This study investigates the structural response of blank-holders (BHs) equipped with spatially distributed magnetorheological (MR) actuators for adaptive deep drawing. While MR actuators provide fast, independent, and high-resolution force modulation, their effectiveness depends critically on the BH’s ability to transmit spatially differentiated loads without excessive diffusion or unrealistic stress localization. The relationships between BH stiffness, actuator spacing, and pressure localization at the sheet interface remain only partially understood, limiting the implementation of distributed blank-holding strategies. To address this gap, a comprehensive finite element (FE) framework is developed, combining a full closed-cup deep-drawing model with a complementary simplified configuration that isolates local deformation mechanisms under single-actuator loading. Parametric analyses examine the influence of BH thickness, local actuator force, and actuator spacing on stress distribution, localization radius, and overlap between adjacent load paths. Results show that BH thickness is the dominant factor governing spatial resolution: thinner BHs enable sharp pressure localization, whereas thicker ones diffuse local loads and suppress stress peaks. The spacing between actuators must therefore be selected as a function of BH stiffness to avoid stress-free regions while preserving distinct pressure footprints. For the reference industrial configuration (60 mm BH thickness), an actuator spacing of approximately 150 mm achieves the optimal compromise between localization capability and continuous sheet support. The proposed framework establishes quantitative design criteria for BH geometries compatible with MR-based adaptive forming and supports the development of next-generation blank-holding systems offering enhanced process stability, reduced scrap, and improved material-flow control.

This study presents an integrated experimental–numerical framework to predict and mitigate instability defects in thermo-bending of polymer-based tubes. A differential local thermal control system was developed to regulate thermo-mechanical behaviour across the glass transition temperature. A modified constitutive model was calibrated for polyamide 12 (PA12) and polyvinyl chloride (PVC), capturing strain softening and hardening regimes. Results show that PA12 provides a wide processing window, while PVC requires asymmetric heating to shift the neutral axis and suppress wrinkling, necking and ovalisation. The framework enables reliable prediction and improved control of thermo-bending processes.

This study examines the influence of laser powder bed fusion (LPBF) layer thickness on the machinability of AlSi7Mg aluminum alloy. Samples fabricated with layer thicknesses of 20, 25, and 30 mu m were heat-treated and then turned under fixed cutting parameters. The machinability was assessed in terms of cutting forces, surface roughness, and surface defects. Results showed that decreasing the layer thickness increased cutting forces and surface roughness, with the samples produced with a 20 mu m layer thickness exhibiting the poorest machinability. The explanation of the lower machinability with decreasing layer thickness was associated with the microstructural and mechanical features characterizing the samples. At lower layer thickness, the microstructure is more anisotropic and ductile, leading to higher cutting forces and rougher surfaces. Contrarily, at greater layer thicknesses, the more uniform and less tough microstructure results in lower cutting forces and smoother surfaces. The presence of different Fe-rich intermetallics at different layer thicknesses also influences the morphology of the defects found on the machined surfaces. The findings highlight the importance of optimizing layer thickness to enhance the machinability of LPBF AlSi7Mg parts.

Ti6Al4V is widely used in aerospace and biomedical applications but is renowned as a difficult-to-machine material due to its thermo-physical characteristics, often leading to premature tool failure and compromised product finishes. The advent of additive manufacturing (AM) technologies has partly alleviated these issues, enabling the production of near-net-shape complex geometries and shortening the process chain. Nonetheless, finishing machining operations are often required to achieve the final shape. In parallel, the increasing demand for greener processes has driven research towards innovative lubricating strategies. Among these, nanofluid-assisted minimum quantity lubrication (NMQL) using vegetable-based nano-cutting fluids has gained growing attention. Nanoparticles are suspended in the main cutting fluid to enhance its thermal and tribological performance, generating a nanofluid, overcoming the inherent limits of vegetable oils regarding their natural heat dissipation and load resistance. In this framework, a comparison between pure soybean oil and a soybean oil-based nanofluid composed of 0.1 wt.% Al₂O₃ nanoparticles and 0.32 wt.% surfactant is proposed when drilling laser powder bed fusion (LPBF) Ti6Al4V samples. Viscosity, wettability, and tribological characteristics were evaluated for both cutting fluids. Tool wear was evaluated and quantitatively assessed through optical and SEM imaging. Hole internal surface quality was assessed through topography and morphology analyses. The results showed that the NMQL approach effectively reduced tool wear compared to conventional MQL with pure soybean oil, achieving a 47% reduction in wear area. Nanoparticles enhanced the tribological characteristics of the base oil and apparently promoted a “rolling-effect” mechanism at the tool/workpiece interface.

