Selective laser melting forming method for rotary body structural part with suspended structure

Abstract

The invention discloses a selective laser melting forming method for a rotary body structural part with a suspended structure. The revolved body structural part comprises at least two revolved body structures which are coaxially arranged. The forming method comprises the following steps that a digital model of the revolved body structural part is obtained; based on a support demand analysis principle, carrying out support demand analysis on the digital model to determine an optimal placement mode; and the supporting structure is optimized and determined based on the optimal placement mode. According to the forming method, supporting demand analysis is conducted on a digital model of the rotary body structural part, the optimal placing mode is determined according to the result of the supporting demand analysis, the supporting structure of the rotary body structural part is optimized based on the optimal placing mode, and the corresponding placing mode and the supporting structure can be matched based on the specific structure of the rotary body structural part; and therefore, the corresponding selective laser melting forming method can be suitable for the rotary body structural part with the suspended structure, and the corresponding rotary body structural part with the suspended structure can be reliably formed.

Description

Technical Field

[0001] The present invention relates to the field of additive manufacturing, in particular to the field of metal laser selective melting forming technology, and in particular to a laser selective melting forming method for a rotating body structural part with a suspended structure. Background Art

[0002] Additive manufacturing, commonly known as 3D printing, uses computer software and numerical control systems to stack special metal materials, non-metallic materials and medical biomaterials layer by layer in the form of extrusion, sintering, melting, light curing, spraying, etc. to produce physical products. Additive manufacturing technology does not require traditional tools or molds. It only requires slicing the model and then inputting the program into the equipment to produce parts with complex shapes. It solves the forming of many complex structural parts and greatly reduces the processing procedures, especially in the product development stage, which greatly shortens the product development cycle.

[0003] Among additive manufacturing technologies, metal additive manufacturing has developed rapidly, among which laser selective melting (SLM) is the mainstream in metal additive manufacturing. SLM is a powder-laying metal additive manufacturing technology that uses a laser beam to selectively melt metal or alloy powders and stack them layer by layer into a dense entity. After simple surface treatment, it can be directly used as a mold and workpiece. SLM technology can be used to manufacture complex part structures more accurately, and the surface quality can be very high. Except for the positions that need to be assembled, all other surface positions do not need to be machined.

[0004] Compared with powder-feeding metal additive manufacturing, SLM has low requirements for powder fluidity and has advantages such as no need to debug the powder convergence before processing; compared with electron beam machining (EBM), which is also a powder-feeding metal additive manufacturing technology, SLM has the advantages of higher processing accuracy, lower surface roughness and easier powder recovery.

[0005] In the actual implementation of SLM process technology, there are certain requirements for the placement of the model. When the forming angle is small, auxiliary structures need to be added to implement the forming. When the tangential angle (forming angle) of the surface in the component is greater than 45°, it can be freely formed without adding auxiliary structures. When there is a surface with a forming angle less than 45° in the inner cavity, it cannot be formed according to the conventional process.

[0006] Because SLM has the characteristic of unlimited theoretical part processing structure, SLM generally manufactures more complex structural parts or parts that are difficult to process with traditional processing methods. However, for some special structures (for example, suspended structures), SLM needs to add additional supports to complete the manufacturing compared to EBM, which can rely on the powder bed to provide support through "pseudo-sintering" of powder.

[0007] Although in actual manufacturing, additive manufacturing engineers hope to avoid adding SLM supports as much as possible to improve processing efficiency and reduce costs, SLM supports are currently indispensable for parts with suspended structures.

[0008] The structure of the axial swirler of the AE gas turbine combustion chamber nozzle is complex and conforms to the SLM manufacturing characteristics, such as Figure 1 As shown, the main body of the axial swirler 1 is composed of two coaxial rotating structures with different diameters. The two rotating structures are connected by eight axial blades 30, and the rotating structure with a smaller diameter has four suspended fuel spray rods. Specifically, the axial swirler 1 includes two rotating structures, the two rotating structures are a first rotating structure 10 and a second rotating structure 20. The diameter of the first rotating structure 10 is larger than the diameter of the second rotating structure 20. The first rotating structure 10 and the second rotating structure 20 are connected by eight axial blades 30, and the end of the second rotating structure 20 away from the first rotating structure 10 has a plurality of suspended structures 40 used as fuel spray rods. For such a complex structure, in the SLM additive manufacturing process, it is necessary to first consider the placement method and then consider adding support.

[0009] Among the patents currently published, most are improvements to the structure of the SLM support itself. For example, lightweighting the support to reduce powder usage and speed up support processing time; or considering the contact structure design between the support and the part to improve the ease of subsequent support removal while meeting strength requirements. However, the SLM placement method for a specific structural part and the relationship between the support design and the structural characteristics of the part are not considered.

[0010] Even the few patent applications related to SLM placement and support design are only for plate-like parts with internal channel structures or blade structures with spatial curved surface structures. For example, the patent application "A SLM Manufacturing Heat Sink Forming Placement Method and Support Adding Method" (publication number CN104289712A) submitted by Beijing University of Technology in 2015 is mainly applicable to the SLM processing of plate-like parts with external through holes or arc transition structures and internal channels. The key points of this patent application include: (1) abandoning the best horizontal placement method that is most conducive to SLM manufacturing of parts with external through holes and other structures, and changing to a vertical placement method to avoid adding supports to the internal channel structure of the parts. Only a few external structures need to add easily removable supports to ensure that the overall support of the parts is reasonable and feasible; (2) During the SLM manufacturing process, the scraper for scraping powder is prevented from colliding with the local sharp corner structure, resulting in distortion or even failure of forming. The plate-like parts are placed at a certain angle to the scraper's movement direction to reduce the contact area between the edge of the part and the scraper.

