Metal 3D Printing Research Articles

Study on the geometrical dimensions and mechanical properties of Ti-6Al-4V alloy blade by laser metal deposition

The most advanced metal 3D printing promises to revolutionize the manufacturing industry and has already played their strengths in the field of part repair and surface coating, but they have not yet reached the best operability in the overall manufacturing. The challenge is how to design the process route. Therefore, the entire process of blade design-manufacture-testing was carried out in this paper. The fifth-degree polynomial is used to construct the blade, and on this basis, a CAD model of a thin-walled blade with torsion was established. After the blade was manufactured by LMD, the geometric dimensions and mechanical properties were tested. The test results show that the standard deviation of the blade body part is less than 0.3 mm, which basically meets the design requirements. The Vickers hardness of LDM blades changes continuously along the deposition direction, mainly due to the changes in the structure caused by different cooling rates. The tensile strength of the blade is basically the same in the 0°, 45°, and 90° directions, which is greater than 770 MPa. The elongation in different directions differs more than 5% and has obvious anisotropy, which is mainly caused by the organization structure and the way of unit cell stacking.

Fabrication and mechanical properties of Al–Si-based alloys by selective laser melting process

ABSTRACT Aluminium (Al)-based alloys have attracted as promising materials for structural applications using metal 3D printing due to their excellent specific mechanical strength, formability, and durability. In this study, highly flowable coarse AlSi10Mg powders with average diameter of 65 µm were prepared and then they were additively manufactured by using the selective laser melting (SLM) process. The relative densities exceeding 99% were consistently obtained from the samples fabricated at the scan speed of 1000–2000 mm·s−1 in the range of laser power from 350 to 390 W. The tensile strengths and elongation of all the samples were characterised. Furthermore, Al alloy processed by coarse AlSi10Mg powders does not show a big change in strength values compared to those fabricated by fine AlSi10Mg powders with 45 µm in diameter. Thus, these results clearly show that the developed coarse AlSi10Mg powders can be effectively utilised for the SLM process.

Resource‐efficient joint fabrication by welding metal 3D‐printed parts to conventional steel: A structural integrity study

AbstractMetal 3D printing technology can increase the Architecture, Engineering and Construction (AEC) industry's resource‐efficiency by removing a major fabrication constraint: geometrical complexity. Since the large part dimensions are a current limit of metal 3D printers, we propose a ‘hybrid’ manufacturing approach by welding optimized printed nodes to conventional steel elements for tubular constructions. In this work, we identified suitable analytical formulations for metal 3D‐printed parts, and calibrated numerical models for hybrid joints by means of experimental results. Finally, we quantified the structural integrity performance of the hybrid joints. Numerical simulations highlighted the joints' most sensitive regions, where the optimisation reduced the stresses up to 40% under tensile loading. The butt weld between the printed node and the conventional profiles guaranteed a simple state of stress in the weld, providing the hybrid joint a fatigue life of 2 × 106 cycles under 100‐MPa cyclic loading. These results confirm that metal 3D printing combined with topology optimisation can remarkably reduce the quantity of resource‐consuming cutting and welding operations to fabricate a structural joint for static and fatigue loads.

Biomechanical Simulation of Sugita Aneurysm Clip: Reverse Engineering Approach using Metal 3D-Printing

Aneurysm clips have helped hundred cased for brain abnormalities including the haemorrhagic strokes over the world, including Indonesia. As one of the contributors of a hundred trillion rupiahs for medical devices imports each year, the technology of aneurysm clips is expected to be self-manufactured. However, there is no study if the process can be done in the whole country of Indonesia. This study aims to conduct a preliminary study by using an approach of reverse engineering for the Sugita aneurysm clips as an effort to independently provide domestic medical devices. The methods consist of a 3D scanning process, a 3D printing process, biomechanical simulations, and tension measurements. The clip has been scanned and printed using SS316L and Ti6Al4V. Biomechanical simulations reach 0.054 GPa for the von Misses stress and deformation number of 4.0302E-6 mm. The tension measurement on the 3D-printed clip shows identical range numbers compared to the original clip. The experiment concludes that the acquired Sugita aneurysm clip can be reversed using a 3D metal printing and shows a significant similarity on geometrical analysis.