This study investigates the effects of pre-quenching treatment prior to quenching and partitioning (P-Q P) on the microstructure and mechanical properties of Fe–0.23C–2.12Mn–1.63Si steel. Increasing the pre-quenching temperature transforms the microstructure from heterogeneous martensite/ferrite with coarse M2/A islands under conventional Q P treatment to a composite structure with near-equiaxed martensite/ferrite and refined lath-like M2/A islands under P-Q P treatment. Excessively high pre-quenching temperatures, however, induce M2/A island coarsening and excessive carbide precipitation, reducing deformation compatibility and elongation. The sample pre-quenched at 790 °C exhibits the optimal strength–ductility synergy, with a tensile strength of 978 MPa, a yield strength of 519 MPa, a total elongation of 26.2 pct, and a strength-elongation product of 25.6 images of PQ specimensGPa pct. This performance is attributed to enhanced deformation compatibility from microstructural refinement, optimized crystallographic orientation, and weak texture. Strength is improved by refined martensitic laths and stabilized retained austenite, while ductility and strain hardening are promoted by uniform Schmid factor distribution and coordinated activation of multiple BCC slip systems (110 〈111〉, 112 〈111〉, 123 〈111〉), suppressing slip localization and enabling homogeneous plastic deformation. This study clarifies the role of pre-quenching-controlled initial microstructures in deformation mechanisms and strength–ductility balance of Q P steels.

Unlocking the potential of laser powder bed fusion (LPBF) AlSi7Mg for high-performance applications hinges on a deep understanding of its microstructural response to processing parameters. Previous studies investigating the layer thickness influence on LPBF AlSi7Mg have primarily focused on thicker printing layers (30 mu m-100 mu m), which neglects the potential impact of very thin layers (e.g., 20-30 mu m) on the microstructure and overall properties like service stability. This study aims to fill this knowledge gap by systematically examining the effect of printing layer thickness within this thin critical range on the microstructural evolution and subsequent corrosion behavior of LPBF AlSi7Mg (after T6 heat treatment). Our results demonstrated that the 30 mu m printing thickness condition consistently exhibited superior microhardness and corrosion resistance. The detailed microstructural and phase formation analysis revealed that layer thickness has a direct impact on cooling rate and resultant element distribution, which can induce the formation of different Fe-bearing phases like it-AlFeMgSi and beta-AlFeSi. Along with different phase formations, the grain boundary (GB) and Si-rich phase concentration and distribution significantly influenced performance by disturbing the passivation layer, which provides valuable insights for optimizing LPBF processing parameters, enhancing the reliability of AlSi7Mg components, and advancing the understanding of this critical material for demanding applications.

Additive manufacturing by laser powder bed fusion (LPBF) is increasingly applied to aluminium alloys; however, the resulting surface quality and machining behaviour remain critical challenges, particularly when post-processing is required. In this context, the interaction between LPBF process parameters and advanced cooling strategies during machining remains largely unexplored.This study examines the impact of cryogenic machining on the surface integrity of LPBF-produced AlSi7Mg components, fabricated with varying layer thicknesses. Specimens were machined under fixed cutting parameters using either conventional flood cooling or cryogenic cooling. Cutting forces, surface roughness, defect morphology, and subsurface microstructure were systematically evaluated.Cryogenic cooling consistently reduced cutting forces and improved surface quality, effectively suppressing tearing formation. In contrast, under flood cooling, the influence of the microstructural differences induced by layer thickness remained significant, with increasing LPBF layer thickness further enhancing both surface and subsurface integrity. Overall, the results reveal a strong interaction between LPBF parameters and cooling strategy, highlighting the unexpectedly beneficial role of cryogenic machining in improving the surface integrity of LPBF-processed AlSi7Mg alloys.

