A method for designing a support structure for controlling shaping of a large annular thin-walled part by SLM

Abstract

The present application relates to a kind of SLM forming large annular thin-walled part control shape support structure design method, belong to laser selective melting additive manufacturing technical field, solve the problem that the deformation of prior art large annular thin-walled part additive manufacturing is difficult to control, shape surface precision is poor, support material is wasted.The design method includes: calculating the minimum support volume of large annular thin-walled part, determining the support volume of first level support structure, carrying out SLM additive manufacturing deformation simulation to large annular thin-walled part and its first level support structure, obtain deformation simulation result, whether need to increase the support volume of first level support structure or increase second level support part according to deformation simulation result;Repeat until deformation simulation result meets control shape target requirement.The present application realizes to improve finished product quality, minimize material waste, simplify manufacturing process, improve finished product accuracy.

Description

Technical Field

[0001] This invention relates to the field of laser selective melting additive manufacturing technology, and in particular to a method for controlling the shape support design of large annular thin-walled parts formed by laser selective melting. Background Technology

[0002] Selective Laser Melting (SLM) is an emerging additive manufacturing technology that has attracted much attention in recent years. Its unique advantages make it a preferred additive manufacturing process in demanding fields such as aerospace. SLM technology uses a device equipped with a high-energy laser to completely melt metal powder, which is then stacked layer by layer to manufacture metal parts. This eliminates many traditional manufacturing steps, shortens production cycles, and improves material utilization.

[0003] In the manufacturing industry, some large-sized thin-walled parts are often difficult to manufacture precisely using traditional processing methods. Therefore, additive manufacturing technology, especially selective laser melting (SLM), is highly sought after by the manufacturing industry due to its excellent forming freedom, and has become a clear trend in the manufacture of large annular thin-walled parts.

[0004] However, large annular thin-walled parts are prone to deformation during SLM forming. Effectively designing the support structure to ensure stability during manufacturing and final quality remains a major challenge. In existing technologies, engineers and operators need to manually design the support structure to prevent deformation or collapse of the thin-walled structure during manufacturing. This requires significant expertise and experience and can lead to uneven distribution of the support structure, resulting in manufacturing defects or material waste.

[0005] Therefore, it is necessary to design a support structure design method that can effectively reduce material waste and improve manufacturing efficiency while ensuring product shape control quality. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a design method for shape control support structure of large annular thin-walled parts formed by SLM, in order to solve at least one of the problems of difficult deformation control, poor surface accuracy, and waste of support material in the existing additive manufacturing of large annular thin-walled parts.

[0007] On one hand, embodiments of the present invention provide a method for designing a shape control support structure for SLM-formed large annular thin-walled parts, including:

[0008] Step 1: Calculate the minimum support volume of the large annular thin-walled component. The minimum support volume is the minimum value of the support volume required to prevent the large annular thin-walled component from collapsing.

[0009] Step 2: Determine the support volume of the first-level support structure based on the calculated minimum support volume. The support volume of the first-level support structure is greater than the minimum support volume of the large annular thin-walled component.

[0010] Step 3: Perform SLM additive manufacturing deformation simulation on the large annular thin-walled part and its first-level support structure to obtain the deformation simulation results;

[0011] Step 4: Determine whether it is necessary to increase the support volume of the first-level support structure or add a second-level support component based on the deformation simulation results;

[0012] Step 5: Repeat step 4 until the deformation simulation results meet the requirements of the shape control target.

[0013] Furthermore, in step one, the minimum support volume V satisfies:

[0014] V = A × d × t × h;

[0015] In the formula, A is a coefficient, with a value ranging from 0.2 to 2.5;

[0016] d is the average diameter of the large annular thin-walled component;

[0017] t represents the overall wall thickness of the large annular thin-walled component;

[0018] h is the height from the top surface to the bottom surface of the large annular thin-walled component.

[0019] Furthermore, in step four, when it is necessary to increase the support volume of the first-level support structure or add a second-level support component, the second-level support component forms a second-level support structure; SLM additive manufacturing deformation simulation is performed on the large annular thin-walled part and its first-level and second-level support structures.