Application of 3D Printing Technology in Machining and Manufacturing

3D printing technology is a rapid prototyping technology, which has been gradually applied in the mechanical automation manufacturing industry. 3D printing technology of mechanical parts is an important development direction of advanced mechanical automation manufacturing technology. At present, the research and development of SLM is a new hotspot in the field of rapid prototyping at home and abroad. The application of this technology can not only reduce the processing time, avoid the resource consumption caused by repeated adjustment of parameters, and make the mechanical manufacturing more accurate, more economical and more efficient. Based on this, this paper focuses on the application of 3D printing technology in mechanical manufacturing automation, and takes SLM as the research object, expounds the basic composition and forming principle of SLM. Based on the comparison of SLM technology at home and abroad, the future development direction of SLM technology is analyzed. At the same time, this paper designs SLM equipment with high efficiency, high cost performance, large range and traditional machining methods. The experimental results show that the 3D printing technology of metal parts is an important development direction of advanced mechanical automation manufacturing technology. The development direction of metal 3D printing in the future is to develop a portable and intelligent 3dslm device with high efficiency, high cost performance, high processing capacity and combination with traditional machining methods.

Thermal field prediction for welding paths in multi-layer gas metal arc welding-based additive manufacturing: A machine learning approach

Gas metal arc welding (GMAW)-based additive manufacturing (AM) is a key metal 3D printing technology for the fabrication of near-net shape parts. The thermal history of the multi-layer GMAW-based AM process has a significant influence on part quality and substrate deformations, but it is computationally expensive to accurately calculate it based on numerical method or analytical method. Existing data-driven approaches for the thermal field prediction of AM processes show great advantages in efficiency, but they are mainly applied to single-layer parts or the multi-layer parts with fixed geometry. The main contribution of this work is to realize the thermal field prediction of the multi-layer GMAW-based AM processes with arbitrary geometries by a machine learning approach. Firstly, a novel method for the discretization of deposition process was proposed to make the numerical simulation method for the thermal analysis of AM processes more adaptive and flexible. Then, a unique data structure was developed to extract the deposition state data from the results of the numerical simulation method, which generate the data for the training of the proposed machine learning model. Finally, a physics-based machine learning method based on an ensemble learning model was designed to identify the correlation between the deposition stage and its corresponding thermal field. Validation results showed that the prediction accuracy of the developed method exceeded 94 % when compared with the results of the numerical simulation method, while the time cost of a single prediction process was only at the millisecond level.

Challenges in Qualifying Additive Manufacturing for Turbine Components: A Review

Gas turbine engine advancements have been enabled by innovation in materials and manufacturing technologies. The evolution of additive manufacturing (AM) has changed the face of direct digital technologies for the rapid production of models, prototypes, and functional parts including repair and maintenance for turbine engines. Metal 3D printing is poised to be an enabler for the next industrial revolution in enabling advancements in turbine engine performance. While there has been tremendous efforts on research and development in utilizing this versatile technology, the number of qualified metallic parts that are running in the engine has not been commensurate with the applied research and development efforts and the benefits that the AM technology offers. This review addresses some of the key technical issues that are currently limiting the prolific usage of AM as a successful vehicle for accelerated progress in gas turbine engines.

Effect of heat treatment on microstructural evolution and properties of cemented carbides (WC-17Co) reinforced with 3% volume hexagonal-boron nitride (h-BN) and processed by selective laser sintering (SLS)

