ABSTRACT Ti-35Nb-7Zr-5Ta is a β-type titanium alloy that possesses wider scope as a future implant material due to its lower Young's modulus property. In this work, high-speed machining influence on tool wear during micro-drilling of Ti-35Nb-7Zr-5Ta alloy was carried out. Coated carbide drill 400 µm size was chosen for the investigation with 10 x 5 x 4 mm size Ti-35Nb-7Zr-5Ta specimen. Spindle speed of 20,000–55,000 rpm and feed rate of 0.0009–0.0075 x 10−3 μm/tooth are chosen as process parameters for the tool wear study. Taguchi L18 orthogonal array-based micro-drilling experiments were carried out under mixed-level operating conditions using a micromachining station. From the measured tool wear results, it is observed that the lower range (20,000–34,000 rpm) of spindle speed condition reduces flank wear considerably. A 8.955 µm flank wear was observed at 20,000 rpm with a feed rate 0.0075 x 10−3 μm/tooth. It is due to the reduction in chip load per tooth and reduced friction between the drill and Ti-35Nb-7Zr-5Ta specimen. Maximum flank wear of 67.06 µm resulted at 48,000 rpm with the feed rate of 0.001 x 10−3 μm/tooth due to excessive cutting force and incomplete chip evacuation problems. Tool bluntness and failure occurred at higher spindle speed conditions are evident for the formulated inference. Hence, for the micro-drilling of Ti-35Nb-7Zr-5Ta alloy, lower range of spindle speed of 20,000 rpm and their feed rate 0.0025–0.0075 x 10−3 μm/tooth are the optimum conditions that can minimize tool wear.

ABSTRACT Aluminum (Al) metallic mirrors are widely used across various manufacturing sectors, putting a premium on producing super-finished surfaces in a variety of geometries. Conventional techniques hinder nano-metric refinement because uncontrolled forces limit precision. This study presents a hybrid chemo-mechanical magnetorheological polishing (CMMRP) process employing microwave-sintered CIP – Al2O3 slurry to achieve consistent refinement of convex surfaces. Slurry media integrating shear-thickening fluids, carbonyl-iron particles (CIP’s) and Al2O3 undergo microwave processing. Experiments on Al-convex surfaces explored influences of composite magnetic abrasives (CMA’s) concentration, work-gap, feed rate, rotational speed. CMMRP experiments decreased roughness (R a ) from approximately 500–600 nm to 13.72 nm within defined cycles. Uniform removal achieved R a improvement exceeding 97%, while maintaining geometric integrity under 2.5 mm work-gap, 180 mm/min feed, 800 rpm tool speed and 25 vol% CMA concentration. Surface observations revealed a smooth Al topography without scratches, pits and abrasion marks, confirming stable material removal and controlled CMMRP interactions.

ABSTRACT Hard turning of AISI 52100 steel often exhibits a brittle white layer underneath the finished surface, which aggravates with an increase in flank wear. This study applies vibration assisted turning to hardened steel and achieves high surface integrity by reducing machining forces and tool wear. As hard turning involves significantly high forces, a special half wavelength-based horn and a sufficiently rigid Vibration Assisted Turning (VAT) setup were developed to provide ultrasonic vibrations to the tool in the cutting speed direction. During experiments with fresh tools, lower forces (15–20%) and a better surface finish (20–25%) were observed with VAT compared to continuous machining (CM). Chip morphology study showed that the primary serration thickness increased with cutting speed, which is evidence of a reduction in work-tool separation time during a single vibration cycle. During machining with slightly worn tools, a condition more conducive to white layer generation, VAT outperformed CM. Reduced main cutting force (10–25%) and a significantly improved surface finish (around 10–20% for low-medium speeds) with a thinner white layer (>40% for high speed) were observed in VAT samples compared to CM. VAT proved to be highly effective at enhancing process performance with both fresh and worn tools for hard turning application.

ABSTRACT Non-uniform residual stress in wire arc additive manufacturing (WAAM) induces deformation and reduces mechanical properties. This study established a multi-source high-energy acoustic beam (HEAB) propagation model and developed a liquid-solid coupled underwater control system. Residual stress was evaluated using self-developed critical refracted longitudinal wave equipment. Results indicate that HEAB significantly refines grain structure by disrupting columnar growth via acoustic streaming and cavitation. Implementing HEAB during WAAM effectively mitigates stress and deformation in aluminum alloy components. For shell components, the stress homogenization rate (SHR) reached 49.1%, and dimensional deviation decreased by 70% (average 0.068 mm). Furthermore, the underwater acoustic field control system reduced average stress in cabin components to 63.08 MPa, a 50% decrease compared to untreated samples. These findings demonstrate that HEAB-integrated WAAM enhances dimensional accuracy and structural integrity, facilitating the engineering application of additive manufacturing.