[0020] Furthermore, in step four, based on the deformation simulation results, the composition of the support structure is finally determined: if the deformation is > ±0.5mm, the support volume of the first-level support structure is increased or a second-level support component is added; if the deformation is ≤ ±0.5mm, the support volume of the first-level support structure is not increased or a second-level support component is added.

[0021] Furthermore, in step four, based on the deformation simulation results, the composition of the support structure is finally determined: if the deformation is greater than ±1mm, the support volume of the first-level support structure is increased; if the deformation is less than ±0.5mm and less than 1mm, a second-level support component is added.

[0022] Furthermore, in step five, the shape control target is to keep the deformation within the range of ±0.5mm.

[0023] Furthermore, a first-level support member is uniformly distributed on the inner or outer surface of the large annular thin-walled component to form a first-level support structure; the height of the first-level support member is the same as the height of the large annular thin-walled component.

[0024] Furthermore, the first-level support member is one or more of the following: axial ribs, cross meshes, and dot matrix.

[0025] Furthermore, the second-level support member is one or more of the following: cantilever ribs, cross grids, and dot matrix.

[0026] On the other hand, embodiments of the present invention provide a support structure for a large annular thin-walled part formed by SLM forming, the support structure being designed by the above-described design method.

[0027] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0028] 1. Improved Finished Product Quality. The finished product quality of SLM additive manufacturing is critical for many applications. Through deformation simulation, the method of this invention can better predict and control deformation, reducing manufacturing defects caused by improper support or material shrinkage. The result is higher quality finished products, reduced scrap rates, and savings in time and resources.

[0029] 2. Minimize material waste. By calculating the minimum support volume of large annular thin-walled components early on, and ensuring a minimum volume for the support structure, material waste is reduced. This helps lower manufacturing costs while supporting sustainable production.

[0030] 3. Adaptive Support. This invention introduces an adaptive support structure that adjusts the support density and position based on deformation simulation results. Precise positioning and control of the support structure helps maintain the surface accuracy of large annular thin-walled components, ensuring the final product meets precise design requirements. Simultaneously, the support structure can be adjusted according to actual needs, thereby minimizing material waste while ensuring the stability of the large annular thin-walled component.

[0031] 4. Simplified Manufacturing Process. Traditional support structure design may require specialized knowledge and tedious manual operations, which can lead to complexity and time-consuming manufacturing processes. The method of this invention simplifies the entire manufacturing process by automating the calculation and adjustment of the supports, reducing the risk of human error and improving production efficiency.

[0032] 5. Improved manufacturing flexibility: Since this invention is applicable to various types of large annular thin-walled parts, including cylindrical thin-walled parts of different shapes and sizes, manufacturers can more easily meet the needs of different projects, increasing manufacturing flexibility.

[0033] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0034] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0035] Figure 1 Schematic diagrams of support structures of various shapes. Figure 1 (a) is a schematic diagram of the overall support structure. Figure 1 (b) is a schematic diagram of the cross-grid support structure. Figure 1 (c) is a schematic diagram of the axial rib support structure. Figure 1 (d) is a schematic diagram of the cantilevered rib support structure. Figure 1 (e) is a schematic diagram of the lattice support structure;

[0036] Figure 2 This is a schematic diagram of the straight cylindrical large annular thin-walled component and its support structure in Example 1;

[0037] Figure 3 This is a diagram showing the deformation effect of the part after the support structure of the present invention is controlled according to Example 1;

[0038] Figure 4 This is a schematic diagram of the first design of a large annular thin-walled cylindrical component with variable diameter and its supporting structure in Example 2;

[0039] Figure 5 This is a diagram showing the deformation effect of the parts after the support structure of the present invention is controlled according to the first design scheme of Example 2;

[0040] Figure 6 This is a schematic diagram of the second design of a large annular thin-walled cylindrical component with variable diameter and its supporting structure in Example 2;

[0041] Figure 7 This is a diagram showing the deformation effect of the parts after the support structure of the second design scheme of Example 2 is controlled according to the present invention;

[0042] Figure 8 This is a schematic diagram of the first design of a large annular thin-walled cylindrical component with a variable diameter and a ring-shaped wall thickness abrupt change region, and its supporting structure, as shown in Example 3.