In the manufacturing and mining industries, cemented carbides (WC-Co) are desired due to their extraordinary properties such as high strength, good wear resistance and high fracture toughness. Moreover, due to design limitations, such as intricate shapes of parts manufactured using conventional powder metallurgy, metal-3D printing is being sought after for better processing and fabrication of parts with complex shapes and geometries. In this study, a cemented carbide (WC-Co) reinforced with 3% Hexagonal-Boron Nitride (h-BN) was processed using selective laser sintering and heat treated to understand the effect of the elemental composition and post-processing heat treatment on the microstructural evolution and mechanical integrity of processed parts. Generally, the as-printed WC-Co-hBN sample had distinct polyangular WC carbides with sizes between 8 μm to 18 μm, W-C-Co matrix and large areas of fused eta phases (40% area fraction). X-ray diffraction analysis revealed that beside the major hexagonal WC phases, the h-BN breaks down to form minor phases such as CoWB, Co5.47N together with W3Co3C, W3Co3N, W9Co3C4 phases. Post-processing heat treatment at 400 °C resulted in the evolution of well-defined WC carbides and eta phases including reduced W-C-Co matrix when compared with the as-printed samples. X-ray diffraction analysis showed the disappearance of the W3Co3N and W3Co3C4 phases coupled coalescence and coarsening of the WC phases and the minor W9Co3C4, CoWB and Co5.47N phases. However, post-processing at 600 °C resulted in the breakdown of the coarsened WC carbides (~10 μm to 12 μm), evolution of more eta phases (63% area fraction) and more W3Co3C phases when compared with the as-printed sample. Nevertheless, post-processing at 800 °C resulted in extensive depletion of the W-C-Co matrix and the growth of irregular WC carbides and eta phases. At 1000 °C, the relative sizes of the WC carbides were smaller but well-defined and closely packed including large volume fractions of the eta phase when compared with the samples at 800 °C. Also, the h-BN phase appeared, for the first time, in this sample with high characteristic peaks. An inverse correlation was observed with the heat treatment on the residual stresses. Thus, the heat treatment aided in relieving the residual stresses in the heat-treated samples. The as-printed sample recorded the highest average hardness value of 4200 HV which is approximately 200% higher than the SLS printed WC-17Co. The as-printed sample had the highest fracture toughness (7.5 MPa√m) whiles the 600 °C had the lowest fracture toughness. Additionally, the wear properties of the W-C-Co-hBN samples were significantly higher with the 1000 °C having the best wear properties. In general, the h-BN reinforcement in this study demonstrated an improvement and stability in the mechanical properties of fabricated parts even up to 1000 °C.

금속 3D 프린팅 공정의 결함 분석

Metal 3D printing is attracting attention as a new production technology. However, various problems need to be solved regarding it. In particular, defects occurring in the process of melting and solidification are relatively serious than those occurring in the traditional casting or cutting process. To solve this problem, this study introduced a tomography using a high-speed camera that can monitor the melting pool. This confirmed the possibility of finding defects by detecting an abnormality in the melting pool. In addition, if it is combined with the YOLO model, which is the latest object detection algorithm, it is judged that the integrity of the parts produced by the casting or cutting process can be secured by stopping or recovering the process through real-time inspection.

Thermal Numerical Analysis of Bulk Parts by Additive Manufacturing

This study deals with an investigation of bulk parts created by an additive manufacturing (AM) process. Numerical simulation of the AM process was used for describing thermal behaviour of bulk parts during the production process. Industrial metal 3D printer InssTek MX-600 was chosen as the experimental AM device because it belongs to Directed Energy Deposition (DED) technology according to ASTM. 316L austenitic stainless steel was chosen because no phase transformations occur in this material during heating. The objectives of this study are twofold: a numerical model of the DED process was created and calibrated to attain high accuracy, and residual stress was determined by the contour method. The numerical model for the method was created using Simufact Welding software. The purpose was describe the thermal behaviour of each layer during the process. Using numerical simulation, the sensitivity of the process parameters to thermal behaviour in the printed part was analysed and compared with experimental results. The contour method was used to evaluate the residual stress in the DED part. The part was cut and measured, and the residual stress was evaluated using FE inverse analysis. Results of this study can help build complex components such as turbine blades for energy facilities, and medical implants.

Prediction of Model Distortion by FEM in 3D Printing via the Selective Laser Melting of Stainless Steel AISI 316L

This paper deals with an experimental analysis of stress prediction and simulation prior to 3D printing via the selective laser melting (SLM) method and the subsequent separation of a printed sample from a base plate in two software programs, ANSYS Addictive Suite and MSC Simufact Additive. Practical verification of the simulation was performed on a 3Dprinted topologically optimized part made of AISI 316L stainless steel. This paper presents a typical workflow for working with metallic 3D printing technology and the state-of-the-art knowledge in the field of stress analysis and simulation of printed components. The paper emphasizes the role of simulation software for additive production and reflects on their weaknesses and strengths as well, with regard to their use not only in science and research but also in practice.

