Production Of Metal Components Research Articles

Effect of Machining-Induced Deformation and Grain Refinement on Microstructure Evolution in Hybrid Wire-Arc Directed Energy Deposition

Abstract Wire-Arc Directed Energy Deposition (DED) offers promise for large-scale metal component production, yet challenges persist in achieving a consistent microstructure and mechanical properties. This paper investigates the effect of machining-induced deformation and grain refinement on microstructure evolution in mild steel structures printed using Hybrid Wire-Arc Directed Energy Deposition (DED), which integrates interlayer machining steps into the Wire-Arc DED process. The study demonstrates that machining with radiused-edge cutting tools induces fragmentation of ferritic/bainitic grains, leading to dispersed and refined grain colonies, that, when subjected to reheating and remelting cycles during subsequent layer depositions, lead to a more refined overall microstructure compared to the Wire-Arc DED process. Comparative analyses revealed a statistically significant 19.5% mean reduction in grain size and 8.5% increment in microhardness of the resulting Hybrid Wire-Arc DED structure. The work points to interlayer machining as a promising strategy for in-situ enhancement of the microstructure and mechanical properties in DED processes.

Sustainable metal-infused polymer feedstock compatible with low-cost metal sinter-based 3D printing

Additive manufacturing has been employed to fabricate metallic parts; however, prevalent techniques are expensive and energy consuming. Therefore, fused deposition modeling (FDM) technique has grabbed the attention of researchers and industries. Despite the promising results, available materials for metal FDM 3D printing are very limited. The current study presents the development of a novel metal-infused polymeric feedstock for FDM 3D printing, consists of spiky-shaped recycled nickel powders and polylactic-acid (PLA) polymer matrix. A low-cost desktop 3D printer is employed to produce green parts; subsequently, debinding/sintering processes can be conducted to achieve a fully metallic part. The low-cost recycled nickel powder that has been used in this study is produced using the low-carbon footprint Mond process, with a significant application in production and recycling of nickel- and iron-based batteries. Furthermore, PLA is chosen because it is bio-based and biodegradable with a lower carbon footprint in the carbon cycle than fossil-fuel-derived polymers. Therefore, the whole process is an ecofriendly cycle, stepping toward the sustainable and affordable production of metallic components. Regarding development of a novel feedstock material compatible with 3D printing, it is important to understand its properties. So, the developed feedstock materials were rheologically and physico-mechanically analyzed to find the optimum filler concentration.

Optimization of welding process parameters of wire arc additive manufacturing

Wire arc additive manufacturing (WAAM) is a cost-effective and efficient method for producing intricate metal geometries. This study employs Design Expert software and the desirability function to optimize WAAM process parameters, focusing on maximizing bead width, height, and microhardness—critical factors determining mechanical properties. Through ANOVA analysis, the research identifies voltage, wire feed speed, and torch speed as significantly influencing welding characteristics. Increased voltage and wire feed speed yield wider beads, while higher torch and wire feed speeds enhance bead height and microhardness. Optimized parameters—16.44 V voltage, 8.99 m/min wire feed speed, and 9 mm/s torch speed—demonstrate precise control over bead properties. This study deepens our understanding of WAAM process parameters, offering valuable insights for consistently producing high-quality weld beads with desired mechanical properties. The findings have profound implications for the manufacturing industry, enabling enhanced efficiency, consistency, and quality in metal component production. Optimized parameters also pave the way for innovative designs, lightweight structures, and rapid prototyping, contributing to the advancement of additive manufacturing, particularly in the context of wire arc technology. This research establishes a foundation for future studies on process optimization, material selection, and widespread WAAM adoption in diverse manufacturing sectors.

Microstructural and Mechanical Properties of CAP-WAAM Single-Track Al5356 Specimens of Differing Scale

The mass production of metallic components requires high agility in the working process conditioned by the necessity of building details of different shapes and sizes. Changing the size of the components theoretically influences the thermal dissipation capability of the same, which could lead to a change in their structure and mechanical properties. This is particularly important when aluminum alloys are concerned. For this reason, two Al5356 single-track specimens were built using the same technological conditions of layer deposition by varying only their geometrical size. In all cases, the specimens were wire and arc additively manufactured (WAAM) using a process based on gas metal arc welding (GMAW) in the cold arc pulse mode (CAP). The structure of both specimens was studied and defects along their surfaces were detected in the form of micro-pores and micro-cracks. A high concentration of undissolved Mg particles was also detected, along with some standalone Si particles. Uniformity in the build-up process was achieved, which led to the formation of nearly identical structures in the specimens. Subsequently, the resultant mechanical properties were also highly comparable. This indicates that the geometry-related variation in thermal conditions has an insignificant influence on the component’s structure and properties.

