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Semi-supervised deep learning based framework for assessing manufacturability of cellular structures in direct metal laser sintering process
摘要： In recent years, metal cellular structures have drawn attentions in various industrial sectors due to their design freedoms and abilities to achieve multi-functional mechanical properties. However, metal cellular structures are dif?cult to fabricate due to their complex geometries, even with modern additive manufacturing technologies such as the direct metal laser sintering (DMLS) process. Assessing the manufacturability of metal cellular structures via a DMLS process is a challenging task as the geometric features of the structures are complex. Besides, via a DMLS process, the manufacturability also depends on the cumulative deformation of the layers during the manufacturing process. Existing methods on Design for Additive Manufacturing (DFAM) provide design guidelines that are based on past successful printed designs. However, they are not effective in predicting the manufacturability of metal cellular structures. In this paper, we propose a semi-supervised deep learning based manufacturability assessment (SSDLMA) framework to assess whether a metal cellular structure can be successfully manufactured from a given DMLS process. To enable ef?cient learning, we represent the complex cellular structures as 3D binary arrays with a simple yet ef?cient voxelisation method. We then train a deep learning based classi?er using only a small amount of experimental data by adopting a semi-supervised learning approach. By running real experiments and comparing with existing DFAM methods and machine learning models, we demonstrate the advantages of the proposed SSDLMA framework. The proposed framework can be extended to predict the manufacturability of various other complex geometries beyond cellular structure in a reliable way even with a small number of training data.
关键词： Design for additive manufacturing,Manufacturability analysis,Direct metal laser sintering,Semi-supervised deep learning,Cellular structures
更新于2025-09-23 15:21:01
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Experimental investigation and optimization of direct metal laser sintering process for shrinkage rate using CL50WS material
摘要： In today’s competitive era, the quality of the die or mould is very significant for tooling industries which is highly influencing the final product. The dimensional inaccuracy of die due to shrinkage rate of parts lead to increase defective parts, and shrinkage can be minimizing by controlling of proper design parameter of process. Hence, the aims of this study to optimize the process parameter of DMLS process for CL50WS die material. In this study, analysis and optimization of four process parameters namely laser power, layer thickness, scan speed and hatch distance, and take shrinkage rate as response. Result shows that optimum process parameter (laser power 129.814 Watt, scan speed 554.439 mm/s, layer thickness 0.05 mm and hatch distance 0.01 mm) gives acceptable range of error (delta H, delta W and delta L are 6.42%, 8.29 % and 10.72% respectively).
关键词： BBD,Direct metal laser sintering,AM,optimization,RSM,Shrinkage rate,DMLS
更新于2025-09-16 10:30:52
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Slotted Hemispherical Resonators for 3-D Printed Waveguide Filters With Extended Spurious-Free Stopbands
摘要： This paper presents a comprehensive study on a new family of slotted hemispherical resonators and their applications in waveguide bandpass filters (BPFs) to extend the spurious-free stopbands. The proposed scheme focuses on suppressing unwanted spurious modes in the air-filled hemispherical resonators by adding functional slots to the metallic cavity shells. The spurious TM2m1 and TE101 modes in the hemispherical resonators are effectively suppressed by interrupting the surface current with slots, without significantly degrading the unloaded quality factor of the fundamental TM101 mode. Resonant modes in the slotted hemispherical resonators are analyzed. Design, fabrication, and measurement of X-band proof-of-concept waveguide BPFs based on slotted hemispherical resonators are expounded. Each filter is monolithically prototyped by employing metallic additive manufacturing technology. The filters demonstrate good passband performance—average insertion loss: 0.6–1.1 dB, frequency shift: 0.9%–1%, and return loss: >20 dB, and more significantly extended stopbands with spurious-free frequency ratios of >1.8:1 and stopband rejections over 36 dB.
关键词： spurious suppression,slotted hemispherical resonator,waveguide filter,direct metal laser sintering,spurious-free stopband,Additive manufacturing
更新于2025-09-16 10:30:52
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Effects of Stress-Relieving Heat Treatment on Impact Toughness of Direct Metal Laser Sintering (DMLS)-Produced Ti6Al4V (ELI) Parts
摘要： The impact toughness of as-built (AB) and stressed-relieved (SR) direct metal laser sintering-produced Ti6Al4V (ELI) was investigated using the standard Charpy impact test over the temperature range of ?130°C to 250°C. Stress-relieving heat treatment was conducted at 650°C for a soaking period of 3 h in argon gas atmosphere. The results showed improvements in the impact toughness after stress-relieving heat treatment. Stress relieving also shifted the established ductile-to-brittle transition temperature to lower temperatures. Comparative analysis of the impact toughness values for AB and SR specimens at ambient temperature showed them to be 48% and 22% lower than recommended values for use in aircraft structures, respectively.
关键词： Impact Toughness,Stress-Relieving Heat Treatment,Ti6Al4V (ELI),Direct Metal Laser Sintering,Charpy Impact Test
更新于2025-09-12 10:27:22
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Direct Metal Laser Sintering of Maraging Steel: Effect of Building Orientation on Surface Roughness and Microhardness
摘要： Direct Metal Laser Sintering (DMLS) is a powder bed fusion based Additive Manufacturing (AM) process in which a part is fabricated using layer by layer deposition. In this work, 18% Ni Maraging steel 300 was fabricated using DMLS to examine the variations in surface finish and microhardness using three building orientations i.e. 0?, 45? and 90?. Surface roughness was found to decrease after 20 mm for 45? and 90?. Correspondingly, microhardness was found to decrease in the building direction. Understanding the effect of building orientation on the surface finish and hardness will allow the producer to fabricate superior quality AM parts with desired properties.
关键词： Direct Metal Laser Sintering,Microhardness,Additive Manufacturing,Surface finish,Maraging Steel
更新于2025-09-11 14:15:04