Comparative study and analysis of 3D printed wheel hub

Purpose Additive manufacturing (AM) promises to reduce the weight of the component, it is required to be shown that the mechanical performance of AM parts meets stringent industrial design criteria. Very few studies are made on finite element analysis (FEA) of the component produced by AM for real-life workload conditions. This study is supposed to do FEA of the wheel hub, manufactured using metal three-dimensional (3D) printing, under static multi-load conditions and effect of infill pattern on maximum stress, deformation and factor of safety. Design/methodology/approach This study conducted FEA on wheel-hub using Ansys. The approach of Orthotropic properties is used to do static analysis of wheel-hub and compared results of different metal 3D printing material (Ti-6Al-4V and Al-Si10-Mg) with hexagonal and triangular infill patterns. Findings Ti-6Al-4V with Honeycomb patterns shows better results in all cases and can be replaced with standard conventional material. Research limitations/implications Because of the chosen research approach, the research results may lack generalisability. Therefore, it is required to do an experimental study. Practical implications Metal components with applications across the automobile industry can be manufactured using AM technology. With the help of AM, components with high strength to weight ratio can be manufactured. Originality/value This paper fulfils the identified need of FEA of the component produced by AM for real-life workload conditions. This study is supposed to do FEA of the wheel hub, manufactured using metal 3D printing, under static multi-load conditions and Effect of infill pattern on maximum stress, deformation and factor of safety.

Additive technologies: an innovative effectdigitalization in industry

The article discusses the integration of additive technologies into production, presents the advantages and disadvantages of 3D metal printing. The data of the current indicators of the effectiveness of technological processes when using 3D equipment are analyzed, the difficulties of introducing additive technologies into production processes are determined. Conclusions on the trends and prospects of development of engineering solutions in the field of additive technologies are formulated. So, additive technologies provide an opportunity for a business entity to reduce production lines, minimize the production time for complex technological parts. In addition, the specifics of the operation process of parts - the result of high-tech production, provide both a long service life of component elements, and a high degree of reliability of materials, functional stability and structural strength, and, simplification of repair work (replacement of parts of parts), which generally determines the quality of manufactured products. This, in turn, determines, in economic realities, the development of economic and technological innovative engineering solutions through the promotion of additive technologies, increasing the economic indicators of the production activity of a business entity. The characteristic features of 3D printing of metals studied in this article make it possible to highlight the defining technological processes of the principles of printing, constructively represent the properties of additive structures. It can be stated that in the current period of development of economic and technological innovative engineering solutions, the field of promoting additive technologies has significant achievements and prospects. Small-scale production is gradually being introduced into additive manufacturing, which has distinctive characteristics for the mechanical engineering industry. The introduction of such technological equipment provides an opportunity to speed up the manufacturing procedure, improve the properties of the product, despite the high cost (0.8-1.5 million euros). At the same time, from a strategic economic position in comparison with classical technologies, high-tech engineering solutions act as highly competitive.

Best of both worlds: A novel, environment-friendly approach to 3D printing metal–plastic hybrid structures

Best of both worlds: A novel, environment-friendly approach to 3D printing metal–plastic hybrid structures

On the influence of the geometrical irregularities in the mechanical response of Wire-and-Arc Additively Manufactured planar elements

The use of Additive Manufacturing (AM) technologies in the construction industry is still at its pioneering stage. The first investigations indicate that, among actually available metal 3D-printing strategies, Wire-and-Arc Additive Manufacturing (WAAM) process appears to be the most suitable for realizing large-scale steel structures. Nonetheless, the limited knowledge of the mechanical response of WAAM-produced alloys requires further experimental work for a reliable evaluation of the structural behavior of WAAM structural members. One specific issue which still needs to be fully investigated is the peculiar geometrical irregularity resulting from WAAM process that could have non-negligible effects on the mechanical behavior, such as anisotropy and non-homogeneous stress-strain fields.The present work explores the influence of the inherent geometrical irregularities of planar 308LSi stainless steel WAAM specimens on the tensile response. For this purpose, detailed geometrical characterization of the external surface of WAAM specimens was carried out with 3D scanning techniques and random field theory. Different sets of specimens were subjected to tensile tests to evaluate the influence of surface finishing (machined vs. as-built), orientation (with respect to the printing layers) and cooling strategy on the key mechanical parameters. The whole strain field was then studied in detail through Digital Image Correlation (DIC) monitoring technique. Key findings are given in terms of geometrical characterization of surface roughness and thickness variability, as well as a quantitative assessment of the influence of geometrical irregularities on the main mechanical parameters. The material response reveals a significant anisotropy related to a marked crystallographic micro-texture. The geometrical irregularities negatively impact some of the mechanical parameters of the as-built material, suggesting further considerations for practical structural design applications.

