A stirring and rolling device and method for improving the quality of additive manufacturing

Abstract

The application discloses a stirring and rolling device and method for improving additive manufacturing quality, and belongs to the technical field of mechanical machining, and comprises a rotating main shaft, and a stirring and rolling part which is detachably connected to the rotating main shaft; when a stirring and friction processing mode is performed, the rolling part does not contact the surface of a deposited layer; when a composite stirring and rolling processing mode is performed, the shaft shoulder of the stirring part is consistent in height with the rolling part, and both contact the surface of the deposited layer; when an interlayer rolling processing mode is performed, the stirring part does not contact the surface of the deposited layer; during the additive manufacturing process, the relative height of the shaft shoulder and the rolling roller on the stirring and rolling device can be adjusted to control the grain structure morphology at different positions of a structural part, and the microstructure control of the structural part is realized; the application integrates the directed energy deposition additive manufacturing, the stirring and friction processing and the interlayer rolling in the additive manufacturing process, shortens the process flow, improves the manufacturing efficiency, is simple in equipment operation and wide in application range.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mechanical processing, and particularly relates to a stirring and rolling device and method for improving the quality of additive manufacturing. BACKGROUND

[0002] Additive manufacturing usually uses an energy beam as a heat source and a wire or powder as a supply material. In the manufacturing process, a structure is guided as a data model, the structure is divided into several layers according to a set layer thickness, each layer is planned to form a track, and the structure is input into an execution mechanism. The execution mechanism melts and covers each layer from bottom to top according to the forming track, and finally completes the additive manufacturing of the structure. Due to the process characteristics of “layered manufacturing”, the technology has unique advantages in preparing complex-shaped structures, and due to the fact that it does not require a mold, the production efficiency is high, and the material utilization rate is high, so in recent years, the technology has attracted attention in the field of aerospace. The principle of layered manufacturing is as follows Figure 1-2 As shown in the figure, a welding gun is used to perform layered deposition on a substrate.

[0003] According to the supply mode of the supply material, additive manufacturing technology can be divided into two categories: directional energy deposition additive manufacturing (DED) and powder bed fusion additive manufacturing (PBF), wherein the directional energy deposition additive manufacturing includes laser powder feeding additive manufacturing (LDM), electric arc wire feeding additive manufacturing (WAAM), electron beam wire feeding additive manufacturing (EBM), etc. The powder bed fusion additive manufacturing is divided into laser selective melting forming (SLM), electron beam selective melting forming (SEM), etc.

[0004] In the process of DED directional energy deposition additive manufacturing, the supply material in the form of metal powder or wire is transported to the substrate of a focused energy beam (laser beam, electron beam or plasma / arc, etc.), thereby forming a small molten pool and continuously depositing material according to the forming track.

[0005] PBF powder bed fusion additive manufacturing is an additive manufacturing method based on a powder bed. A powder re-coating device is used to spread and flatten a thin layer of dry powder on the powder bed layer by layer. A galvanometer scanner guides a focused energy beam (laser beam, electron beam) and selectively melts the powder in the pre-designed area according to the three-dimensional (3D) model data of the slice. The powder is sintered layer by layer, and finally an integral structure is formed.

[0006] Due to the unique material supply mode of the directional energy deposition additive manufacturing technology, the technology is particularly suitable for the fields of additive manufacturing of large structures, additive connection, additive repair, etc.

[0007] Directed energy deposition (DED) additive manufacturing technology offers highly flexible equipment, high material utilization, and high deposition efficiency due to its on-demand material supply, eliminating the need for pre-supply. It also has lower environmental requirements, making it particularly suitable for additive manufacturing of large structural components. However, additive bonding and repair processes require work on the connected or repaired parts, whose working surfaces are typically complex, making it difficult to pre-lay powder of a suitable thickness. Therefore, DED additive manufacturing technology has advantages in the fields of additive bonding and repair.

[0008] Due to the "layered manufacturing" process characteristics of additive manufacturing, structural components inevitably undergo complex thermal histories during the additive manufacturing process, leading to stress concentration within the components, such as... Figure 3 As shown, phenomena such as cracking, deformation, and porosity can occur. When internal stress is too high, it will cause deformation and cracking of the structural components. Deformation and cracking generally occur during the additive manufacturing process or the cooling process after additive manufacturing, both of which will affect the manufacturing accuracy of the structural components, and in severe cases, will lead to the scrapping of the structural components. In addition, there are many porosity defects in the interlayer region of the structural components. These pores can become the initiation sites of cracks under the action of force, thereby impairing the mechanical properties of the structural components. These pores can be classified according to their formation mechanism into near-spherical pores formed by the failure of protective gas to escape in time, and irregularly shaped pores caused by poor fusion. Regardless of the type of pore, when subjected to external forces, they will reduce the load-bearing area and impair the mechanical properties. Summary of the Invention

[0009] The purpose of this invention is to provide a stirring and rolling apparatus and method for improving the quality of additive manufacturing, so as to solve the above-mentioned problems.

