Achieving CO2-neutral transportation requires large-scale electric vehicle production, posing significant manufacturing challenges. Electric vehicles consist of components with multi-physical functionalities and intricate interdependencies that exceed the capabilities of current production systems. This paper examines key drivetrain components, including power supply systems, batteries, power electronics, and traction motors. It reviews state-of-the-art manufacturing and associated challenges. Analytical and numerical modeling approaches as well as product-specific trends are highlighted. Furthermore, the paper puts emphasis on life cycle assessment (LCA) and life cycle engineering (LCE), as electric drivetrains pose distinct challenges compared to conventional drivetrains. Lastly, future research demands for electric mobility production technology and component-specific research fields are outlined. (c) 2025 The Authors. Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Additive manufacturing has advanced rapidly since its origins in the 1980s. While some processes are now commercially viable, others remain experimental. A key ambition has been to combine multiple materials in a single part, enabling novel properties and overcoming traditional limitations of fabrication and assembly. Multi-material additive manufacturing offers a potential step change across industries, though scaling from lab to industry remains a challenge. This work explores the enabling technologies and science behind metal multi-material additive manufacturing and proposes how the research community can advance these innovations for meaningful industrial impact. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Workpiece clamping systems (WPCS) constitute core elements of machining systems. As part of the force flow and accuracy path, WPCS influence the performance and efficiency of the manufacturing processes. By functional integration, enhanced capability can be introduced to the machining system. Monitoring, active adjustment and process control can be achieved. The layout, design and optimisation of WPCS should be an integrated element in process planning. For this, computer aided support systems are available. Modelling of WPCS enables virtual analyses of process-workpiece-fixture interaction and makes optimisation possible. This paper gives an overview of the technology of WPCS and introduces future perspectives. (c) 2025 The Authors. Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Traditional production scheduling and control are increasingly inadequate in light of the rapid evolution of manufacturing technology, the growing impact of unforeseen disruptions, and the generally increasing complexity of production. A framework for future-proof production scheduling and control is introduced to close this gap, providing a comprehensive overview of future requirements and the necessary technologies and approaches. Robust decision criteria are derived, explained and filled with major recent advances in production scheduling and control, digital twins, artificial intelligence, and knowledge formalisation. Emerging trends are discussed, and an outlook for future research and decision-making is derived. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Gears are subject of increasing accuracy requirements. The measuring processes are usually traced back to calibrated gear standards. Differences between the calibration process and serial inspections led to enhanced measurement uncertainty, especially for gear standards with intentionally modified flanks. This article analyses the dimension-over-balls parameter (MdK) on cylindrical gear standards with modifications. MdK-values, calculated from measured pitch points, show significant deviations from calibration values. A mathematical solution is presented that interprets flank angle modifications as changes of the standard's basic geometry. Experiments showed that this approach offers improved MdK-evaluations, even if the pitch probing points differ from the contact points of MdK-probing balls. (c) 2025 CIRP. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Robotic milling systems are increasingly used for light alloys and composites, but face challenges due to high dynamic flexibility of robots. A key issue is low-frequency chatter, linked to the robot's structural modes during high-speed operations. Therefore, this study deals with a dominant flexible mode with high tooth-passing frequencies, highlighting the influence of the directional factor. Negative directional factors can cause lowfrequency chatter at high spindle speeds. Polar stability lobes show that optimal feed direction and radial engagement zones align with positive directional factors. The study shows that slotting operations assure a chatter free machining. Experimental validation confirms theoretical findings. (c) 2025 Published by Elsevier Ltd on behalf of CIRP.
Action to cut emissions is likely to reduce production of the bulk metals. However, up to 80% of steel and 90 % of aluminium made today are wasted in three forms of scrap: manufacturing scrap cut off in the supply chain, specification scrap from over-design and property scrap in which materials are under exploited. Innovations in product design and forming technology can reduce this scrap, but only if delivered in high-throughput processes, to overcome trade-offs with the economies of scale. The priority for innovation is to adapt tooling and controls in existing forming processes, not to attempt to replace them. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Complex surfaces are increasingly used in optics, biomedical devices, and aerospace industries. Additive manufacturing and five-axis milling can produce complex shapes, but additional finishing processes are needed to meet the surface quality demands. This keynote paper reviews shape-adaptive finishing processes that enable uniform surface quality improvement without altering the shape. Key factors affecting shape adaptability, processing efficiency, and material applicability are analyzed and optimal process selection strategies for finishing complex surfaces are discussed. Future possibilities and research topics in this area, including process modeling/simulation, digital twin, surface/subsurface metrology, functionality evaluation, and applications of advanced robotics and artificial intelligence, are outlined. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
The mainstream of diagnostic approaches of printed circuit board assemblies is optimised for large-scale industrial production, and is less suited for repair and maintenance during later stages of the product life-cycle. Main challenges include sparse documentation, small batch sizes and high product diversity, to which existing solutions are too costly, bulky or parameter-sensitive for industrial use. The paper presents a novel approach using computer vision, visual servoing and digital twins for robotic positioning of a measuring probe head. Subject to patent application, the method has proven its feasibility and affordability in live industrial practice with 99.80% success rate. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
The term "machinability", introduced over hundred years ago, is vague and cannot fully describe the performance of machining systems. Machinability databases established over many decades are outdated: missing recent advances, e.g., cutting tool grades, geometry, coatings, and cutting fluids effects. This keynote paper summarizes findings of a CIRP-sponsored three-year collaborative study in five interrelated topics. The paper presents a critical review of the state-of-the-art on these topics, the results of two major round robin tests, three industry-based case studies, and a novel predictive system of machining performance, utilizing advanced deep learning methods. Outlook and future directions are also presented. (c) 2025 CIRP. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
This paper presents a new trajectory generation algorithm that consists of a cascaded Finite Impulse Response (FIR) and a half-sine filter. FIR filter is used to set the acceleration, and the half-sine wave generates continuous velocity-acceleration and jerk motions along the tool path while avoiding the excitation of the machine vibrations. The algorithm allows for control of cornering errors between the discontinuous path segments. The algorithm is experimentally validated to damp the vibrations of a cantilevered beam, a mode of an industrial machine's ball screw drive, and a tool path with sharp curvatures on a two-axis machine. Crown Copyright (c) 2025 Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
The demand for higher precision and efficiency in the ultrashort pulse laser processing of diamonds is growing as the industrial applications of diamonds expand. However, surface modification layers generated during laser irradiation negatively impact processing efficiency and remain difficult to actively control. This study improves processing efficiency by proposing and validating a two-step method that removes the surface modification layer after each pulse. Removing the modified layer increases the material removal volume and provides new insights into the impact of the modified layer on processing outcomes, laying the groundwork for future advancements in the ultrashort pulse laser processing of diamonds. (c) 2025 Published by Elsevier Ltd on behalf of CIRP.