[0011] However, the above design is not suitable for SLM manufacturing of special structural parts such as the axial swirler of a gas turbine, which is a rotating body structural part with a suspended structure. Summary of the invention

[0012] The technical problem to be solved by the present invention is to overcome the defect that the laser selective melting forming method in the prior art is not suitable for manufacturing a rotating body structural part with a suspended structure, and to provide a laser selective melting forming method for a rotating body structural part with a suspended structure.

[0013] The present invention solves the above technical problems through the following technical solutions:

[0014] A laser selective melting forming method for a rotating body structure with a suspended structure, wherein the rotating body structure comprises at least two coaxially arranged rotating body structures, and the forming method comprises the following steps:

[0015] S1, obtaining a digital model of the rotating structure;

[0016] S2. Based on the principle of support demand analysis, perform support demand analysis on the digital model to determine the best placement method; and

[0017] S3. Optimize and determine the support structure based on the best placement method;

[0018] The support requirement analysis principle includes: if the angle between the structure to be processed and the processing reference plane is smaller than a preset angle, a support structure needs to be added.

[0019] In this solution, a support demand analysis is performed on the digital model of the rotating structural part, and the optimal placement method is determined based on the results of the support demand analysis. The support structure is optimized based on the optimal placement method. As a result, the corresponding placement method and support structure can be matched based on the specific structure of the rotating structural part, and the corresponding laser selective melting forming method can be applied to the rotating structural part with a suspended structure, which means that the corresponding rotating structural part with a suspended structure can be reliably formed.

[0020] Preferably, step S2 comprises the steps of:

[0021] S21. Based on the support demand analysis principle, perform support demand analysis on the digital model in different placement modes to obtain support demand analysis results;

[0022] S22, based on the target conditions, determine the best placement method;

[0023] The target condition includes at least one of the following:

[0024] Whether the number of supporting structures reaches the preset value; and

[0025] Whether the support structure can be easily removed.

[0026] In this scheme, by analyzing the support requirements under different placement methods, the support requirements can be intuitively, objectively and truly reflected, which is conducive to ensuring the reliability of the forming process. Among them, the small number of support structures is conducive to improving the processing efficiency of laser selective melting, and is also conducive to reducing the subsequent process operations of removing the support structures, thereby improving the overall efficiency of the forming process. Furthermore, if the number of support structures is too large, the possibility of the support structure contacting the structure of the rotating body structure itself is greater, and the structure of the rotating body structure itself is easily damaged in the process of removing the support structure. Therefore, setting the number of support structures within the preset range is also conducive to protecting the structure of the rotating body structure itself, thereby ensuring the forming quality of the rotating body structure; the support structure is easy to remove, which can reduce the difficulty and time spent on removing the support structure, and is conducive to improving the processing efficiency of laser selective melting. At the same time, if the support structure is difficult to remove, the structure of the rotating body structure itself is also easy to damage in the process of removing the support structure. Therefore, the support structure is easy to remove and is also conducive to protecting the structure of the rotating body structure itself, thereby ensuring the forming quality of the rotating body structure. Therefore, setting the target conditions to include whether the number of support structures reaches a preset value and / or whether the support structures are easy to remove is beneficial to improving the processing efficiency of laser selective melting and ensuring the forming quality of the rotating body structure.

[0027] Preferably, step S22 comprises the steps of:

[0028] S221, based on the first target condition, screening out at least two placement methods to be selected;

[0029] S222, performing support structure filling on the structures in the at least two placement modes to be selected through simulation analysis, and obtaining filling results of the support structures in these placement modes;

[0030] S223, determining the best placement method based on the second target condition;

[0031] The first target condition is that the number of supporting structures is the least, and the second target condition is whether the supporting structures are easy to remove.

[0032] In this solution, the optimal placement method is obtained while taking into account the number of support structures and whether the support structures are easy to remove, so that the processing efficiency of laser selective melting and the forming quality of the rotating structure can be maintained at a high level, which is beneficial to ensuring the overall forming energy efficiency of the rotating structure.

[0033] Preferably, in the filling result, if at least a portion of the support structure is wrapped inside the rotating body structure, it is determined that the support structure is not easy to remove;

[0034] The second target condition is embodied in: determining whether at least a portion of the support structure is located inside the rotating structure.

[0035] In this solution, whether the support structure is easy to remove is determined by judging whether the support structure is partially or completely located inside the rotating body structure. The judgment method is simple and reliable, which is conducive to optimizing the method of obtaining the best placement method or simplifying the process of obtaining the best placement method.

[0036] Preferably, in step S21, the different placement modes include a vertical placement mode, a horizontal placement mode and an inclined placement mode, wherein in the inclined placement mode, the central axis of the rotating body structure forms an acute angle with the horizontal plane;

[0037] When the diameters of all the rotating body structures of the rotating body structural member are not completely equal, the vertical placement method includes a vertical forward placement method and a vertical reverse placement method;

[0038] Among them, the vertical placement method in which the end of the rotating structure with the largest diameter is located at the bottom is a vertical reverse placement method, and the vertical placement method in which the end of the rotating structure with the smallest diameter is located at the bottom is a vertical forward placement method.