[0043] Figure 9 This is a diagram showing the deformation effect of the parts after the support structure of the present invention is controlled according to the first design scheme of Example 3;

[0044] Figure 10 This is a schematic diagram of the large annular thin-walled cylindrical component with a variable diameter and a ring-shaped wall thickness abrupt change region, and its supporting structure, as designed in Example 3.

[0045] Figure 11 This is a diagram showing the deformation effect of the part after the support structure of the second design scheme of Example 3 is controlled according to the present invention;

[0046] Figure 12 This is a schematic diagram of the large annular thin-walled cylindrical component with a variable diameter cylindrical shape and its supporting structure, designed for the third time in Example 3, featuring an annular wall thickness abrupt change region.

[0047] Figure 13 This is a diagram showing the deformation effect of the part after the support structure of the third design scheme of Example 3 is controlled according to the present invention;

[0048] Figure 14 This is a schematic diagram of a large, thin-walled, straight cylindrical annular component without a support structure, as shown in Comparative Example 1.

[0049] Figure 15 The deformation effect of the part in Comparative Example 1 without the shape control of the supporting structure is shown in the figure.

[0050] Figure label:

[0051] 1-Cross grid; 2-Axial rib; 3-Cantilever rib; 4-Dot matrix. Detailed Implementation

[0052] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0053] A specific embodiment of the present invention discloses a method for designing a shape-controlled support structure for a large annular thin-walled part formed by SLM (Sequencing Machine Tooling). The large annular thin-walled part is a straight cylindrical shape, a straight elliptical cylindrical shape, or a variable-diameter cylindrical shape. The specific steps of the method of the present invention include:

[0054] Step 1: Calculate the minimum support volume of the large annular thin-walled component; the minimum support volume is the minimum value of the support volume required to prevent the large annular thin-walled component from collapsing.

[0055] Step 2: Determine the support volume of the first-level support structure based on the calculated minimum support volume; the support volume of the first-level support structure is greater than the minimum support volume of the large annular thin-walled component.

[0056] Step 3: Perform SLM additive manufacturing deformation simulation on the large annular thin-walled part and its first-level support structure to obtain the deformation simulation results;

[0057] Step 4: Based on the deformation simulation results, determine whether it is necessary to increase the support volume of the first-level support structure or add a second-level support component; if so, increase the support volume of the first-level support structure or add a second-level support component, with the second-level support component forming the second-level support structure; perform SLM additive manufacturing deformation simulation on the large annular thin-walled part and its first-level and second-level support structures;

[0058] Step 5: Repeat step 4 until the deformation simulation results meet the requirements of the shape control target.

[0059] The method of this invention significantly reduces material waste by calculating the minimum support volume of large annular thin-walled parts in the early stage to ensure the minimum possible support structure addition; the design method of minimum support volume minimizes the contact area between the support structure and the large annular thin-walled parts, thereby making the removal of the support structure after additive manufacturing easier and more efficient; and the use of simulation to adjust and design adaptive supports helps maintain the surface accuracy of large annular thin-walled parts, ensuring that the final product meets the precise design requirements.

[0060] Specifically, in step one, the minimum support volume V satisfies:

[0061] V = A × d × t × h;

[0062] In the formula, A is a coefficient, with a value ranging from 0.2 to 2.5;

[0063] d is the average diameter of the large annular thin-walled component;

[0064] t represents the overall wall thickness of the large annular thin-walled component;

[0065] h is the height from the top surface to the bottom surface of the large annular thin-walled component.

[0066] Specifically, the average diameter d is the average of the maximum and minimum outer diameters of the large annular thin-walled component, in mm.

[0067] Specifically, the comprehensive wall thickness t is the average of the maximum and minimum wall thicknesses of the large annular thin-walled component, in mm;

[0068] Specifically, h is the height from the bottom surface to the top surface of the large annular thin-walled component, in mm.

[0069] In practice, the support structure prepared by the design method of this invention is integrally manufactured by laser selective melting additive manufacturing with a large annular thin-walled part. After the additive manufacturing is completed, the substrate is removed from the equipment for powder cleaning. Then, the entire substrate is subjected to stress-relief annealing. The parts and support are then cut off from the substrate, and finally the support structure is removed.

