Laser Additive Manufacturing Technologies

Chapter 3 - Laser additive manufacturing of SiC ceramics

12CrNi2 high strength steel thin wall with few defects was fabricated by laser additive manufacturing technology. The microstructure of as-built sample was studied using optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Additionally, the mechanical property was also investigated by microhardness tests. It was found that the microstructure of the as-built sample mainly consists of columnar dendrites aligned in building direction because of the fast directional cooling during LAM. Cellular grains, and equiaxial dendrites are also observed in different regions of the as-built sample due to heat accumulation effect. Furthermore, many types of microstructure, such as tempered martensite, M-A constituent, retained austenite, lower and upper bainitic ferrite, are appeared in the as-built sample resulting from complex heat history and wide temperature range during LAM process. The maximum and minimum microhardness (499 HV0.2 and 272 HV0.2) occur in the top and bottom region respectively, while microhardness of the middle region with value of 452 HV0.2 just slightly reduces compared to the top section of as-built sample.

Nickel-based superalloy matrix composites fabricated by laser additive manufacturing: A critical review of recent advances and overcoming challenges

Laser-based additive manufacturing (LBAM) is a group of advanced manufacturing processes used to produce metal components and functionally graded products. Production in LBAM is either limited to the formation of thin or thick coatings on a substrate by laser metal deposition or the production of a fully functional metallic product by selective laser melting. In every case, LBAM fabricated components require optimization for the process parameters to avoid defects, such as porosity, crack holes, thermal deformation, and mechanical strength. As a key link in the laser additive manufacturing (LAM) process, laser scanning path planning is an effective strategy for balancing the temperature field of the formed part, avoiding stress concentration, and preventing deformation and cracking. Efficient, accurate, and reasonable planning of the laser scanning path is of great significance for improving the processing efficiency of the process data, prolonging the life of the laser scanning system, and improving the forming quality of the specimen. Through many studies, it was found that the scanning pattern of the lasers has a significant impact on the mechanical properties and deformations caused by a thermal mismatch during the process. Therefore, it is essential to have in-depth knowledge about path planning in LBAM. Our review mainly focuses on the influence of scanning patterns on deformation, temperature, and mechanical properties in LBAM. Finally, our paper discusses the current study limitations and some future studies in LAM technology.

Compared to traditional processing techniques, laser additive manufacturing technology has advantages such as short processing cycles, no molds, and is not limited by complex structures. However, the forming quality of GH3625 nickel-base alloy metal parts is affected by various process parameters, in which the distribution characteristics of laser beam energy density, microstructure and mechanical properties play a key role. In order to investigate the influence of beam energy density distribution on the main properties of GH3625 nickel-based alloy metal parts, the beam energy density distribution was changed by controlling the defocusing amount. Then it sets 5 different defocusing parameters to obtain the corresponding energy density distribution characteristics. Observing and analyzing the various properties of alloy powder from the perspectives of different scanning speeds, laser power, and energy density distribution characteristics. The results show that when the laser power is 600 W, the scanning speed is 700 mm/min, and the energy density distribution is characteristic 4, the metal parts have the best performance. Its density is 99.90%, microhardness is 350.44 HV, tensile strength is 1328 Mpa, friction coefficient is about 0.51, and wear rate is 0.55%. This indicates that the laser additive forming method proposed in this study can effectively improve the hardness, density and other properties of GH3625 nickel-based alloy metal parts to achieve the best state, which provides an important reference for the further optimization of the material preparation process.

Evolution of plastic deformation and its effect on mechanical properties of laser additive repaired Ti64ELI titanium alloy

Selective laser melting (SLM), a significant branch of laser additive manufacturing (LAM) technology, has become a popular topic of research in engineering, materials and many other disciplines. SLM can transform metallic powders directly into 3D components, which allows SLM to offer the unique flexibility of manufacturing parts with complex structures. The quality of the product is closely related to the characteristics of the temperature field, as well as that of the molten pool. Because of the high localized temperatures and the rapid cycles of melting and solidification during SLM, it’s difficult to monitor the temperature field in real time. Hence, numerical simulation is often used to study the SLM process. In this work, the SLM process of ZL104 aluminum alloy was simulated using the CFD method, and the influences of processing parameters, including laser power and scan speed, on the temperature field and the characteristics of the molten pool have been investigated. Results showed that when the laser power increased, the peak temperature of the molten pool also mounted, however, the maximum temperature of the molten pool fell as the scan speed rose. The dimensions of heat affected zone (HAZ), including the width and depth, increased with growing laser power, but decreased with the increase of scan speed.

