A high-throughput evaluation and optimization method for transverse hole formability in additive manufacturing

Abstract

The application discloses a kind of high-throughput evaluation and optimization method for additive manufacturing transverse hole formability, comprising the following steps: establishing transverse hole high-throughput evaluation model;Using target process parameters to prepare evaluation model;Based on the formability of different hole diameters, determine the limit forming size, and establish the high-throughput optimization model of the corresponding structure size for the transverse hole with the actual part hole diameter greater than the limit forming size;Using corresponding process parameters to prepare optimization model;Step five, based on the optimization model structure of the best formability.This application can efficiently screen the transverse hole forming capacity of different materials and the corresponding optimization target, under the condition of ensuring the minimum machining allowance and the best forming quality, quickly obtain the feature structure model suitable for additive manufacturing, greatly reduce the optimization time.

Description

Technical Field

[0001] The present invention relates to the technical field of metal additive manufacturing, and in particular to a high-throughput evaluation and optimization method for the formability of transverse holes in additive manufacturing. Background Art

[0002] Additive manufacturing technology involves depositing metal materials layer by layer into the desired shape, facilitating the production of complex components and freeing up design freedom. However, in actual component production, transverse holes often form due to the influence of part placement, and the diameter of the transverse holes affects the formability of this area. Generally speaking, larger hole diameters result in poorer formability, resulting in the final component's surface quality, dimensional accuracy, and microstructure failing to fully meet technical requirements. Therefore, model optimization is often required to improve the formability of transverse holes. The limiting formable dimensions of transverse holes vary for different materials and process parameters, so the corresponding limiting formable dimensions are required for each material and process parameter to assist in model preprocessing and optimization. Discrete specimens are typically used to determine the formability of features at different sizes. This method requires extensive model processing and analysis, resulting in a long cycle. Furthermore, discrete specimens cannot analyze the formability of continuous dimensions. Improving the accuracy of the limiting formable dimensions requires further specimens, which is both costly in terms of material and time. Summary of the Invention

[0003] The main purpose of the present invention is to provide a high-throughput evaluation and optimization method for the formability of transverse holes in additive manufacturing, which can realize the rapid screening and optimization of the limit forming size of transverse holes and improve the efficiency of model optimization.

[0004] To this end, the present invention provides a high-throughput evaluation and optimization method for additive manufacturing transverse hole formability, comprising the following steps:

[0005] Step 1: Establish a high-throughput evaluation model for transverse pores with a gradually changing pore size along the axial direction;

[0006] Step 2: Assign process parameters to the transverse hole high-throughput evaluation model, prepare additive manufacturing high-throughput specimens, and analyze whether the forming quality of the high-throughput specimens at different apertures meets the design technical requirements, and determine the limit forming aperture that meets the design technical requirements;

[0007] Step 3: Compare the limit forming aperture with the actual transverse hole diameter of the part model to be printed. If the actual transverse hole diameter to be printed is smaller than the limit forming aperture, directly use the actual part model to be printed for printing. If the actual transverse hole diameter to be printed is larger than the limit forming aperture, go to step 4.

[0008] Step 4: Based on the transverse aperture of the actual part model to be printed, a high-throughput optimization model for transverse holes is established. The cross-sectional contour lines of the transverse holes at various locations in the high-throughput optimization model for transverse holes are composed of a lower arc segment and an upper inverted V-shaped segment. The lower ends of the inverted V-shaped segment are respectively connected to the two ends of the arc segment, and the upper end is located at the vertex position of the transverse hole before optimization. The radius of the arc segment is equal to the aperture of the transverse hole before optimization. The arc segment of each transverse hole cross-sectional contour line of the high-throughput optimization model intercepted along the axial direction gradually becomes longer, and the angle of the inverted V-shaped segment gradually becomes larger.

