Industrial manufacturing increasingly requires reliable and repeatable dimensional and geometric inspection of small metal components, while minimizing inspection time, operational cost, and operator dependency. Conventional manual inspection based on mechanical fixtures remains widely used but is limited by operator variability, reduced flexibility, and poor scalability in high-mix production environments. This work presents a preliminary proof-of-concept for an automated dimensional and geometric inspection system based on a collaborative SCARA robot, whose primary role is to ensure repeatable positioning, handling, and automation of the inspection process. At this stage, the industrial problem is intentionally simplified to a representative squared tubular metal plate, preserving key length and width requirements while postponing full three-dimensional profile verification to later development phases. This incremental strategy reduces technical risk while enabling early validation of referencing, repeatability, and automated cycle execution. Rather than committing to a single measurement technology, the proposed system architecture remains measurement-agnostic, allowing the integration of different inspection approaches, such as vision-based methods, dedicated mechanical gauges, contact or non-contact sensors, and instrumented fixtures. In this context, the robot enables the automated manipulation and placement of parts into predefined inspection setups, replacing manual handling while preserving measurement reliability. A structured analysis of functional and operational requirements is used to justify this flexible architecture and to highlight its potential economic and operational benefits. Virtual validation is carried out using MATLAB-based simulation tools, namely Simulink 3D Animation and Simscape Multibody, to assess system layout, robot motion, accessibility, and cycle execution prior to physical integration. The results demonstrate the feasibility of the proposed concept and support a phased roadmap towards more advanced geometric inspection capabilities in subsequent development stages.

Fused Filament Fabrication (FFF) is without a doubt the most widely adopted additive manufacturing method for polymer components. As in every additive manufacturing process, the mechanical performance of manufactured components is a result of process parameters and design considerations. These include the infill pattern and parameters, the build orientation, and the temperature and layer height, amongst others, and all play a significant role in the flexural, tensile and compression properties of components. The present study aims to uncover the underlying mechanisms behind the performance of FFF-manufactured components using a combination of analytical and experimental methods to understand the developed stresses on components and the failure mechanisms of said components.

The performance of additively manufactured components was evaluated using a standardised 3-point bending setup both in the numerical and experimental domains. Three-point bending tests were conducted in accordance with relevant standards to evaluate flexural strength and stiffness. Standardised test specimens from polylactic acid (PLA) were deposited with varying infill patterns and build orientations whilst keeping all other parameters stable. The results of the experimental campaign were combined with analytical modelling (based on classical beam theory) and finite element modelling to achieve an all-round view of the performance of components.

We investigated the possibility of developing super austenitic stainless steel Avecta SMO 254 X1NiCrMoCuN20-18-7 (EN 10088-4) and austenitic stainless steel X15CrNiSi25-21 (EN 10095) coated with SiC, resulting in the obtainment of a Metal Matrix Composite (MMC) by Additive Manufacturing (AM) for the upgrade of nozzles for sulphur recovery thermal reactors. One layer of the MMC targets the outer surface of the part that is in constant contact with the flame and the area is subjected to high friction erosion. The Directed Energy Deposition Laser (DED-LB) method has made it possible to produce a high strength-to-weight ratio. The aim is to engage lower-cost material with similar thermal stability and durability in extreme conditions. The robotic unit used for the application allowed for the computer control of the positioning, feeding of the SiC particles inside the shielding gas and deposition in the melted pool. After the solidification process, visual testing (VT) and ultrasonic testing (UT) were applied for the non-destructive evaluation, checking for disbonding and subsurface imperfections. Then, samples were tested with microhardness measurements, bond strength, microcracking detection, porosity, interface zone assessments and microstructural analysis. The process achieved 0.4 to 0.7 KJ/mm heat input with no defects and the intended nozzle surface passed UT and VT. Controlled parameters provided strong metallurgical bonding.

Funding: The author acknowledges support from project BG16RFPR002-1.014-0005.

In recent decades, numerical methods have become indispensable tools in solving complex problems in science and engineering, where the finite element method (FEM) is widely recognized as an effective computational approach. However, the traditional FEM often encounters significant limitations in modeling discontinuities such as cracks, holes, or material interfaces, especially when dealing with functionally graded materials (FGMs). To overcome these challenges, this study introduces an advanced framework that integrates the Extended Finite Element Method (XFEM) with the Isogeometric Analysis (XIGA) approach to simulate the stress concentration factors (SCFs) around circular holes in isotropic and FGM plates. The methodology employs the level-set method to represent discontinuous boundaries and incorporates enrichment functions into the displacement field, enabling accurate modeling of stress concentrations without remeshing. MATLAB codes were developed to implement this integration, offering a flexible computational platform for practical applications. The performance of the proposed method was evaluated through several benchmark problems, including isotropic plates with circular holes near material boundaries and FGMs subjected to uniaxial loading. The results obtained by means of XFEM–XIGA were compared against analytical solutions, standard FEM, and available experimental data. For isotropic plates, the XFEM–XIGA model achieved a stress concentration error of 1.71%. For FGM plates with cracks or circular holes, the error of XFEM–XIGA was 2.55% when compared with exact solutions. These findings highlight the robustness and accuracy of the integrated method in handling complex geometries and heterogeneous material properties. Overall, this study demonstrates that the combination of XFEM and XIGA provides an efficient and reliable tool for analyzing SCFs in FGM structures, paving the way for improved modeling of industrial components where stress concentrations at material boundaries are critical to structural performance.

