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Distortion and Dilution Behavior for Laser Metal Deposition onto Thin Sheet Metals
摘要： The combination of additive manufacturing and incremental sheet forming offers great flexibility in the manufacture of function-integrated parts. In this study, both processes were carried out by the same CNC machine. This offers the possibility to manufacture large-scale lightweight parts with smaller additive parts on it in one machine and clamping device. Additionally, the process combination can lead to a reduced energy and material consumption for small batch sizes. DC01 sheets are used as a substrate with two different initial conditions. The first condition is as delivered steel sheet and the second is an incrementally formed with a thickness of 0.5 mm. The additive manufacturing was conducted by laser metal deposition (LMD). The powder material is a stainless steel 316 L. A segmentation of the cladding surface was applied and the path strategy of the laser movement was varied simultaneously to analyse the warpage of the thin substrate. It is shown that there is a dependency between the build-up strategies and the melt pool temperature, the thermal distortion, the dilution and the size of the cladding area. A segmentation of the working surface causes a lower melt pool temperature and thermal distortion. The lower melt pool temperature also generates a reduced dilution zone.
关键词： Thermal distortion,Laser metal deposition,Incremental sheet forming,Stainless steel
更新于2025-09-23 15:19:57
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Surface based variable thickness slicing modeling for laser metal deposition
摘要： Laser metal deposition (LMD) has been a promising additive manufacturing technology widely used in mold rapid manufacturing. In order to improve the capacity of LMD for complex curved surface structures, a surface based variable thickness slicing (S-VTS) model is proposed to adaptively generate the LMD process based on the geometric characteristics of structures. Two deposition strategies in scanning and overlapping directions are designed to enable variable thickness of each cladding layer by dynamically adjusting the scanning speed and overlapping rate. To improve the surface quality and forming efficiency, the discrete particle swarm optimization (DPSO) algorithm is adopt to optimize the process parameters of S-VTS model, including the number of cladding layer, scanning pass, and segment per pass. Several experiments are conducted to form the cuboid samples with wavy and freeform surface and verify the feasibility of the S-VTS model. The results demonstrate that under the open-loop control condition, the geometric accuracy, surface quality, and efficiency of the proposed method is improved in comparison with uniform thickness slicing (UTS) deposition. Moreover, heterogeneous microstructure is always generated by the S-VTS method in terms of grain size and growth direction.
关键词： Variable thickness slicing (S-VTS),Laser metal deposition (LMD),Curved surface,Mold
更新于2025-09-23 15:19:57
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Laser metal deposition of copper on diverse metals using green laser sources
摘要： Green laser sources are advantageous in the processing of copper due to the increase of absorptivity compared with more commonly available infrared lasers. Laser metal deposition of copper with a green laser onto various substrate metals namely copper, aluminium, steel and titanium alloy was carried out and observed through high-speed imaging. The effects of process parameters such as laser power, cladding speed and powder feed rate, and material attributes such as absorptivity, surface conditions and thermal conductivity are tied together to explain the size and geometry of the melt pool as well as the fraction of the power used for melting material. The copper substrate has the smallest melt pool with a high angle, followed by aluminium, steel and titanium alloy. The incorporation times for powder grains in the melt pools vary based on the substrate materials. Its dependency on material properties, including surface tension forces, melting temperatures and material density, is discussed. Oxide skins present on melt pools can affect powder incorporation, most significantly on the aluminium substrate. The lower limits of the fraction of power irradiated on the surface used purely for melting were calculated to be 0.73%, 2.94%, 5.95% and 9.78% for the copper, aluminium, steel and titanium alloy substrates, respectively, showing a strong dependence on thermal conductivity of the substrate material. For a copper wall built, the fraction was 2.66%, much higher than a single clad on a copper substrate, due to reduced workpiece heating. The results of this paper can be transferred to other metals with low absorptivity such as gold.