Particle-reinforced metal matrix composites (MMCs) are gaining prominence as engineering materials for advanced aerospace and automotive applications, owing to their superior mechanical and tribological properties compared to monolithic alloys. However, the inclusion of hard reinforcement particles can pose significant machinability challenges, leading to increased tool wear and reduced surface integrity. MMCs can be fabricated using various methods, each influencing particularly the size and distribution of the reinforcing particles, which in turn affect their response to machining. Among these fabrication techniques, stir casting offers cost-effective and scalable production suitable for large-volume applications. Hot isostatic pressing, in contrast, is typically reserved for specialized, low-volume components that require high-performing mechanical properties. In this study, drilling performance is evaluated for two MMCs, one produced via stir casting and the other via hot isostatic pressing. The analysis focuses on tool wear, cutting forces, and surface integrity, including surface roughness evaluation (Sa), assessment of drilled surface defects, and examination of subsurface defects. The obtained results are interpreted in relation to the distinct microstructural characteristics introduced by each fabrication method.

Additive manufacturing (AM) technologies have enabled the production of complex titanium alloy (Ti6Al4V) components for aerospace and biomedical applications. However, these components often require subsequent machining as a post-processing step, where the high temperatures involved and the alloy's poor thermal conductivity may accelerate tool wear and compromise surface finish. Minimum quantity lubrication (MQL) with vegetable-based oils offers a sustainable alternative to conventional flood cooling, though its performance is limited by low heat dissipation and reduced pressure resistance. To enhance lubrication efficiency, nanoparticles may be dispersed in the base oil. In this study, a nanofluid composed of 0.1 wt% Al2O3 nanoparticles and 0.32 wt% SLS surfactant in soybean oil was tested along with pure soybean oil during drilling of two Ti6Al4V as-received states: wrought and electron beam melted (EBM). The cutting fluids were characterized for thermal conductivity, viscosity, wettability, and tribological behaviour. Fifty holes were drilled per condition, showing tool adhesion and abrasion as the main wear mechanisms, but with adhesion less severe when cutting the EBM alloy. In addition, the nanofluid reduced the worn area of the cutting edges by 42 % in the wrought alloy and by 75 % in the EBM alloy, effectively mitigating abrasive wear and chipping. Hole surface roughness values remained consistently low (Ra < 0.9 mu m) across all conditions. Overall, the nanoparticles promoted a rolling effect at the tool-workpiece interface, with a superior response on the EBM alloy, ascribed to its higher hardness and acicular microstructure, possibly inducing more stable nanoparticle interactions and improved lubrication performance.

Metal additive manufacturing (AM) enables the flexible and free fabrication of parts with complex geometries and tailored structures, thereby offering a wide range of applications. However, surface imperfections and defects in the as-built state can significantly compromise part performance, leading to issues such as high surface roughness, accelerated wear, corrosion susceptibility, and poor aesthetic quality. To address these challenges, this study investigates electrochemical polishing (ECP) as a promising surface post-treatment technique for achieving smooth and bright surfaces. Experiments were conducted on direct metal laser sintering (DMLS) 316 L stainless steel using an acetic acid electrolyte under low current densities. Nyquist, Tafel, and Mott-Schottky analyses confirmed enhanced surface integrity and density, and the film thickness for polished surface is increased from 2.16 nm to 2.34 nm,. Pin-on-disk tests further demonstrated that the ECP-treated surface exhibits minimal waviness and low friction under lubrication, reducing the friction coefficient from 0.201 to 0.103. The results support the feasibility of ECP with a mild acid electrolyte for smoothing AM components, Sa roughness was reduced by over 50.8 %, with uniform polishing of deposited cavities and no loss of dimensional accuracy. This process represents an effective post-processing route for achieving homogeneously smooth surface layers.

