A Review on Energy Consumption and Efficiency of Selective Laser Melting Considering Support: Advances and Prospects

Qingyang Wang,Mengdi Gao,Qiang Li,Conghu Liu,Lei Li,Xinyu Li,Zhifeng Liu 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.11 No.1

Selective laser melting (SLM) exhibits excellent manufacturing accuracy and forming ability. However, the laser beam layering process is characterized by high specific energy consumption, long manufacturing cycle, and low energy efficiency. The use of supports increases the SLM building quality and eliminates defects caused by thermal and residual stresses; however, an improper support structural design increases the process energy consumption for manufactured parts. To control energy consumption and building quality during SLM, this study first discusses the main challenges related to energy saving and improving the building quality by performing an energy consumption analysis, process energy consumption optimization, and supporting structure optimization. The obtained results reveal that it is difficult to achieve high building quality only by controlling the process parameters and energy consumption by the SLM equipment. Next, the effect of supporting structures on the process energy consumption is examined to enable the construction of an SLM energy consumption model that considers the presence of supports. Finally, the effect of supports on the building quality is elucidated by studying the influence of supporting structures on thermal and residual stresses. By identifying the most energy-efficient support, the process energy efficiency and building quality may be simultaneously optimized. The proposed method represents a new approach to reducing energy consumption and improving the building quality during SLM. This study establishes a theoretical foundation for the subsequent industrial applications, providing a thorough literature review and describing the existing challenges in the SLM manufacturing field.

구로자와 아키라의 영화 속 색채구성에 관한 연구

리칭양 ( Li Qingyang ) 한국영화교육학회 2023 영화교육연구 Vol.17 No.3

본 논문은 영화의 의미와 감정 표현을 구성하는 영화적 색채의 역할을 연구하는 것을 목적으로 한다. 색채는 영화의 중요한 서술 도구이며, 관객들에게 시각적 충격과 감정적 공감을 줌으로써 영화의 표현력과 감성을 향상시킨다. 본 연구에서는 구로사와 아키라의 대표적인 영화 '영문이자 '남'과 '꿈' 3편을 사례 연구 대상으로 선정하였다. 이 글은 영화 '영문이자 '난'과 '꿈'의 색채 구성에 대한 심층 분석을 통해 영화 속 색채의 상징 기능, 서술 논리, 감정 표현을 탐구하여 영화 제작 연구에 귀중한 참고 자료를 제공합니다. 본 연구는 영화 색채 활용의 의미와 영향을 더 이해하는 데 큰 의미가 있으며, 향후 영화 연구와 실천을 위한 새로운 아이디어와 방법을 제공한다. This paper aims to study the role of film color in the composition of film's meaning and emotional expression.Color is an important narrative tool in movies that can enhance their expressive and emotional abilities by providing visual shock and emotional empathy to the audience.In this study, three representative films of Akira Kurosawa, including Shadow Warrior, Chaos, and Dreams, were selected as the subject of case studies. Through an in-depth analysis of the color composition of the films 'Permanent', 'Nan', and 'Dream', this paper explores the symbolic function, narrative logic, and emotional expression of colors in the film, providing valuable references for film production and research.This research is critical for further understanding the meaning and impact of the use of film color and provides new ideas and methods for future film research and practice.

Effects of Mo and B Additives on Hardness and the Resistance of Cu–Ni Alloy to Wear, Corrosion and Corrosive Wear

Runfang Hou,Mingyu Wu,Qingyang Li,Wei Li,D. L. Chen,D. Y. Li 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

Due to its corrosion resistance, modifiable mechanical properties, and electrical conductivity, etc., CuNi alloy has found awide variety of industrial applications, especially in the marine environment. It is highly desired if the mechanical strengthand wear resistance of CuNi alloy can reach a level comparable to that of steel while keeps its corrosion resistance. In thisstudy, effects of Mo, B, and their combinations on microstructure and performance of CuNi alloy were investigated, includingformation of second phases, hardness, and resistances to wear, corrosion and corrosive wear. It was demonstrated thatthe Mo and B additives were effective in strengthening the CuNi alloy while maintaining reasonable corrosion resistance. In particular, the combination of Mo and B additives was more effective than a single additive to strengthen the alloy. Moand B additives have demonstrated their great promise as new alloying elements to modify CuNi alloys.