[0010] To achieve the above objectives, the present invention provides the following solution: a stirring and rolling device for improving the quality of additive manufacturing, comprising a rotating spindle, wherein a stirring and rolling part is detachably connected to the rotating spindle, the stirring and rolling part includes a stirring and rolling head detachably connected to the rotating spindle, and a stirring element and a rolling element are detachably connected to the bottom of the stirring and rolling head; the rolling element is arranged circumferentially along the stirring element.

[0011] When the stirring friction processing mode is performed, the rolling element does not contact the surface of the deposited layer;

[0012] When the composite stirring and rolling process is performed, the stirring component and the rolling component are at the same height and both are in contact with the surface of the deposited layer.

[0013] When the interlayer rolling process is performed, the stirring element does not contact the surface of the deposited layer.

[0014] Preferably, the stirring part comprises a shaft shoulder and a stirring needle, the shaft shoulder and the stirring needle are fixedly connected, the shaft shoulder is detachably connected to the stirring spinning head, and the rolling part is a roller.

[0015] Preferably, the diameter of the stirring spinning head is 10-30 mm, and the height is 1-15 mm.

[0016] To achieve the above-mentioned purpose, the application also provides the following scheme: a stirring and rolling method for improving the quality of additive manufacturing, based on the stirring and rolling device for improving the quality of additive manufacturing disclosed in any one of claims 1-3, the steps are:

[0017] (1) Data modeling: the overall data modeling of the structure to be manufactured is performed by software, then the structure is sliced, the trajectory is planned, and the output is obtained;

[0018] (2) Directional energy deposition additive manufacturing: the number of deposition layers is set, the supply material is put on the substrate by the directional energy deposition device, the directional energy deposition device deposits step by step along the forming trajectory, the stirring and rolling device is used to stir and roll the deposited layer after deposition, and different types of processing modes are selected by adjusting the stirring and rolling part;

[0019] When the height of the roller is lower than the height of the shaft shoulder, the friction stirring processing mode is selected;

[0020] When the height of the roller is consistent with the height of the shaft shoulder, the composite stirring rolling processing mode is selected;

[0021] When the height of the roller is higher than the height of the shaft shoulder, the interlayer rolling processing mode is selected;

[0022] (3) On the surface of the treated deposition layer, steps (1) to (2) are repeated until the directional energy deposition additive manufacturing of the overall structure to be manufactured is completed.

[0023] Preferably, during the directional energy deposition additive manufacturing process, the rotating speed of the stirring spinning head is 200-2000 r / min, and the feeding speed is 1-500 mm / min, so as to obtain better friction stirring processing quality.

[0024] Preferably, during the directional energy deposition additive manufacturing process, when the friction stirring processing mode is selected, the height of the shaft shoulder is 1-5 mm higher than the height of the roller, so that the processing surface is not affected by the roller;

[0025] When the interlayer rolling processing mode is selected, the height of the roller is 1-5 mm higher than the height of the top of the stirring needle, so that the processing surface is not affected by the stirring head.

[0026] Preferably, the length of the stirring needle is 1-20 mm.

[0027] Preferably, in the directed energy deposition additive manufacturing process, the pressing amount of the working surface after the stirring roll head processing is 1-10 mm.

[0028] Compared with the prior art, the application has the following advantages and technical effects: the stirring and rolling device and method for improving the additive manufacturing quality disclosed in the application can perform composite stirring and rolling processing, stirring and friction processing, and interlayer rolling processing on the deposited layer in the directed energy deposition additive manufacturing process, can provide sufficient plastic deformation for the deposited layer, reduce internal pores and cracks and other defects in the deposited layer, and release internal stress accumulated in the additive manufacturing process, thereby avoiding deformation and cracking of the structural part. Under the action of sufficient plastic deformation, the grain of the structural part is refined, which can improve the mechanical properties of the structural part and improve the anisotropy thereof.