[0039] In this solution, a vertical placement method (a vertical forward placement method and a vertical reverse placement method are optionally set according to the relationship between the diameters of multiple rotating body structures), a horizontal placement method and an inclined placement method are available, so that it can be applicable to rotating body structural parts of various structural types, which is conducive to increasing the reliability of obtaining the optimal placement method.

[0040] Preferably, the rotor structure is an axial swirler and includes two rotor structures, the two rotor structures are a first rotor structure and a second rotor structure, the diameter of the first rotor structure is larger than the diameter of the second rotor structure, the first rotor structure and the second rotor structure are connected by a plurality of axial blades, and the second rotor structure has a plurality of suspended structures used as fuel spray rods at one end away from the first rotor structure;

[0041] The vertical placement mode in which the first rotating body structure is located at the bottom is a vertical reverse placement mode, and the vertical placement mode in which the second rotating body structure is located at the bottom is a vertical forward placement mode;

[0042] In step S21, the number of the supporting structures in the vertical forward placement mode is three, including the initial processing end surface, the suspended structure and the first rotating body structure; the number of the supporting structures in the vertical reverse placement mode is two, including the initial processing end surface and the suspended structure;

[0043] In step S221, the at least two placement modes to be selected are a vertical forward placement mode and a vertical reverse placement mode;

[0044] In step S223, the optimal placement is the vertical forward placement.

[0045] In this scheme, the optimal placement of the axial cyclone is set to a vertical forward placement, while taking into account the number of supporting structures and whether the supporting structures are easy to remove, so that the processing efficiency of laser selective melting and the forming quality of the axial cyclone can be maintained at a high level, which is beneficial to ensuring the overall forming energy efficiency of the axial cyclone.

[0046] Preferably, the forming method further comprises the steps of:

[0047] S4. On the substrate, based on the optimal placement method and the optimized support structure, a rotary structure is formed by a laser selective melting forming method to obtain a preformed rotary structure;

[0048] The initial processing end surface is bonded to the substrate, and the substrate is used as a supporting structure at the initial processing end surface.

[0049] In this solution, the substrate is used as the support structure of the starting processing end face, and there is no need to set up an additional support structure for the starting processing end face, which is beneficial to reducing the number of support structures, thereby improving the processing efficiency of laser selective melting, and ensuring the forming quality of the axial cyclone.

[0050] Preferably, in the optimal placement mode, the support structure at the suspended structure is a support column extending from the suspended structure toward the starting processing end face, and the end face of the support column is aligned with the starting processing end face;

[0051] And / or, the support structure at the first rotating body structure is a support sleeve extending from the end face of the first rotating body structure toward the starting processing end face, and the end face of the support sleeve is aligned with the starting processing end face.

[0052] In this solution, the corresponding supporting structure is set as a supporting column and a supporting sleeve, which has a relatively simple structure and is easier to remove, which is beneficial to ensuring the processing efficiency of laser selective melting and the forming quality of the axial cyclone.

[0053] Preferably, step S3 comprises the steps of:

[0054] The support sleeve is configured as a plurality of tapered support units spaced apart along the circumferential direction of the first rotating body structure, wherein the small diameter end of the tapered support unit is attached to the first rotating body structure and the large diameter end faces the starting processing end surface;

[0055] and / or, the support column is arranged to have a gap with an outer wall surface of the second rotating structure, so as to separate the support column and the second rotating structure;

[0056] And / or, meshing is performed on at least one of the support column and the contact portion between the support column and the suspended structure.

[0057] In this solution, the support sleeve is configured as a plurality of spaced-apart conical support units, so that the dense support sleeve can be optimized and converted into discrete conical support units. On the basis of ensuring the support strength, the time and materials required for processing the support are reduced, and it is also beneficial for the subsequent rapid removal of the support structure. The support column is configured to have a gap with the outer wall surface of the second rotating body structure, and the support column is not close to the axial surface of the axial cyclone, so that the workload of subsequent mechanical segmentation or removal of the support structure can be reduced, and the axial surface damage of the axial cyclone caused by mechanical cutting can be avoided. By adopting a gridding process, the dense body support structure of the original contact part is configured as a hollow wire support, which can achieve the purpose of easy removal of the support structure, and can improve the manufacturing efficiency of the axial cyclone support and the efficiency of subsequent removal of the support structure.

[0058] Preferably, the forming method further comprises the steps of:

[0059] S5. Remove all supporting structures from the preformed rotating body structure.

[0060] The positive and progressive effects of the present invention are:

[0061] In the forming method of the present invention, a support demand analysis is performed on the digital model of the rotating body structural part, and the optimal placement method is determined based on the result of the support demand analysis, and its support structure is optimized based on the optimal placement method. Thus, the corresponding placement method and support structure can be matched based on the specific structure of the rotating body structural part, and the corresponding laser selective melting forming method can be applied to the rotating body structural part with a suspended structure, so that the corresponding rotating body structural part with a suspended structure can be reliably formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a schematic diagram of the structure of the axial swirler in the combustion chamber of an AE gas turbine.

[0063] Figure 2The present invention is a flowchart of a method for selective laser melting of a rotating body structure with a suspended structure according to a preferred embodiment of the present invention.

