High-throughput evaluation and optimization method for formability of additively manufactured suspended structures

Abstract

The present invention discloses a high-throughput evaluation and optimization method for the formability of suspended structures in additive manufacturing, comprising the following steps: establishing a high-throughput evaluation model for suspended structures; preparing the evaluation model using target process parameters; determining the limit forming dimensions based on the formability of different suspended lengths, and establishing a high-throughput optimization model for the corresponding structural dimensions of suspended structures with actual component suspended lengths greater than the limit forming dimensions; preparing the optimization model using the corresponding process parameters; and preparing a verification part based on the optimized model structure with the best formability. The present invention can efficiently screen the formability of suspended structures of different materials and the corresponding optimization targets. While ensuring minimum machining allowances and optimal forming quality, it can quickly obtain a characteristic structural model suitable for additive manufacturing, significantly reducing optimization time.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal additive manufacturing, and in particular relates to a high-throughput evaluation and optimization method for the formability of an additively manufactured suspended structure. Background Art

[0002] High-energy beam metal additive manufacturing primarily includes selective laser melting (SLM), selective electron beam melting (EBM), and direct energy deposition (DED). These processes use a high-energy beam to melt powder, depositing the metal material layer by layer into the desired shape. This facilitates the production of complex parts and frees up design freedom. However, when producing parts with overhanging structures, selective support must be added based on the size of the overhanging structure to ensure part formability. The limit size of the support required varies for different materials and process parameters. Therefore, the limit forming dimensions of the overhanging structure must be determined for each material and process parameter to assist in model preprocessing and optimization. Discrete specimens are typically used to determine the formability of overhanging structures at different sizes. This method requires extensive model processing and analysis, resulting in a lengthy production cycle. Furthermore, discrete specimens cannot analyze the formability of continuous dimensions. Improving the accuracy of the limit forming dimensions requires further specimens, which incurs high material and time costs. 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 suspended structures in additive manufacturing. This method uses the minimum processing allowance as the criterion, can achieve rapid screening and optimization of the ultimate forming dimensions of the suspended length, and improve the efficiency of model optimization.

[0004] To this end, the present invention provides a high-throughput evaluation and optimization method for the formability of suspended structures manufactured using additive manufacturing, which is characterized by comprising the following steps:

[0005] Step 1: Establish a high-throughput overhang evaluation model with a gradually varying overhang length along the width direction. The overhang thickness of the high-throughput overhang evaluation model is consistent with the overhang thickness of the actual part model to be printed.

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

[0007] Step 3: Compare the maximum overhang length with the actual overhang length of the component model to be printed. If the actual overhang length to be printed is less than the maximum overhang length, directly use the actual component model to be printed for printing. If the actual overhang length to be printed is greater than the maximum overhang length, go to step 4.

[0008] Step 4: Based on the actual overhang length of the part model to be printed, a high-throughput overhang optimization model is established. The high-throughput overhang optimization model includes a base segment, a overhang segment set on the base segment, and a 45° chamfer set at the connection between the bottom of the overhang segment and the base segment. The overhang length and thickness of the overhang segment are consistent with the actual part model to be printed, and the length of the chamfer varies gradually along the width of the overhang segment.

[0009] Step 5: Assign the same process parameters as in step 2 to the suspended high-throughput optimization model, prepare additive manufacturing high-throughput specimens, and analyze the forming quality of the specimens at different chamfer lengths to determine the minimum allowable chamfer length when the forming quality meets the design technical requirements;

[0010] A 45° chamfer is added to the root corner of the suspended structure of the actual part model to be printed. The length of the chamfer is the minimum chamfer length determined above. This optimizes the actual part model to be printed, and the optimized part model is used to complete the part printing.

[0011] Specifically, the suspended section is composed of a plurality of gradient sections, and the suspended lengths of the plurality of gradient sections gradually decrease or increase along the width direction.

[0012] Specifically, the maximum and minimum overhang lengths to be evaluated were determined, and a model with continuously changing overhang lengths was established with these two length dimensions as boundaries. The model was then divided into 10-20 gradient segments, with each gradient segment length varying by 1-2 mm and with a 0.5 mm interval between each gradient segment, thereby establishing an overhang high-throughput evaluation model.

[0013] Specifically, the chamfer length size of the overhang high-throughput optimization model varies in the range of 1 / 10*overhang length to 2 / 3*overhang length.

[0014] Specifically, the forming quality includes surface integrity, roughness and / or deformation.

