A method for constructing a process database of typical characteristic structures in arc additive manufacturing

Abstract

The present invention provides a method for constructing a process database for typical characteristic structures of arc additive manufacturing, characterized by comprising the following steps: establishing the types, morphology curves, and characteristic dimensions of typical characteristic structures; inputting target characteristic structures, morphology curves, and characteristic dimensions; establishing the types, grades, and diameters of molten wires; establishing the grades and states corresponding to substrate materials; establishing the types of arc additive heat sources and their process modes; establishing the types of shielding gases; establishing a characteristic structure model optimization scheme; recommending an additive path for any characteristic structure model optimization scheme; establishing parameters related to actuators and external axes; and establishing process parameters related to arc additive manufacturing. The present invention achieves rapid matching of process parameters related to arc additive manufacturing, actively controls the forming quality of arc additive manufacturing while meeting the preset characteristic structure shape and size requirements, improves the surface quality, forming accuracy, and forming efficiency of arc additive manufacturing parts, and ensures the mechanical properties of the parts.

Description

Technical Field

[0001] The present invention belongs to the technical field of arc additive manufacturing of aerospace structural parts, and relates to a method for constructing a process database of typical characteristic structures of arc additive manufacturing. Background Art

[0002] Wire and Arc Additive Manufacturing (WAAM) uses an arc as a heat source and a layer-by-layer buildup process to create dense metal components. Compared to traditional casting / forging subtractive manufacturing processes, WAAM offers shorter manufacturing cycles, greater flexibility, higher material utilization, and faster design response. It is particularly well-suited for the manufacture of small batches and a wide variety of products, and therefore holds broad application prospects in aerospace, automotive, and shipbuilding industries.

[0003] Patent application number 202011436187.1 discloses a GMWA arc additive manufacturing system and method for cross-metal parts with auxiliary wire filling. This method uses a visual inspection and feedback system to adjust the current and voltage, and adjust the wire feeding speed of the composite wire feeder to change the amount of cladding at the intersection position, so that the intersection remains flat during the forming process, achieving arc additive manufacturing of cross-metal structures. This method does not optimize the intersection structure and path from a process perspective, but instead uses a visual inspection system to correct the process parameters of the intersection, which is not very applicable.

[0004] Patent application number 201610408053.6 discloses a method for arc-wire additive manufacturing of inclined thin-walled structural parts. When preparing a single-pass inclined thin-walled part, the first layer is formed by overlapping two weld passes. The second and subsequent layers are formed by offsetting the welding torch perpendicular to the height direction to form the inclined structure. This overcomes the problems of high equipment cost, complex system, and low forming accuracy in the preparation of inclined structural parts. The inclined structural parts can be prepared without the need for a positioner to flip the substrate. This method is generally only suitable for the preparation of inclined thin-walled parts with small angles and cannot be used to prepare thick-walled structural parts or structural parts with large inclination angles. It also does not consider the impact of temperature gradients on forming and the possibility of collapse and failure.

[0005] The invention with patent application number 201811512386.9 discloses an arc additive manufacturing method for aluminum alloy suspended structural parts. After pre-processing the area to be added to the aluminum alloy suspended structural part, it is fixed on the work platform, and the arc starting point, arc ending point position and additive path are set, including multiple layers to be added. The inter-layer offset method is used to balance the gravity of the deposited metal and the surface tension to achieve the formation of the suspended structure. This method is a method of forming thin-walled suspended structures without using a positioner. In actual formed parts, a positioner and a welding gun need to be used in combination to achieve the formation of thick-walled suspended structures.

[0006] Arc additive manufacturing technology has low surface quality of molded parts due to the accuracy limitations of arc deposition itself. Its high heat input and temperature gradient lead to large residual stress and deformation as well as poor microstructure in the molded parts, which affects the molding and performance of structural parts. Based on functional and weight-reduction design requirements, typical characteristic structures often included in arc additive molded parts include cross-type structures, boss-type structures, inclined-type structures and suspended-type structures. If reasonable process parameters, additive paths or characteristic structure optimization are not adopted in the process of such characteristic structures, various problems such as bulges, necking, collapse, poor overlap quality and lack of fusion are prone to occur, which may even lead to forming failure in severe cases, greatly reducing the forming efficiency and forming accuracy.

