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Optimising the mechanical properties required for biomedical applications is something that porous Ti-6Al-4V structures offer the opportunity to do. Triply periodic minimal surface (TPMS) structures, such as the Diamond and Gyroid structures, provide interconnected pores that can be used to adjust strength, stiffness and deformation. The mechanical behaviour of these two architectures under compressive and bending loads is compared in this study, with the use of additively manufactured samples. The results demonstrate that pore geometry significantly impacts mechanical behaviour. Diamond structures exhibit higher stiffness and strength, whereas Gyroid structures provide a more isotropic and flexible response. These findings emphasise the importance of architecture when designing implants and other components for which optimised mechanical properties and geometry are essential.

This study examines the influence of FDM printing parameters on replica parts for an educational robotics kit, targeting functional compatibility without post-processing. A VEX Robotics 2×12 Beam (228‑2500‑026) was used as the reference part. Reference dimensions were obtained as mean values from 10 original VEX IQ parts. Replicas were printed from PLA and PETG on Original Prusa MK4 printers using four infill patterns and six infill densities (15–70%). For each material–pattern–density combination, 10 parts were produced, resulting in 480 printed samples. Width, length, and height were measured with a Mitutoyo MiSTAR 555 CNC CMM in accordance with ISO 10360-2. Results are expressed as mean deviations from reference dimensions, standard deviations, and expanded uncertainty of the mean. Maximum deviations reached 0.062, 0.092, and 0.032 mm for PLA, and 0.046, 0.090, and 0.028 mm for PETG. The results provide guidance for selecting non-solid infill settings that reduce material use and printing time while maintaining dimensional compatibility

To address cracking and deformation in large-size ceramic slabs during firing induced by thermo-structural coupling, this study established an indirect thermo-structural coupling finite element model in Ansys to analyze an 820 mm×100 mm×6.32 mm slab. The evolution of temperature field, stress field, and deformation was investigated across four firing stages. Results indicate that the rapid cooling stage, with a high convective heat transfer coefficient, forms the cycle’s maximum thermal gradient, showing the most asymmetric temperature field of mid-plane high, surfaces low and a ~17°C surface-mid-plane temperature difference. The stress field follows a low-high-declining-stable trend, peaking in rapid cooling of 23 MPa maximum equivalent stress in the thickness section and 11 MPa maximum principal stress at the glaze-body interface. Thermal gradient, glaze-body CTE mismatch, and boundary constraints respectively drive stress generation, interface concentration, and asymmetric distribution. Deformation obeys length > width > thickness in rapid cooling, lengthwise deformation is 8.2 times the width. Thickness-direction drum-shaped deformation stems from glaze-body CTE mismatch. This study reveals the firing thermo-structural coupling mechanism, providing theoretical support for optimizing firing processes and glaze-body formulations, with significant engineering value for reducing cracking and improving dimensional stability.

This article deals with the experimental investigation of the influence of tire pressure on fuel consumption and tire life in passenger cars. Using laboratory and real-world operational measurements, the dependence between tire pressure and temperature, contact patch size, tread wear, and changes in driving characteristics was analyzed. The results show that even slight deviations from the prescribed pressure can lead to increased fuel consumption, shortened tire life, and reduced driving comfort and safety. The article also draws attention to the insufficient use of pressure monitoring systems in practice and points to the economic and ecological impacts of underinflation. The experimental data are supplemented with graphs and tables that demonstrate the influence of pressure on tire behavior during driving.

An agricultural tractor equipped with appropriately rated guards can often replace specialized forestry machinery. Currently, few authorized dealers on the Polish market offer tractors adapted to harsh forest conditions, so this work involved designing a tubular guard for the Kubota M135GX-VI agricul-tural tractor. The aim of this work was to develop a conceptual design for a tubular guard, together with a strength analysis based on FOPS procedures, dedicated to the KUBOTA M135GX-IV agricul-tural tractor. To properly design the tubular guard, applicable standards and regulations regarding the construction of cabs and tubular guards for agricultural and forestry machinery were first analyzed. Subsequently, the available solutions were analyzed and two original concepts were developed. These concepts were evaluated based on the adopted criteria, selecting the variant with the highest score. Furthermore, the most advantageous variant was subjected to a strength analysis using the finite el-ement method (FEM) in accordance with the FOPS procedure. The test results showed that all nodes included in the developed concept met the strength requirements.