The Band Offset at CdS/Cu2ZnSnS4 Heterojunction Interface

Ji Li,Qingyang Du,Weifeng Liu,Guoshun Jiang,Xuefei Feng,Wenhua Zhang,Junfa Zhu,Changfei Zhu 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.4

The band offset at the CdS/Cu2ZnSnS4 heterojunction interface is studied by measuring the valence band spectra using synchrotron radiation photoemission spectroscopy. The Cu2ZnSnS4 thin films are prepared by the sulfurization of electrodeposited Cu-Zn-Sn precursors. A CdS overlayer is sequentially grown on the Cu2ZnSnS4 thin films from a chemical bath deposition process. Valence band spectra were obtained before and after each period of growth to study the electronic structure at the heterojunction interface. The valence band offset was determined to be 0.96 eV, and the conduction band offset was determined to be .0.06 eV. This means that the CdS/Cu2ZnSnS4 hetrojunction has a ‘type II’ band alignment which will cause largescale recombination at the interfaces and will not be suitable for solar cells fabrication.

Integration of Additive Manufacturing in Casting: Advances, Challenges, and Prospects

Mengdi Gao,Lei Li,Qingyang Wang,Zhilin Ma,Xinyu Li,Zhifeng Liu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.1

Additive manufacturing (AM) is a novel manufacturing technology that can create highly customized products with more complex geometries than traditional techniques. Despite its significant advantages, including the freedom of design, mass customization, and ability to produce complex structures, AM consumes a large amount of energy and incurs high costs. In addition, AM suffers from long production cycles and low production efficiency in the large-scale manufacturing of metal structures. This study offers a review of the existing literature focused on metal AM technology. To avoid the shortcomings of AM and highlight its bene fits, which are widely used for manufacturing in combination with casting. The current combination application of AM and casting is reviewed to provide solutions to the problem of manufacturing large metal components from the perspective of the use of different AM technology and quality control in casting. However, such integration is insufficient for producing large castings with complex shapes, structures, or multiple features. Therefore, a novel method for integrating AM into casting to enable the manufacture of large scale metal parts with complex shapes is introduced as a topic for possible future research. This method divides complex castings with multiple features into an AM processing part and the casting substrate. The complex features were processed by AM on the fabricated casting substrate. This study provides a review of the application of AM into casting and presents a novel idea for the integration application of AM and other processes. This promising method has significant value for future study.

Influence of raw material grain composition on the properties of fused silica ceramics

Qingtao Wang,Sen Li,Huaqin Yu,Fengzhi Li,Huijun Xu,Haibo Qiao,Juncheng Liu,Qingyang Du 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.8

Fused silica ceramics were prepared by slip casting method with various particle sizes (d50 ≈ 2.31 μm, 19.79 μm, and 71.46 μm)from three types of fused silica powder. The influence of raw material grain composition on the viscosity of slurry, bulk density,porosity, water absorption, and flexural strength of the fused silica ceramics was investigated. The slurry viscosity wasmeasured by an XND-1 viscometer. The bulk density, porosity, and water absorption of the sintered samples were obtainedby the Archimedes method. The flexural strength was measured by a three-point bending test. The phase composition andmicrostructure of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Theresults show that when the grain composition was 5 : 3 : 2, slurry viscosity was 150.79 mPa·s with solid content of 75%, thefused silica ceramic particles were packed most tightly and demonstrate bulk density of 2.02 g/cm3, porosity of 6.99%, waterabsorption of 3.47%, and flexural strength of 51.27 MPa.

Energy Efficiency and Dynamic Analysis of a Novel Hydraulic System with Double Actuator

Mengdi Gao,Lei Li,Qingyang Wang,Conghu Liu 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.3

At present, increased attention has been given to energy effi ciency promotion and energy saving of manufacturing equipment and systems. Hydraulic system is widely used in engineering machinery industries; however, the high energy consumption and low energy effi ciency of which limit its development and application. On the basis of previous research on hydraulic system, an energy-effi cient hydraulic system with double actuator is proposed in this study. This hydraulic system can reduce the energy consumption by reusing the potential energy loss of the system. In this novel hydraulic system, the chambers of two actuators are connected with rod by pipes and valves. During the operating processes, the falling operation of one cylinder and the returning operation of the other are synchronized. That is, one actuator remains at the top point performing the demanded operation, whereas the other one remains at the bottom performing the corresponding operation. System models are developed to address the energy consumption and dynamic performance of the proposed hydraulic system. This hydraulic system is applied into a press to study its energy-saving mechanism and dynamic performance during transient under various working conditions. On the basis of the simulation and experimental results, energy and production effi ciency are compared and discussed. Results show that in comparison with the energy and time consumption of the original 630 kN hydraulic press, the energy-saving potential has reached 17.34%, and the production effi ciency can be improved by 18.85%.