Influence of pollution of passenger car wheels on the quality of their balance

The article has a methodological intent, which consists in the desire to digitize the degree of influence of contamination of the wheel rims of passenger cars on the quality of their balancing. In a specific study, other aspects that influence the magnitude of the residual imbalance of wheels of cars and SUVs will be omitted, such as: the production of metal components of the machine (shaft, cone, flange), the central hole of the wheel rims, the difference in the angle of attack of the cones, the use of finger adapters and others. These parameters are taken as a constant; we will consider the effect of only dirt on the wheels of various cars. Three cars took part in the experiment: Lada Largus, UAZ Patriot, BMW X4M Competition. Keywords road transport, wheel, operation, balancing stand, safety, wheel imbalance, wheel washing, road safety

Sustainable production of copper components using concentrated solar energy in material extrusion additive manufacturing (MEX-CSE)

Material extrusion is a suitable technology for the additive manufacturing of complex components from any family of materials. The processing of metallic parts involves a three-stage methodology known as PDS (Printing-Debinding-Sintering). In the printing stage, filaments made of metallic powder and a polymeric binder system are used. After printing, the binder must be removed, and the parts sintered to obtain densified metal components with the final properties. These last two stages, in particular sintering, require high temperatures, and are thus high-energy demanding processes. The use of the Concentrated Solar Energy (CSE) is increasingly the focus of research in materials science as it is a clean, non-polluting, renewable energy resource, which is highly efficient for high temperature materials processing. This is the first study to analyse the feasibility of using CSE in the thermal debinding and sintering stages in the production of metallic components via Printing-Debinding-Solar Sintering (PDSS) technology. The objective is to develop a new sustainable process for producing metallic components by combining additive manufacturing and solar energy. In this study, pure copper cylindrical parts were produced and sintered in a low-cost Fresnel lens. The results revealed that solar sintering occurred at lower temperature (975 °C) and much shorter time (∼1 h) than in the conventional process, enhancing the economic and environmental efficiency of the conventional manufacturing process.

Vision on metal additive manufacturing: Developments, challenges and future trends

Additive Manufacturing (AM) is one of the innovative technologies to fabricate components, parts, assemblies or tools in various fields of application due to its main characteristics such as direct digital manufacturing, ability to offer both internal and external complex geometries without additional cost, and the potential of varying materials at the voxel level. However, despite high anticipations, AM as a real revolution for serial production of metal components has yet to be seen, mostly due to lacks of fundamental understanding, design engineering tools, and the global robustness of the value chains. This paper aims to provide a vision about the future of metal AM based on the collective knowledge of all ten scientific and technical committees of the International Academy of Production Engineering (CIRP).

Comparison of forming processes for micro textured cups

Friction losses are present in all kinds of technical systems. This is always associated with additional energy consumption, which can be partly avoided as it arises. Energy savings can be achieved by a wide range of approaches. The application of friction reducing coatings on bodies in relative motion is widespread. The coating of parts is however only suitable to a limited extent for the production in large batches. Therefore, research approaches consider alternative methods to achieve friction reductions. A promising approach is the integration of miniaturized pockets on the surface of the component. In lubricated contacts, the lubricant can then accumulate in these indentations. The relative motion between two bodies thus builds up a hydrodynamic pressure and consequently reduces friction. Forming technology is suitable for the efficient production of metallic components in large quantities. The aim of this study is therefore to identify challenges in the integration of micro coining in established forming processes. Two processes from sheet metal forming and bulk metal forming are investigated. In a combined experimental and numerical approach, process-specific challenges are derived regarding the texturing process and the numerical process modelling for combined micro coining. The analysis is carried out on a cup geometry, as used in the automotive sector as tappets in the valve train. The case hardening steel 16MnCr5 (1.7131) is used as workpiece material.