Introduction. Vibratory technological equipment is widely employed for conveying, screening, compaction, and surface-treatment operations, where drivetrain sizing is dictated by peak power and torque and their pulsations. Prior studies predominantly report dynamics of individual vibration exciters and frequently rely on mean-power or linearized harmonic estimates, which prevents a like-for-like comparison of drive power demand across exciter architectures under identical vibration output and process loading. This study addresses these gaps by introducing a unified comparative framework for planetary, differential, double crank–slider, and cam-type exciters.

Methods. A unified kinematic-dynamic model was formulated in generalized coordinates for each vibratory system. Instantaneous drive torque was obtained from the balance of inertial forces, suspension elastic–damping reactions, and technological resistance forces mapped through mechanism-specific transmission ratios. Instantaneous mechanical power demand was evaluated as P(t) = M(t)·ω(t). To enable a fair comparison, all mechanisms were assessed over a common operating set (target vibration amplitude and frequency, payload mass, and technological resistance characteristics). Evaluation metrics included mean and peak power demand, peak torque, and power pulsation index (peak-to-mean ratio), supplemented by decomposition of inertia-driven versus process-driven contributions.

Results. The framework produces power demand maps that reveal pronounced mechanism-dependent power pulsations that would be underestimated by average power methods. For the same vibration output, planetary and differential exciters exhibit lower peak power demand and reduced torque ripple, whereas cam and double crank–slider exciters show higher peaks and pulsation indices due to more non-sinusoidal motion. Mean power demand is primarily governed by payload and technological resistance, while kinematic nonlinearity largely determines peaks and pulsations.

Conclusions. The proposed framework is novel in providing an objective, harmonized, multi-metric comparison of drive power demand across distinct exciter mechanisms, extending beyond conventional averaged and linearized assessments. It enables evidence-based exciter selection and drivetrain sizing to improve energy performance and durability of vibratory technological equipment.

Next-generation aerospace platforms require structural systems with exceptional strength-to-weight ratios and reduced part counts. Unlike the capabilities of traditional subtractive techniques, AM provides us with the geometrical complexity and material structure that we require to achieve these objectives. Current mechanical CAD practices are ill-equipped to fully exploit AM's potential. The main drawbacks, including thermal distortion or anisotropic behavior, are not a concern when working with innovative new materials, like titanium alloys or high-performance materials. As a result, the components are ultimatelytoo expensive and do not meet the requirements. This research aims to create a new combined CAD-based Design for Additive Manufacturing (DFAM) that directly links a component's functional requirements with the material behavior and machine settings so that we can create advanced aerospace structural systems. Topology optimization, as an initial step in the workflow, takes aerospace load cases as input, and then we make AM constraints, such as minimum feature size and optimal build orientation. We then run FEA and thermal–mechanical AM analyses to optimize the geometry, reduce residual stresses, and conduct distortion forecasting prior to fabrication. Ultimately, when the DFAM framework is used, the average mass of our demo parts decrease by 34-38 percent compared to the initial designs. On top of this, we incorporated these do-it-right mitigation defect-reduction tricks directly into the CAD models, which cut the distortion in the post-build step by 82%. The suggested CAD-DfAM approach combines the design, material behavior, and aerospace physics of the AM process, providing us with a sound and proven method of creating lighter, more accurate, and higher-quality aerospace structural systems.

The value of applying wire arc additive manufacturing (WAAM) to impellers, a key component of turbomachinery including pumps, has been variously discussed. WAAM is a metal additive manufacturing technology suitable for fabricating medium to large components by applying arc welding. Many of these studies are intended to fabricate components using only a single material. While welding wires for WAAM are commercially available in various materials, enabling the potential for multi-material components, research focused on industrial applications of multi-materialization has been limited. This study conducted experimental investigations aimed at extending the service life of a fan-type inducer. The inducer is an axial flow impeller attached to a centrifugal pump in order to improve pump suction performance. The service life of inducers is affected by cavitation erosion of the blades. Therefore, it is planned to use a multi-material blade combining Stellite 6, which is highly resistant to cavitation erosion, and SST 316L, a general purpose austenitic stainless steel. Two experiments were conducted. The aim of the first experiment was to evaluate mechanical properties using WAAM fabricated multi-material test specimens. The aim of the second experiment was the fabrication of an inducer with a multi-material blade using WAAM and machining. Experimental results of multi-material test specimens confirmed that the mechanical properties are suitable for industrial applications. The inductor was fabricated within industrial-grade dimensional tolerances. These results clarify that multi-material blades combining Stellite 6 and SST 316L are feasible using WAAM.