[0070] In step two, the support volume of the first-level support structure is greater than the minimum support volume of the large annular thin-walled component to ensure stability during the manufacturing process, reduce the risk of deformation, prevent collapse, and minimize material waste.

[0071] Specifically, a first-level support structure can be formed by uniformly distributing first-level support members on the inner or outer surface of the large annular thin-walled component; the height of the first-level support members is the same as the height of the large annular thin-walled component. By uniformly distributing multiple first-level support members to form a first-level support structure, it is beneficial to balance stress distribution, thereby improving the manufacturing stability and quality of the large annular thin-walled component.

[0072] Specifically, to improve the applicability of the method of the present invention, the first-level support member is one or more of the following: axial rib, cross mesh, and dot matrix.

[0073] For example, the first-level support is an axial rib with a corresponding coefficient A of 0.8-1.2. The axial rib is uniformly arranged along the inner or outer surface of the large annular thin-walled component, its height direction is parallel to the axial direction, and its height is the same as the height of the large annular thin-walled component. One end of the axial rib in the width direction is connected to the inner or outer surface of the large annular thin-walled component, and its width direction is the gradient direction at the connection point with the inner or outer surface. The gradient direction refers to the normal direction of a point on the inner or outer surface, and the normal direction is perpendicular to the tangent direction of that point on the inner or outer surface.

[0074] Specifically, by adjusting the width, thickness, and number of axial ribs, the support volume of the first-level support structure is controlled to be greater than the minimum support volume of the large annular thin-walled component.

[0075] Preferably, the thickness of the axial rib is 3-5 mm, and the width of the axial rib is >30 mm.

[0076] For example, the first-level support is a cross-grid with a corresponding coefficient A of 0.2-0.6; the cross-grid is composed of angled ribs and covers the inner or outer surface of the large annular thin-walled component. By adjusting the width, thickness, and grid spacing of the ribs in the cross-grid, the support volume of the first-level support structure is controlled to be greater than the minimum support volume of the large annular thin-walled component.

[0077] Preferably, the width of the rib is less than 80% of the overall wall thickness t of the large annular thin-walled part, and the thickness of the rib is 1-2 mm.

[0078] For example, the first-level support is a lattice, with a corresponding coefficient A of 2-2.5; the lattice is composed of lattice cells, which cover the inner or outer surfaces of the large annular thin-walled component. By adjusting the dimensions of the lattice cells, the diameter of the cell rods, and the number of radial cell layers, the support volume of the first-level support structure is controlled to be greater than the minimum support volume of the large annular thin-walled component.

[0079] Preferably, the size of the lattice cell is (5-8)mm×(5-8)mm×(5-8)mm, the cell rod diameter is 0.4-0.6mm, and the number of layers is adjusted according to the wall thickness, ranging from 2 to 4 layers.

[0080] Specifically, in step three, the SLM additive manufacturing deformation simulation uses Inspire 2022 software. The blank model and support structure are imported into the software to simulate the additive manufacturing process. The parameter settings are the same as the printing equipment parameter settings.

[0081] Specifically, in step four, if the deformation simulation result shows that the deformation exceeds ±0.5mm, it is determined that the support volume of the first-level support structure needs to be increased or a second-level support component needs to be added; if the deformation simulation result shows that the deformation does not exceed ±0.5mm, it is determined that the support volume of the first-level support structure does not need to be increased or a second-level support component needs to be added.

[0082] Preferably, when the deformation simulation result is that the deformation exceeds ±1mm, it is determined that the support volume of the first-level support structure needs to be increased; when the deformation simulation result is that the deformation exceeds ±0.5mm but does not exceed ±1mm, it is determined that the second-level support needs to be increased.

[0083] For example, a second-level support is added to the abrupt wall thickness region on the inner or outer surface of a large annular thin-walled component; the abrupt wall thickness region is the part where the wall thickness suddenly decreases compared to the adjacent region, and the boundary between the abrupt wall thickness region and the adjacent region has a cantilever or boss structure; the second-level support includes cantilever ribs, intersecting grids, and dot matrix, such as... Figure 1 As shown.