[0007] Therefore, it is necessary to establish a process database of typical characteristic structures of arc additive manufacturing to achieve rapid matching of typical characteristic structures, morphology curves, characteristic sizes and ranges of arc additive manufacturing with molten wire, substrate material and state, arc additive heat source type and process mode, shielding gas type and flow rate, actuator-related parameters, characteristic structure model optimization scheme and additive path, and arc additive-related process parameters. Summary of the Invention

[0008] The purpose of the present invention is to provide a process database construction method for typical characteristic structures of arc additive manufacturing, which can realize the rapid matching of typical characteristic structures, morphology curves, characteristic sizes and ranges of arc additive manufacturing with molten wire, substrate material and state, arc additive heat source type and process mode, shielding gas type and flow rate, actuator-related parameters, characteristic structure model optimization scheme and additive path, and arc additive-related process parameters.

[0009] The present invention provides a method for constructing a process database of typical characteristic structures of arc additive manufacturing, which is characterized by comprising the steps of:

[0010] Step 1: Establish typical characteristic structure types, morphology curves and characteristic dimensions;

[0011] Step 2: Input the target feature structure, topography curve and feature size;

[0012] Step 3: Establish the type, grade and diameter of the molten wire;

[0013] Step 4: Establish the brand and status corresponding to the substrate material;

[0014] Step 5: Establish the type of arc additive heat source and its process mode;

[0015] Step 6: Establish the type of protective gas;

[0016] Step 7: Establish a feature structure model optimization plan;

[0017] Step 8: Select the optimization scheme of the characteristic structure model and the additive path with the minimum residual stress;

[0018] Step 9: Establish parameters related to the actuator and external axis;

[0019] Step 10: Establish arc additive process parameters.

[0020] Preferably, in step 1, typical characteristic structure types include cross-type structures, boss-type structures, inclined-type structures and suspended-type structures.

[0021] Preferably, in step 3, the molten wire comprises metal, intermetallic compound and functional gradient material therebetween.

[0022] Preferably, in step 4, the substrate material includes metals, intermetallic compounds and functionally gradient materials therebetween; the substrate state includes: normalized state, annealed state, quenched state, modulated state, solution treated state, aging state and other heat treatment states.

[0023] Preferably, in step 5, the arc additive heat source includes submerged arc welding (SAW), gas tungsten arc welding (GTAW), argon tungsten arc welding (TIG), metal inert / active gas welding (MIG / MAG), cold metal transfer (CMT), plasma arc welding (PAW) and other arc welding methods as heat sources; the process modes include DC / AC, pulse, variable polarity, variable polarity pulse and other process modes.

[0024] Preferably, in step 6, the types of protective gas include argon, helium, carbon dioxide and mixed gases.

[0025] Preferably, in step 7, the characteristic structure model optimization scheme complies with the principle of minimum arcing and arcing extinction times, minimum path corners, and completeness of the filled path, including adding transition fillets / transition margins, reducing dead angles, short straight lines, and irregular trajectories, optimizing cross paths, optimizing corners, and increasing continuity between paths, so that the paths change smoothly and stably. After the characteristic structure optimization scheme is iteratively completed, a characteristic structure model optimization scheme library is established.

[0026] Preferably, in step 8, after selecting a characteristic structure model optimization scheme, a corresponding matching additive path is given based on the principle of minimum residual stress after simulation calculation;

[0027] Preferably, in step 9, the actuator-related parameters include the actuator angle, additive path, swing parameters (swing length, swing width, and swing curve), and the distance between the actuator and the contact nozzle and the end surface of the deposited layer. The external axis-related parameters include the external axis angle and rotation speed;

[0028] Preferably, in step 10, the arc additive related process parameters include shielding gas flow rate, arc starting current, arc starting time, transition time, arc extinction current, transition time, arc extinction time, deposition speed, wire feeding speed and current-voltage curve, deposition interlayer temperature range, substrate initial temperature and interlayer waiting time, etc.