[0029] In the additive manufacturing process, by adjusting the relative height of the shaft shoulder and the roll on the stirring roll device, the grain organization form at different positions of the structural part can be controlled, and the microstructure control of the structural part can be realized. In addition, the surface of the processed deposited layer is smoother, which is beneficial to improving the overall surface forming quality and manufacturing precision of the structural part. The application integrates the directed energy deposition additive manufacturing, stirring and friction processing, and interlayer rolling in the additive manufacturing process, shortens the process flow, improves the manufacturing efficiency, and is simple to operate and has a wide application range. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings:

[0031] Figure 1 An additive manufacturing device in the prior art;

[0032] Figure 2 A schematic diagram of the additive manufacturing process of the additive manufacturing device in the prior art;

[0033] Figure 3 A schematic diagram of specific problems in the directed energy deposition additive manufacturing in the prior art;

[0034] Figure 4 A structure schematic diagram of the stirring and rolling device in the application when in use;

[0035] Figure 5 A bottom view of the stirring and rolling device in the application;

[0036] Figure 6 Structure diagram of various forms of rolling rolls in the present application;

[0037] Figure 7 Structure diagram of various forms of stirring needles and shaft shoulders in the present application;

[0038] Figure 8 Device diagram of the stir-friction processing in the present application;

[0039] Figure 9 Device diagram of the composite stir-rolling processing in the present application;

[0040] Figure 10 Device diagram of the interlaminar rolling processing in the present application;

[0041] Figure 11 Flow chart of the specific implementation process of the stir-rolling device in the present application;

[0042] Figure 12 Process structure diagram of the stir-friction processing in the present application;

[0043] Figure 13 Process structure diagram of the composite stir-rolling processing in the present application;

[0044] Figure 14 Process structure diagram of the interlaminar rolling processing in the present application;

[0045] Figure 15 Structure diagram of the structural member after the processing process of the present application;

[0046] Figure 16 Structure diagram of the grain refinement;

[0047] Figure 17 Structure diagram of the influence of different processing methods on the porosity;

[0048] Figure 18 Structure diagram of the comparison of the macroscopic metallography of the aluminum-steel interface before and after the stir-friction processing;

[0049] Figure 19 Structure diagram of the comparison of the microscopic structure of the aluminum-steel interface before and after the stir-friction processing;

[0050] Figure 20 Structure diagram of the influence of the interlaminar rolling before and after on the porosity;

[0051] Figure 21 Structure diagram of the influence of the interlaminar rolling on the grain refinement;

[0052] 1-rotating main shaft; 2-stirring spinning head; 21-shoulder; 22-stirring needle; 3-rolling roller. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be apparently and completely described below with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0054] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with the accompanying drawings and specific embodiments.

[0055] As shown in the drawings, Figures 4-9 The present application discloses a stirring and rolling device for improving the quality of additive manufacturing, which comprises a rotating main shaft 1, and a stirring and rolling part detachably connected to the rotating main shaft 1. The stirring and rolling part comprises a stirring spinning head 2 detachably connected to the rotating main shaft 1, and a stirring part and a rolling part detachably connected to the bottom of the stirring spinning head 2. The rolling part is arranged along the circumference of the stirring part. The rotating main shaft 1, the stirring spinning head 2, the stirring spinning head 2, the stirring part and the rolling part are mechanically connected, for example, the rotating main shaft 1 and the stirring spinning head 2 can be connected by a bearing screwing mode, and the stirring part and the rolling part can be connected by a threaded mode.

[0056] When the stirring and friction processing mode is performed, the rolling part does not contact the surface of the deposited layer.

[0057] When the composite stirring and rolling processing mode is performed, the stirring part and the rolling part are consistent in height and both contact the surface of the deposited layer.

[0058] When the interlayer rolling processing mode is performed, the stirring part does not contact the surface of the deposited layer.

[0059] Further optimization scheme, the stirring part comprises a shoulder 21 and a stirring needle 22, the shoulder 21 and the stirring needle 22 are fixedly connected, the shoulder 21 is detachably connected to the stirring spinning head 2, and the rolling part is a rolling roller 3.

[0060] Further, the diameter of the stirring spinning head 2 is 10-30 mm, and the height is 1-15 mm.