[0084] Preferably, when the minimum wall thickness of the region with a sudden change in wall thickness is 1-3 mm, a dot matrix is ​​selected as the second-level support; when the minimum wall thickness of the region with a sudden change in wall thickness is <1 mm, a cross grid is selected as the second-level support.

[0085] For example, the second-level support is a cantilever rib, and there are multiple cantilever ribs, which are arranged below the cantilever structure; the height direction of the cantilever rib is perpendicular to the cantilever plane, and one end of its height direction is connected to the cantilever plane; one end of the cantilever rib in the width direction is connected to the inner surface of the large annular thin-walled member, and its width direction is the gradient direction at the connection between it and the inner surface.

[0086] Preferably, the thickness of the cantilever rib is 0.4-0.6mm, and the height and width are unlimited. The width is set according to the cantilever protrusion distance. Its shape is a slanted triangle with an angle of 35°-45° to the printing direction. The height is automatically generated based on the angle between the width and the 35°-45° angle. The spacing between each cantilever rib is 0.4-0.6mm.

[0087] For example, the second-level support is a cross-grid, which is composed of angled ribs and covers areas where the wall thickness changes abruptly.

[0088] Preferably, the width of the rib is less than 80% of the overall wall thickness t of the large annular thin-walled part, and the thickness of the rib is 1-2.5 mm.

[0089] For example, the second-level support is a lattice, which is composed of lattice cells and covers regions with abrupt changes in wall thickness.

[0090] Preferably, the size of the lattice cell is (5-8)mm×(5-8)mm×(5-8)mm, and the cell rod diameter is 0.4-0.6mm.

[0091] For example, to facilitate the removal of the support structure after additive manufacturing, the first-stage support is set on a surface without cantilever or boss structures.

[0092] Specifically, if the inner surface has a cantilever or a boss, but the outer surface does not have a cantilever or a boss, then the first-level support is set on the outer surface.

[0093] For example, to further facilitate the removal of the support structure after additive manufacturing, the portion where the axial rib connects to the inner or outer surface of the large annular thin-walled part is thinned to a thickness of 0.8-1.5 mm, and the thinned portion is perforated with a hole diameter of 2 mm and a hole spacing of 3.5 mm.

[0094] For example, to further facilitate the removal of the support structure after additive manufacturing, the portion where the cross mesh connects to the inner or outer surface of the large annular thin-walled part is weakened to form a trapezoidal sawtooth connection structure with a bottom width of 1 mm, a top width of 0.5 mm, a spacing of 0.75 mm, and a tooth height of 0.5 mm.

[0095] In step five, repeat step four until the deformation simulation results meet the shape control target requirements. Specifically, the shape control target can be a deformation range of ±0.5mm.

[0096] Compared with existing methods for determining support structures, this invention can reduce material waste by 25% and significantly reduce manufacturing costs. At the same time, by introducing deformation simulation into the design of the support structure, deformation can be better predicted and controlled, reducing manufacturing defects caused by incorrect support or material shrinkage, improving finished product quality, reducing scrap rate, and saving time and resources.

[0097] Furthermore, by calculating the minimum support volume of the large annular thin-walled component in the early stage, this invention ensures the minimum volume of the support structure and introduces an adaptive support structure. This structure can adjust the support density and position according to the deformation simulation results, achieving precise positioning and control of the support structure. This helps maintain the surface accuracy of the large annular thin-walled component (surface accuracy can reach ±0.5mm), reducing material waste while ensuring the stability of the large annular thin-walled component.

[0098] Example 1

[0099] This embodiment provides a method for designing a shape-controlled support structure for SLM-formed large annular thin-walled straight cylindrical parts. For example... Figure 2 As shown, the outer diameter of this large, straight cylindrical annular thin-walled component is 500 mm, the height is 200 mm, the wall thickness is uniform at 5 mm, and the design method of its shape-controlling support structure includes:

[0100] (1) Calculate the minimum support volume of a large annular thin-walled component;

[0101] Assuming A is 1, the minimum support volume V = A × d × t × h = 1 × 500 × 200 × 5 = 500000 mm 3 .