Biomimetic Soft Polymer Microstructures and Piezoresistive Graphene MEMS Sensors Using Sacrificial Metal 3D Printing.

Recent advances in 3D printing technology have enabled unprecedented design freedom across an ever-expanding portfolio of materials. However, direct 3D printing of soft polymeric materials such as polydimethylsiloxane (PDMS) is challenging, especially for structural complexities such as high-aspect ratio (>20) structures, 3D microfluidic channels (∼150 μm diameter), and biomimetic microstructures. This work presents a novel processing method entailing 3D printing of a thin-walled sacrificial metallic mold, soft polymer casting, and acidic etching of the mold. The proposed workflow enables the facile fabrication of various complex, bioinspired PDMS structures (e.g., 3D double helical microfluidic channels embedded inside high-aspect ratio pillars) that are difficult or impossible to fabricate using currently available techniques. The microfluidic channels are further infused with conductive graphene nanoplatelet ink to realize two flexible piezoresistive microelectromechanical (MEMS) sensors (a bioinspired flow/tactile sensor and a dome-like force sensor) with embedded sensing elements. The MEMS force sensor is integrated into a Philips 9000 series electric shaver to demonstrate its application in “smart” consumer products in the future. Aided by current trends in industrialization and miniaturization in metal 3D printing, the proposed workflow shows promise as a low-temperature, scalable, and cleanroom-free technique of fabricating complex, soft polymeric, biomimetic structures, and embedded MEMS sensors.

Studying Powdery Admixture Supply to the Laser Heating Zone in 3D Metal Printing

The pattern of the interaction between powder particles and metal vapors is developed. To ensure a guaranteed supply of PAs to the heated region with the use of laser irradiation, a model for theoretically analyzing the motion paths of PA particles carried to the zone of construction with a gas jet in 3D Metal Printing is proposed.

Development of a 3D Printed Bipedal Robot: Towards Humanoid Research Platform to Study Human Musculoskeletal Biomechanics

The objective of this study is to develop a bio robot with a high degree of biomechanical fidelity to the human musculoskeletal system in order to investigate the biomechanical principles underlying human walking. The robot was designed to possess identical biomechanical characteristics to the human body in terms of body segment properties, joint configurations and 3D musculoskeletal geometries. These design parameters were acquired based on the medical images, 3D musculoskeletal model and gait measurements of a healthy human subject. To satisfy all the design criteria simultaneously, metal 3D printing was used to construct the whole-body humanoid robot. Flexible artificial muscles were fabricated in accordance with the predefined 3D musculoskeletal geometries. A series of physical tests were conducted to demonstrate the capacity of the robot platform. The fabricated robot shows equivalent mechanical characteristics to the human body as originally designed. The results of the physical tests by systematically changing environmental conditions and body structures have successfully demonstrated the capability of the robot platform to investigate the structure-function interplay in the human musculoskeletal system and also its interaction with the environment during walking. This robot might provide a valuable and powerful physical platform towards studying human musculoskeletal biomechanics by generating new hypotheses and revealing new insights into human locomotion science.

Development Status of 4N Class Low-Cost Thrusters Manufactured by 3D-Printed Metals

Development Status of 4N Class Low-Cost Thrusters Manufactured by 3D-Printed Metals

Zeolites on 3D-printed open metal framework structure: metal migration into zeolite promoted catalytic cracking of endothermic fuels for flight vehicles.

Selective laser melting printed metal lattice structures functionalised using zeolites have been shown as a promising new generation of catalysts. The unprecedented catalytic activity can be explained by metal migration (most likely chromium) from the support into the zeolite phase making it a promising candidate for endothermic fuels for high-speed flight vehicles.