Explore the vast range of titles available.

Although additive manufacturing (AM) is becoming increasingly popular for various applications, few studies have addressed design and potential problems in thin wall fabrication for the laser powder bed fusion (LPBF) process. In the LPBF process, rapid cooling induces thermal shrinkage, which in turn, results in high residual stress and complicates thin wall fabrication. The minimum wall thickness is limited by the parameters and machine settings while the dimensional accuracy is controlled by the powder size, scan strategy, and part geometry. The ability to fabricate thin-wall components is important for applications such as heat exchangers (HX). This study explores the performance of the LPBF process by fabricating thin walls with extreme geometries in different processing conditions and alloys using an EOS M290 LPBF machine. Results show that the material, part design, and scanning strategy contribute to the variation in thin wall dimensions. A maximum inclination angle of 60° and a minimum wall thickness of ~ 100 μm in Ti-6Al-4V, Inconel 718, and AlSi10Mg were achieved using optimized part design and processing conditions. The effects of part design and material on the thermal distortion and surface finish of thin walls were also investigated leading to a discussion on how the scan mode assigned by the EOS software affects design and fabrication. Additionally, synchrotron-based X-ray micro-tomography (μSXCT) was utilized to quantify the porosity in thin-wall structures and to correlate it with the integrity of the structures. Comprehensive design guidelines presented in this work can increase the success rate of fabricating thin-wall geometries.

Online prediction of the dynamic characteristics of thin-walled workpieces, such as turbine blades, during the material removal process, plays an important role in the construction of digital twins systems for high-performance machining processes. However, the complex surfaces, thin-walled structures and time-varying characteristics of the blade machining process bring great challenges. The existing methods are either for simple structures or unadaptable to the continuous variation of the modal parameters, which cannot meet the requirements of online prediction for complex blade machining. To this end, this paper constructs a generative adversarial network with two output branches. By taking geometric information as input, online prediction of the modal parameters during the machining of complex thin-walled blades is realized. Considering the deviation between measured and predicted frequencies, an eXtreme Gradient Boosting model is established to modify the frequency branch of the network, which enables the model to be adaptive to machining uncertainties. By integrating the proposed network into the self-developed computer-aided manufacturing software, a digital shadow system of modal parameters prediction during blade machining is constructed. The verification experiments show that the calculation time of the proposed model is 1.35 s. The results demonstrate that the above system can achieve high-performance online prediction of modal parameters in the thin-walled complex blade machining process.

Additive manufacturing (AM) enables the consolidation of components and the integration of new functionalities in metallic parts, but layered fabrication often results in poor surface quality and geometric deviations. Among various surface treatment techniques, machining is often favoured for its capability to enhance not only surface finish but also critical geometric tolerances such as flatness and circularity, in addition to dimensional accuracy. However, machining AM components, particularly thin-walled structures, poses challenges related to unconventional material properties, complex fixturing, and heightened susceptibility to chatter. This study investigates the vibrational behaviour of thin-walled Ti6Al4V components produced via laser powder bed fusion, using a jet-engine compressor blade demonstrator. Four stock envelope designs were evaluated: constant, tapered, and two topologically optimised variants. After fabrication by Laser Powder Bed Fusion, the blades underwent tap testing and subsequent machining to assess changes in modal characteristics. The results show that optimised geometries can enhance modal performance without increasing the volume of the stock material. However, these designs exhibit more pronounced in situ modal changes during machining, due to greater variability in material removal and chip load, which amplifies vibration sensitivity compared to constant or tapered stock designs.

The machining of thin-wall components made of titanium alloys is challenging because the poor machinability of the material leads to severe problems such as accelerated tool wear and poor surface quality, while the weak rigidity of the thin-wall structure results in unavoidable vibration and surface form errors. To address these issues, this paper investigated the mechanisms and performance of cooling minimum quantity lubrication (CMQL) in milling titanium thin-wall parts. To verify the efficiency of CMQL, different cooling/lubrication strategies, including conventional flood cooling, minimum quantity lubrication (MQL) and CMQL with different temperature levels, were investigated. The cutting force, tool wear state, chip formation, surface integrity, and surface form errors were compared and analysed in detail. The experiment results show that MQL is inadequate at higher spindle speeds due to its ineffective cooling capacity and weakened lubrication ability. In contrast, CMQL has demonstrated its feasibility and superiority in milling titanium thin-wall parts under all conditions. The outcomes indicate that a lower temperature level of CMQL is advantageous to producing better wear resistance and lower thermomechanical loads, and the CMQL (− 15 ºC) machining environment can remarkably improve the overall machining performance and control the surface form errors of the machined thin-wall parts. At the spindle speed of 3000 rpm, the surface roughness measured under CMQL (− 15 °C) condition is reduced by 16.53% and 23.46%, the deflection value is decreased by 54.74% and 36.99%, while the maximum thickness error is about 53.51% and 20.56% smaller in comparison to flood cooling and MQL machining. In addition, CMQL is an economical and sustainable cooling/lubrication strategy; the outcomes of this work can provide the industry with useful guidance for high-quality machining of thin-wall components.