To achieve precise finite element simulation of the vibration-assisted cold heading process of titanium alloys, this study focuses on Ti-45Nb titanium alloy as the research object. A constitutive model for vibration-assisted cold heading is established, incorporating both viscoelastic and viscoplastic deformation. The model is transformed into a programmable incremental form, and the control equations for elastic-viscoplastic deformation are derived. Secondary development is conducted using the VUMAT interface of ABAQUS, and the model is applied in simulation. Multi-condition simulations of Ti-45Nb titanium alloy cold heading are performed, and the results are compared with experimental data. The average relative error is found to be within 5%, verifying the accuracy of the finite element numerical simulation based on the secondary development. The developed constitutive model is used to simulate the cold heading process of Ti-45Nb titanium alloy internal wire joint components. The significant effects of vibration assistance in reducing maximum stress, optimizing stress distribution, and improving material flow are intuitively observed. This study provides technical support for the application of vibration-assisted cold heading technology in the forming of difficult-to-deform materials.

The use of supercritical water in energy applications is motivated by the aim of increasing the thermal efficiency of power systems. However, structural materials exposed to this environment may undergo corrosive degradation. The objective of this study was to conduct experiments on samples exposed to simulated operational conditions in supercritical water, steam, and air. The material surfaces were sub-sequently analyzed using optical microscopy and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS). Particular attention was given to the formation of oxide layers on the nickel-based alloy Inconel 718 produced by additive manufacturing by PBF-SLM technology. The corrosion behavior was evaluated by monitoring mass gains. The results were compared with materials manufactured using conventional techniques.

This study examines the effect of accelerated weathering on the mechanical and viscoelastic properties of thermoplastics produced by fused filament fabrication (FFF). Three polymers, acrylonitrile styrene acrylate (ASA), polyethylene terephthalate glycol (PETG), and polylactic acid (PLA), were subjected to alternating UV radiation and condensation cycles in a QUV chamber simulating environmental exposure. Tensile testing and dynamic mechanical analysis (DMA) were used to evaluate the changes in strength, stiffness, and glass-transition behavior. The results revealed distinct responses depending on the polymer structure. ASA maintained its ductility and even showed improved strength, confirming high UV resistance. PETG exhibited a moderate decrease in strength with negligible change in elongation, indicating partial photo-oxidation but stable viscoelastic behavior. PLA demonstrated the most significant stiffening and a noticeable upward shift of the glass-transition temperature due to crystallization and physical aging. Overall, short-term QUV exposure acted as a conditioning process, enhancing the thermal and structural stability of the tested FFF-printed polymers.

The fatigue assessment of a Class 300 valve body with a bore diameter of 450 mm under vari-ous pressures is discussed using Section VIII, Division 2 of the ASME BPVC. Finite element analysis (FEA) results are compared to fatigue test results, and correlations are obtained. The material used for the valve is A216 WCB, which is widely used for making API ball valves. Elastic stress analysis was used to study the influence of various parameters on the results. This method is widely accepted and is used for static components. The body and flange de-signs were performed in accordance with ASME and API standards. Various pressure loads were applied to the inner surface of the valve body, ranging from 4 MPa to 6 MPa. The defor-mation, equivalent stress and stress intensity over the critical areas were analyzed using AN-SYS Workbench. As the pressure increases, the maximum compressive stress over the valve body surface also increases. However, the design of the valve for a pressure of 5.1 MPa (for a Class 300 valve) remained within the safe limit. Increasing the pressure beyond 5.1 MPa also indicates a safe design; the valve can withstand pressure up to 6 MPa (beyond the design pres-sure).