Chapter 1 - Overview of additive manufacturing technology and materials

Purpose Manufacturing companies still struggle to integrate additive manufacturing (AM) technologies with existing traditional manufacturing technologies. This paper explores AM technology integration into a global manufacturing company from an operational capability perspective. Design/methodology/approach The research was conducted using a single case study in collaboration with a global heavy-duty vehicle manufacturer. Data were collected through a focus group and interviews representing management and engineering roles. Additional data were collected from meetings, company documents, field notes and observations. Subsequently, the collected data were analyzed thematically. Findings The findings reveal that, despite the company embarking on its AM technology integration journey, it encountered challenges, including cognitive fixation, manufacturing fixation, situational awareness, ambiguous ownership and the make-or-buy dilemma. Furthermore, the findings showed that the company developed operational capabilities – such as developing proficiency in AM know-how, continuous use of AM technology, operational practices for AM technology, cross-collaboration for AM initiatives and business cases for AM technology – to address these challenges. A facilitation model was developed, outlining essential actions prioritized for the short-term, mid-term and long-term. These actions leverage the operational capabilities to address challenges in AM technology integration. Originality/value This paper offers an in-depth exploration of AM technology integration in a global heavy-duty vehicle manufacturer. It introduces a novel application of operational capability theory and proposes a facilitation model for managers and academics in pursuit of achieving AM technology integration.

Spherical powder materials are essential raw materials for manufacturing processes such as metal additive manufacturing and powder metallurgy. They possess characteristics that are key factors influencing the performance of additive manufacturing. This paper introduces the fundamental principles and characteristics of laser additive manufacturing technology and analyzes the technical principles, advantages, and disadvantages of three alloy powder preparation methods: gas atomization, centrifugal atomization, and plasma atomization. It further elucidates the influence of process parameters of these three powder preparation techniques on the characteristics of alloy powders. Finally, the development trends in alloy powder preparation for laser additive manufacturing are projected.

This paper describes the use of Additive Manufacturing (AM) technologies in permanent magnet synchronous machines (PMSM) for electric aircraft. Due to economic aspects and government restrictions, conventional manufacturing technologies like punching reach their limits when aiming for fulfilling future requirements. In the past years, AM has become a more and more relevant technology. In this paper, we present an investigation on how AM can be used in order to improve electric machines for electric flight propulsion. More precisely, the aim is to obtain an increasing torque and power density. Nevertheless, giving a brief overview of the feasibility of AM in electric aircraft is focused more than discussing technical issues in detail in this paper. The research starts with an extensive analysis on the current state of research of AM on electric machines and an evaluation of the degree of maturity. Moreover, geometric approaches for the rotor and the winding, which can only be built by AM, are pointed out and will be evaluated. Therefore, the winding and the rotor are modified. This results in lower ohmic loss density and lower eddy current loss for the winding as well as in higher torque density due to the decreased rotor leakage flux. So finally, the power density is increased which is crucial for flight propulsion. In summary, the huge potential of AM in all-electric aircraft is presented and performance improvements are quantified in this paper.

Proceedings of the Stated Meeting held Wednesday, October 15, 1902

State-of-the-art Laser Additive Manufacturing for Hot-work Tool Steels

Additive manufacturing (AM) technologies provide the possible method to manufacture the new suspension for ultra-weight green vehicles. In spite of traditional suspension system with a large amount of small components, Additive Manufacturing technologies allow the manufacturers to manufacture complicated mechanical structure in single piece which could efficiently decrease the number of components, the mass of new suspensions and the time for assembling. With the support of the modelling software, such as Creo® and AutoCAD®, the design concepts can be easily presented departments and made modifications when it is necessary. Finite element analysis software, such as ANSYS®, will provide the platform to do structural analysis by simulation without physically making the prototypes. Integrating these tools and technologies, time for products development will be dramatically reduced and ready-to-make products can be achieved. In this research, various concepts of the wishbones for the new suspension system will be designed based on the design constraints and the new designs will then be analysed by finite element analysis (FEA) in terms of stress distribution and total deformation of the model under a defined load. Creo® will be used to create the models of wishbones and ANSYS Workbench® will be employed for the structural analysis. Prototypes will also be built by Selective laser melting (SLM).Additive manufacturing (AM) technologies provide the possible method to manufacture the new suspension for ultra-weight green vehicles. In spite of traditional suspension system with a large amount of small components, Additive Manufacturing technologies allow the manufacturers to manufacture complicated mechanical structure in single piece which could efficiently decrease the number of components, the mass of new suspensions and the time for assembling. With the support of the modelling software, such as Creo® and AutoCAD®, the design concepts can be easily presented departments and made modifications when it is necessary. Finite element analysis software, such as ANSYS®, will provide the platform to do structural analysis by simulation without physically making the prototypes. Integrating these tools and technologies, time for products development will be dramatically reduced and ready-to-make products can be achieved. In this research, various concepts of the wishbones for the new suspension system wil...

Fundamentals of Mechanical Design and Analysis for AM Fabricated Parts