[0029] The present invention proposes a process database construction method for typical characteristic structures of arc additive manufacturing, which realizes the rapid matching of typical characteristic structures of arc additive manufacturing and their characteristic dimensions with molten wire, substrate material and state, arc additive heat source type and process mode, shielding gas type and flow rate, actuator-related parameters, characteristic structure model optimization scheme and additive path, and arc additive-related process parameters, while meeting the preset characteristic structure shape and size requirements and realizing active control of arc additive manufacturing forming quality, thereby improving the surface quality, forming accuracy and forming efficiency of arc additive manufacturing formed parts and ensuring the mechanical properties of the formed parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Building a roadmap for the process database of typical characteristic structures of arc additive manufacturing of the present invention;

[0031] Figure 2 Schematic diagram of the cross-class feature structure and its characteristic size;

[0032] Figure 3 It is a schematic diagram of the cross-type characteristic structure path;

[0033] Figure 4 Schematic diagram of the actuator and external axis posture. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] The main elements of the process database for arc additive manufacturing deposited layers include (1) typical characteristic structure types, morphology curves and characteristic dimensions; (2) molten wire and substrate materials and states; (3) arc additive heat source types and process modes; (4) shielding gas types; (5) characteristic structure model optimization scheme; (6) additive path with minimum residual stress of the optimization scheme; (7) actuator-related parameters; and (8) arc additive-related process parameter composition. The corresponding relationships between the above main components are established.

[0036] The present invention takes the fuse material brand and diameter, arc additive heat source and process mode, and preset characteristic structure, morphology curve, and characteristic size as input, and outputs the characteristic structure model optimization plan and the matching additive path, actuator-related parameters, and arc additive-related process parameters. While meeting the preset characteristic structure shape and size requirements, it realizes active control of the arc additive manufacturing forming quality, improves the surface quality, forming accuracy and forming efficiency of the arc additive manufacturing formed parts, and ensures the mechanical properties of the formed parts.

[0037] Figure 1 A roadmap is constructed for the process database of typical characteristic structures of arc additive manufacturing of the present invention. Figure 1 As shown, the present invention provides a method for constructing a process database of typical characteristic structures of arc additive manufacturing, which is characterized by comprising the steps of:

[0038] Step 1: Establish typical characteristic structure types, morphology curves and characteristic dimensions;

[0039] According to one embodiment of the present invention, in step 1, typical characteristic structure types include cross-type structures, boss-type structures, inclined-type structures and suspended-type structures.

[0040] Step 2: Input the target feature structure, topography curve and feature size;

[0041] Step 3: Establish the type, grade and diameter of the molten wire;

[0042] According to one embodiment of the present invention, in step 3, the molten wire includes metal, intermetallic compound and functional gradient material therebetween.

[0043] Step 4: Establish the brand and status corresponding to the substrate material;

[0044] According to one embodiment of the present invention, in step 4, the substrate material includes metals, intermetallic compounds, and functionally gradient materials therebetween. The substrate conditions include normalized, annealed, quenched, tempered, solution treated, aged, and other heat treated conditions.

[0045] Step 5: Establish the type of arc additive heat source and its process mode;

[0046] According to one embodiment of the present invention, in step 5, the arc additive heat source includes non-metallic electrode gas shielded welding (TIG), metal inert / active gas shielded welding (MIG / MAG), cold metal transfer (CMT), plasma arc welding (PAW) and other arc welding methods as heat sources; the process modes include DC / AC, pulse, variable polarity, variable polarity pulse and other process modes.

[0047] Step 6: Establish the type of protective gas;

[0048] According to one embodiment of the present invention, in step 6, the types of protective gas include argon, helium, carbon dioxide and mixed gases.