This study presents the design of a novel rotary PBF-LB/M machine where the recoater and gas system rotate synchronously with laser exposure. Unlike previous setups, the rotating nozzle covers only part of the powder bed, enabling higher localized gas velocities. CFD simulations indicate that a fine-mesh square grid improves flow uniformity with minimal powder disturbance. An angled recoater design supports stable rotary powder deposition. Trial builds, in-process measurements, and analyses of timing and powder efficiency demonstrate the system's effectiveness for annular parts, offering a significant speed advantage over rectilinear designs. (c) 2025 The Authors. Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Cycle time is critical in robotic cells where material handling often presents a bottleneck and in turn depends on the cell layout. Optimizing robot cell layouts is therefore essential for improving cycle time. We show that the proxy objectives used for this optimization are poor approximations of the real cycle time and introduce a optimizer that directly measures the duration of the time-optimal robot trajectory. We show that it can offer competitive performance even faster than proxy-based optimization. We validate this performance on multiple problems and show how to integrate it into the cell design process of a manufacturing cell. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
X-ray computed tomography (XCT) is developing into a dimensional metrology tool. However, its quality control remains challenging due to the unknown correlation between radiographic image quality and surface measurement quality. This paper investigates this correlation by comparing the modulation transfer function (MTF) of radiographic image with the surface amplitude transfer function (SATF). Results indicate that the limit of measurable surface scale can be predicted by MTF10%. While the shape of the filtering effect on XCT measured surface can be predicted from MTF, the measurement error from this effect cannot be predicted due to the influence of surface determination. (c) 2025 The Authors. Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Preloaded ball screw drives are widely used in high-precision linear motion applications, particularly in machine tool feed drives. To compensate for the loss of preload due to wear over the service life and to maintain typical operational characteristics such as zero backlash and high rigidity, ball screws are usually preloaded to high values. However, this results in increased wear and friction, with a consequent increase in temperature. To address these issues, this paper introduces a novel double nut design for ball screws, featuring a passive preload adjustment mechanism, enabling reduced preload levels while enhancing operating characteristics and operational service life. (c) 2025 Published by Elsevier Ltd on behalf of CIRP.
Lightweight machine tool components provide the potential of improved system dynamics and reduced energy consumption. In this research, pre-stressed fiber-reinforced polymer concrete (PFRPC) structures were investigated, focusing on lightweight design and functional integration. An integrated strain measurement functionality was realized by embedding Fiber Bragg Gratings (FBG). Two versions of machine tool cantilever arms in the form of a Stewart platform were built using remaining plastic molds. The mechanical properties and operational characteristics were analyzed and compared with those of a conventional steel structure showing the high potential of the hybrid material with regard to the improved system dynamics. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
This work optimises and analyses the processing of a new lean tool steel (Osprey (R) HWTS 50), using laser powder bed fusion (PBF-LB) at 80 degrees C preheating and different layer thicknesses (20 mu m vs. 40 mu m). Full density is reached via a higher volumetric energy density (VED) for the lower layer thickness. After optimising contours, reducing surface roughness and ensuring no microcrack formation, the tensile properties are rather comparable in both cases (UTS >> 1500 MPa, elongation >> 10-12%). However, yield strength, hardness and residual stresses are slightly higher for the lower layer thickness. The geometrical freedom for intricate features is nevertheless comparable. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Unique clamping mechanism adopted in double-sided polishing (DSP) enables free rotation of workpieces, which is critical for achieving uniform material removal. However, the DSP process has long faced the issue of non-rotating workpieces, resulting in tapered shapes-an issue particularly relevant to silicon wafer polishing. In this study, a kinetic analysis is conducted to investigate workpiece rotation during DSP and to clarify the mechanism underlying tapering. This analysis identifies key variables governing rotational speed and primary factors contributing to workpiece nonrotation. These findings are validated experimentally, and a practical approach to preventing tapering is proposed. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Scaffolds play a key role in bone repair and should have a degradation rate that matches the rate of bone regeneration. However, the slow degradation of bone tissue scaffolds is a major challenge. This research investigated the degradation rate of Polyethylene terephthalate glycol (PETG) bone-tissue scaffolds printed with different lay-up patterns (0/45, 0/60/120, and 0/90). Degradation kinetics were explored using design-informed processing conditions, considering variations in the printing path length, crystallinity and fibre contact points. The findings revealed that changing scaffold lay-up increased the degradation rate by up to 50 % while maintaining compressive modulus. The research contributes a new and novel material-independent approach for controlling scaffolds degradation rate and mechanical performance. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of CIRP. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