ABSTRACT As a productive rivet-free joining process, clinching forms mechanical interlocks but often suffers from limited process windows and poor interlock quality in aluminum alloys, compromising joint performance. This study proposes a laser-assisted clinching approach for 5182 aluminum alloy and compares three processing conditions: conventional clinching(C), laser-etched pre-processing clinching (LC), and laser-fusion post-treatment clinching(CL). Finite element modelling is used as a process-analysis tool to interpret deformation and interlock evolution, and tensile-shear testing is conducted to quantify the process outcome. Laser-etched pre-processing markedly improves joint performance, with average failure load and energy absorption increased by 101% and 247% relative to conventional clinching, whereas laser-fusion post-treatment provides improvements of 15.6% and 47% only within an appropriate thermal-input window. The dominant failure mode is neck fracture. Results show that pre-clinching interface texturing effectively enhances 5182 aluminum interlocks, while post-fusion requires precise thermal management to avoid adverse effects.

ABSTRACT This study examines the influence of ultrasonic-assisted turning (UAT) on the surface finish of hardened Mo40 steel under various cutting speeds, feed rates, and ultrasonic excitation voltages (Vg) at 21 kHz. Compared to conventional turning (CT), UAT improves surface quality most effectively at lower cutting speeds and higher ultrasonic amplitudes. Increasing Vg enhances vibration-induced surface micro-disruptions, producing finer textures and reduced roughness. These benefits are maximized at low-to-moderate cutting speeds and feed rates. Above a critical cutting speed, UAT efficiency declines due to continuous tool contact, causing a slight roughness increase. Optimization identifies an ideal combination of feedrate (0.07 mm/rev), ultrasonic voltage (130 V), and cuttingspeed (27 m/min) for minimal surface roughness. Findings highlight ultrasonic excitation voltages (vibration amplitude) as a key factor in achieving superior surface finish and demonstrate UAT’s potential to enhance machining of hardened steels, offering improved precision and component longevity for industrial applications.

ABSTRACT Conventional cladding involves depositing a protective layer onto a substrate, whereas reverse cladding entails applying the substrate material onto a surface-treated insert. The thermal energy generated during substrate fabrication promotes metallurgical bonding through interdiffusion. In this study, the die-casting technique was employed to integrate austenitic stainless-steel sheet inserts with hypo-eutectic aluminum–silicon alloys, focusing on the effect of insert size on the reverse cladding process. Inserts measuring 80 mm × 30 mm × 1 mm exhibited significant distortion due to shrinkage cavities at the casting base, caused by elevated thermal resistance. Inserts of 80 mm × 30 mm × 2 mm showed reduced distortion as a result of improved undercooling, while inserts of 79 mm × 30 mm × 2 mm and 78 mm × 30 mm × 2 mm demonstrated minimal distortion owing to decreased thermal resistance due to filling of aluminum into the gaps between die and insert. The findings reveal that thinner, longer inserts tend to deform due to higher thermal resistance, whereas thicker, shorter inserts enhance heat conduction and dimensional stability. This study provides a practical framework for selecting optimal insert dimensions to achieve defect-free metallurgical bonding during reverse cladding through die casting.

ABSTRACT This review provides a comprehensive analysis of Digital Twin – enabled Model Predictive Control (DT – MPC) in Additive Manufacturing (AM), highlighting its potential to enable predictive, adaptive, and sustainable production. Digital twins – constructed using finite element models, data-driven surrogates, and hybrid physics-informed neural networks – offer dynamic, real-time process representation, while MPC provides optimal control under complex, multi-physics constraints. Comparative studies from 2015–2025 reveal significant advances in melt-pool stability, defect mitigation, and energy efficiency, though industrial adoption remains constrained by computational cost, synchronization lag, and limited interpretability. The proposed research roadmap identifies short-term goals in real-time scalability, mid-term objectives in uncertainty management and explainable AI, and long-term priorities in lifecycle-aware, eco-efficient manufacturing. Bridging these challenges requires standardized digital frameworks and interdisciplinary collaboration. DT – MPC emerges as a cornerstone of Industry 5.0—transforming AM into an intelligent, self-adaptive, and sustainable manufacturing paradigm.

ABSTRACT Composite materials have significantly influenced human history by offering superior properties over traditional materials like steel and aluminum. Their high strength, rigidity, lightweight, corrosion resistance, and design flexibility have led to their widespread use across various industries, including aerospace, automotive, construction, and biomedical. Glass Fiber Reinforced Polymer (GFRP) composites, in particular, are known for their excellent mechanical properties and performance. However, the unique properties of GFRP composites, such as anisotropy and heterogeneity, present challenges in machining, often resulting in defects like fiber rupture and delamination when using traditional techniques. To address these issues, unconventional and hybridized machining methods are explored. This study investigates the machinability of GFRP composites using a Laser-Assisted Micro Electrochemical Discharge Machining (LA-µ-ECDM) system. The experimental setup, involving a custom-built LA-µ-ECDM system, utilizes a combination of electrochemical and laser heating techniques to enhance machining performance. Key process parameters, such as voltage, electrolyte concentration, and duty factor, are optimized using a response surface methodology (RSM) and a multi-objective JAYA algorithm. The results demonstrate that LA-µ-ECDM significantly improves material removal rates and reduces overcut compared to conventional µ-ECDM, providing a promising approach for machining GFRP composites with high precision and minimal defects.