten pool, the type of protective gas, the airflow mode, and environmental factors, etc.

[0081] At the same time, the inner protective gas pressure P should also be guaranteed. g ≥ p l gh Where Pg is the inner protective gas pressure, h is the molten pool depth, and ρ l Where Pg is the metal density and g is the acceleration due to gravity. Under normal circumstances, the Pg value meets the above requirements. If the Pg value does not meet the requirements, the flow rate of the inner protective gas layer needs to be appropriately increased. This ensures a stable and pure molten pool, effectively preventing material oxidation and providing better structural properties for the finished product in the additive manufacturing process.

[0082] In step S1, the feeding rates of the filament and each type of powder are preset according to the material composition, target performance, and deposition process requirements. The feeding rates of the filament and powder affect the material supply and composition distribution of the molten pool, thereby affecting the melting process and final quality of the material.

[0083] A suitable wire feeding rate is preset based on the wire diameter, material, melting point, and the proportion of the target component. For example, for high-melting-point metal wires, a lower wire feeding rate may be needed to ensure sufficient melting and synthesis.

[0084] The powder feeding rate is preset based on the powder's particle size, melting point, absorption characteristics, and the proportion of the target component. For powders with smaller particle sizes, a higher feeding rate is usually required to improve deposition efficiency.

[0085] In step S7, during the deposition process, according to the formula F = ρVACAccording to the device condition, a proportional coefficient K is set to adjust the powder / silk rate, F is the powder / silk rate, p is the powder / silk material density, V is the deposition speed, A is the molten pool cross-sectional area, and C is the proportion of the powder / silk material in the target component. According to the monitoring of the change of the molten pool cross-sectional area, the change of the device deposition speed and the change of the proportion of the powder / silk material, the silk rate and the powder rate are corrected in time.

[0086] In step S1, when the composition gradient material of the multi-layer structure is formed, the powder and silk concentration switching process of each layer of material also needs to accurately control the switching time and the transition area to avoid the influence of composition mutation on the material performance, and therefore a mathematical model of the change of the material composition with time and space needs to be established for control. According to the formula: wherein C is the composition concentration, t is the time, and D is the diffusion coefficient, so as to preset the time point t of completing the switching of the composition concentration;

[0087] In step S7, during the deposition process, according to the formula: wherein D0 is the diffusion constant, Q is the diffusion activation energy, R is the gas constant, and T is the molten pool temperature. The time t of switching the composition concentration is corrected by real-time monitoring of the molten pool temperature, so as to realize the accurate control of the composition and improve the quality of the variable composition gradient material.

[0088] Example 1

[0089] Preparation of variable composition gradient material by using arc laser composite process

[0090] In the device selection and preparation, a laser with red and blue composite wavelengths, six powder feeding and arc and hot wire functions are selected. According to the product configuration table, the components of the device are installed and debugged to ensure that the laser system, powder feeding system, arc system and robot motion system are in normal operation. Three kinds of metal powder with different compositions are prepared and loaded into the corresponding powder feeder. The powder particle size is controlled within 80-150 μm.

[0091] Process parameter setting and correction during deposition

[0092] Laser power setting: the near-infrared laser power is set to 800 W, and the blue laser power is set to 300 W; the laser scanning speed is 50 mm / s; and the laser spot diameter is 1 mm.

[0093] Arc parameter setting: the arc current is set to 150 A, the voltage is set to 20 V, and the wire feeding speed is set to 5 m / min.

[0094] Protection gas parameter setting: the inner layer protection gas argon flow is set to 15 L / min, and the inner layer protection gas argon flow is set to 8 L / min.

[0095] The powder feeding rate is set: according to the gradient material design, the powder feeding rates of the three kinds of powder gradually change from 2 g / min to 0.5 g / min, from 0.5 g / min to 1.5 g / min, and from 1.5 g / min to 0.5 g / min from the bottom layer to the top layer.

[0096] The device is started, and the path generated by the slicing path planning software is used to control the robot to drive the deposition head to deposit layer by layer. The slicing path planning uses a finite element analysis optimization algorithm to simulate the stress distribution under different paths and selects the path with the smallest stress for deposition. During the deposition process, the molten pool camera is used to monitor the molten pool state in real time, and the parameters and robot motion speed are automatically optimized according to the monitoring data.