[0049] Step 7: Establish a feature structure model optimization plan;

[0050] According to one embodiment of the present invention, in step 7, the characteristic structure model optimization scheme complies with the principles of minimum arcing and arcing extinction times, minimum path corners, and completeness of the filled path. This includes adding transition fillets / transition margins, reducing dead angles, short straight lines, and irregular trajectories, optimizing intersecting paths, optimizing corners, and increasing continuity between paths, thereby ensuring smooth and stable path changes. After the characteristic structure optimization scheme is iterated, a characteristic structure model optimization scheme library is established.

[0051] Step 8: Select the feature structure model optimization scheme and the matching additive path;

[0052] According to one embodiment of the present invention, in step 8, an additive path based on minimizing residual stress is established for any characteristic structure simulation optimization solution. After a characteristic structure model optimization solution is selected, a corresponding additive path is determined based on the principle of minimizing residual stress after simulation calculation.

[0053] Step 9: Establish the actuator and external axis related parameters;

[0054] According to one embodiment of the present invention, in step 9, the actuator-related parameters include the actuator angle, additive path, swing parameters (swing length, swing width and swing curve), the distance between the actuator and the conductive nozzle and the end face of the deposited layer, and the external axis-related parameters include the worktable angle and rotation speed.

[0055] Step 10: Establish arc additive process parameters.

[0056] According to one embodiment of the present invention, in step 10, the arc additive related process parameters include shielding gas flow rate, arc starting current, arc starting time, transition time, arc extinction current, transition time, arc extinction time, deposition speed, wire feeding speed and current-voltage curve, deposition interlayer temperature range, substrate initial temperature and interlayer waiting time, etc.

[0057] The following is combined with Figure 2-4 Specific embodiments of the present invention are described below. The following examples will help those skilled in the art further understand the present invention, but are not intended to limit the present invention in any way. It should be noted that those skilled in the art may make various modifications and improvements without departing from the scope of the present invention. These modifications and improvements are all within the scope of the present invention.

[0058] Figure 2 is a schematic diagram of the cross-class feature structure and its characteristic size. Figure 2 Taking the cross-shaped structure shown in the figure as an example, the black dotted line is the target cross-shaped structure model. After inputting the characteristic dimensions L1 / H1, L2 / H2, L3 / H3, L4 / H4, a1 / a2 / a, fuse material grade and diameter, arc additive heat source and process mode, the model optimization solution is obtained as follows: Figure 3 shown. Figure 3 The figure is a schematic diagram of the cross-shaped characteristic structure path. The thin black solid line is a "cross" cross structure after model optimization, and the thick black solid line represents the melt channel. P1P2P3P4 are the arc starting and arc extinguishing points, A1A2A3A4 are the melt channel corner points, and R1R2 are the corner arc radii. Then, the parameters related to the actuator and the external axis are obtained. These parameters are as follows: Figure 4 shown. Figure 4 Figure 1 is a schematic diagram of the actuator and external axis positions. The angle between the actuator (welding gun) and the workpiece is α, and the distance from the workpiece is h. From the top view of the external axis, the external axis rotation angle is β, and the rotation angular velocity is w. From the main view of the external axis, the inclination angle is γ. Finally, the parameters related to arc additive manufacturing are obtained. These parameters include shielding gas flow rate, arc starting current, arc starting time, transition time, arc extinction current, transition time, arc extinction time, deposition speed, wire feed speed and current-voltage curve, deposition interlayer temperature range, substrate initial temperature, and interlayer waiting time.

[0059] The present invention establishes a process database for typical characteristic structures of arc additive manufacturing, takes the fuse material brand and diameter, arc additive heat source and process mode, and preset characteristic structures, morphology curves, and characteristic dimensions as input, and outputs arc additive process parameters corresponding to the deposited layer morphology curve and characteristic dimensions. This allows for rapid matching of typical characteristic structures and their characteristic dimensions with molten wire, substrate material and state, arc additive heat source type and process mode, shielding gas type and flow rate, actuator and external axis-related parameters, characteristic structure model optimization scheme and additive path, and arc additive process parameters. The present invention actively controls the quality of arc additive manufacturing while meeting the preset requirements for the shape and size of typical characteristic structures. This improves the surface quality, forming accuracy, and forming efficiency of arc additive manufacturing parts, while ensuring the mechanical properties of the parts.