In-situ tailoring microstructures to promote strength-ductility synergy in laser powder bed fusion of NiCoCr medium-entropy alloy

Laser powder bed fusion (LPBF) has received widespread attention owing to its digital, flexible, and controllable fabrication process, which opens new possibilities for the direct and fast production of metal components with extremely complex geometries and good performance. Generally, post-treatments are conducted to further regulate the microstructure and performance of as-deposited geometrically-complex metal components. In this work, instead of applying post-treatments, we demonstrate a novel in-situ remelting strategy to effectively enhance the strength without sacrificing the ductility of LPBF-fabricated NiCoCr medium-entropy alloy by in-process tailoring microstructures. We find that in-situ remelting processing not only changes the melt pool geometry in favor of optimizing densification and developing unique crystallographic lamellar microstructures, but also promotes inherent thermal distortions and heat treatments during manufacturing resulting in increased dislocation density and grain refinement in the LPBF-remelted specimen. The present work paves a new way in additively manufacturing metal materials to tailor microstructures for enhanced mechanical performance without additional treatments.

ANALISIS PENGENDALIAN KUALITAS PADA PROSES PRODUKSI REINF RR NO.1 SEAT LEG RR DI PT XX

PT. XX. is a company engaged in the automotive sector, precisely in the production of metal components, always prioritizing and trying to create products with high quality, but in the process until now, reject products are still found both during the production process and after passing inspection, while zero defects become standard in the production process. Based on data obtained from August to November 2021, part number 57835-0K020 is the product with the highest rejects. In this study, quality improvement efforts were carried out using the Statistical Quality Control (SQC) method. Several methods used in this research include normality test of data with Kolmogorov Smirnov, Pareto diagram, np control chart and process capability. The results of this study are the observation data is normally distributed, the weld porous is the dominant type of defect, the control chart is statistically controlled, and the Cp index is around 0.83 and the Cpk is around 0.77 so it can be concluded that the process does not have a good capability. Keywords: SQC, Normality Test, Control Chart, CP, Cpk

Industrial Applications of Lattice Structures in Components Made with EBM Additive Technology

AbstractThe aim of this study is to promote the industrial use of “lattice” structures in metal components made with Electron Beam Melting (EBM) technology.The degree of customization and the level of geometric complexity achieved with EBM technology in the production of metal components in the Aerospace and Racing sectors, favors the use of lighter and more performing designs characterized by reticular (or “lattice”) structures. Starting from the original massive design of the component and taking into account the geometric constraints and load conditions acting on the component, the search for the new design takes place in a software environment through the topological optimization process. At the end of the process, the optimized design is created by replacing the solid parts with a unit cell that is repeated periodically. From the comparison between the component with original layout, built using the standard Melt theme of EBM technology, and the equivalent component with optimized layout, created with the Net theme of the same technology, the advantage of using reticular structures to lighten the components and the possibility offered by EBM technology to practically implement these structures are highlighted.The search for lighter and more performing designs for metal components promotes the use of “lattice” structures, which can be created by exploiting the potential of Additive Manufacturing technologies.The possibility of creating very complex geometries makes EBM technology perfect for sectors where particular characteristics are required in the components produced, such as the Aerospace and the Racing sector. The existence of the Net theme also ensures that it is possible to print reticular structures with EBM technology, that allow to reduce the weight of the components and, at the same time, improve performance.

Laser Metal Deposition with Coaxial Wire Feeding for the Automated and Reliable Build-Up of Solid Metal Parts

Due to their outstanding characteristics, additive manufacturing processes are attracting increasing industrial interest. Among these processes, laser metal deposition (LMD) is an innovative technology for the production of metal components. In order to create three-dimensional parts, wire or powder is deposited layer-wise onto a substrate. When wire is used as feedstock, major drawbacks of the powder-based process, such as the low material usage, contamination of the process cell with metal powder, and health or safety issues, can be overcome or even avoided. In addition, recent developments in laser optics allow for a coaxial wire feeding in the center of an annular laser beam. This eliminates the strong directional dependence of the process when feeding the wire laterally. However, wire-based LMD is highly sensitive to process disturbances, which impedes its broader industrial application. Since it is necessary to completely melt the fed wire to achieve a stable process, self-regulating effects such as overspray in powder-based LMD are not present. In contrast to the widely investigated thin walls, the build-up of multi-track solid structures poses a particular challenge. Therefore, process strategies for producing such solid structures are presented in this paper. The experiments were carried out using a laser processing head that enables coaxial wire feeding (CoaxPrinter, Precitec). By systematically varying the lateral overlap between adjacent weld beads, it was shown that an optimum exists at which minimum surface waviness is achieved. Based on this, defect-free multi-layer solid components could be generated in a reproducible manner. During the process, the melt pool temperature was evaluated using a pyrometer. Furthermore, a microscopic examination of the resulting parts was conducted. The results obtained show the need for process monitoring and control, for which a novel and holistic approach has been developed.