[0061] Specifically, as shown in the drawings, Figures 6-7As shown, in order to meet the requirements of different processes for additive processing of different structural parts, the size of the stirring spin head 2 can be determined according to the actual situation; at the same time, the number of the roller 3 is at least 1, and the size is 1mm-50mm, and the shape of the roller 3 is diversity, including but not limited to ball shape, cylindrical roller shape, tapered roller shape, drum roller shape, etc. In addition, in order to meet the requirements of different processes, the diameter of the stirring needle 22 is 1mm-20mm, and the length is 1mm-50mm, but it can be adjusted according to the actual situation, and the shape includes but is not limited to cylindrical or spiral shape, which can be adjusted according to different processes.

[0062] As shown in the Figures 11-20 The application also discloses a stirring and rolling method for improving the quality of additive manufacturing, based on the stirring and rolling device for improving the quality of additive manufacturing disclosed in any one of claims 1-3, and the steps are as follows:

[0063] (1) Data modeling: the overall data modeling of the structural part to be manufactured is performed by software, then the structural part is sliced, the stirring track is formulated, and the stirring track is outputted;

[0064] (2) Directional energy deposition additive manufacturing: the number of deposition layers is set, the feeding material is put onto the substrate by the directional energy deposition device, the directional energy deposition device deposits step by step along the forming track, the stirring and rolling device is used to stir and roll the deposited layer after deposition, and different types of processing modes are selected by adjusting the stirring and rolling part;

[0065] When the height of the roller 3 is lower than the height of the shaft shoulder 21, the stirring friction processing mode is selected,

[0066] When the height of the roller 3 is consistent with the height of the shaft shoulder 21, the composite stirring and rolling processing mode is selected;

[0067] When the height of the roller 3 is higher than the height of the shaft shoulder 21, the interlayer rolling processing mode is selected;

[0068] (3) The steps (1) to (2) are repeated on the surface of the processed deposition layer until the directional energy deposition additive manufacturing of the overall structural part to be manufactured is completed.

[0069] Specifically, as shown in the Figures 11-14The stirring track is not limited to straight lines, curves and broken lines, and can be a straight line, a straight line reciprocating, a zigzag, a bow-shaped, a spiral line or the like to adapt to different process requirements. The stirring track can be set according to actual conditions. Meanwhile, the surface of the deposited layer is not limited to a flat surface, and is also applicable to a curved surface with reasonable curvature and a concave-convex surface within a reasonable range. In use, first, a data model of the structure to be manufactured is established, and then the established overall model is sliced, the stirring track is selected, and the substrate is selected and subjected to surface treatment, so as to facilitate the subsequent directed energy deposition additive manufacturing process. Before the directed energy deposition additive manufacturing is started, the directed energy deposition device is moved under the control of the actuator, the supply material is melted into a molten pool, and is deposited layer by layer along the forming track. The corresponding parameters of the directed energy deposition device are adjusted according to the specific process. After a certain number of layers are deposited, the surface of the last deposited layer is required to be cleaned of impurities and subjected to air cooling to reduce the temperature. The number of layers and the temperature are adjusted according to different processes, and the selection of the stirring and rolling part is selected according to different requirements.

[0070] At any deposited layer and any position of the deposited layer in the additive manufacturing process, the relative height of the stirring needle 22 on the stirring roller press device and the roller 3 is adjustable to adapt to different processing schemes and to apply different types and degrees of interlayer plastic deformation processing, including stirring rolling processing mode, i.e. the stirring needle 22 and the roller 3 are at an appropriate height, stirring friction processing mode, i.e. the roller 3 does not contact the deposited layer, or interlayer rolling processing mode, i.e. the stirring needle 22 does not contact the deposited layer, and the internal grain structure of the structure can be controlled during the directed energy deposition additive manufacturing process. The number of deposited layers before the interlayer plastic deformation processing can be set according to actual requirements, which can be one layer or multiple layers. The number of times of applying the interlayer plastic deformation processing can be set according to actual requirements, which can be one time or multiple times.

[0071] Further optimization scheme, in the process of directed energy deposition additive manufacturing, the rotating speed of the stirring spinning head 2 is 200r / min-2000r / min, and the feeding speed is 1mm / min-500mm / min, so as to obtain better stirring friction processing quality. The rotating speed and the feeding speed of the stirring spinning head 2 can change the stress of the organization in the deposited layer, so that the quality after different rotating speeds and feeding speeds are selected is also different.

[0072] Further optimization scheme, in the process of directed energy deposition additive manufacturing, when the stirring friction processing mode is selected, the height of the shaft shoulder 21 is 1-5mm higher than the height of the roller 3, so that the processing surface is not affected by the roller.