[0009] Step 5. Assign the same process parameters as in step 2 to the high-throughput optimization model of the transverse hole, prepare the additive manufacturing high-throughput specimen, and analyze the forming quality of the inverted V-shaped segment at different cross-sections of the specimen. Determine the maximum design angle allowed for the inverted V-shaped segment when the forming quality meets the design technical requirements, and use the transverse hole cross-sectional contour line corresponding to the inverted V-shaped segment as the transverse hole contour of the final component printing model for printing.

[0010] Specifically, the transverse pore high-throughput evaluation model consists of a plurality of gradient segments, and the apertures of the plurality of gradient segments gradually become smaller or larger along the axial direction of the transverse pore.

[0011] Specifically, the maximum and minimum transverse pore diameters to be evaluated are determined, and with these two diameters as boundaries, a transverse pore model with continuously changing diameters is established. The transverse pore model is then divided into 10-20 gradient segments, with each gradient segment having an pore diameter change of 1-2 mm and a 0.5 mm interval between each gradient segment, thereby establishing a high-throughput evaluation model for transverse pores.

[0012] Specifically, the angle of the inverted V-shaped segment of the high-throughput optimization model is set to 90°-150°, and the top of the inverted V-shaped segment is rounded.

[0013] Specifically, the forming quality includes surface integrity, roughness, hardness and / or microstructure.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention takes the minimum machining allowance as the criterion and establishes a high-throughput evaluation model for transverse holes. The high-throughput evaluation model uses a high-throughput sample to quickly obtain the ultimate forming size of the transverse hole, and quickly screens the forming size and forming process that meet the technical conditions based on the technical requirements of the target component, and determines the aperture range for direct forming. There is no need to obtain the required forming capacity by repeatedly refining the size structure as in the case of discrete samples. The high-throughput optimization model can quickly screen the optimization scheme of the transverse hole model with the minimum machining allowance, greatly reducing the difficulty of post-processing, which is conducive to improving the process and model optimization iteration efficiency, and improving the quality and efficiency of the forming and post-processing processes of the components. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a flow chart for evaluating and optimizing the transverse hole formability of the present invention;

[0018] Figure 2 Schematic diagram of the high-throughput evaluation model for lateral pores;

[0019] Figure 3 Schematic diagram of the high-throughput optimization model for lateral pores. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] See also Figure 1 A high-throughput evaluation and optimization method for additive manufacturing transverse hole formability comprises the following steps:

[0022] Step 1: Determine the maximum and minimum transverse pore diameters to be evaluated. Using these two pore diameters as boundaries, establish a transverse pore model with continuously changing pore diameters. In order to reduce the mutual influence between the formability of different pore diameters, the transverse pore model is divided into 10-20 gradient segments. The pore diameter of each gradient segment varies by 1-2 mm (based on the difference between the maximum and minimum pore diameters). The interval between each gradient segment is 0.5 mm. In this way, a high-throughput evaluation model for transverse pores is established (e.g. Figure 2 ).

[0023] Step 2: Assign process parameters to the evaluation model, use the metal powder to be evaluated as raw material, prepare high-throughput additive manufacturing samples, and analyze whether the surface integrity, roughness, hardness, microstructure, etc. at different apertures meet the technical requirements, and determine the limit forming aperture that meets the technical requirements;

[0024] Step 3: Compare the limit forming aperture with the actual transverse aperture of the part model to be printed. For transverse holes whose actual diameter is smaller than the limit forming aperture, no model processing is required and they can be formed directly. For transverse holes whose actual diameter is larger than the limit forming aperture, the next step of model optimization is required to obtain transverse holes with the minimum machining allowance.