The use of recycled aluminum alloys is increasing, driven by sustainability goals, as they require less energy than primary alloys while maintaining comparable mechanical properties. While significant research has focused on the mechanical properties of recycled parts, research on their machinability is relatively limited.This study investigates the machinability of primary and recycled (secondary) aluminum alloys, focusing on surface finish and integrity after machining. The alloys were analyzed using optical and scanning electron microscopy to characterize intermetallic particles, influencing machinability. Turning trials were then conducted at varying feeds under conventional lubrication. The surface finish was evaluated through roughness and defect analysis, while surface integrity was assessed by examining the severe plastic deformation layer caused by cutting.Results show that the primary alloy produced higher cutting forces and rougher surfaces compared to the secondary alloy. Tearing was the predominant surface defect observed in all alloys, but it was most severe in the primary alloy. This study underscores the potential of secondary aluminum alloys to deliver competitive machining performance while advancing sustainable manufacturing practices.

Rotary draw bending (RDB) is widely used for the production of tubular components in sectors such as automotive, aerospace, and construction. The process is affected by several quality issues, including springback, wrinkling, and cross-section ovalization. Among these, tube slippage at the clamp-tube interface is particularly critical, as it alters the final geometry and damages the tube surface. Despite its industrial relevance, slippage remains largely unaddressed in terms of in-line monitoring and control. Its small displacement scale and occurrence within the clamping zone make detection particularly challenging. This work presents a novel in-process measurement and feedback approach for tube slippage, based on compact VCSEL (Vertical-Cavity Surface-Emitting Laser) optical sensors integrated directly into the clamping dies. The system enables real-time detection of relative axial displacement at the tool-workpiece interface with high resolution and supports closed-loop correction of clamping and bending parameters. A signal processing and estimation framework is developed to quantify slippage from the sensor data, which is then used to drive a correction strategy without interrupting the production cycle. Experimental validation confirms the proposed approach effectiveness in detecting and compensating slippage, demonstrating its potential for integration into modern intelligent forming machines. Thanks to the integrated sensing and control scheme, slippage events as small as 0.1 mm are detected and compensated without disrupting the bending sequence.

PEEK is a high-performance polymer widely used for biomedical applications, but its machinability remains a critical issue. Traditional coolants are unsuitable for biomedical use, and dry machining produces long, entangled chips that hinder surface quality. Cryogenic machining has been recently introduced for PEEK chip breaking. Textured tools can be exploited to modify the chip formation further. In this context, the study examines the effects of tool rake face texturing on chip formation in cryogenic and dry cutting conditions. Turning trials were conducted with plain and laser-textured tools with grooves of different geometry at varying depths of cut. The results indicate that cryogenic cooling promotes chip breakage, with textured tools enhancing the fragmentation process. A correlation was observed between groove design and chip morphology, highlighting the potential of these solutions to improve machining efficiency.

Laser Based Powder Bed Fusion for Metal (PBF-LB/M) is an additive manufacturing (AM) technique capable of producing geometrically complex, high-performance components. Among the aluminium alloys suitable for PBF-LB/M yet underexplored, AlSi9Cu3(Fe) stands out for its high strength-to-weight ratio and corrosion resistance. While the overall characteristics of AlSi9Cu3(Fe) are firmly established for cast products, studies on its mechanical performance and corrosion behaviour after the PBF-LB/M process and subsequent heat treatments remain scarce, with finishing operations often overlooked. In this framework, the paper gives novel insights into the performance of AlSi9Cu3(Fe) fabricated through a process chain comprising PBF-LB/M, heat treatment, and final machining, showing the correlation of the alloy microstructural features and surface finish with the corrosion resistance. Besides the as-built (AB) condition, two different heat treatment conditions were proposed: direct ageing (T5), and solubilisation and ageing (T6). Microstructural analysis showed that, after T5, Si network remained intact, with minor Si precipitation. On the other hand, T6 fully homogenised the microstructure, dissolving the network and activating a massive precipitation of Si, Cu and Fe phases. Afterwards, turning tests were carried out at fixed cutting parameters, showing better surface results by increasing the treatment temperatures. Potentiodynamic polarisation tests on both machined and unmachined samples gave the corrosion potential and current density at varying initial microstructural conditions. The AB samples proved to have the highest corrosion resistance before and after machining, while the lowest was always offered by the T6 samples. An explanation of such behaviour was given based on a detailed microstructural analysis together with the evaluation of the surface quality.