[0073] When the interpass rolling treatment mode is selected, the height of the roller 3 is 1-5mm higher than the height of the top of the stirring needle 22, so that the treatment surface is not affected by the stirring head.

[0074] Further optimization scheme, the length of the stirring needle 22 is 1-20mm.

[0075] Further optimization scheme, in the directed energy deposition additive manufacturing process, the amount of pressing of the working surface treated by the stirring spinning head 2 is 1-10mm.

[0076] Embodiment 1

[0077] As Figure 12 , 16-19, when the working surface of the additive part is relatively flat, and the additive part needs to be subjected to severe plastic deformation to obtain ultra-fine grain structure with greatly weakened internal defects and residual stress, the friction stirring treatment mode is selected, and the specific implementation scheme is as follows:

[0078] (1) Data modeling: After the overall data modeling of the structure with a size of 180*200*50mm is performed by related software, the "zigzag" forming track is established by slicing at a thickness of 2mm.

[0079] (2) Directed energy deposition additive manufacturing: First, remove the surface impurities and oxide film on the 2219 aluminum alloy substrate with a size of 200*200*20mm, and fix it on the workbench (not shown in the figure). Dry the 2219 aluminum alloy wire with a diameter of 1.2mm and supply it to the directed energy deposition device; at the same time, the directed energy deposition device moves under the control of the actuator, and the supplied material is melted into a molten pool and deposited layer by layer along the forming track, wherein the corresponding parameters of the directed energy deposition device are: current 220A, voltage 15V, wire feeding speed 8m·min -1 , moving speed 20mm·s -1Simultaneously, after every 1-3 layers or 1-5mm of deposition (the specific height can be set according to actual conditions), surface impurities in the deposited portion are removed, and air cooling is performed to lower the temperature to below 80℃. During the interlayer stirring and friction treatment, the stirring and spinning part is installed with the shoulder 21 higher than the roller 3, where the shoulder 21 is 1-5mm higher than the roller 3. Depending on the actual situation, stirring and spinning heads 2 of different specifications and sizes are selected to adjust the length of the stirring needle 22 to control the depth of the stirring and friction treatment, ranging from 1-10mm. When depositing one layer, the shoulder 21 is 1-5mm higher than the roller 3, and the stirring needle 22 is 1-5mm long; when depositing two layers, the shoulder 21 is 3-8mm higher than the roller 3, and the stirring needle 22 is 5-10mm long. After adjusting the relevant parameters, the stirring roller press device, under the control of the actuator, applies stirring and friction treatment to the deposited portion 1-3 times along the set movement trajectory. The rotation speed of the stirring roller press device is 800 r / min, the moving speed is 200 mm / min, and the movement trajectory and the number of stirring and friction treatments are set according to the actual situation.

[0080] (3) Repeat steps (1) and (2) on the treated deposited surface until the overall directional energy deposition additive manufacturing of the structure is completed.

[0081] like Figure 16 Schematic diagram of the stirring friction treatment and attached diagram Figures 17-19 As shown, specifically, attached Figure 16 The accompanying figure shows a comparison of the grain refinement process before and after refinement. Figure 17 As shown in the attached diagram of the friction stir treatment, the internal grains are refined after the friction stir treatment, while the attached... Figure 18 and 19 The comparison showed a significant decrease in porosity and refinement of grain size. In summary, after friction stirring treatment, the internal structure of the component was refined, the grain size was between 1-50 μm, the internal stress was reduced by 20%-60%, the porosity was reduced to below 0.5%, the surface smoothness was improved, and the standard deviation between the highest and lowest points was within 0.2 mm.

[0082] Example 2

[0083] like Figure 13 and 17 As shown, when the working surface of the additive part is relatively uneven and the additive part needs to undergo relatively intense plastic deformation to obtain an ultrafine grain structure with significantly reduced internal defects and residual stress, a composite stirring rolling treatment mode should be selected. The specific implementation scheme is as follows:

[0084] (1) Data modeling: through the relevant software, the overall data modeling of the structure with the size of 180*200*50mm is carried out, then the layered slicing is carried out with the thickness of 2mm, and the "zigzag" forming track is formulated.