The metalworking industry plays a decisive role in the economy. Among the various metal-forming processes, sheet metal bending is essential due to its ability to produce bends with high precision and structural strength. However, the bending quality depends not only on the performance of the bending machine but also on the correct stabilisation of the sheet during the process. In this context, sheet followers are essential auxiliary equipment, designed to accompany the upward movement of the sheet. The main objective of this work was to develop a new sheet follower model, capable of replacing the equipment currently used in a given company. The aim was to design a robust and functional solution that would accurately follow the natural movement of the sheet metal during the bending operation, ensuring operator safety and material integrity. To this end, mechanical design concepts, CAD tools, and structural and kinematic dimensioning methodologies were integrated, as well as the careful selection of materials and manufacturing processes. In addition, the drive system was analysed, costs were estimated, and the proposed solution was compared with competing equipment on the market. This work also aimed to reinforce technical knowledge in the area of auxiliary tilting devices by identifying technological trends and proposing a viable and optimised solution. As a result, the developed bending monitor fully complies with the defined requirements and limitations and demonstrates high functionality and performance. The solution presented is economically more advantageous than the equipment currently in use, without compromising the reliability and accuracy of the process. Thus, all the established objectives were fully achieved, validating the proposal as an effective and competitive alternative for industrial application.

Bistable dome shell structures exhibit snap-through instabilities that enable rapid shape changes and mechanical switching behavior. These elements have been reported as key components in soft valves, oscillators, and grippers, where they provide energy-efficient actuation and the ability to maintain stable configurations without continuous power input. However, their design involves facing nonlinear mechanics and high sensitivity to geometric parameters such as shell thickness, curvature, and height–radius ratio. Traditional design approaches rely on computationally expensive parametric sweeps or trial-and-error experimentation. While differentiable simulation has been successfully applied to beam-based bistable structures, its application to dome shell geometries remains less established. Differentiable simulations allow computing gradients of design objectives with respect to geometric and material parameters, enabling gradient-based optimization that can significantly accelerate the design process. In this research, an axisymmetric dome shell model under quasi-static loading conditions is used to study the existence of bistability, snap-through threshold, and force–displacement response using differentiable simulations. Key geometric parameters governing bistable behavior are identified, and their influence on snap-through characteristics is analyzed through gradient information. The results are validated against conventional finite element approaches to assess numerical accuracy and gradient reliability. The expected outcome is a set of guidelines on when differentiable simulation provides reliable gradients for bistable dome shell design, and what modeling choices are necessary to handle snap-through behavior in a stable and reproducible manner.

Accurate measurement of electrical resistance is a critical requirement in the characterization of piezoresistive polymer composites, particularly when resistance variations induced by mechanical deformation are small relative to the nominal resistance value. This challenge is especially relevant for conductive polymers produced by additive manufacturing (AM), where contact resistance, material anisotropy, and process-induced variability can significantly affect measurement reliability. This paper presents a methodological review and benchmarking of electrical resistance measurement techniques applicable to piezoresistive 3D-printed polymer composites. Classical approaches, including two- and four-point measurements, Wheatstone bridge configurations, and Kelvin-based techniques, are reviewed and compared in terms of accuracy, sensitivity, robustness to parasitic resistances, and experimental complexity. Beyond conventional methods, the paper discusses the potential of recent and emerging measurement strategies, such as advanced bridge configurations, digitally assisted techniques, and hybrid analog–digital approaches enabled by modern data acquisition systems and embedded electronics. Although not exhaustively implemented, these approaches are considered to frame current trends and future directions in high-resolution resistance measurement for self-sensing materials. Analytical formulations and circuit-level models are employed to describe the operating principles of the reviewed methods, supported by simplified electrical simulations using accessible electronic circuit simulators. In parallel, a concise overview of commercially available measurement hardware—including precision source–measure units, data acquisition systems, and instrumentation amplifiers—is provided to contextualize practical implementation choices. The comparative analysis indicates that the four-point measurement method constitutes a robust and practically viable reference approach for detecting small resistance variations in conductive AM polymers within typical laboratory constraints. Rather than establishing a definitive hierarchy among techniques, this work positions the four-point method as a justified baseline for comparison. Overall, the proposed benchmark combines theory, simulation, and hardware considerations, offering practical guidance for experimental design while leaving scope for future investigation of emerging measurement techniques and recent developments in resistance sensing for self-sensing AM materials.