[0015] Compared with the existing technology, the present invention has the following beneficial effects: the present invention uses the minimum machining allowance as the criterion to establish a high-throughput evaluation and optimization model for overhangs. The high-throughput evaluation model can use a high-throughput sample to quickly obtain the ultimate forming size of the overhang length, and quickly screen the forming size and forming process that meet the technical conditions based on the technical requirements of the target parts, and determine the size range for direct forming. There is no need to repeatedly refine the dimensional structure to obtain the required forming capacity as with discrete samples. The high-throughput optimization model can quickly screen the overhang model optimization solution with the minimum machining allowance, greatly reducing the difficulty of post-processing, and is conducive to improving the iterative efficiency of process and model optimization, thereby improving the quality and efficiency of the forming and post-processing processes of parts. 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 is a flow chart of the present invention;

[0018] Figure 2 Schematic diagram of the suspended high-throughput evaluation model;

[0019] Figure 3 Schematic diagram of the suspended high-throughput optimization model; 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 the formability of an additively manufactured suspended structure comprises the following steps:

[0022] Step 1: Establish a high-throughput overhang evaluation model with a gradually varying overhang length along the width direction. The overhang thickness of the high-throughput overhang evaluation model is consistent with the overhang thickness of the actual component model to be printed.

[0023] Specifically, the suspended high-throughput evaluation model includes a base segment and a suspended segment arranged on the base segment. The suspended segment is composed of several gradient segments. The suspended lengths of the several gradient segments gradually decrease or increase along the width direction, such as Figure 1 shown.

[0024] In practice, the specific process for establishing the overhang segment is to determine the maximum and minimum overhang lengths to be evaluated. Using these two lengths as boundaries, a model with continuously varying overhang lengths is established. To mitigate the impact of varying overhang lengths on formability, the model is divided into 10-20 gradient segments, each varying by 1-2 mm (based on the difference between the maximum and minimum overhang lengths), with 0.5 mm intervals between each segment. This creates a high-throughput overhang evaluation model.

[0025] Step 2: Assign process parameters to the suspended high-throughput evaluation model, prepare additive manufacturing high-throughput specimens using the metal powder to be evaluated as raw material, and analyze whether the forming quality of the high-throughput specimens at different cantilever lengths meets the design technical requirements, and determine the maximum suspended length that meets the design technical requirements;

[0026] Step 3: Compare the maximum overhang length with the actual overhang length of the part model to be printed. If the actual overhang length to be printed is less than the maximum overhang length, directly use the actual part model to be printed for printing. If the actual overhang length to be printed is greater than the maximum overhang length, go to step 4 to further optimize the actual part model to be printed.

[0027] Step 4: Based on the actual overhang length of the part model to be printed, a high-throughput overhang optimization model is established. The high-throughput overhang optimization model includes a base segment, a overhang segment set on the base segment, and a 45° chamfer set at the connection between the bottom of the overhang segment and the base segment. By adding a 45° chamfer at the root corner of the overhang segment (forming a chamfered boss), the overhang length and thickness of the overhang segment are consistent with the actual part model to be printed, and the length of the chamfer gradually changes along the width of the overhang segment;

[0028] Step 5: Assign the same process parameters as in step 2 to the suspended high-throughput optimization model, prepare additive manufacturing high-throughput specimens using the metal powder to be optimized as raw material, and analyze the forming quality of the specimens at different chamfer lengths to determine the minimum allowable chamfer length when the forming quality meets the design technical requirements;

[0029] A 45° chamfer is added to the root corner of the suspended structure of the actual part model to be printed to form a chamfered boss that supports the suspended section (which will be removed later through machining). The length of the chamfer is the minimum chamfer length determined above. This optimizes the actual part model to be printed, and the optimized part model is used to complete the part printing.

[0030] Specifically, a 45° chamfer is added at the overhang corner, and the chamfer length is set within the range of 2 / 3*overhang length to 1 / 10*overhang length. This is because usually when the chamfer length is less than 1 / 10*overhang length, the formability of the overhang structure cannot be improved by the structure. When the chamfer size is greater than 2 / 3*overhang length, the excessive chamfer allowance is added, which is contrary to the minimum machining allowance goal.

[0031] The present invention uses the minimum machining allowance as the criterion to establish a high-throughput evaluation and optimization model for overhangs. The high-throughput evaluation model can use a high-throughput specimen to quickly obtain the ultimate forming dimensions of the overhang length, and based on the technical requirements of the target parts, quickly screen the forming dimensions and forming processes that meet the technical conditions, and determine the size range for direct forming. There is no need to repeatedly refine the dimensional structure to obtain the required forming capacity as in the case of discrete specimens. The high-throughput optimization model can quickly screen the overhang model optimization solution with the minimum machining allowance, greatly reducing the difficulty of post-processing of the chamfered boss, which is conducive to improving the iterative efficiency of process and model optimization, and improving the quality and efficiency of the forming and post-processing processes of the parts.

[0032] like Figure 2 A suspended high-throughput evaluation model was established, with the suspended length set to 0-5 mm, divided into 10 gradient segments, each with a suspension length change of 0.5 mm, and an interval of 0.5 mm between each gradient segment.