[0102] (2) Based on the calculated minimum support volume, the support volume of the first-level support structure is determined to be greater than 500,000 mm². 3 .

[0103] Specifically, 18 axial ribs are evenly distributed on the outer surface of the large annular thin-walled component. The height of the axial ribs is parallel to the axial direction and is the same as the height of the large annular thin-walled component. The thickness of the axial ribs is 5 mm and the width is 31 mm. The total volume of the 18 axial ribs, measured using UG software, is 508046 mm². 3 .

[0104] (3) SLM additive manufacturing deformation simulation was performed on the large annular thin-walled component and its first-level support structure. The simulation results showed that the deformation was 0.479 mm, which did not exceed the ±0.5 mm range. Figure 3 As shown.

[0105] (4) Determine that the simulation results meet the requirements of the shape control target, that is, determine that the composition of the support structure is the first-level support structure, and the first-level support structure is the axial rib support.

[0106] The designed shape control support structure includes a first-level support structure with axial ribs, and 18 axial ribs are evenly arranged on the outer surface of the large annular thin-walled part.

[0107] Example 2

[0108] This embodiment discloses a method for adding a shape-controlling support structure to a large annular thin-walled cylindrical part with variable diameter formed by SLM. The diameter of the large annular thin-walled cylindrical part with variable diameter gradually increases from top to bottom along the axis, with a minimum diameter of 400mm and a maximum diameter of 500mm. The wall thickness is uniform at 3mm, and the height is 200mm. The shape-controlling support structure design method includes:

[0109] (1) Calculate the minimum support volume of a large annular thin-walled component;

[0110] Assuming A is 2, the minimum support volume V = 2 × 450 × 3 × 200 = 540000 mm² 3 .

[0111] (2) Based on the calculated minimum support volume, the support volume of the first-level support structure is determined to be 540,000 mm². 3 .

[0112] Specifically, in the first design, eight axial ribs were evenly distributed on the inner surface of the large annular thin-walled component, such as... Figure 4 As shown, the height of the axial ribs is parallel to the axial direction, and its height is the same as that of the large annular thin-walled component; the thickness of the axial ribs is 4 mm, and the average width is 31 mm; the total volume of the eight axial ribs, measured using UG software, is 179512 mm². 3 Simultaneously, a dot matrix is ​​uniformly set on the inner surface of the large annular thin-walled component, covering the outer surface of the component. The size of the dot matrix cell is 8mm×8mm×8mm, and the cell rod diameter is 0.6mm. The number of layers is adjusted to 2 based on the 3mm wall thickness. The total volume of the dot matrix, measured using UG software, is 413673mm². 3 .

[0113] The total volume of the axial ribs and intersecting mesh is 179512 + 413673 = 593185 mm. 3 .

[0114] (3) SLM additive manufacturing deformation simulation was performed on the large annular thin-walled component and its first-level support structure. The simulation results showed that the deformation was 1.428 mm, which is greater than ±1 mm. Figure 5 As shown.

[0115] (4) It is determined that the support volume of the first-level support structure needs to be increased.

[0116] In the second design, the number of axial ribs was adjusted to 12, such as... Figure 6 As shown, the total volume of the 12 axial ribs, measured using UG software, increased to 89756 mm. 3 .

[0117] (5) A second SLM additive manufacturing deformation simulation was performed on the large annular thin-walled component and its first-level support structure. The simulation results showed that the deformation was 0.438 mm, which is less than 0.5 mm. Figure 7 As shown.

[0118] (6) Determine that the simulation results meet the requirements of the shape control target, that is, determine that the support structure is the first-level support structure, which is a combination of 12 axial ribs and a dot matrix.

[0119] The designed shape-controlling support structure includes 12 axial ribs and a dot matrix. The axial ribs and the dot matrix are evenly distributed on the inner surface of the large annular thin-walled part, and the dot matrix is ​​distributed between the axial ribs.