[0064] Figure 3 This is a schematic diagram of an axial cyclone in a preferred embodiment of the present invention in a vertical forward arrangement.

[0065] Figure 4 This is a schematic diagram of an axial cyclone in a preferred embodiment of the present invention in a vertically reversed arrangement.

[0066] Figure 5 This is a schematic diagram of an axial cyclone in a preferred embodiment of the present invention in a horizontal arrangement.

[0067] Figure 6 This is a schematic diagram of an axial cyclone in a preferred embodiment of the present invention in an inclined arrangement.

[0068] Figure 7 for Figure 3 Schematic diagram of support requirement analysis for a mid-axial cyclone in a vertical forward orientation, where a grid schematically illustrates the starting machining datum plane.

[0069] Figure 8 for Figure 4 Schematic diagram of support requirement analysis for a mid-axial cyclone in a vertical reverse orientation, where a grid schematically illustrates the starting machining datum plane.

[0070] Fig. 9 for Figure 5 Schematic diagram of the support requirement analysis when the central axial cyclone is in a horizontal position, where the grid schematically shows the starting processing reference plane.

[0071] Fig.10 for Figure 6 Schematic diagram of the support requirement analysis when the central axial cyclone is in an inclined position, where the grid schematically shows the starting processing reference plane.

[0072] Fig.11 for Figure 3 Schematic diagram of the support structure filling when the central axial cyclone is in a vertical positive arrangement, wherein the grid schematically shows the starting processing reference plane.

[0073] Fig.12 for Figure 4 Schematic diagram of the support structure filling when the central axial cyclone is in a vertical reverse arrangement, wherein the grid schematically shows the starting processing reference plane.

[0074] Fig.13 for Figure 3Schematic diagram of the optimization of the support sleeve when the central axial swirler is in a vertical positive arrangement, wherein the grid schematically shows the starting machining reference surface.

[0075] Fig.14 for Figure 3 Schematic diagram of the optimization of the support column by separating the support column and the second rotor structure when the central axial cyclone is in a vertical forward arrangement, wherein the grid schematically shows the starting processing reference plane.

[0076] Fig.15 for Figure 3 Schematic diagram of optimizing the support column by gridding the support column and the contact portion between the support column and the suspended structure when the central axial cyclone is in a vertical forward arrangement, wherein the grid schematically shows the starting processing reference plane.

[0077] Description of reference numerals:

[0078] 1Axial cyclone

[0079] 10The first rotating structure

[0080] 20 Second Rotating Structure

[0081] 30 axial blades

[0082] 40 Suspended structure

[0083] 50 Support structure

[0084] 501 support column

[0085] 502 support sleeve

[0086] 503 support cone unit DETAILED DESCRIPTION

[0087] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0088] This embodiment provides a laser selective melting forming method for a rotating body structure with a suspended structure 40, wherein the rotating body structure comprises at least two coaxially arranged rotating body structures, such as Figure 2 As shown, the forming method comprises the following steps:

[0089] S10, obtaining a digital model of a rotating body structure;

[0090] S20. Based on the support demand analysis principle, perform support demand analysis on the digital model to determine the best placement method; and

[0091] S30, optimizing and determining the support structure 50 based on the best placement method;

[0092] The support requirement analysis principle includes: if the angle between the structure to be processed and the processing reference plane is smaller than a preset angle, a support structure 50 needs to be added.

[0093] In this embodiment, a support demand analysis is performed on the digital model of the rotating structure, and the optimal placement method is determined based on the results of the support demand analysis. The support structure 50 is optimized based on the optimal placement method. As a result, the corresponding placement method and support structure 50 can be matched based on the specific structure of the rotating structure, so that the corresponding laser selective melting forming method can be applied to the rotating structure with the suspended structure 40, and the corresponding rotating structure with the suspended structure 40 can be reliably formed.

[0094] It should be noted that when the angle between the structure to be processed and the processing reference plane (the horizontal plane that continuously rises during the actual processing process) is 50°-90°, the structure itself can be used as a support to complete subsequent manufacturing, that is, there is no need to add an additional support structure 50; when the angle between the structure to be processed and the processing reference plane is 30°-50°, the structure itself can still be used as a support structure 50, but there is a risk of insufficient support strength, which can easily cause subsequent structural deformation and parts are not dense. Whether to add an additional support structure 50 needs to be decided based on actual conditions; when the angle between the structure to be processed and the processing reference plane is 0°-30°, the structure itself cannot be used as a support structure 50, and an additional support structure 50 must be added to ensure part manufacturing.

[0095] Based on the above principle, in this embodiment, the above preset angle is set to 30°, that is, when the angle between the structure to be processed and the processing reference plane is less than 30°, it is necessary to add a support structure 50. Of course, as an alternative embodiment, according to the requirements of support strength, the above preset angle can be set to any angle of 50° and below, and no specific limitation is made here.

[0096] Further, step S20 includes the steps of:

[0097] S201. Based on the support demand analysis principle, perform support demand analysis on the digital model in different placement modes to obtain support demand analysis results;

[0098] S202, determining the best placement method based on the target conditions;

[0099] The target condition includes at least one of the following:

[0100] Whether the number of support structures 50 reaches a preset value; and

[0101] Whether the support structure 50 is easy to remove.