[0025] Step 4: Based on the actual transverse hole diameter in the part model to be printed, establish a transverse hole high-throughput optimization model, such as Figure 3 As shown in the figure, the cross-sectional contour lines of the transverse holes at various locations in the transverse hole high-throughput optimization model are composed of a lower arc segment and an upper inverted V-shaped segment. The lower two ends of the inverted V-shaped segment are respectively connected to the two ends of the arc segment, and the upper end is located at the vertex of the transverse hole before optimization. The radius of the arc segment is equal to the aperture of the transverse hole before optimization (the aperture of the transverse hole of the actual component model to be printed). The arc segments of the cross-sectional contour lines of each transverse hole in the transverse hole high-throughput optimization model intercepted along the axial direction gradually become longer, and the angle of the inverted V-shaped segment gradually becomes larger.

[0026] Specifically, the optimized transverse hole cross-sectional profile replaces the upper circular arc with a straight line to improve formability for large apertures. These two straight lines are arranged in an inverted V-shape, forming an inverted V-shaped segment. The top of the segment is the highest point of the arc, and the two ends of the bottom connect to the two ends of the lower arc, symmetrically about the center of the hole. To minimize machining allowance, a high-throughput optimization model for transverse holes was established. The angle of the inverted V segment in this model was set between 90° and 150° (a larger angle reduces the allowance), and a 0.5mm fillet was added to the top of the segment to avoid stress concentration there.

[0027] Step 5. Assign corresponding process parameters to the optimized model, use the metal powder to be optimized as raw material, prepare additive manufacturing high-throughput specimens, and analyze whether the surface integrity, roughness, hardness, microstructure, etc. at different inverted V-shaped segment angles meet the technical requirements. Determine the maximum inverted V-shaped segment angle that meets the technical requirements, obtain the optimized transverse hole optimization scheme, replace the transverse hole scheme in the actual part model to be printed with the optimized transverse hole scheme, obtain the final part printing model, and print it.

[0028] The present invention takes the minimum machining allowance as the criterion and establishes a high-throughput evaluation and optimization model for transverse holes. The high-throughput evaluation model uses a high-throughput sample to quickly obtain the ultimate forming size of the transverse hole, and quickly screens the forming size and forming process that meet the technical conditions based on the technical requirements of the target component, and determines the aperture range for direct forming. There is no need to obtain the required forming capacity by repeatedly refining the size structure as in the case of discrete samples. The high-throughput optimization model can quickly screen the optimization scheme of the transverse hole model with the minimum machining allowance, greatly reducing the difficulty of post-processing, which is conducive to improving the process and model optimization iteration efficiency, and improving the quality and efficiency of the forming and post-processing processes of the components.

[0029] Specific cases

[0030] like Figure 2 A transverse pore high-throughput evaluation model was established, with the pore size set to 1-20 mm, divided into 10 gradient segments, each with a pore size change of 2 mm, and each gradient segment separated by 0.5 mm.

[0031] The evaluation models were assigned process parameters. High-throughput specimens were prepared using a selective laser melting machine using GH4169 alloy powder as the raw material. Three evaluation models were printed using three different scanning speeds. The laser power was 285W, the scanning speeds were 960, 1160, and 1360 mm / s, the scanning pitch was 0.1 mm, and the layer thickness was 0.04 mm.

[0032] The high-throughput sample was cut horizontally along the aperture, and the surface quality was observed using a 3D profilometer. The sample with a scanning speed of 1360 mm / s exhibited poor fusion when the aperture diameter exceeded 13.6 mm, and obvious gaps appeared at 18.1 mm. The sample with a scanning speed of 1160 mm / s began to exhibit poor fusion when the aperture diameter exceeded 11.2 mm, and obvious gaps appeared at 16.8 mm. The sample with a scanning speed of 960 mm / s began to exhibit poor fusion when the aperture diameter exceeded 8.9 mm, and obvious gaps appeared when the aperture diameter exceeded 13.4 mm.

[0033] Since there is a 20mm transverse hole in the actual component, it cannot be directly formed. Therefore, a transverse hole optimization model is established with a hole diameter of 20mm, and the process parameters are set consistent with the previous ones.