A single-stage evaporator with natural circulation was used to densify the plasticizing bath through continuous evaporation and to prepare a solution used in the production of viscose fiber. During the process, sodium calcium sulfate salts were formed, leading to fouling of the heat transfer surfaces in the heat exchangers. This fouling created a layer of deposits that gradually reduced the efficiency of the evaporation process in the evaporator. It was determined that a processing medium with a volumetric flow rate of 6 m³·h⁻¹ required a heat exchanger power of 1448 kW. A fouling layer with a thickness of 0.1 mm reduced the heat exchanger's performance by approximately 40%. When the fouling layer increased to 0.5 mm, the heat exchanger power decreased by nearly 74%, down to 889 kW. The purpose of this paper was to analyze the process parameters of the densification technology in order to identify potential optimisations that could increase equipment availability and reliability. Alternatively, the study aimed to provide recommendations for design modifications to the existing technology.

Wire + Arc Additive Manufacturing (WAAM) based on Gas Metal Arc Welding (GMAW) has emerged as a cost-effective and high-deposition process for fabricating large-scale aluminum components. However, its application to non-heat-treatable aluminum 5083 remains limited by thermal-cycle in-stabilities, porosity, and non-uniform mechanical performance. This study presents an integrated experimental and artificial-intelligence framework for optimizing key GMAW parameters—welding current, wire-feed speed, and welding speed—to enhance the mechanical properties of WAAM-fabricated aluminum 5083 walls. An L9 Taguchi design was employed to quantify parameter effects, followed by analysis of variance (ANOVA) to identify dominant factors. Results indicated that weld-ing speed exerted the greatest influence on tensile strength (≈ 58.8 % contribution), whereas wire-feed speed and current primarily affected hardness through solidification behavior. An Artificial Neural Network (ANN) model was then developed to predict tensile strength and hardness with high accuracy (R > 0.99; MAPE < 1 %), demonstrating superior predictive performance over Taguchi and regression models. Integration of the trained ANN with a Genetic Algorithm (GA) enabled global optimization of process parameters, yielding an optimum set of 85.3 A current, 7.7 m/min wire-feed speed, and 3.8 mm/s welding speed, corresponding to predicted properties of 242.5 MPa tensile strength and 108.4 HV hardness. Experimental validation confirmed deviations below 1 %, verifying the model’s robustness. The proposed ANN–GA hybrid framework effectively captures nonlinear process–structure–property relationships, providing a reliable, data-driven pathway for achieving high-strength, defect-free aluminum components in WAAM and other additive manufacturing sys-tems.

This article is dedicated to exploring the potential enhancement of mechanical properties, such as hardness and tensile strength, in selected Al-Si alloys (AlSi7Mg0.3, AlSi7Cu4, and Al-Si10.5Cu1.2Mn0.8Ni1.2). High-melting-point elements, such as chromium and molybdenum, are rarely utilized as additives in Al-Si alloys. However, the article demonstrates the feasibility of improving the mechanical properties of these alloys through the addition of high-melting-point elements. High-melting-point metals, often referred to as refractory metals, typically have melting points above 2000 degrees Celsius. Common refractory metals include tungsten, molybdenum, tantalum, niobium, rhenium, and others. These metals exhibit excellent mechanical properties at elevated temperatures and often possess high density and good corrosion resistance. All casts were made using by gravity casting with different heat treatment conditions at 740 °C. The microstructures, hardness, microhard-ness and tensile strenght of the samples were analyzed. Hardness measurements were conducted using two types of hardness testers according to ČSN EN ISO 6506-1 for the Brinell hardness test method and ČSN EN ISO 6507-1 for the Vickers hardness test method. A static tensile test was performed on a universal testing machine, Inspekt 100, in accordance with the standard ČSN EN ISO 6892-1. The measured data demonstrated that high-melting-point metals affect each alloy differently. In some alloys, mechanical properties improved after heat treatment, while in others, a significant deterioration was observed, particularly in tensile strength.