[0085] (2) Directional energy deposition additive manufacturing: first, the surface impurities and oxide film on the 2219 aluminum alloy substrate with the size of 200*200*20mm are removed, and then the substrate is fixed on the workbench. The 2219 aluminum alloy wire with the diameter of 1.2mm is dried and supplied to the directional energy deposition device. Then the directional energy deposition device moves under the control of the actuator, the supplied material is melted into a molten pool, and is deposited layer by layer along the forming track; at the same time, the corresponding parameters of the directional energy deposition device are: current 220A, voltage 15V, wire feeding speed 8m·min -1 , moving speed 20mm·s -1 , in addition, after depositing 1-3 layers or 1-5mm high, the surface impurities of the deposited part are removed, and air cooling treatment is carried out to reduce the temperature to below 80℃, wherein the number of deposited layers or the height of deposition can be set according to the actual situation; specifically, when the interlayer composite stirring rolling treatment is carried out, the stirring part and the rolling part on the stirring rotary pressure head 2 have the same height, and then they are installed at the specified position, that is, the height of the shaft shoulder 21 and the stirring needle 22 stacked together is consistent with the height of the roller 3, and the specific form can be that the shaft shoulder 21 and the stirring needle 22 are arranged at the center of the stirring rotary pressure head 2, and the four rollers 3 are symmetrically distributed around the central axis. Adjust the relative height of the stirring roller pressure device and the work surface to make the depression amount of the work surface after the composite stirring roller pressure treatment be 1-10mm. According to the actual situation, different specifications and sizes of stirring rolling parts are selected to adjust the length of the stirring needle 22 to control the depth of the stirring friction treatment, which ranges from 1-10mm. When depositing 1 layer, the height of the shaft shoulder 21 is consistent with the height of the roller 3, the length of the stirring needle 22 is 1-5mm, and the depression amount of the work surface after the composite stirring rolling treatment is 1-2mm; when depositing 2 layers, the height of the shaft shoulder 21 is consistent with the height of the roller 3, the length of the stirring needle 22 is 3-8mm, and the depression amount of the work surface after the composite stirring rolling treatment is 1-5mm; when depositing 3 layers, the height of the shaft shoulder 21 is consistent with the height of the roller 3, the length of the stirring needle 22 is 5-10mm, and the depression amount of the work surface after the composite stirring rolling treatment is 1-10mm.

[0086] After adjusting the relevant parameters, the stirring roller pressure device moves along the set moving track under the control of the actuator to apply the composite stirring roller pressure treatment to the deposited part for 1-3 times. The rotating speed of the stirring roller pressure device is 800r / min, the moving speed is 200mm / min, and the moving track and the stirring roller pressure treatment times are set according to the actual situation.

[0087] (3) Repeat step (1) and step (2) on the surface of the deposited layer after processing until the whole structure is completed by the directed energy deposition additive manufacturing.

[0088] As shown in the accompanying drawings, after the composite stir-rolling treatment, the internal structure of the structure is refined, the grain size is between 1-100 μm, the internal stress is reduced by 60%-80%, the porosity is reduced to below 1%, the surface flatness is significantly improved, and the standard deviation of the highest point and the lowest point is within 0.5 mm. Figure 17

[0089] Example 3

[0090] As shown in the accompanying drawings, after the composite stir-rolling treatment, the internal structure of the structure is refined, the grain size is between 1-100 μm, the internal stress is reduced by 60%-80%, the porosity is reduced to below 1%, the surface flatness is significantly improved, and the standard deviation of the highest point and the lowest point is within 0.5 mm. Figures 15-17 , 20-21, when the working surface of the additive part is relatively uneven, and the plastic deformation of the additive part needs to be smaller to obtain a fine-grained structure with internal defects and residual stress part weakened, interpass rolling treatment needs to be applied, and the specific implementation scheme is as follows:

[0091] (1) Data modeling: After the whole data modeling of the structure with a size of 180*200*50 mm is completed by related software, the "zigzag" forming track is established by slicing with a thickness of 2 mm.