[0102] Here, by analyzing the support requirements under different placement methods, the support requirements can be intuitively, objectively and truly reflected, which is conducive to ensuring the reliability of the forming process. Among them, the small number of support structures 50 is conducive to improving the processing efficiency of laser selective melting, and is also conducive to reducing the subsequent process operation of removing the support structure 50, thereby improving the overall efficiency of the forming process. Further, if the number of support structures 50 is too large, the possibility of the support structure 50 contacting the structure of the rotating body structure itself is greater, and the structure of the rotating body structure itself is also easily damaged in the process of removing the support structure 50. Therefore, setting the number of support structures 50 within a preset range is also conducive to protecting the structure of the rotating body structure itself, thereby ensuring the forming quality of the rotating body structure; the support structure 50 is easy to remove, which can reduce the difficulty and time spent on removing the support structure 50, and is conducive to improving the processing efficiency of laser selective melting. At the same time, if the support structure 50 is difficult to remove, the structure of the rotating body structure itself is also easily damaged in the process of removing the support structure 50. Therefore, the support structure 50 is easy to remove and is also conducive to protecting the structure of the rotating body structure itself, thereby ensuring the forming quality of the rotating body structure. Therefore, setting the target conditions to include whether the number of support structures 50 reaches a preset value and / or whether the support structures 50 are easy to remove is beneficial to both improving the processing efficiency of laser selective melting and ensuring the forming quality of the rotating body structure.

[0103] Further, step S202 includes the steps of:

[0104] S2021. Based on the first target condition, select at least two placement methods to be selected;

[0105] S2022, filling the structures in at least two to-be-selected placement modes with the support structure 50 through simulation analysis, and obtaining filling results of the support structure 50 in these placement modes;

[0106] S2023, determining the best placement method based on the second target condition;

[0107] The first target condition is that the number of the support structures 50 is the least, and the second target condition is whether the support structures 50 are easy to remove.

[0108] Here, the best placement method takes into account the number of support structures 50 and whether the support structures 50 are easy to remove, so that the processing efficiency of laser selective melting and the forming quality of the rotating structure can be maintained at a high level, which is beneficial to ensuring the overall forming energy efficiency of the rotating structure.

[0109] As an example, in the filling result, if at least a portion of the support structure 50 is wrapped inside the rotating body structure, it is determined that the support structure 50 is not easy to remove;

[0110] It should be noted that if support is added between two blades, the support structure needs to be removed by machining, because the blade is anisotropically curved. Therefore, whether the support can be removed or whether it is easy to remove is related to the minimum distance between the blades and the depth of the support's inward extension. If the minimum distance between the blades is less than 10mm and the support's inward extension depth is greater than 15mm, the support cannot be removed by machining. If the minimum distance between the blades is greater than 10mm and the support's inward extension depth is no more than 4 times the minimum distance between the blades, the support can be removed by machining.

[0111] The second target condition is reflected in: determining whether at least a portion of the support structure 50 is located inside the rotating structure.

[0112] With such arrangement, whether the support structure 50 is easy to remove can be determined by judging whether the support structure 50 is partially or completely located inside the rotating structure. The judgment method is simple and reliable, which is conducive to optimizing the method of obtaining the best placement method or simplifying the process of obtaining the best placement method.

[0113] In addition, refer to Figures 3 to 6 It is understood that in step S201, the different placement methods include a vertical placement method (such as Figure 3 and Figure 4 ), horizontal placement (such as Figure 5 ) and tilted placement (such as Figure 6 ), wherein, in the inclined placement mode, the central axis of the rotating structure forms an acute angle with the horizontal plane;

[0114] When the diameters of all the rotating body structures of the rotating body structural member are not completely equal, the vertical placement method includes a vertical forward placement method and a vertical reverse placement method;

[0115] Among them, the vertical placement method in which the end of the rotating structure with the largest diameter is located at the bottom is a vertical reverse placement method, and the vertical placement method in which the end of the rotating structure with the smallest diameter is located at the bottom is a vertical forward placement method.

[0116] Here, by setting a vertical placement mode, a horizontal placement mode and an inclined placement mode (wherein, according to the relationship between the diameters of multiple rotating body structures, the vertical placement mode can be optionally set to a vertical forward placement mode and a vertical reverse placement mode), it can be applicable to rotating body structural parts of various structural types, which is conducive to increasing the reliability of obtaining the best placement mode.

[0117] Specifically in this embodiment, the rotor structure is an axial swirler 11 and includes two rotor structures, the two rotor structures are a first rotor structure 10 and a second rotor structure 20, the diameter of the first rotor structure 10 is larger than the diameter of the second rotor structure 20, the first rotor structure 10 and the second rotor structure 20 are connected by a plurality of axial blades 30, and the second rotor structure 20 has a plurality of suspended structures 40 used as fuel spray rods at one end away from the first rotor structure 10;

[0118] The vertical placement of the first rotating structure 10 at the bottom is a vertical reverse placement, and the vertical placement of the second rotating structure 20 at the bottom is a vertical forward placement;

[0119] like Figure 7 As shown, in step S201, the number of the supporting structures 50 in the vertical forward arrangement is three, including the initial processing end surface, the suspended structure 40 and the first rotating body structure 10, as shown in FIG. Figure 7 As shown in red in the figure on the right. Figure 8 As shown, the number of the supporting structures 50 in the vertical reverse arrangement is two, including the initial processing end surface and the suspended structure 40, such as Figure 8 As shown in the red position in the figure on the right;

[0120] In step S2021, at least two placement modes to be selected are a vertical forward placement mode and a vertical reverse placement mode;

[0121] In step S2023, the best placement is vertical and forward placement.