关键词： Multi-material,DED,High-speed imaging,LMD,Copper,Green 515-nm laser,Laser metal deposition,Powder grain incorporation,Additive manufacturing,Directed energy deposition,Absorptivity
更新于2025-09-19 17:13:59
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Analysis of laser cladding of Titanium alloy
摘要： In this study, laser cladding of Grade 5 Titanium alloy Ti6Al4V was investigated with the main goal being to optimize the cladding process by specifically optimizing the scanning speed. The scanning speed was varied from 0.5m/min to 3.5m/min in increments of 0.5m/min; while the other parameters were kept constant. Thereafter, a geometrical analysis, porosity analysis, microscopic analysis in the form of optical microscopy and SEM, atomic force microscopic analysis, Vickers microhardness testing and corrosion testing were all performed to ascertain the integrity of the clads and to optimize the process. These tests were corroborated and it was revealed that a scanning speed of 1.5m/min yielded the best all-round clad, i.e. most efficient while maintaining the quality at a relatively high level and can therefore be recommended for typical cladding processes.
关键词： titanium,Laser-metal deposition,laser cladding,scanning speed
更新于2025-09-19 17:13:59
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In-Process Laser Re-Melting of Thin Walled Parts to Improve Surface Quality after Laser Metal Deposition
摘要： Laser metal deposition (LMD) is an additive manufacturing process highly adaptable to medium to large sized components with bulky structures as well as thin walls. Low surface quality of as-deposited LMD manufactured components with average roughness values (Ra) around 15-20μm is one of the main drawbacks that prevent the use of the part without the implementation of costly and time-consuming post-processes. In this work laser re-melting is applied right after LMD process with the use of the same equipment used for the deposition to treat AISI 316L thin walled parts. The surface quality improvement is assessed through the measurement of both areal surface roughness Sa(0.8mm) and waviness Wa(0.8mm) parameters. Moreover, roughness power spectrum is used to point out the presence of principal periodical components both in the as-deposited and in the re-melted surfaces. Then, the transfer function is calculated to better understand the effects of laser re-melting on the topography evolution, measuring the changes of individual components contributing to the surface roughness such as the layering technique and the presence of sintered particles. Experiments showed that while low energy density inputs are not capable to properly modify the additive surface topography, excessive energy inputs impose a strong periodical component with wavelength equal to the laser scan spacing and directionality determined by the used strategy. When a proper amount of energy density input is used, laser re-melting is capable to generate smooth isotropic topographies without visible periodical surface structures.
关键词： laser metal deposition,direct energy deposition,Additive manufacturing,post-processing,surface roughness,laser re-melting
更新于2025-09-16 10:30:52
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Additive Manufacturing of Functionally Graded Metallic Materials Using Laser Metal Deposition
摘要： Functionally graded materials (FGMs) have attracted much research interest in the industry due to their graded material properties, which result from gradually distributed compositions or structures. In recent years, metallic FGMs have been widely studied, and additive manufacturing (AM) has become an important approach to build metallic FGMs. This paper aims to provide an overview of the research progress in metallic FGMs fabricated by laser metal deposition (LMD), an AM process that is widely used in metallic materials. Firstly, the unique material properties and advantages of FGMs are introduced. Then, typical recent findings in transition path design, fabrication, and characterization for different types of metallic FGMs via LMD are summarized and discussed. Finally, challenges in fabricating metallic FGMs via LMD are discussed, and other related aspects in the area of FGMs such as model representation and numerical simulation are proposed for further investigation.
关键词： Laser Metal Deposition,Intermediate Section,Transition Path,Metal Additive Manufacturing,Material Characterization,Functionally Graded Materials
更新于2025-09-16 10:30:52
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Study for Combined Wire + Powder Laser Metal Deposition of H11 and Niobium
摘要： Laser additive manufacturing (LAM) has been proved to be a successful technique to fabricate metallic components for a number of industries; for instance, die & mold, forging and cutting tools, and aerospace. It is, however, facing multitude obstacles due to lack of maturity in terms of process knowledge, design, and qualification. This paper deals with parameters’ study and optimization of combined hot-work tool steel wire (H11) and niobium powder (Nb) deposition by laser. The process is closely analysed and compared with as well as without using Nb powder. Especially, the importance of Nb in order to refine the microstructure is discussed while taking into account the microstructure-property relationships of H11.