[0092] (2) Directed energy deposition additive manufacturing: remove the surface impurities and oxide film on the 2219 aluminum alloy substrate with a size of 200*200*20 mm, fix it on the workbench, dry treat the 2219 aluminum alloy wire with a diameter of 1.2 mm, and supply it to the directed energy deposition device. Then the directed energy deposition device moves under the control of the actuator, the supplied material is melted into a molten pool, and is deposited layer by layer along the forming track. The corresponding parameters of the directed energy deposition device are: current 220 A, voltage 15 V, wire feeding speed 8 m·min -1 , moving speed 20 mm·s -1 ​Furthermore, after every 1-3 layers or 1-5 mm in height, surface impurities of the deposited portion are removed, and air cooling is performed to lower the temperature to below 80°C. The number of layers and the deposition height can be set according to actual conditions. Specifically, during interlayer rolling, the relative height between the stirring pin 22 at the head of the stirring roller press device and the roll 3 is adjusted so that the roll 3 is 1-5 mm higher than the stirring pin 22, or the stirring pin 22 is removed so that it does not contact the working surface. Depending on the actual situation, the relative height between the stirring roller press device and the working surface is adjusted so that the downward pressure on the working surface after interlayer rolling is 1-10 mm. When depositing one layer, the roll 3 is 1-5 mm higher than the stirring pin 22, and the stirring pin 22 does not contact the working surface, so that the downward pressure on the working surface after interlayer rolling is 1-2 mm; when depositing two layers, the roll 3 is 1-5 mm higher than the stirring pin 22, and the stirring pin 22 does not contact the working surface, so that the downward pressure on the working surface after interlayer rolling is 1-5 mm; when depositing three layers, the roll 3 is 1-5 mm higher than the stirring pin 22, and the stirring pin 22 does not contact the working surface, so that the downward pressure on the working surface after interlayer rolling is 1-10 mm.

[0093] After adjusting the relevant parameters, the stirring roller pressing device, under the control of the actuator, applies interlayer rolling treatment to the deposited portion 1-3 times along the set moving trajectory. The rotation speed of the stirring roller pressing device is 800 r / min, the moving speed is 200 mm / min, and the moving trajectory and the number of interlayer rolling treatments are set according to the actual situation.

[0094] (3) Repeat steps (1) and (2) on the treated deposited surface until the overall directional energy deposition additive manufacturing of the structure is completed.

[0095] like Figure 17 The attached drawings and appendices for the inter-layer rolling process Figures 20-21 As shown, specifically as follows Figure 20 As shown, Figure 20 Figure (a) shows the deposition state without rolling and heat treatment, exhibiting high porosity after deposition. Figure 20 Figure (e) shows the process of interlayer rolling. A comparison clearly shows that the porosity of the internal structure is significantly reduced after interlayer rolling. Figure 21 As shown, Figure 21 Figure (a) shows a rolling pass applied only to the penultimate layer, with a load of 50 kN. Figure 21 Figure (b) shows a rolling pass applied only to the penultimate layer, with a load of 75 kN. Figure 21 Figure (c) shows the application of one rolling pass to each layer, with a load of 50 kN. Figure 21 Figure (d) shows the application of one rolling pass to each layer, with a load of 75 kN. This is compared to...Figure 21 As can be seen from the four figures in FIG. 1, when the deposited layers with fewer layers are rolled, the grains are relatively large, and when the number of layers is the same, the load is different, the larger the load, the finer the grains, and the larger the load applied to each layer, the finer the grains, thus, after the interlayer rolling treatment, the internal structure of the structural part is refined, the grain size is between 20-100 mu m, the internal stress is reduced by 60%-80%, the porosity is reduced to below 1%, the surface flatness is significantly improved, and the standard deviation of the highest point and the lowest point is within 0.5 mm.

[0096] The stirring and rolling device and method for improving the quality of additive manufacturing disclosed in the application have the following implementation effects:

[0097] (1) In the process of directional energy deposition additive manufacturing, the interlayer plastic deformation treatment is applied to the deposited layers, which can improve the forming quality and surface precision of the structural part. Stirring friction treatment, interlayer rolling treatment and composite stirring roller treatment can make the surface of the deposited layer more flat. The surface flatness is improved, the standard deviation of the highest point and the lowest point is within 0.5 mm, and the line deviation in the adjacent deposited layers is within ±0.2 mm.

[0098] (2) In the process of directional energy deposition additive manufacturing, the interlayer plastic deformation treatment is applied to the deposited layers, which can improve the internal quality of the structural part. Stirring friction can significantly refine the grains to obtain ultra-fine grain structure and eliminate pore defects; the rotating roller can reduce the internal stress of the structural part and refine the grains by applying mechanical force to close the pores. The grain size is reduced to 1-100 mu m, the grain size in the stirring friction treatment zone is between 1-10 mu m, the grain size after interlayer rolling treatment is between 10-100 mu m, and the porosity is below 1%.