[0120] Example 3

[0121] This embodiment discloses a shape-controlling support structure design method for a large annular thin-walled cylindrical part with variable diameter formed by SLM. The diameter of the large annular thin-walled cylindrical part with variable diameter gradually increases from top to bottom along the axis, with a minimum diameter of 442 mm, a maximum diameter of 512 mm, and a height of 131 mm. On the inner surface of the large annular thin-walled cylindrical part with variable diameter, there is a coaxial annular wall thickness abrupt change region in the axial middle. The upper boundary of the annular wall thickness abrupt change region is a cantilever structure, and the lower boundary is a boss structure. The wall thickness of the non-annular wall thickness abrupt change region is: an average wall thickness of 20 mm at the large end and an average wall thickness of 12.5 mm at the small end. The wall thickness of the annular wall thickness abrupt change region is 1.5 mm, and the height is 70 mm. The shape-controlling support structure design method includes:

[0122] (1) Calculate the minimum support volume of a large annular thin-walled component;

[0123] Setting A to 0.5, the minimum support volume V is calculated as: V = 0.5 × 477 × 12 × 131 = 374922 mm. 3 .

[0124] (2) Based on the calculated minimum support volume, the support volume of the first-level support structure is determined to be 374922 mm². 3 .

[0125] Specifically, the first design, such as Figure 8 As shown, 24 axial ribs are uniformly arranged on the inner surface of the large annular thin-walled component. The height of the axial ribs is parallel to the axial direction and is the same as the height of the large annular thin-walled component. The thickness of the axial ribs is 5 mm and the width is 30 mm. The total volume of the 24 axial ribs is 333810 mm². 3Simultaneously, a cross-grid is uniformly distributed on the outer surface of the large annular thin-walled component, covering the entire outer surface. The cross-grid consists of angled ribs, each 2mm wide and 2.5mm thick, with a grid spacing of 25mm. The total volume of the cross-grid, measured using UG software, is 76646mm². 3 .

[0126] The axial ribs and intersecting meshes combine to form the first-level support structure, with a total volume of 333810 + 76646 = 410456 mm². 3 .

[0127] (3) SLM additive manufacturing deformation simulation was performed on the large annular thin-walled component and its first-level support structure. The simulation results showed that the deformation was 0.944 mm, which is greater than 0.5 mm. Figure 9 As shown.

[0128] (4) It is determined that a second-level support component is needed.

[0129] Second design, such as Figure 10 As shown, multiple cantilever ribs are installed below the large annular thin-walled component cantilever structure. The height direction of the cantilever rib is perpendicular to the cantilever plane, and one end of its height direction is connected to the cantilever plane; one end of the cantilever rib in the width direction is connected to the inner surface of the large annular thin-walled component, and its width direction is the gradient direction at the connection point with the inner surface; the thickness of the cantilever rib is 0.5 mm, the height is 20 mm, the width is 12 mm, and the spacing between each cantilever rib is 1.5 mm.

[0130] (5) A second SLM additive manufacturing deformation simulation was performed on the large annular thin-walled component and its first-level support structure. The simulation results showed that the deformation was 0.546 mm, which is still greater than 0.5 mm. Figure 11 As shown.

[0131] (6) It is determined that a second-level support component is needed.

[0132] The third design, such as Figure 12 As shown, lattice supports are added in the region of abrupt change in wall thickness, and the lattice covers the region of abrupt change in wall thickness. The lattice is composed of lattice cells with dimensions of 6mm×6mm×6mm and cell rod diameter of 0.5mm. The number of lattice layers is adjusted to 2 layers according to the wall thickness.

[0133] (7) The third SLM additive manufacturing deformation simulation was performed on the large annular thin-walled component and its first-level support structure. The simulation results showed that the deformation did not exceed ±0.5mm. Figure 13 As shown.

[0134] (8) Determine that the simulation results meet the requirements of the control target, that is, determine that the support structure is a combination of the first-level support structure and the second-level support structure. The first-level support structure is a combination of axial ribs and cross meshes, and the second-level support structure is a combination of cantilever ribs and lattice supports.

[0135] The designed shape-controlling support structure includes a cross-grid structure evenly distributed on the outer surface of the large annular thin-walled component. The inner surface is provided with axial ribs, cantilever ribs, and a lattice. The cantilever ribs are located below the cantilever structure of the large annular thin-walled component. The height direction of the cantilever ribs is perpendicular to the cantilever plane, and one end of its height direction is connected to the cantilever plane. One end of the cantilever ribs in the width direction is connected to the inner surface of the large annular thin-walled component, and its width direction is the gradient direction at the connection between it and the inner surface. A lattice is evenly distributed between the axial ribs.