Blanking at sub-zero temperatures using liquid nitrogen is presented as an innovative method for cutting non-oriented electrical steel (NOES) to reduce the plastic deformation required for separation and minimize microstructural changes that could impact the sheet's characteristics. Three process temperatures - room temperature, -50 degrees C, and -100 degrees C - were investigated, and the results were evaluated in terms of cut edge quality, microstructural features, and hardness evolution. The results demonstrated a significant reduction in the plastically deformed zone and hardness variation at the cut edge, accompanied by decreased microstructural misorientation, highlighting this method's potential to minimize the drawbacks of conventional blanking. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Magnesium alloy-based fiber metal laminates (FMLs) represent a novel composite type, increasingly recognized for their potential in high-performance engineering applications, particularly in the aerospace and automotive industries. A strong bonding interface is a key factor in improving the durability of these laminates; to achieve this, appropriate surface treatments of the magnesium alloy sheets need to be applied.The study aims to compare different metal surface treatments, specifically phosphating and sandblasting, to enhance the interfacial strength between the metal skins and the composite core of the fiber metal laminates. The morphology, composition, and surface energy of the differently treated metal surfaces were analyzed using scanning electron microscopy, chemical analysis, and measurements of wettability and roughness. Subsequently, the resistance of the interfacial strength was evaluated through lap shear tests under mode II loading conditions. After mechanical testing, the characteristics of the fractured surfaces were analyzed.Although the FML samples with phosphatized metal surfaces exhibit a less defective interface than those with sandblasted metal surfaces, they are characterized by a lower mechanical strength. This behavior is attributed to the premature peeling off of the phosphating layer from the magnesium alloy sheets. With the gained insights, further research avenues open up towards optimized interfaces for FML components.

An innovative approach in electrochemical polishing (ECP) has been developed to enhance surface quality and precision in post-processing additive manufacturing surfaces, with a particular focus on leveling adhered powders and mitigating surface waviness. This study introduces a novel 2D model for quantitatively simulating the material removal process of spherical powder residues and waviness on sintered surfaces, utilizing adaptive triangular meshing technology. The initial geometric profiles of surface defects were modeled using the ellipse equation for spherical powder particles and the sine function for surface waviness. Key profile control nodes were tracked to observe changes over time, with detailed analyses of electric field strength, current density, material removal thickness, and removal rate. Predictive modeling results indicate that the electric field direction remains parallel to the surface, and the current density is approximately 0.23A cm-2 after ECP, achieving a consistent material removal rate of 0.28 mu m min-1 during polishing. Surface roughness measurements, taken over a sampling length of 500 microns, showed a reduction from Ra 3.74 mu m to Ra 0.21 mu m, and the comparison of simulated and experimental surface profiles was presented with an error of only 0.04 mu m, demonstrating the method's efficacy in finishing both adhered powders and waviness. This study provides a new perspective to investigate the mechanism of ECP additive manufacturing parts. (c) 2025 The Authors. Published by ELSEVIER Ltd. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0)

Machining Nitinol (NiTi), one of the most exploited shape memory alloys in biomedical and aerospace fields, is challenging, with rapid cutting tool wear being a significant issue. This study evaluates how the anisotropy of martensitic NiTi, induced by laser powder bed fusion (LPBF), affects tool wear. NiTi samples were printed in two orientations, 0 degrees and 90 degrees, corresponding to vertical and horizontal directions relative to the building one. The printed samples were machined on a CNC lathe and flank wear was measured via SEM analysis. LPBF induced an anisotropic microstructure with different grain sizes, phase distributions, and mechanical properties, which, in turn, affected the material response to cutting. Tool wear analysis showed how the printing orientation influenced the interaction between the workpiece and tool, with the 0 degrees samples causing higher tool wear than the 90 degrees. This behavior was ascribed to the different morphology of the microstructure in the turned sections and a higher amount of austenitic phase characterizing the 0 degrees samples than the 90 degrees ones.