[0099] (3) In the process of directional energy deposition additive manufacturing, the interlayer plastic deformation treatment is applied to the deposited layers, which can significantly improve the mechanical properties of the structural part. By refining the grains, reducing internal defects and weakening residual stress, the mechanical properties are further improved; the interlayer plastic deformation treatment applied to the deposited layers can release the internal residual stress of the structural part, reduce the risk of deformation and cracking of the structural part during manufacturing, and also help to improve the manufacturing precision. The internal residual stress is reduced by 20%-80%; when the interlayer plastic deformation treatment is applied to the working surface, the moving track is not limited to a straight line in a single direction, and can be set as a variable-direction polyline, curve and the like according to the actual situation. It has high flexibility and is suitable for most directional energy deposition additive manufacturing scenarios.

[0100] (4), the present application can be applied to the structure in the additive manufacturing process of the deposition layer and the deposition layer of any position, by adjusting the relative height of the shaft shoulder 21 and the roller 3 on the stirring roller pressing device, different types of interlayer plastic deformation processing. Different processing methods can bring different microstructure, can realize the microstructure controllability of the structure in the process of directional energy deposition additive manufacturing. Any position of the structure can obtain different microstructure according to the technical requirements, such as columnar crystal, fine equiaxed crystal, coarse equiaxed crystal, etc.;The deposition layer surface does not require high flatness, can be replaced by different types of roller 3, to act on the curved surface, the concave-convex surface in the reasonable range, etc.

[0101] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation to the present application.

[0102] The above examples are only to describe the preferred mode of the present application, and not to limit the scope of the present application, without departing from the design spirit of the present application, the ordinary skilled in the art to the technical scheme of the present application makes various modifications and improvements, should fall within the scope of the present application determined by the claims.

Claims

1. A stirring and rolling device for improving the quality of additive manufacturing, comprising a rotating spindle (1), characterized in that: A stirring and rolling part is detachably connected to the rotating spindle (1). The stirring and rolling part includes a stirring and rolling head (2) detachably connected to the rotating spindle (1). A stirring component and a rolling component are detachably connected to the bottom of the stirring and rolling head (2). The rolling component is arranged circumferentially along the stirring component. When the stirring friction processing mode is performed, the rolling element does not contact the surface of the deposited layer; When the composite stirring and rolling process is performed, the stirring component and the rolling component are at the same height and both are in contact with the surface of the deposited layer. When the interlayer rolling process is performed, the stirring element does not contact the surface of the deposited layer; The stirring component includes a shoulder (21) and a stirring needle (22), the shoulder (21) and the stirring needle (22) are fixedly connected, the shoulder (21) is detachably connected to the stirring spinning head (2), and the rolling component is a roller (3). The diameter of the stirring spinning head (2) is 10mm-30mm and the height is 1-15mm; A stirring and rolling method for improving the quality of additive manufacturing, using the aforementioned stirring and rolling apparatus for improving the quality of additive manufacturing, comprises the following steps: (1) Data modeling: The structural components to be manufactured are modeled as a whole using software, then sliced ​​into layers, the trajectory is determined and output; (2) Directional Energy Deposition Additive Manufacturing: Set the number of deposition layers, use a directional energy deposition device to place the supply material onto the substrate, the directional energy deposition device deposits step by step along the forming trajectory, and use a stirring and rolling device to stir and roll the deposited layers after deposition, and select different types of processing modes by adjusting the stirring and rolling part; When the height of the roll (3) is lower than the height of the shoulder (21), the stirring friction treatment mode is selected; When the height of the roll (3) is consistent with the height of the shoulder (21), the composite stirring rolling process mode is selected; When the height of the roll (3) is higher than the height of the shoulder (21), the interlayer rolling processing mode is selected; (3) Repeat steps (1) to (2) on the treated deposited layer surface until the directional energy deposition additive manufacturing of the entire structure to be manufactured is completed; In the directional energy deposition additive manufacturing process, the rotational speed of the stirring spinneret (2) is 200 r / min-2000 r / min, and the feed speed is 1 mm / min-500 mm / min, so as to obtain better stirring friction treatment quality; In the directional energy deposition additive manufacturing process, when the friction stir treatment mode is selected, the height of the shoulder (21) is 1-5mm higher than the height of the roll (3), so that the treated surface is not affected by the roll. When the interlayer rolling processing mode is selected, the height of the roll (3) is 1-5mm higher than the height of the top of the stirring needle (22), so that the processing surface is not affected by the stirring head; The length of the stirring needle (22) is 1-20 mm; In the directional energy deposition additive manufacturing process, the pressure applied to the working surface after treatment by the stirring spinneret (2) is 1-10 mm.

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