[0097] According to the monitoring data of the molten pool, the laser and arc power are adjusted in real time:

[0098] The first correction of laser power is estimated according to the thermal physical properties of the material. The specific heat capacity of the first material is 0.5 J / (g.℃), the melting point is 1500℃, the room temperature is 25℃, the latent heat of fusion is 300 J / g, the mass of the melted material per unit time is 0.5 g / s, the laser action time is 0.1 s, and the laser energy utilization rate is 0.6. By substituting the formula, the near-infrared laser power is about 792 W. The blue light laser power can be determined according to the material's absorption characteristics of blue light and other factors.

[0099] At the same time, considering that the blue light wavelength is 450 nm and the near-infrared wavelength is 1064 nm, for this material, assuming A=10000 and n=4 in the blue light absorption coefficient formula, A=5000 and n=3 in the near-infrared light absorption coefficient formula, the blue light energy utilization rate is 0.55, and the near-infrared energy utilization rate is 0.65. According to the power distribution ratio formula, the blue light power and near-infrared power ratio is about 0.37:1, which can be used to adjust the blue light again.

[0100] That is, the blue light power and near-infrared power ratio is about 0.37:1, which can be used to adjust the blue light again. Finally, according to the actual molten pool temperature monitored, the formula P new old +K p (T ref -T actual ) is used to fine-tune the power of red and blue light to complete the third correction.

[0101] The first correction of arc power is based on the arc heat input formula. Assuming that the specific heat capacity of the wire material is 0.4 J / (g.℃), the melting point is 1400℃, the room temperature is 25℃, the latent heat of fusion is 350 J / g, the arc efficiency is 0.7, the wire feeding speed is 5 m / min, and the wire material density is 7 g / cm 3 ​, diameter is 1.2mm, the calculated arc heat input is about 3200W, in the arc additive process, it is generally recognized that the electric energy is completely converted into heat energy, so the set arc power 3000W is corrected to 3200W, and then the arc parameters are further corrected according to the molten pool state and the material forming effect, combined with the formula P new = P old + K p (T ref -T actual ).

[0102] The first correction of the protective gas flow is based on the molten pool size (the molten pool length is 5mm, the width is 5mm, and the surface area is 25mm2=2.5×10-5m 2 ) and the protective gas flow rate on the molten pool surface is 0.5m / s, the flow coefficient is taken as 1.2, and the formula is substituted to calculate that the inner layer protective gas flow is about 15L / min, so it does not need to be adjusted, and the outer layer protective gas flow can be adjusted and calculated according to the actual situation. At the same time, considering that the molten pool depth is 2mm, the liquid metal density is 8g / cm 3 , and the gravitational acceleration is 9.8m / s 2 , the protective gas pressure is at least 156.8Pa according to the protective gas pressure formula, which can be adjusted within a suitable range according to the equipment situation and the stability of the molten pool in actual operation, that is, the second correction can be completed.

[0103] The powder / speed rate is corrected, the first powder material density is p1=8g / cm 3 , the deposition speed is V1=1cm / min, the molten pool cross-sectional area is A1=0.1cm 2 , and the proportion of the powder material in the target composition in the bottom layer is C1=0.8 (the initial value is higher), so the bottom layer powder feeding rate F1= p1V1 A1 C1=8×1×0.1×0.8=0.64g / min. According to the equipment situation, the correction coefficient K value is taken as 3, so the bottom layer powder feeding rate of the first material is finally corrected from 2g / min to 0.96×3=1.92g / min. The corresponding powder feeding rate of each layer is calculated, and the powder feeding rate and wire feeding rate of the other two powders can be calculated in the same way. In the calculation process, the flowability of the powder and the accuracy of the powder feeding system also need to be considered, and the accuracy of the powder feeding rate is ensured through actual test and adjustment.