[0060] By repeatedly testing the same process and iteratively optimizing typical characteristic structure optimization schemes and additive paths through process simulation, a process database of typical characteristic structures of arc additive manufacturing can be established to achieve rapid matching of the above parameters.

[0061] Obviously, those skilled in the art may make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for constructing a process database of typical characteristic structures of arc additive manufacturing, characterized in that: Including steps: Step 1: Establish typical characteristic structure types, morphology curves and characteristic dimensions, wherein the typical characteristic structure types include cross-type structures, boss-type structures, inclined-type structures and suspended-type structures; Step 2: Input the target feature structure, topography curve and feature size; Step 3: Establish the type, grade and diameter of the molten wire; Step 4: Establish the brand and status corresponding to the substrate material; Step 5: Establish the type of arc additive heat source and its process mode; Step 6: Establish the type of protective gas; Step 7: Establish a characteristic structure model optimization scheme, where the characteristic structure model optimization scheme complies with the principle of minimum arcing and arcing extinction times, minimum path corners, and completeness of the filled path, including adding transition fillets / transition margins, reducing dead corners, short straight lines, and irregular trajectories, optimizing cross paths, optimizing corners, and increasing continuity between paths to make the paths smooth and stable. After the characteristic structure optimization scheme is iteratively completed, a characteristic structure model optimization scheme library is established. Step 8: Establishing an additive path for any characteristic structure model optimization scheme. After selecting a characteristic structure model optimization scheme, after simulation calculation, a corresponding additive path is given based on the principle of minimum residual stress. Step 9: Establish the actuator and external axis related parameters; Step 10: Establish arc additive process parameters.

2. The method for constructing a process database of typical characteristic structures of arc additive manufacturing according to claim 1, characterized in that: In step 3, the molten wire includes metal, intermetallic compound and functional gradient material therebetween.

3. The method for constructing a process database of typical characteristic structures of arc additive manufacturing according to claim 1, characterized in that: In step 4, the substrate material includes metals, intermetallic compounds and functionally gradient materials between them; the substrate states include: normalized state, annealed state, quenched state, modulated state, solution treated state and aged state.

4. The method for constructing a process database of typical characteristic structures of arc additive manufacturing according to claim 1, characterized in that: In step 5, the arc additive heat source includes submerged arc welding (SAW), gas tungsten arc welding (GTAW), argon tungsten arc welding (TIG), metal inert / active gas welding (MIG / MAG), cold metal transfer (CMT), and plasma arc welding (PAW) as heat sources; the process modes include DC / AC, pulse, variable polarity, and variable polarity pulse process modes.

5. The method for constructing a process database of typical characteristic structures of arc additive manufacturing according to claim 1, characterized in that: In step 6, the types of protective gases include argon, helium, carbon dioxide and mixed gases thereof.

6. The method for constructing a process database of typical characteristic structures of arc additive manufacturing according to claim 1, characterized in that: In step 9, the actuator-related parameters include the actuator angle, additive path, swing parameters, and the distance between the conductive nozzle and the end face of the cladding layer. The swing parameters include the swing length, swing width, and swing curve. The external axis-related parameters include the external axis angle and rotation speed.

7. The method for constructing a process database of typical characteristic structures of arc additive manufacturing according to claim 1, characterized in that: In step 10, the arc additive related process parameters include shielding gas flow rate, arc starting current, arc starting time, arc starting transition time, arc extinction current, arc extinction transition time, arc extinction time, deposition speed, wire feeding speed and current-voltage curve, deposition interlayer temperature range, substrate initial temperature and interlayer waiting time.

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