[0034] The formed parts were cut horizontally along the vertical holes, and the surface quality was observed using a 3D profilometer. The samples with a scanning speed of 1360 mm / s had a complete formed surface when the straight edge angle was less than 143°; the samples with a scanning speed of 1160 mm / s had a complete formed surface when the straight edge angle was less than 120°; and the samples with a scanning speed of 960 mm / s had a complete formed surface when the straight edge angle was less than 105°.

[0035] Based on the above, the ultimate forming size of the transverse hole and the optimized structure of the difficult-to-form size of the GH4169 alloy at different scanning speeds can be obtained.

[0036] The above embodiments are merely examples to clearly illustrate the present invention and are not intended to limit its implementation. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to provide an exhaustive list of all embodiments. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A high-throughput evaluation and optimization method for additive manufacturing transverse hole formability, characterized in that: The steps include: Step 1: Establish a high-throughput evaluation model for transverse pores with a gradually changing pore size along the axial direction; Step 2: Assign process parameters to the transverse hole high-throughput evaluation model, prepare additive manufacturing high-throughput specimens, and analyze whether the forming quality of the high-throughput specimens at different apertures meets the design technical requirements, and determine the limit forming aperture that meets the design technical requirements; Step 3: Compare the limit forming aperture with the actual transverse hole diameter of the part model to be printed. If the actual transverse hole diameter to be printed is smaller than the limit forming aperture, directly use the actual part model to be printed for printing. If the actual transverse hole diameter to be printed is larger than the limit forming aperture, go to step 4. Step 4: Based on the actual transverse hole diameter of the part model to be printed, a transverse hole high-throughput optimization model is established. The transverse hole cross-sectional contour lines at various locations in the transverse hole high-throughput optimization model are composed of a lower arc segment and an upper inverted V-shaped segment. The lower ends of the inverted V-shaped segment are respectively connected to the two ends of the arc segment, and the upper end is located at the vertex position of the transverse hole before optimization. The radius of the arc segment is equal to the aperture of the transverse hole before optimization. The arc segment of each transverse hole cross-sectional contour line of the transverse hole high-throughput optimization model intercepted along the axial direction gradually becomes longer, and the angle of the inverted V-shaped segment gradually becomes larger; Step 5. Assign the same process parameters as in step 2 to the high-throughput optimization model of the transverse hole, prepare the additive manufacturing high-throughput specimen, and analyze the forming quality of the inverted V-shaped segment at different cross-sections of the specimen. Determine the maximum design angle allowed for the inverted V-shaped segment when the forming quality meets the design technical requirements, and use the transverse hole cross-sectional contour line corresponding to the inverted V-shaped segment as the transverse hole contour of the final component printing model for printing.

2. The high-throughput evaluation and optimization method for additive manufacturing transverse hole formability according to claim 1, characterized in that: The transverse pore high-throughput evaluation model consists of several gradient segments, and the pore diameters of the several gradient segments gradually decrease or increase along the axial direction of the transverse pore.

3. The high-throughput evaluation and optimization method for additive manufacturing transverse hole formability according to claim 2, characterized in that: Determine the maximum and minimum transverse pore diameters that you want to evaluate, and use these two diameters as boundaries to establish a transverse pore model with continuously changing diameters. Then, divide the transverse pore model into 10-20 gradient segments, with each gradient segment having an pore diameter change of 1-2 mm and a 0.5 mm interval between each gradient segment, thereby establishing a transverse pore high-throughput evaluation model.

4. The high-throughput evaluation and optimization method for additive manufacturing transverse hole formability according to any one of claims 1 to 3, characterized in that: The angle of the inverted V-shaped segment of the transverse hole high-throughput optimization model is set to 90°-150°, and the top of the inverted V-shaped segment is rounded.

5. The high-throughput evaluation and optimization method for additive manufacturing transverse hole formability according to any one of claims 1 to 3, characterized in that: Forming quality includes surface integrity, roughness, hardness and / or microstructure.

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