[0104] The composition ratio switching time point is corrected, different powder feeding channels are switched layer by layer according to the preset program, the composition gradient change is realized, and a variable component gradient material with a thickness of 10mm is prepared. The raw material switching process controls the composition gradient according to the diffusion equation, and the diffusion coefficient is 10-6cm 2The switching time and the transition area are controlled by calculation to ensure smooth transition of the composition. For example, when switching between two kinds of powder, the length of the transition area is estimated according to the size of the molten pool and the deposition speed. Assuming that the length of the molten pool is 5 mm and the deposition speed is 1 cm / min, the length of the transition area is about 5 mm. The time required for smooth transition of the composition in the transition area is calculated according to the diffusion equation, so as to correct the time point of switching the raw material. Then, the time point of switching the raw material is corrected again according to the actual temperature of the molten pool detected.

[0105] Post-processing and detection

[0106] The support structure of the formed part is removed, and the formed part is subjected to heat treatment at 500 DEG C for 2 hours to eliminate residual stress, and then subjected to surface polishing. The heat treatment process parameters are optimized by a thermal simulation analysis software to ensure that the residual stress is effectively eliminated and does not affect the material properties. During the heat treatment process, the stress change during the heat treatment process is predicted according to the thermal expansion coefficient and the elastic modulus of the material and other parameters, and the appropriate heating rate, holding time and cooling rate are selected to avoid the generation of new cracks or deformation.

[0107] The material is detected by XRD and SEM, and the results show that the composition of the material is gradient distribution, the structure is uniform, and there is no obvious defect, which verifies the effectiveness of the method of the application in preparing variable composition gradient material. XRD analysis shows that the crystal structure and phase composition of different layers meet the expectation, and SEM observation shows that the microstructure of the material is uniform, and there is no obvious hole, crack and composition segregation phenomenon, which further proves the reliability of the process.

[0108] Example 2

[0109] Preparation of high-entropy alloy by multi-laser processing technology

[0110] A suitable model device is selected, which is a full blue wavelength, double-path powder feeding device with a hot wire function. The installation and commissioning of the device are completed to ensure that each system works normally. Five kinds of high-purity metal powders (Fe, Co, Ni, Cr, Mn) are prepared, mixed uniformly and then loaded into the double-path powder feeder, and the powder particle size is 80-150 μm.

[0111] Process parameter setting and correction

[0112] The blue laser power is set to 1200 W, the laser frequency is 50 KHz, and the scanning speed is 30 mm / s. The laser power is corrected according to the average thermophysical properties of the high-entropy alloy. According to the average specific heat capacity of the mixed powder of 0.45 J / (g. DEG C), the average melting point of 1400 DEG C, the room temperature of 25 DEG C, the average melting latent heat of 280 J / g, the mass of the melted material per unit time of 0.4 g / s, the laser action time of 0.12 s, and the energy utilization rate of 0.55, the power is calculated to be about 1185 W by substituting the formula, and the first correction is performed.

[0113] During the deposition process, the molten pool situation is monitored by the molten pool camera, the process parameters are adjusted by the intelligent collaborative optimization plug-in to ensure the stability of the molten pool. The molten pool temperature monitoring data feedback controls the laser power, the reference temperature is 1500℃, the actual monitoring temperature is 1480℃, the proportional coefficient Kp=50, the current blue laser power is 1185W, according to the formula, the adjusted power Pnew=1185+50×(1500-1480)=1285W, and the laser power is adjusted in real time to maintain the stability of the molten pool temperature.

[0114] The hot wire current is set to 100A, and the hot wire wire feeding speed is 3m / min. The hot wire current is determined according to the heat demand of the material and the heating efficiency of the hot wire, to ensure that enough heat is provided to melt the powder uniformly. The heating power Pwire of the hot wire is related to the resistance R and current I of the hot wire, which can be calculated by the formula Pwire=I2R. The resistance R is determined according to the material characteristics and size of the hot wire, and then the heating power is calculated, which is compared with the heat required for melting the material to adjust the hot wire current to achieve the best heating effect.