关键词： Laser additive manufacturing,Niobium (Nb),Hot-work tool steel,Laser metal deposition,H11
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Las Vegas, NV, USA (2019.5.28-2019.5.31)] 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Additive Laser Metal Deposition Onto Silicon for Enhanced Microelectronics Cooling
摘要： We previously demonstrated how the Sn3Ag4Ti alloy can robustly bond onto silicon via selective laser melting (SLM). By employing this technology, thermal management devices (e.g., micro-channels, vapor chamber evaporators, heat pipes) can be directly printed onto the electronic package (silicon die) without using thermal interface materials. Under immersion two-phase cooling (pool boiling), we compare the performance of three chip cooling methods (conventional heat sink, bare silicon die and additively manufactured metal micro-fins) under high heat flux conditions (100 W/cm2). Heat transfer simulations show a significant reduction in the chip temperature for the silicon micro-fins. Reduction of the chip operating temperature or increase in clock speed are some of the advantages of this technology, which results from the elimination of thermal interface materials in the electronic package. Performance and reliability aspects of this technology are discussed through experiments and computational models.
关键词： Performance and Reliability,Thermal Management,Laser Metal Deposition,Additive Manufacturing,Electronic Cooling
更新于2025-09-16 10:30:52
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Hierarchical Composite Materials (Materials, Manufacturing, Engineering) || 4. Fabrication of stainless steel-based FGM by laser metal deposition
摘要： Recent advancement in materials processing has resulted in the evolution of advanced composite known as functionally graded materials (FGMs). FGMs are multilayered structures with composition and/or microstructure that vary spatially across the volume of the material. This chapter presents an overview of the concept of FGMs in terms and its history. The present and potential applications of FGMs are briefly described, as well as various classification methods. Processing of FGM using laser metal deposition (LMD) is also discussed as well as the influence of LMD process parameters on the quality of laser-processed materials. Studies that have been conducted on metal–metal FGM produced by LMD are presented. Finally, a study on the microstructure and microhardness of laser deposited compositionally graded 316L/17-4PH was also presented.
关键词： Laser metal deposition,Advance composite,Microstructure,Microhardness,Functional graded material
更新于2025-09-16 10:30:52
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[Laser Institute of America ICALEO? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22–26, 2017)] International Congress on Applications of Lasers & Electro-Optics - Laser metal deposition with 316L stainless wire: Macro morphologies and microstructures
摘要： Laser metal deposition (LMD) with wire as the filler material has demonstrated to be a potential method in addictive manufacturing due to its higher material deposition efficiency, improved surface quality, reduced material wastage and cleaner process environment without metal dust pollution. In this study, single beads samples and block samples of 316L stainless wire were successfully deposited on the surface of 316L stainless steel under optimized depositing conditions using a YLR-4000 S2 CW Fiber Laser, a Fronius MAG arc welding machine and an ABB industrial robot. The macro morphologies, geometric characteristics and microstructures were examined. The influence of process parameters to macro morphologies and geometric characteristics of different samples were carefully studied. A 5*5 block sample was finally deposited with appropriate parameters based on the single bead experiments. The results showed that satisfied single bead samples with smooth surface and high aspect ratio (height-width ratio) can be deposited under appropriate process conditions and parameters during the stable deposit process. Uniform structures of fine equiaxed austenite grains with good metallurgical bonding to the substrate were also obtained. Uniform bond-like microstructures of block samples was also obtained and investigated. All these results will provide guidance for further large study of laser metal-wire deposition with structures.
关键词： Laser metal deposition,macro morphology,geometric characteristic,316L stainless wire,microstructure
更新于2025-09-16 10:30:52