Microstructural Characterization of Additively Manufactured Metal Components Using Linear and Nonlinear Ultrasonic Techniques.

Metal additive manufacturing (AM) is an innovative manufacturing technology that uses a high-power laser for the layer-by-layer production of metal components. Despite many achievements in the field of AM, few studies have focused on the nondestructive characterization of microstructures, such as grain size and porosity. In this study, various microstructures of additively manufactured metal components were characterized non-destructively using linear/nonlinear ultrasonic techniques. The contributions of this study are as follows: (1) presenting correlation analyses of various microstructures (grain size and texture, lack of fusion, and porosity) and ultrasonic properties (ultrasonic velocity, attenuation, and nonlinearity parameters), (2) development of nondestructive microstructural characterization techniques for additively manufactured components; and (3) exploring the potential for the online monitoring of AM processes owing to the nondestructive nature of the proposed technique. The performance of the proposed technique was validated using additively manufactured samples under varying laser beam speed conditions. The characteristics of the target microstructures characterized using the proposed technique were consistent with the results obtained using destructive optical microscopy and electron back-scattered diffraction methods.

Enhanced surface properties and bioactivity of additively manufactured 316L stainless steel using different post-treatments

It is well documented that the surface characteristics of each component play a key role in its performance. In particular, in the case of Metal Additive Manufacturing (MAM) processes, surface quality is one of the key challenges in the production of metallic components. Therefore, this work investigates the influence of two post surface treatments on surface features such as surface roughness, microhardness, wettability and bioactivity of the AISI 316 L stainless steel alloys produced by the laser powder bed fusion technique. The as-built samples were subjected to two different post-treatments of laser polishing and shot peening. The outcomes indicate that the shot peening process resulted in lower surface roughness and higher surface hardness compared to the as-built state. The X-ray diffraction results indicated that there was no considerable phase change after the post-treatments. The in vitro bioactivity analysis reveals the increment in apatite formation due to better wettability and high surface energy for treated samples. It is concluded that post surface treatment of the AISI 316L samples can improve their surface properties and their bioactivity behaviour, making them promising candidates for orthopaedic implants.

Evolution of residual stress behavior in selective laser melting (SLM) of 316L stainless steel through preheating and in-situ re-scanning techniques

The premature fractures, cracks, distortions, and delamination in selective laser melting manufactured components are among the most prominent challenges. These issues in selective laser melting manufactured components restrict their widespread application. Residual stresses are among the most common reasons for these behaviors. Post processing techniques are therefore used for most of the selective laser melting fabricated components to either eliminate or decrease these stresses. However, this increases the production time and fabrication costs. Therefore, in process techniques to reduce these residual stresses are of paramount importance in promoting the largescale production of metallic components. In this paper, a finite element method-based investigation of preheating and in-situ rescanning techniques during selective laser melting of 316L stainless steel is presented. The influence of various preheating temperatures on the final residual stress profile was observed. Similarly, the variations in residual stresses with different rescanning parameters were also investigated. Both baseplate and powder bed preheating procedures were observed to have considerable effects on the residual stresses. The residual stresses were significantly decreased with increasing preheating temperatures. Baseplate and powder bed preheating at 400 °C were observed to have decreased the residual stresses from 353.57 MPa (stress values without preheating or rescanning) to 27 MPa and 30 MPa, respectively. In-situ rescanning was also observed to be beneficial in decreasing the stresses in SLM fabricated components. However, their influence is relatively smaller in comparison with the preheating. No significant influence of rescanning on the stress distribution was also observed.

Corrosion Resistance Measurement of 316L Stainless Steel Manufactured by Selective Laser Melting.

