This bibliographic analysis explores the evolving landscape of additive manufacturing (AM) in the context of Industry 4.0 and the emerging paradigms of Industry 5.0. This research critically examines the key literature and scholarly works to clarify the evolution, challenges, and opportunities presented by integrating AM technologies with digital transformation and advanced industrial practices. The exploration begins by tracing the foundational concepts of Industry 4.0, emphasizing the role of cyber–physical systems, data analytics, and automation in reshaping manufacturing ecosystems. It then moves to the developments of Industry 5.0, focusing on human-centric approaches, collaborative robotics, and sustainable manufacturing strategies that extend beyond automation. The impact of AM technologies across various sectors, from aerospace and automotive industries to healthcare and consumer goods, is central to this analysis. This article synthesizes empirical studies, case analyses, and theoretical frameworks to discern the synergies, challenges, and prospects of integrating AM into Industry 4.0 and the evolving Industry 5.0. Through this bibliographic journey, readers gain insights into the transformative potential of AM as a catalyst for innovation, agility, and sustainability in the digital age. The findings underscore the need for interdisciplinary collaborations, policy frameworks, and technological advancements to harness AM’s full potential within Industry 4.0 and 5.0.

This study displays the effect of laser surface hardening parameters on the hardness profile (case depth) of a splined shaft made of AISI 4340 steel. The approach is mainly based on experimental tests wherein the hardness profile of laser hardened splines is acquired using micro-hardness measurements. These results are then evaluated with statistical analysis (ANOVA) to determine the principal effect and the contributions of each parameter in the laser hardening process. Using empirical correlations, the case depth of splined shaft at tip and root of spline’s teeth is also estimated and verified with measured data. The obtained results were then used to study the sensitivity of the measured case depths according to the evolution of laser process parameters and geometrical factors. The feasibility and efficiency of the proposed approach lead to a reliable statistical model in which the hardness profile of the spline is estimated with respect to its specific geometry.

This paper presents a new approach in laser welding of Al-5052 and heat Al-6061 aluminum alloys, which are challenging materials for a good laser welding quality. The process consists of applying very small size of 0.1 mm to provide a high density of power that aims at imposing a high amount of heat that is required for aluminum alloys; simultaneously the wobbling technique is implemented to reduce the risk of overheating in the welding area. Having relied on the capability of the wobbling technique to distribute the generated heat, welding results contained negligible thermal defects compared to the usual defects such as underfill, undercut, and root reinforcement. The resulted welding zones show a fully penetrated welding quality for both alloys with a smooth weld seam at the top and root surface. Analysis indicates a higher tensile strength of 190 MPa for Al-5052 corresponding to an 18% decrease from the base metal, while this reduction of mechanical strength in the welded zone for Al-6061 was about 27%. Also, the hardness profile of Al-5052 reveals a small reduction in the fusion zone in contrast to Al-6061, for which a high hardness decrease happens in the welded zone. This approach is more profitable for the cost-effectiveness of the process since the laser power is set at a low range as the high-power density is mainly related to the small size of the spot diameter.