[0115] The inner layer protective gas flow rate is set to 12L / min of argon, and the outer layer protective gas flow rate is set to 6L / min of argon. According to the size of the molten pool (molten pool length 4mm, width 4mm, surface area 16mm 2 =1.6×10-5m 2 ) and the protective gas flow rate (0.4m / s), the flow coefficient is 1.1, and the main flow rate is calculated to be about 11.5L / min and corrected. At the same time, considering the molten pool depth of 1.5mm, the liquid metal density of 7.5g / cm 3 , and the gravitational acceleration g=9.8m / s 2 , the protective gas pressure is calculated to be at least 110.25Pa, and the protective gas pressure is adjusted in actual operation to ensure the stability of the molten pool.

[0116] The powder feeding rate of the double-channel is set to 1.5g / min. The powder feeding rate calculation: assuming the average density of the mixed powder is p mix =7g / cm 3 , the deposition speed is V2=0.8cm / min, and the cross-sectional area of the molten pool is A2=0.08cm 2 , since the proportion of the five kinds of powder in the high-entropy alloy is roughly the same (C equal =0.2), then the powder feeding rate F mix =p mix V2 A2C equal =7×0.8×0.08×0.2=0.896g / min. According to the flowability of the powder, the accuracy of the powder feeding system, and the appropriate excess powder feeding to ensure the uniformity of the high-entropy alloy composition, the correction coefficient K is 2, that is, the powder feeding rate is corrected to F mix= 2 x 0.896g = 1.792g / min. During the powder feeding process, the vibration frequency and gas flow of the powder feeder need to be adjusted according to the particle size distribution and shape factor of the powder and other parameters to ensure stable powder delivery.

[0117] The deposition is continued until a high-entropy alloy sample with a size of 50mm x 50mm x 5mm is prepared. During the deposition process, the layer height error is corrected by real-time monitoring of the layer height change and using an intelligent collaborative optimization plug-in to ensure the size accuracy of the sample. For example, when the layer height deviation is monitored to be more than 0.05mm, the powder feeding rate and robot movement speed are automatically adjusted to restore the layer height to the normal range.

[0118] Post-processing and detection

[0119] The sample is line-cut to obtain a test sample, and then hardness testing and microstructure analysis are performed. The test results show that the prepared high-entropy alloy has uniform hardness and a typical disordered structure, proving the feasibility of the method in the preparation of high-entropy alloys. The hardness test results show that the hardness value fluctuates little within a certain range, indicating good composition uniformity. Microstructure analysis by SEM shows that the elements in the high-entropy alloy are uniformly distributed without obvious segregation and agglomeration, and XRD analysis confirms the formation of the expected solid solution phase, further verifying the effectiveness of the process.

[0120] Example 3

[0121] The application also provides a high-throughput material additive manufacturing equipment for implementing the high-throughput material additive manufacturing method of the application.

[0122] As Figure 2 and Figure 3 A high-throughput material additive manufacturing equipment, comprising a wire feeding assembly 1 and a mounting seat 2, the wire feeding assembly 1 passing through and being fixed on the mounting seat 2, the wire feeding assembly 1 being located at the center of the mounting seat 2, the wire feeding assembly 1 being used for conveying wire materials and keeping the wire materials coaxial with the mounting seat 2.

[0123] The bottom of the mounting seat 2 is provided with six coaxial powder feeding nozzles 3, the coaxial powder feeding nozzles 3 being provided with an annular powder feeding channel 31 and a laser conveying channel 32, the annular powder feeding channel 31 being arranged around the laser conveying channel 32, the six coaxial powder feeding nozzles 3 being arranged around the wire feeding assembly 1 and all being directed towards the wire feeding assembly 1, all the coaxial powder feeding nozzles 3 being asymmetric about the central axis of the mounting seat 2, and the central axes of all the coaxial powder feeding nozzles 3 being compared with the central axis of the mounting seat 2 at the same point.

[0124] The top of the mounting base 2 is provided with six mirror group modules 4, which correspond to the coaxial powder feeding nozzles 3 one by one. Each mirror group module 4 is connected with an optical fiber plug 5. The laser passes through the mirror group module 4 and is sent out through the laser delivery channel 32 of the coaxial powder feeding nozzle 3, and the laser is coaxial with the central axis of the coaxial powder feeding nozzle 3. Therefore, when processing, the central axes of all the lasers intersect with the central axis of the wire at a point.