[0136] Comparative Example 1

[0137] The large annular thin-walled component used is the same as the straight cylindrical large annular thin-walled component in Example 1, such as... Figure 14 As shown, using conventional methods in existing technology, this structure has no overhanging surfaces and cannot be directly printed, so it can be formed directly without adding any supports. However, the accuracy of the formed surface cannot be guaranteed. Figure 15 As shown.

[0138] The surface accuracy achieved by the present invention in Example 1 is as follows: its maximum deformation is 0.4788mm, and except for the axial rib support (which will be removed later), its large-area deformation is about 0.3mm, and the surface accuracy control is relatively ideal.

Claims

1. A method for designing a shape-controlling support structure for large annular thin-walled parts formed by SLM (Sequencing Machine Tooling), characterized in that, The large annular thin-walled component is a straight cylindrical shape, a straight elliptical cylindrical shape, or a variable-diameter cylindrical shape. The design method includes: Step 1: Calculate the minimum support volume of the large annular thin-walled component. The minimum support volume is the minimum value of the support volume required to prevent the large annular thin-walled component from collapsing. The minimum support volume V satisfies: V = A × d × t × h; In the formula, A is a coefficient, with a value ranging from 0.2 to 2.5; d is the average diameter of the large annular thin-walled component; the average diameter is the average of the maximum and minimum outer diameters of the large annular thin-walled component; t represents the overall wall thickness of the large annular thin-walled component; the overall wall thickness is the average of the maximum and minimum wall thicknesses of the large annular thin-walled component. h is the height from the top surface to the bottom surface of the large annular thin-walled component; Step 2: Determine the support volume of the first-level support structure based on the calculated minimum support volume. The support volume of the first-level support structure is greater than the minimum support volume of the large annular thin-walled component. The first-level support members are uniformly distributed on the inner or outer surface of the large annular thin-walled component to form the first-level support structure. The height of the first-level support members is the same as the height of the large annular thin-walled component. The first-level support members are placed on surfaces without cantilever or boss structures. If the inner surface has cantilever or boss structures, but the outer surface does not, then the first-level support members are placed on the outer surface. Step 3: Perform SLM additive manufacturing deformation simulation on the large annular thin-walled part and its first-level support structure to obtain the deformation simulation results; Step 4: Determine whether to increase the support volume of the first-level support structure or add a second-level support based on the deformation simulation results. Based on the deformation simulation results, the final composition of the support structure is determined: if deformation > ±1mm, increase the support volume of the first-level support structure; if ±0.5mm < deformation ≤ 1mm, add a second-level support. For areas with abrupt changes in wall thickness on the inner or outer surfaces of large annular thin-walled parts, add a second-level support. When the minimum wall thickness of the abrupt wall thickness area is 1-3mm, a lattice is selected as the second-level support; when the minimum wall thickness of the abrupt wall thickness area is <1mm, a cross-grid is selected as the second-level support. The abrupt wall thickness area is the part where the wall thickness suddenly decreases compared to adjacent areas, and the boundary between the abrupt wall thickness area and the adjacent areas has a cantilever or boss structure. Step 5: Repeat step 4 until the deformation simulation results meet the shape control target requirements; the shape control target is a deformation within ±0.5mm.

2. The method for designing a shape control support structure for large annular thin-walled parts formed by SLM according to claim 1, characterized in that, In step four, when it is necessary to increase the support volume of the first-level support structure or add a second-level support component, the second-level support component forms the second-level support structure; SLM additive manufacturing deformation simulation is performed on the large annular thin-walled part and its first-level and second-level support structures.

3. The method for designing a shape control support structure for large annular thin-walled parts formed by SLM according to claim 1, characterized in that, The first-level support component is one or more of the following: axial ribs, cross meshes, and dot matrix.

4. A support structure for a large annular thin-walled part formed by SLM (Surface Mount Technology), characterized in that, The supporting structure is designed by the design method of any one of claims 1-3.

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