[0033] Evaluation models were prepared using GH4169 alloy powder using a selective laser melting machine. Three different scanning speeds were set. The laser power was 285W, and the scanning speeds were 960, 1160, and 1360 mm / s, respectively. The scanning pitch was 0.1 mm, and the layer thickness was 0.04 mm. Warping and deformation are common during the forming process of suspended structures. Printing of warped areas required immediate termination to prevent damage to the scraper and compromised forming.

[0034] A 3D scanner was used to detect deformation in areas of the evaluation model without noticeable warping. As the overhang length increased, the amount of deformation increased. For samples scanning at a speed of 1360mm / s, the deformation exceeded 0.2mm when the overhang length exceeded 3.4mm (design requirement). For samples scanning at a speed of 1160mm / s, the deformation exceeded 0.2mm when the overhang length exceeded 3.1mm. And for samples scanning at a speed of 1160mm / s, the deformation exceeded 0.2mm when the overhang length exceeded 2.3mm.

[0035] In actual parts, there is a 5mm overhang, which prevents direct forming. Therefore, a high-throughput optimization model was established based on this 5mm overhang, with the chamfer length varying from 1 to 2.5mm. The model was then prepared using the same process parameters as previously used.

[0036] A 3D scanner was used to detect deformation in areas of the optimized model without noticeable warping. As the chamfer length increased, the amount of overhang deformation decreased. For samples scanned at a speed of 1360 mm / s, the deformation was greater than 0.2 mm when the chamfer length was less than 1.3 mm (the limit of forming chamfer dimensions). For samples scanned at a speed of 1160 mm / s, the deformation was greater than 0.2 mm when the chamfer length was less than 1.7 mm. And for samples scanned at a speed of 1360 mm / s, the deformation was greater than 0.2 mm when the chamfer length was less than 2 mm.

[0037] Based on the above, the ultimate forming size of the suspended structure and the optimized chamfer length of the GH4169 alloy at different scanning speeds can be obtained, and a structure with high formability and minimum machining allowance is obtained.

[0038] 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 the formability of additively manufactured suspended structures, characterized in that: The steps include: Step 1: Establish a high-throughput overhang evaluation model with a gradually varying overhang length along the width direction. The overhang thickness of the high-throughput overhang evaluation model is consistent with the overhang thickness of the actual part model to be printed. Step 2: Assign process parameters to the high-throughput evaluation model, prepare additive manufacturing high-throughput specimens, and analyze whether the forming quality of the high-throughput specimens at different cantilever lengths meets the design technical requirements, and determine the maximum cantilever length that meets the design technical requirements; Step 3: Compare the maximum overhang length with the actual overhang length of the component model to be printed. If the actual overhang length to be printed is less than the maximum overhang length, directly use the actual component model to be printed for printing. If the actual overhang length to be printed is greater than the maximum overhang length, go to step 4. Step 4: Based on the actual overhang length of the part model to be printed, a high-throughput overhang optimization model is established. The high-throughput overhang optimization model includes a base segment, a overhang segment set on the base segment, and a 45° chamfer set at the connection between the bottom of the overhang segment and the base segment. The overhang length and thickness of the overhang segment are consistent with the actual part model to be printed, and the length of the chamfer varies gradually along the width of the overhang segment. Step 5: Assign the same process parameters as in step 2 to the suspended high-throughput optimization model, prepare additive manufacturing high-throughput specimens, and analyze the forming quality of the specimens at different chamfer lengths to determine the minimum allowable chamfer length when the forming quality meets the design technical requirements; A 45° chamfer is added to the root corner of the suspended structure of the actual part model to be printed. The length of the chamfer is the minimum chamfer length determined above. This optimizes the actual part model to be printed, and the optimized part model is used to complete the part printing.

2. The high-throughput evaluation and optimization method for additive manufacturing suspended structure formability according to claim 1, characterized in that: The suspended section is composed of a plurality of gradient sections, and the suspended lengths of the plurality of gradient sections gradually become smaller or larger along the width direction.

3. The high-throughput evaluation and optimization method for additive manufacturing suspended structure formability according to claim 2, characterized in that: Determine the maximum and minimum overhang lengths you want to evaluate, and use these two length dimensions as boundaries to establish a model with continuously changing overhang lengths. Then, divide the model into 10-20 gradient segments, with each gradient segment length varying by 1-2 mm and a 0.5 mm interval between each gradient segment, to establish a high-throughput overhang evaluation model.

4. The high-throughput evaluation and optimization method for additively manufactured suspended structure formability according to any one of claims 1 to 3, characterized in that: The chamfer length of the overhang high-throughput optimization model varies in the range of 1 / 10*overhang length to 2 / 3*overhang length.

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

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