[0125] An air inlet 41 is formed on the mirror group module 4, which is in communication with the laser delivery channel 32 of the coaxial powder feeding nozzle 3. The side of the coaxial powder feeding nozzle 3 away from the wire feeding assembly 1 is provided with an air inlet pipe 34. The coaxial powder feeding nozzle 3 is also provided with at least two powder feeding pipes 33, which are in communication with the annular powder feeding channel 31. The air inlet 41 is used to deliver the inner protective gas, and the air inlet pipe 34 is used to deliver the outer protective gas. The wire feeding assembly 1 is provided with an electrically conductive pipe 6 through which the wire passes.

[0126] The optical fiber plug 5 can use various existing suitable products, and SMA905, D80, QCS, QBH, etc. can be generally used. The electrically conductive pipe 6 can be connected with a hot wire power supply / MIG additive melting wire power supply / MAG additive melting wire power supply, etc.

[0127] The mirror group module 4 contains a collimating lens group and a focusing lens group. The collimating lens group collimates the laser beam introduced through the optical fiber plug 5, so that the laser rays in the laser beam are parallel to each other. The focusing lens group focuses the parallel laser beam so that it irradiates within the set range on the workpiece, melts the workpiece base material and the additive material to form a molten pool.

[0128] Each optical fiber plug 5 can emit different types of laser individually and achieve independent real-time adjustment. Multiple coaxial powder feeding nozzles 3 can also achieve independent powder adjustment. By applying electricity to the electrically conductive pipe 6, the hot wire and arc additive functions can be realized. The cooperation of the air inlet 41 and the air inlet pipe 34 realizes the delivery of the inner protective gas and the outer protective gas, and the powder can be uniformly distributed around the laser, so that the powder uniformly absorbs the laser energy. Therefore, the above device can realize arc melting wire additive, laser melting wire additive, laser powder feeding additive, laser arc composite wire feeding additive, laser arc composite wire and powder feeding additive, etc. multiple additive methods, thereby realizing the above processing method and improving the manufacturing efficiency and quality of high-throughput materials.

[0129] The above are preferred embodiments of the present application, which do not limit the protection scope of the present application. Therefore, any equivalent changes made on the basis of the structure, shape, and principle of the present application should be covered by the protection scope of the present application.

Claims

1. A high-throughput additive manufacturing method for materials, characterized in that: Includes the following steps: Feeding filaments to the additive manufacturing area provides energy to the filaments; Multiple laser beams are directed around the wire and into the molten pool area, where the laser beams converge within the molten pool. The powder is conveyed in multiple paths, with each path of powder being conveyed coaxially around a laser. The method for setting and correcting laser parameters is as follows: Preset laser parameter values ​​based on the type of material and target properties; During the deposition process, according to the formula Where P is the laser power, m is the mass of material melted per unit time, Cp is the specific heat capacity of the material, ΔT is the temperature change of the material from room temperature to melting point, Lf is the latent heat of fusion of the material, t is the laser treatment time, and η is the laser energy utilization rate. The laser treatment time is adjusted in combination with process factors, and then the laser power is corrected. The methods for setting and correcting powder feeding and wire feeding parameters are as follows: Preset the wire / powder feeding rate according to the material composition and structural requirements; During the deposition process, according to the formula Then, adjust the powder / filament feeding rate by setting the proportional coefficient K according to the equipment conditions. F is the powder / filament feeding rate, ρ is the density of the powder / filament material, V is the deposition rate, A is the cross-sectional area of ​​the molten pool, and C is the proportion of the powder / filament material in the target composition. When developing multilayered materials with gradually varying compositions, a mathematical model is established to control the changes in material composition over time and space, based on the formula: Where C is the component concentration, t is time, and D is the diffusion coefficient, the time point t at which the component concentration completes the switching is preset; During the deposition process, according to the formula: Where D0 is the diffusion constant, Q is the diffusion activation energy, R is the gas constant, and T is the molten pool temperature. The time t for switching component concentrations is corrected by real-time monitoring of the molten pool temperature.