[0122] Among them, the optimal placement of the axial cyclone 11 is set to a vertical forward placement, while taking into account the number of support structures 50 and whether the support structures 50 are easy to remove, so that the processing efficiency of laser selective melting and the forming quality of the axial cyclone 11 can be maintained at a high level, which is beneficial to ensuring the overall forming energy efficiency of the axial cyclone 11.

[0123] It should be noted that, refer to Figure 7 and Figure 8 It is understood that the number of support structures 50 in the vertical reverse placement is less than the number of support structures 50 in the vertical forward reverse placement. Therefore, if the target condition is only whether the number of support structures 50 is the least or reaches a preset value, the vertical reverse placement should be given priority as the best placement. Correspondingly, if the target condition is only whether the support structure 50 is easy to remove, the vertical forward placement should be given priority as the best placement.

[0124] Furthermore, the forming method further comprises the steps of:

[0125] S40, on the substrate, based on the optimal placement method and the optimized support structure 50, a rotary structure is formed by a laser selective melting forming method to obtain a preformed rotary structure;

[0126] The initial processing end surface is attached to the substrate, and the substrate is used as a support structure 50 at the initial processing end surface.

[0127] Here, the substrate is used as the support structure 50 of the starting processing end face, and there is no need to set up an additional support structure 50 for the starting processing end face, which is beneficial to reducing the number of support structures 50, thereby improving the processing efficiency of laser selective melting and ensuring the forming quality of the axial swirler 11.

[0128] Fig. 9 for Figure 5 Schematic diagram of support requirement analysis when the central axial cyclone 11 is in a horizontal arrangement. Compared with the structural positions in the vertical forward arrangement and the vertical reverse arrangement, when placed horizontally, there is a possibility of transforming the suspended structure 40 into a structure 50 that does not require support. However, at the same time, when placed horizontally, due to the limited contact area between the rotating body structure and the base plate (see the following content, corresponding to the starting processing reference surface or the starting processing end surface), even if the suspended structure 40 existing in the vertical arrangement is "eliminated", a new structure 50 that requires support will generally be created at the same time, and an analysis result that requires support addition will usually be generated inside the rotating body (such as Fig. 9 As shown in the figure). Once support needs to be added inside the rotating body, it will increase the difficulty of removing the support from the part later. Therefore, this placement method is basically not suitable for SLM manufacturing of rotating body structural parts.

[0129] Fig.10 for Figure 6 Schematic diagram of support requirement analysis when the central axial cyclone 11 is in an inclined placement. When the "self-supporting" ability of the part structure is strong, its placement angle can be adjusted to minimize or even eliminate the suspended structure 40 when placed vertically, and also to avoid generating a "new" suspended structure 40 similar to that when placed horizontally. That is, when such structural parts are placed at a certain angle, there may actually be an optimal solution that can optimize the problem of suspended structure 40 when placed vertically and horizontally.

[0130] After analyzing the support requirements for different placement methods of the coaxial rotating body assembly parts with suspended structures 40 (i.e., rotating body structural parts with suspended structures 40), a preliminary evaluation of the schemes is performed based on manufacturing feasibility or manufacturing efficiency, and unfeasible manufacturing schemes are removed. The remaining schemes are filled with support structures 50 through the software Phenix, and then the best placement method of the parts and the corresponding support structure 50 design are analyzed and selected based on the filling results of the support structure 50. According to the above analysis, the horizontal placement method is first abandoned. Secondly, considering that not all parts can achieve the best support design when placed at a certain angle, and the characteristics of the rotating body assembly structure determine that the closer the angle between its axis and the horizontal plane is to 90°, the more conducive it is to the design of the support structure 50. That is, the best support design for placement at a certain angle is approximately the support design for vertical placement. Therefore, when filling the specific support, only the support filling results of the parts when placed vertically are given in this embodiment. Specifically, Fig.11 is a schematic diagram of the support structure 50 when the axial cyclone 11 is in a vertical forward arrangement. Fig.12 It is a schematic diagram of the support structure 50 when the axial swirler 11 is in a vertical reverse arrangement.

[0131] in, Fig.11 The corresponding placement method is the vertical forward placement method. As mentioned above, this placement method makes the starting processing end face of the part, the suspended structure 40, and the end face of the first rotating body structure 10 all at 0° relative to the horizontal processing base surface, that is, these three places need to add support. Because the starting processing end face is close to the substrate, the starting end face can rely on the substrate as a support for processing during the SLM manufacturing process, while the other two structures are suspended relative to the substrate, and the transition structure of the part itself cannot play a "self-supporting" effect, so it is necessary to add a certain shape of axial support at the end face of the suspended structure 40 and the first rotating body structure 10. Fig.11 The axial support is schematically shown in brown, and the axial support is easy to remove. The cylindrical ring structure (corresponding to the support sleeve 502 described below) processed on the end face of the external support first rotating body structure 10 and the cylindrical-like structure (corresponding to the support column 501 described below) processed on the internal support suspended structure 40 can be removed by simple mechanical cutting.