The aim of this work is to verify the reliability of optical inspection of tires during their transport on a roller conveyor, with an emphasis on the accuracy of 3D scanning in real and simulated operating conditions. A measuring box was designed and constructed to eliminate environmental interference, and measurements were subsequently compared with different degrees of site coverage. Testing was carried out using a 3D sensor O3D302 operating on the Time-of-Flight principle, and spatial data in the form of point clouds were obtained and compared with the reference dimensions of the Nokian WR D4 tire. The effects of solar IR radiation, rain, surface moisture, and natural lighting conditions were analyzed, which caused different levels of deformation, noise, and measurement deviations. The results show that significant errors occur without coverage, while the measuring box significantly reduces these deviations and increases the stability of point data. Complete coverage from above and below proved to be the most effective solution, but the wet tire surface remains a significant source of interference. The work further proposes structural modifications to the box and recommends the application of a matte surface and the expansion of tests to include the effects of vibrations and real conveyor operation. The result is a technical evaluation of the measurements and recommendations for improving optical tire detection in the industrial process.

The cutting performance of abrasive water jet (AWJ) machining is commonly evaluated using cutting depth, cutting efficiency, and specific cutting energy. To systematically investigate the influence of process parameters on AWJ cutting performance, a five-axis CNC cutting platform was developed, allowing precise control of operating conditions. Single-factor experiments were conducted to analyze the effects of pump pressure, traverse speed, cutting angle, abrasive mass flow rate, standoff distance, and nozzle diameter. Both qualitative analysis and quantitative evaluation were employed to identify parameter ranges that maximize cutting efficiency or minimize specific cutting energy. The results indicate that the minimum specific cutting energy is achieved when the pump pressure is approximately three times the threshold pressure, the traverse speed is 110 mm/min, the cutting angle is 90°, and the abrasive mass flow rate approaches its optimal value. The effects of standoff distance and nozzle diameter on specific energy depend on their combined influence on cutting depth and kerf width. In addition, repeated cutting passes were found to increase energy consumption, indicating that complete material penetration in a single pass is more energy-efficient. These findings provide practical guidance and theoretical support for achieving high-efficiency and energy-saving AWJ cutting processes.

Cobalt-based alloys are widely used for orthopedic implants due to their excellent mechanical properties and corrosion resistance. Biomedical Co-Cr-Mo alloy, commonly applied in knee replacements, is typically produced by precision casting. However, in cases requiring patient-specific geometries, additive manufacturing technologies, such as Selective Laser Melting (SLM), offer promising alternatives. This study compares the microstructure and mechanical properties of Co-Cr-Mo alloy in the as-cast state and after SLM processing. The SLM-produced samples exhibited a fine, cellular microstructure and superior mechanical strength. Specifically, the printed alloy achieved a yield strength of 688 ± 8 MPa and an ultimate tensile strength of 994 ± 11 MPa, exceeding that of the cast material by about 495 ± 1 MPa. These results demonstrate the potential of SLM technology for manufacturing customized orthopedic implants with improved mechanical properties and dimensional accuracy.

This article presents the research findings on the flow behaviour of thermoplastic resin in foam core sandwich composites for aerospace applications during the vacuum assisted infusion process. After optimizing the process parameters, two sandwich panels were manufactured using glass fibre fabrics, a polymethacrylimide (PMI) foam core, and a liquid acrylic resin. To compare the sandwich and monolithic structure process behaviour, a monolithic composite panel was also manufactured. By combining experimental monitoring with Darcy's law, permeability differences between the structures were evaluated. The results indicate that PMI foam does not significantly affect the resin flow trend, and that Darcy´s law can be applied to both monolithic and sandwich structures when a thermoplastic liquid resin is used. These findings offer theoretical guidance for process parameter design and real-time in situ monitoring of the vacuum infusion process.