2. The high-throughput material additive manufacturing method according to claim 1, characterized in that: Before introducing the electric arc, an inner protective gas is supplied to the current additive manufacturing area, and an outer protective gas is supplied to the surrounding area of ​​the additive manufacturing area. The outer protective gas is controlled to be injected from behind the direction of the deposition head movement.

3. The high-throughput material additive manufacturing method according to claim 2, characterized in that: Preset laser parameters, arc parameters, protective gas parameters, powder feeding parameters, and wire feeding parameters; During the deposition process, the molten pool status is monitored in real time to obtain molten pool information. Based on the equipment conditions, the system automatically corrects the laser parameters, arc parameters, protective gas parameters, powder feeding parameters, and wire feeding parameters.

4. The high-throughput material additive manufacturing method according to claim 1, characterized in that: When using composite lasers for deposition and considering the absorption characteristics of different wavelengths of laser light in materials, according to the formula: and The power parameters of each laser are adjusted and allocated, where A and n are material-related constants, λ is the wavelength, η is the laser energy utilization rate, and P is the laser power.

5. The high-throughput material additive manufacturing method according to claim 3, characterized in that: The method for setting and correcting arc parameters is as follows: Based on the type of material and the target performance, the preset values ​​of arc current and wire feeding speed can be used to obtain the preset values ​​of arc voltage and arc power. During the deposition process, according to the formula The arc power is adjusted, where Q arc The heat input of the electric arc is μ, the arc efficiency is Vs, the wire feed speed is L melt C is the latent heat of fusion of the wire. wire T represents the specific heat capacity of the wire. m T0 is the melting point of the wire, and T0 is room temperature.

6. The high-throughput material additive manufacturing method according to claim 3, characterized in that: The method for setting and correcting the protective gas is as follows: Preset the inner protective gas flow rate and the outer protective gas flow rate; During the deposition process, according to the formula The flow rates of the inner and outer protective gases are adjusted, where Q is the protective gas flow rate, v is the velocity of the protective gas on the surface of the molten pool, A is the surface area of ​​the molten pool, and α is the flow coefficient, which is selected according to the actual situation. At the same time, the pressure of the inner protective gas layer should also be guaranteed. Where Pg is the inner protective gas pressure, h is the molten pool depth, and ρ l Let g be the density of the metal and g be the acceleration due to gravity.

7. The high-throughput material additive manufacturing method according to claim 3, characterized in that: During the deposition process, the laser power and arc power should be corrected a second time based on the molten pool temperature monitoring data, according to the formula: , where P new For the adjusted power, P old For the current power, K p T is the proportionality coefficient. ref For reference temperature, T actual This represents the actual molten pool temperature.

8. A high-throughput additive manufacturing equipment, characterized in that: The high-throughput material additive manufacturing method described in any of 1-7 includes a wire feeding assembly (1) and a mounting base (2). The mounting base (2) is provided with a plurality of coaxial powder feeding nozzles (3) and a plurality of mirror modules (4). The mirror modules (4) correspond one-to-one with the coaxial powder feeding nozzles (3). The mirror modules (4) are connected to an optical fiber plug (5). The plurality of coaxial powder feeding nozzles (3) are arranged around the wire feeding assembly (1). The wire feeding assembly (1) is provided with an energizing tube (6). The filament passes through the energized tube (6) and is conveyed through the filament feeding assembly (1). The laser is emitted from the central axis along the coaxial powder feeding nozzle (3). The coaxial powder feeding nozzle (3) has an annular powder feeding channel (31) arranged around its own central axis, so that the powder is fed out around the laser. Several lasers intersect the central axis of the filament at the same point. The mirror module (4) is provided with an air inlet (41), which is connected to the laser delivery channel (32) of the coaxial powder delivery nozzle (3). The coaxial powder delivery nozzle (3) is provided with an air inlet pipe (34) on the side away from the wire feeding assembly (1). The air inlet (41) is used to deliver the inner protective gas, and the air inlet pipe (34) is used to deliver the outer protective gas. The coaxial powder delivery nozzle (3) is provided with a powder delivery pipe (33) that is connected to the annular powder delivery channel (31).

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