[0132] Fig.12 The corresponding placement method is the vertical reverse placement method. As before, in this placement method, only the starting processing end face of the part and the suspended structure 40 are at 0° relative to the horizontal processing base surface. In addition, the starting processing end face is close to the substrate. During the SLM manufacturing process, the part needs to add support only at the suspended structure 40. Fig.12The support structure 50 is schematically shown in brown. Although the parts rely on this arrangement to obtain a smaller number of supports, which theoretically has the advantage of improving processing efficiency and raw material utilization, if the rotating body structure only has an interfering structure inside, the filled support structure 50 will be wrapped inside the part, which will increase the difficulty of removing the support and reduce the part processing efficiency.

[0133] In summary, in this embodiment, the processing efficiency and the forming quality of the parts are comprehensively considered, and the vertical forward placement is taken as the best placement method.

[0134] like Fig.11 and Fig.12 As shown, in the best arrangement, the support structure 50 at the suspended structure 40 is a support column 501 extending from the suspended structure 40 toward the starting processing end face, and the end face of the support column 501 is aligned with the starting processing end face. In this embodiment, each suspended structure 40 is provided with a support column 501.

[0135] Optionally or alternatively, the support structure 50 at the first rotating structure 10 is a support sleeve 502 extending from the end face of the first rotating structure 10 toward the starting processing end face, and the end face of the support sleeve 502 is aligned with the starting processing end face.

[0136] Among them, the corresponding support structure 50 is set as a support column 501 and a support sleeve 502, the structure is relatively simple and easy to remove, which is conducive to ensuring the processing efficiency of laser selective melting and the forming quality of the axial cyclone 11.

[0137] Furthermore, step S30 includes the steps of:

[0138] (1) The support sleeve 502 is configured as a plurality of conical support units 503 spaced apart along the circumferential direction of the first rotating structure 10, wherein the small diameter end of the conical support unit 503 is attached to the first rotating structure 10 and the large diameter end faces the starting processing end surface, such as Fig.13 As shown (where Fig.13 The rightmost side of FIG. 1 schematically shows a single conical support unit 503); and / or,

[0139] (2) The support column 501 is set to have a gap with the outer wall surface of the second rotating structure 20 to separate the support column 501 from the second rotating structure 20, such as Fig.14 as shown; and / or,

[0140] (3) Meshing the support column 501 and at least one of the contact portions between the support column 501 and the suspended structure 40, such as Fig.15 shown.

[0141] Specifically in this embodiment, the above three methods (1)-(3) are simultaneously used to optimize the support structure 50.

[0142] Among them, the support sleeve 502 is set to a plurality of spaced conical support units 503, so that the dense support sleeve 502 can be optimized and converted into discrete conical support units 503, which reduces the time and materials required for processing the support while ensuring the support strength, and is also conducive to the subsequent rapid removal of the support structure 50. The support column 501 is set to have a gap with the outer wall surface of the second rotating body structure 20, and the support column 501 is not close to the axial surface of the axial cyclone 11, so that the workload of subsequent mechanical segmentation or removal of the support structure 50 can be reduced, and the axial surface damage of the axial cyclone 11 caused by mechanical cutting can be avoided. By adopting a gridding process, the dense body support structure 50 of the original contact part is set as a hollow wire support, which can achieve the purpose of easy removal of the support structure 50, and can improve the manufacturing efficiency of the axial cyclone 11 support and the efficiency of subsequent removal of the support structure 50.

[0143] In other alternative embodiments, only one or two of the three methods (1)-(3) may be used, which can be determined according to actual setting requirements.

[0144] Finally, the forming method further comprises the steps of:

[0145] S50, removing all supporting structures 50 from the preformed rotating body structure.

[0146] During forming, the 3D System ProX 200 SLM equipment can be selected as the manufacturing equipment for the axial cyclone.

[0147] By adopting the support structure optimization method in this embodiment, the processing cycle of the axial swirler after the support structure optimization is shortened to 32 hours compared with the processing cycle of 40 hours before the support structure optimization. However, considering that the axial swirler currently prepared is prepared for the AE series V64.3 model gas turbine, and the AE V64.3 is a small gas turbine, the size of its axial swirler is relatively small and the suspended end face is narrow. In order to ensure the manufacturing success rate, the above-mentioned support structure optimization method (1) may not be adopted temporarily, and only the support structure optimization method of the separation design in the above-mentioned (2) and the support structure optimization method of the contact structure grid in the above-mentioned (3) may be adopted. After the support structure optimization, the actual processing cycle is 35 hours.

[0148] It should be noted that whether an inverted cone support can be added to the suspended end face is related to the thickness of the suspended wall and the height of the inverted cone (corresponding to the conical support unit). If the thickness of the suspended wall is less than 0.2mm, an inverted cone support cannot be added. If the suspended wall is greater than 0.2mm, the average cone diameter of the conical support unit is D, and if 0.1mm≤D<0.3mm, the inverted cone height does not exceed 10mm, then an inverted cone can be added. If 0.3mm≤D<0.5mm, the inverted cone height does not exceed 30mm, then an inverted cone can be added. If 0.5mm≤D<0.8mm, the inverted cone height does not exceed 60mm, then an inverted cone can be added.

[0149] In summary, in this embodiment, a support demand analysis is performed on the digital model of the rotating structure, and the optimal placement method is determined based on the results of the support demand analysis. The support structure 50 is optimized based on the optimal placement method. As a result, the corresponding placement method and the support structure 50 can be matched based on the specific structure of the rotating structure, so that the corresponding laser selective melting forming method can be applied to the rotating structure with the suspended structure 40, and the corresponding rotating structure with the suspended structure 40 can be reliably formed. The forming method can effectively form the axial cyclone 11, and the processing efficiency and forming quality can be maintained at a high level.