Investigation of cutting forces in metal cutting is of great importance for defining the effectiveness of the production as well as its impact on product quality. Several researchers studied the effect of cutting parameters on the cutting forces through statistical analysis; however, very few studies use the normalization of the data. Normalization reduces the skewness in the data and increases the accuracy of the results, which can be beneficial in modern industry where AI is being integrated with manufacturing. This research aimed to study the statistical analysis of cutting parameters and cutting forces using log-normalization and compare the accuracy of results with absolute data. The study uses a three-axis piezoelectric dynamometer to measure the cutting forces in the turning of X5CrNi18-10 steel. The results suggested that feed influences the cutting forces during machining. Coolant helps to reduce the cutting forces during the turning of hard steel. Log-normalization increases the accuracy of the results. These results can be used to predict cutting forces during the turning of chromium-nickel alloy steel.

This paper examines the detection of internal defects in composite specimens composed of Onyx, a material featuring a nylon matrix reinforced with chopped carbon fibers. Artificial defects, in the form of flat-bottom holes of various geometries, were intentionally introduced during the additive manufac-turing process. The primary objective is to determine the depth detection capabilities of ultrasound by varying the excitation frequency and determining whether these defects remain identifiable at different subsurface levels. Ultrasonic lock-in thermography is utilized to excite specimens. As the frequency is modified, the depth of wave propagation also changes, a phenomenon well established in homogene-ous materials. However, the heterogeneous nature of Onyx introduces complexities into wave propa-gation. The recorded thermographic data are processed in MATLAB to calculate contrast ratio values, enabling a quantitative comparison of defect detectability for different defect geometries.

In drilling operations, hole quality is affected by factors such as drill diameter, drilling parameters, drill bit properties, workpiece material. A large portion of the drilling energy is converted into thermal energy, which can be measured as temperature. In this study, surface roughness of holes, drill tip wear and drill tip temperatures were determined using two different workpiece materials and three different drill tips. Furthermore, the costs of holes drilled with different drill bits were determined and interpreted based on drill bit characteristics. The results obtained can be optimized according to the process parameters and it has been shown that a more sustainable and much more economical manufacturing can be achieved by avoiding the use of additional reaming or internal grinding for the desired surface quality and eliminating negative environmental effects.

The paper deals with the influence of various quenching media based on polymer aqueous solutions on the quenching process of carbon steel C45, connecting theoretical knowledge about heat transfer, surface phenomena and phase transformations with experimental verification. Surface phenomena at the interface of the hardened sample and the quenching medium were monitored using a high-speed camera. Cooling curves of the samples were obtained using the method according to ISO 9950 (Determination of cooling characteristics – Nickel-alloy probe test method). The paper contains practical recommendations for optimizing industrial hardening processes, especially when choosing polymer hardening baths as an alternative to water hardening baths and confirms their ability to ensure a more controlled cooling process, reduce the risk of cracks and deformations, and achieve higher hardness of hardened parts.

Today, machine learning regression methods are quietly but fundamentally transforming cost and time estimation in manufacturing: from early pricing to labor planning to operational order management. This survey offers a comprehensive map of approaches - from linear models, to tree ensembles (RF, GBM, XGBoost) and shallow neural networks, to multi-target and tensor regressions that can exploit data structure across BOM items and sequences of operations. With an emphasis on SME conditions, we show how to reconcile three often conflicting requirements of practice: accuracy, explainability, and integration into existing data flows (MES/ERP). The paper presents a comparative taxonomy of methods, recommended validation practices (MAE, RMSE, MAPE, R² including confidence intervals) and a pragmatic adoption trajectory: from regularized multiple regressions to tree models to multi-output formulations sharing re-presentations across operations. Consolidated findings show that modern learners consistently outperform traditional baselines when supported by careful flag engineering, drift management, and data standardization. As a major research-application contribution, we propose a unified multi-objective framework for simultaneous cost and time prediction that combines domain (queueing/simulation) features with data-driven regression to enable transparent decision making in pricing and capacity planning. The study thus creates a bridge between theory and manufacturing practice and invites the reader to systematically but achievably deploy ML in everyday decision making.