Analysis and Optimization of Energy Consumption for Multi-part Printing Using Selective Laser Melting and Considering the Support Structure

Zhilin Ma,Mengdi Gao,Kai Guo,Qingyang Wang,Lei Li,Conghu Liu,Guang Zhu,Zhifeng Liu 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.3

Selective laser melting (SLM) can form complex and precise metal parts simultaneously and is widely used in medical and aerospace fields. The support structure plays an important role in SLM process, including supporting the overhanging structure, dissipating heat, and minimizing geometric deformation caused by internal stress. However, a non-optimal support structure causes increased energy and material consumption during processing and must be removed afterward to allow for utilization of the parts. Existing support structure design methods only consider reducing the support of a single part, and research on the support and energy consumption of simultaneous multi-part printing is lacking. Therefore, to reduce the energy and material consumption of simultaneous multi-part printing by SLM and improve processing efficiency, an energy consumption analysis and optimization method is proposed in this study from the perspective of the support structure. Based on previous studies on energy consumption distribution of the additive manufacturing process, a multi-component SLM energy consumption and material consumption model was established. Furthermore, a shared-support optimization strategy for simultaneous multi-part processing is proposed. For optimization, the method selects the appropriate printing direction of one part, and then combines multiple parts to form a shared support structure to minimize energy consumption. Finally, under the constraint of minimizing the mass, an optimization strategy of the SLM multi-part shared support combination is established, and the purpose of reducing the energy consumption and material consumption of the SLM is achieved under the premise of ensuring the geometric accuracy of the parts. The method was applied to the manufacturing process of a group of parts with a beam structure. Compared with the printing method using independent support, the shared support structure method reduced energy consumption more than 5.5%, material consumption for the support structure more than 17.2%, and printing time to a certain extent. This method effectively improves SLM production efficiency and sustainability and provides strategic support for additive manufacturing designers and producers.

Electron transport properties of Y-type zigzag branched carbon nanotubes

MaoSheng Ye,HangKong, OuYang,YiNi Lin,Quan Ynag,QingYang Xu,Tao Chen,LiNing Sun,Li Ma Techno-Press 2023 Advances in nano research Vol.15 No.3

The electron transport properties of Y-type zigzag branched carbon nanotubes (CNTs) are of great significance for micro and nano carbon-based electronic devices and their interconnection. Based on the semi-empirical method combining tight-binding density functional theory and non-equilibrium Green's function, the electron transport properties between the branches of Y-type zigzag branched CNT are studied. The results show that the drain-source current of semiconducting Y-type zigzag branched CNT (8, 0)-(4, 0)-(4, 0) is cut-off and not affected by the gate voltage in a bias voltage range [-0.5 V, 0.5 V]. The current presents a nonlinear change in a bias voltage range [-1.5 V, -0.5 V] and [0.5 V, 1.5 V]. The tangent slope of the current-voltage curve can be changed by the gate voltage to realize the regulation of the current. The regulation effect under negative bias voltage is more significant. For the larger diameter semiconducting Y-type zigzag branched CNT (10, 0)-(5, 0)-(5, 0), only the value of drain-source current increases due to the larger diameter. For metallic Y-type zigzag branched CNT (12, 0)-(6, 0)-(6, 0), the drain-source current presents a linear change in a bias voltage range [-1.5 V, 1.5 V] and is symmetrical about (0, 0). The slope of current-voltage line can be changed by the gate voltage to realize the regulation of the current. For three kinds of Y-type zigzag branched CNT with different diameters and different conductivity, the current-voltage curve trend changes from decline to rise when the branch of drain-source is exchanged. The current regulation effect of semiconducting Y-type zigzag branched CNT under negative bias voltage is also more significant.

Reliability of Jack-up against Punch-through using Failure State Intelligent Recognition Technique

Tao Lyu,Changhang Xu,Guoming Chen,Yipei Zhao,Qingyang Li,Tantan Zhao 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.3

The preload operation of jack-up in complex multi-layered foundation requires enhanced understanding of its behaviour in punchthrough accident and suitable safety analysis tools for the assessment of their reliability for a particular site. In this study, reliability analysis model of jack-up against punch-through is established considering structural uncertainty. In order to identify the failure state, an improved reliability solution method has been developed based on Sparse Auto-Encoder (SAE) deep learning network model. Sparse self-coding algorithm is used to the training of the deep network, and Softmax regression model is established to solve the identification and classification problem of the output layer. The first application of the technique was the study of HYSY 941 jack-up platform. More specifically, numerical calculations of structure ultimate bearing capacity have been undertaken, and the influence of model parameters on the prediction accuracy of the failure state is discussed. The results show that implicit performance function can be constructed accurately using SAE-MC method by reflecting the relationship between different critical safety state and structural vulnerability. Compared with traditional BP neural network, deep learning network has higher prediction accuracy to failure probability. The dynamic risk grade in the process of preload operation can be determined quantitatively using the reliability analysis method mentioned in this paper.