[0150] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A laser selective melting forming method for a rotating body structure with a suspended structure, wherein the rotating body structure comprises at least two coaxially arranged rotating body structures, characterized in that: The forming method comprises the following steps: S1, obtaining a digital model of the rotating structure; S2. Based on the principle of support demand analysis, perform support demand analysis on the digital model to determine the best placement method; and S3. Optimize and determine the support structure based on the best placement method; The support requirement analysis principle includes: if the angle between the structure to be processed and the processing reference plane is smaller than a preset angle, a support structure needs to be added.

2. The laser selective melting forming method of a rotating body structural member with a suspended structure according to claim 1, characterized in that: Step S2 comprises the steps of: S21. Based on the support demand analysis principle, perform support demand analysis on the digital model in different placement modes to obtain support demand analysis results; S22, based on the target conditions, determine the best placement method; The target condition includes at least one of the following: Whether the number of supporting structures reaches the preset value; and Whether the support structure can be easily removed.

3. The laser selective melting forming method of a rotating body structural member with a suspended structure according to claim 2, characterized in that: Step S22 includes the steps of: S221, based on the first target condition, screening out at least two placement methods to be selected; S222, performing support structure filling on the structures in the at least two placement modes to be selected through simulation analysis, and obtaining filling results of the support structures in these placement modes; S223, determining the best placement method based on the second target condition; The first target condition is that the number of supporting structures is the least, and the second target condition is whether the supporting structures are easy to remove.

4. The laser selective melting forming method of a rotating body structural member with a suspended structure according to claim 3, characterized in that: In the filling result, if at least a portion of the support structure is wrapped inside the rotating body structure, it is determined that the support structure is not easy to remove; The second target condition is embodied in: determining whether at least a portion of the support structure is located inside the rotating structure.

5. The laser selective melting forming method of a rotating body structural member with a suspended structure as claimed in claim 3, characterized in that: In step S21, the different placement modes include a vertical placement mode, a horizontal placement mode, and an inclined placement mode, wherein in the inclined placement mode, the central axis of the rotating structure forms an acute angle with the horizontal plane; When the diameters of all the rotating body structures of the rotating body structural member are not completely equal, the vertical placement method includes a vertical forward placement method and a vertical reverse placement method; Among them, the vertical placement method in which the end of the rotating structure with the largest diameter is located at the bottom is a vertical reverse placement method, and the vertical placement method in which the end of the rotating structure with the smallest diameter is located at the bottom is a vertical forward placement method.

6. The laser selective melting forming method of a rotating body structural member with a suspended structure according to claim 5, characterized in that: The rotor structure is an axial swirler and includes two rotor structures, the two rotor structures are a first rotor structure and a second rotor structure, the diameter of the first rotor structure is greater than the diameter of the second rotor structure, the first rotor structure and the second rotor structure are connected by a plurality of axial blades, and the second rotor structure has a plurality of suspended structures used as fuel spray rods at one end away from the first rotor structure; The vertical placement mode in which the first rotating body structure is located at the bottom is a vertical reverse placement mode, and the vertical placement mode in which the second rotating body structure is located at the bottom is a vertical forward placement mode; In step S21, the number of the supporting structures in the vertical forward placement mode is three, including the initial processing end surface, the suspended structure and the first rotating body structure; the number of the supporting structures in the vertical reverse placement mode is two, including the initial processing end surface and the suspended structure; In step S221, the at least two placement modes to be selected are a vertical forward placement mode and a vertical reverse placement mode; In step S223, the optimal placement is the vertical forward placement.

7. The laser selective melting forming method of a rotating body structural member with a suspended structure according to claim 6, characterized in that: The forming method further comprises the steps of: S4. On the substrate, based on the optimal placement method and the optimized support structure, a rotary structure is formed by a laser selective melting forming method to obtain a preformed rotary structure; The initial processing end surface is bonded to the substrate, and the substrate is used as a supporting structure at the initial processing end surface.

8. The laser selective melting forming method of a rotating body structural member with a suspended structure according to claim 7, characterized in that: In the optimal placement mode, the support structure at the suspended structure is a support column extending from the suspended structure toward the starting processing end surface, and the end surface of the support column is aligned with the starting processing end surface; And / or, the support structure at the first rotating body structure is a support sleeve extending from the end face of the first rotating body structure toward the starting processing end face, and the end face of the support sleeve is aligned with the starting processing end face.

9. The laser selective melting forming method of a rotating body structural member with a suspended structure according to claim 8, characterized in that: Step S3 includes the steps of: The support sleeve is configured as a plurality of tapered support units spaced apart along the circumferential direction of the first rotating body structure, wherein the small diameter end of the tapered support unit is attached to the first rotating body structure and the large diameter end faces the starting processing end surface; and / or, the support column is arranged to have a gap with an outer wall surface of the second rotating structure, so as to separate the support column and the second rotating structure; And / or, meshing is performed on at least one of the support column and the contact portion between the support column and the suspended structure.

10. The laser selective melting forming method of a rotating body structure with a suspended structure according to any one of claims 7 to 9, characterized in that: The forming method further comprises the steps of: S5. Remove all supporting structures from the preformed rotating body structure.

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