Vehicle Routing Problem is a common problem in logistics, which can simulate in-plant and out-plant material handling. In the article, we demonstrate a Vehicle Routing Problem, which contains period, time window and multiple depots. In this case, customers must be served from several depots. The position of the nodes (depots and customers), the demand and time window of the customers are known in advance. The number and capacity constraint of vehicles are predefined. The vehicles leave from one depot, visit some customers and then return to the depot. The above-described vehicle routing is solved with construction algorithms and Ant Colony algorithms. The Ant Colony algorithms are used to improve random solutions and solutions generated with construction algorithms. According to the test results the Elitist Strategy Ant System and the Rank-Based Version of Ant System algorithms gave the best solutions.

Hollow TiO₂ architectures are attractive for catalysis and sensing but typically produced by wet-chemical templating and sub-micron sizes. Here we demonstrate a dry, template-free route to nanoscale hollow shells by combining DC magnetron sputtering with in situ TEM heating. Heating to 900 °C produces sub-50 nm TiO₂ hollow shells with ~20 nm compact walls via oxidation-driven Kirkendall hollowing. The oxide evolves from amorphous at low temperature to anatase locally (~500 °C) and then to a rutile/brookite mixture by ~600 °C. The hollow architecture withstands a temperature of 900 °C without measurable sintering. Beam-off regions and ex-situ air annealing show the same hollowing and phase evolution, confirming a thermally driven, not beam-induced, transformation reproducible in air.

The introduced work deals with the microscopic analysis of metallographically prepared selected metal materials structures, using a scanning electron microscope (SEM). Prepared samples of seamless steel pipes were subjected to a thorough microscopic examination from the outer surface to the inner regions in order to interpret the spe-cific structure, including the change of the inner surfaces due to wear. The experiment showed that the micro-structure and character of the surfaces play a crucial role in the behavior of metallic materials under real condi-tions. Four types of pipes were monitored according to their use. The unused steel pipe (designated as sample No. 1) exhibited a rough outer surface with identified inclusions, while the used pipe (designated as sample No. 2) showed marks of intergranular corrosion and significant wear after long-term use. The older pipe (designated as sample No. 3) showed a decarburized area and inclusions containing sulfides and aluminum. The steel pipe with corrosion layers (designated as sample No. 4) exhibited a continuous corrosion layer with cavitation and cracks. The results of this study offer a comprehensive view relating to the influence of the nature of the micro-structure and wear on the water flow (performance) of metal pipes, with an emphasis on the identification of possible risks associated with geometry change, corrosion and wear. The recommendations create a basis for predicting the degradation as well as appropriate maintenance to ensure their long and reliable service life under real-world conditions of use.

Cast iron with nodular graphite is one of the most important structural materials that exhibit really good mechanical properties already in the as-cast condition. Nowadays, cast iron with nodular graphite is used in many areas of the manufacturing industry, the most widespread being in the engineering and automotive industries. The applicability of this material for construction purposes is mainly due to its mechanical properties, which are close to those of steel, but the production cost of cast iron is lower. This experiment was aimed at optimizing the production of ductile iron castings in the casting pits so that the foundry could produce ductile iron castings in the casting pits. Therefore, the optimization of the moulding compound database material was carried out in numerical simulation and at the same time, the heat transfer measurement of the foundry sand mould was carried out.