Selective laser melting (SLM) technology is ushering in a new era of advanced industrial production of metal components. It is of great importance to understand the relationship between the surface features and electrochemical properties of manufactured parts. This work studied the influence of surface orientation on the corrosion resistance of 316L stainless-steel (SS) components manufactured with SLM. The corrosion resistance of the samples was measured using linear polarization resistance (LPR) and electromechanical noise (EN) techniques under three different environments, H2O, 3.5 wt.% NaCl, and 20% H2SO4, analyzing the horizontal (XY) and vertical (XZ) planes. The microstructure and morphology of the samples were obtained by optical (OM) and scanning electron microscopy (SEM). The obtained microstructure showed the grains growing up from the fusion line to the melt pool center and, via SEM-EDS, the presence of irregular and spherical pores was observed. The highest corrosion rate was identified in the H2SO4 solution in the XZ plane with 2.4 × 10−2 mm/year and the XY plane with 1.31 × 10−3 mm/year. The EN technique along with the skewness factor were used to determine the type of corrosion that the material developed. Localized corrosion was observed in the NaCl electrolyte, for the XY and XZ planes (−1.65 and −0.012 skewness factors, respectively), attacking mainly the subgrains of the microstructure and, in some cases, the pores, caused by Cl ions. H2O and H2SO4 solutions presented a uniform corrosion mechanism for the two observed orientations. The morphology identified by SEM was correlated with the results obtained from the electrochemical techniques.

A parametric neutron Bragg edge imaging study of additively manufactured samples treated by laser shock peening

Laser powder bed fusion is an additive manufacturing technique extensively used for the production of metallic components. Despite this process has reached a status at which parts are produced with mechanical properties comparable to those from conventional production, it is still prone to introduce detrimental tensile residual stresses towards the surfaces along the building direction, implying negative consequences on fatigue life and resistance to crack formations. Laser shock peening (LSP) is a promising method adopted to compensate tensile residual stresses and to introduce beneficial compressive residual stress on the treated surfaces. Using neutron Bragg edge imaging, we perform a parametric study of LSP applied to 316L steel samples produced by laser powder bed fusion additive manufacturing. We include in the study the novel 3D-LSP technique, where samples are LSP treated also during the building process, at intermediate build layers. The LSP energy and spot overlap were set to either 1.0 or 1.5 J and 40% or 80% respectively. The results support the use of 3D-LSP treatment with the higher LSP laser energy and overlap applied, which showed a relative increase of surface compressive residual stress (CRS) and CRS depth by 54% and 104% respectively, compared to the conventional LSP treatment.

Assessing the Economic Effectiveness of Additive Sheet Lamination

Methodological aspects of assessing the economic efficiency of an additive manufacturing technology are discussed; specifically, the production of metal components by additive sheet lamination is considered. A model is proposed for cost calculation in laminated object manufacturing.

Effect Of The Support Structure On Flexural Properties Of Fabricated Part At Different Parameters In The Fdm Process

Traditional fused deposition modeling (FDM) is an additive manufacturing method in which a part is fabricated using layer upon layer approach. Due to the imminent nature of this approach, support structures are needed to sustain overhanging elements of the parts, particularly for the production of metal components and complex geometries. Several works are going on to minimize the usage of supports by using improved support strategies. However, the use of different support strategies at different pre-defined machine settings may lead to varied properties of the final printed part. In this work, the influence of support strategies on flexural properties at four different parameters is experimentally determined in the fused deposition modeling process. Two support strategies, Line and Grid, are adopted while fabricating the same 3D part at three different printer parameter settings. The flexural properties of the samples are compared for assessing the impact of two support strategies, as well as the support material usage and printing time. Results reveal that two support methods lead to varied flexural strength and print qualities at varied parameters.

Correlations between thermal history and keyhole porosity in laser powder bed fusion

Additive manufacturing has the potential to revolutionize the production of metallic components as it yields near net shape parts with complex geometries and minimizes waste. At the present day, additively manufactured components face qualification and certification challenges due to the difficulty in controlling defects. This has driven a significant research effort aimed at better understanding and improving processing controls – yielding a plethora of in-situ measurements aimed at correlating defects with material quality metrics of interest. In this work, we develop machine-learning methods to learn correlations between thermal history and subsurface porosity for a variety of print conditions in laser powder bed fusion. Un-normalized surface temperatures (in the form of black-body radiances) are obtained using high-speed infrared imaging and porosity formation is observed in the sample cross-section through synchrotron x-ray imaging. To demonstrate the predictive power of these features, we present four statistical machine-learning models that correlate temperature histories to subsurface porosity formation in laser fused Ti-6Al-4V powder.