The CuZn10 alloy, a prominent brass variant known for its excellent cold formability, corrosion resistance, and suitability for various cold forming processes such as bending and stamping, finds widespread application across numerous industries. Optimizing its performance for specific industrial demands necessitates a thorough understanding of how different preparation technologies influence its intrinsic properties. This study provides a comprehensive examination into the impact of various processing routes on both the structural evolution and mechanical characteristics of deep-drawing CuZn10 brass. Utilizing advanced analytical techniques, including Electron Backscatter Diffraction (EBSD) analysis, the research systematically investigates microstructural changes, grain orientation, and texture development resulting from distinct manufacturing processes. The findings delineate clear correlations between specific preparation methodologies and the resulting mechanical properties, such as hardness, strength, and ductility. This work aims to establish a foundational understanding that can guide industrial practitioners in selecting optimal processing technologies to tailor CuZn10 alloy for enhanced performance and efficiency in its diverse applications. The insights gained are critical for refining manufacturing protocols and improving material quality in an industrial context.

Core-shell powders have been extensively studied due to their complex structure and wide range of applications. W@Ag core-shell powders are particularly interesting due to the synergy between the tungsten and silver, which can be beneficial in the electronics industry. However, knowledge of their thermal stability is limited, particularly concerning the impact of annealing temperatures on structural integrity and oxidation resistance. In this work, W@Ag core-shell powder was heat-treated in the temperature range 100–700 °C for 1 h in air. Investigation of the microstructural changes using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy showed that the limiting temperature is 500 °C, when the shell began to decompose and the core began to oxidize. Moreover, X-ray diffraction analysis determined that the phase composition of the thus heat-treated material consisted of approxi-mately 50 % Ag and 50 % Ag2WO4.

As part of my research work, in its practical part, I deal with the selection of suitable 3D printing pa-rameters for parts of a robotic kit, as well as the selection of a 3D printer and the determination of a set of experimental measurements and testing in order to obtain the necessary data to determine a suitable filament material for 3D printing of a part of a robotic kit and setting the appropriate 3D printing parameters to obtain the desired mechanical properties of the parts while maintaining the economic benefits of 3D printing. The main aspects for choosing a filament material are printability in primary and secondary school conditions, easy printing (beginner level), minimal postprocessing, adequate mechanical properties – these are obtained by experimental measurement and correspon-ding destructive tests on a real part from the VEX GO and IQ kit.

Additive manufacturing (AM) is rapidly developing with emerging technology of wire arc additive manufacturing (WAAM) process due to its ability to manufacture large components and high deposition rate. However, WAAM faces mechanical properties problems like porosity, distortion, and strength due to the large heat affected zone (HAZ) from commonly used heat sources such as metal inert gas (MIG) and tungsten inert gas (TIG). Utilization of micro plasma as the heat source should reduce this problem since it has a smaller heat source diameter. Therefore, this study investigates the thermal distribution of micro plasma wire arc additive manufacturing (MPWAAM) by developing a finite element method (FEM) model. This paper focuses on the fabrication of single-layer multitrack deposition and tool path planning of multi-layer multitrack depositions by MPWAAM process. The melt pool size and peak temperature are mainly governed by heat input per unit travel speed of the worktable, with current and voltage being the significant factors. Besides, tool path planning strategy influences the properties and quality of the final product, where parallel tool path design with longer interlayer cooling time minimized part distortion and residual stresses.

Fused silica is a key material for high-precision applications such as micro-optics and microfluidics. One route to improving direct laser writing (DLW) of fused silica is the use of shorter laser wavelengths, which enable tighter focusing and enhanced absorption. In this study, the influence of process parameters on surface quality and material removal during DLW using a deep ultraviolet (DUV) ultrafast laser (257 nm, 1 ps) was investigated. A full-factorial design of the experiment was used to identify conditions that optimise both surface quality and ablation efficiency. Surface roughness as low as Sa ≈ 200 nm and material removal rates up to 0.048 mm³∙min-1 were achieved. Conditions that led to surface degradation were also identified. Finally, the optimised parameters were applied to fabricate a microfluidic demonstrator. These results confirm that DUV ultrafast DLW is a powerful technique for fabricating high-fidelity features in fused silica with exceptional precision and quality that can be used for micro-optics or microfluidics devices.