Thin-walled parts have been widely employed as critical components in high-performance equipment due to the high specific strength and light weight. However, owing to their relatively weak rigidity and poor damping properties, chatter vibration is likely to occur during the milling process, which severely deteriorates surface quality and decreases machining productivity. Therefore, chatter suppression is essential for improving the dynamic machinability of thin-walled structures and has attracted extensive attention over the past few decades. This paper reviews the current state of the art in research concerning chatter suppression during the milling of thin-walled workpieces. In consideration of the dynamic characteristics of this process, the challenges in design and application of chatter attenuation methods are highlighted. Moreover, various chatter suppression techniques, involving passive, active, and semi-active methods, are comprehensively discussed in terms of basic concepts, working mechanism, optimal design, and application. Finally, future research opportunities in chatter mitigation technology for thin-wall milling are recommended. Challenges in suppressing chatter during thin-wall milling are systematically reviewed. Working mechanisms of various strategies for mitigating regenerative vibrations are summarized. Application scenarios of different approaches are highlighted considering their specific characteristics. Perspectives on research opportunities in chatter suppression of thin-wall milling are outlined.

Yttria stabilized zirconia (YSZ) thin wall components were fabricated using laser engineered net shaping (LENS) technique. It was found that after LENS processing, the monoclinic (m) phase in as-received YSZ powders transformed to tetragonal (t) and cubic (c) phases with the lenticular shaped t-ZrO 2 embedded in the c-ZrO 2 matrix. The relative density of the parts reached up to 98.7%. Our investigation showed that micro cracks within the wall structure were reduced by judiciously choosing laser power parameter. The fabricated parts have surface roughness values that ranged from 20 to 40 μm. The maximum hardness and elastic modulus achieved from the LENSed YSZ parts were 19.8 GPa and 236.1 GPa, respectively. We also demonstrated that dark brown color of the LENSed parts could be removed via heat treatment.

Although additive manufacturing (AM) has gained significant attention in academia, limited studies have thoroughly examined the design considerations and challenges in fabricating thin walls using laser powder-directed energy deposition (LP-DED). This study assesses the feasibility of producing Inconel 718 thin walls with thicknesses below 0.8 mm. It examines the influence of key LP-DED parameters, such as laser power, scanning speed, and mass flow rate, on geometrical dimensions (average height and width), surface texture (3D surface roughness, waviness, and straightness), microhardness, and microstructure. Additionally, analysis of variance (ANOVA) is used to evaluate the impact of process parameters on response variations. The findings show that a higher scanning speed reduces wall dimensions, while an increased powder feeding rate raises wall height with minimal effect on width. Additionally, greater laser power widens the wall but reduces its height and microhardness. The optimal process parameters are identified as a laser power of 300 W, a scanning speed of 2000 mm/min, and a mass flow rate of 4 g/min. Under these conditions, the fabricated thin wall achieved a minimum thickness of 0.70 mm. It also exhibited a minimum surface roughness (Sa) of 8.235 µm and a minimum waviness (Wa) of 14.02 µm, while demonstrating the highest recorded microhardness of 342.7 HV. A clear understanding of as-built surface texture in the LP-DED process is crucial for fluid flow applications, such as heat exchangers, as it can either enhance heat transfer efficiency or negatively impact pressure drop.

The cast AlSi12CuNiMg alloy finds broad applications in automotive components. The manufacture of defect-free castings, especially for long, thin-walled structures, requires an understanding of filling properties. The main aim of this investigation is to understand the fluidity of an AlSi12CuNiMg alloy in a multi-spiral channel with varying thickness through the casting simulation and validate it through casting experimentation. Furthermore, the effect of pouring temperature and section thickness on fluidity was investigated, and an optical microscopy was carried out for microstructure observation. The results showed that the flow length (L) of the alloy increased with increasing pouring temperature (T) and decreased with a reduction in the section thickness. In order to predict the fluidity of AlSi12CuNiMg alloy obtained from the spiral tests, mathematical models (Lf=-705+1.044T+46.17x) were developed based on the functional relationship between the fluidity and casting parameters by fitting the fluidity data. The simulation results show good agreement (91%) with the fluidity length obtained in the experimental study. The benchmark can also be used to develop the fluidity database of different alloys for thin sections.

High-aspect-ratio vortex curved thin wall is widely used in electronics, precision instruments, aerospace, and other fields. It is a typical flexible geometrical structure with varying curvature making it very difficult to be fabricated with high quality due to burrs, dimensional errors, tool marks, and other defects in the machining process. In order to improve the machining quality of vortex curved thin walls, a new micromilling process with large cutting depth and slow feed is proposed. Firstly, through the single factor finite element simulation and micromilling experiment, the influences of radial depth of cut ae and feed per tooth fz on milling forces are analyzed under the condition of large axial depth of cut ap. Then, under the guidance from the results of single-factor experiments, the orthogonal experiments are conducted selecting surface roughness Ra, dimensional error △w, and burr height h as the evaluation indexes of machining quality. The influences of key milling parameters (feed per tooth fz, axial depth of cut ap, radial depth of cut ae, and spindle speed n) on machining quality are explored. By comprehensively analyzing the key milling parameters and their effects, an optimum combination of cutting parameters is identified. Finally, the new micromilling process is validated for the fabrication of high quality vortex curved thin walls.

In recent years, high-Si ductile cast irons (3–6% Si) have begun to be used more and more in the automotive and maritime industries, but also in wind energy technology and mechanical engineering. Si-alloyed ferrite has high strength, hardness and oxidation and corrosion resistance, but it has low ductility, toughness and thermal conductivity, with graphite as an important influencing factor. In this study, 4.5% Si uninoculated ductile iron solidified in thin wall castings (up to 15 mm section size) via a permanent (metal) mold versus a sand mold, was evaluated. Solidification in a metal mold led to small size, higher graphite particles (less dependent on the section size). The graphite particles’ real perimeter was 3–5% higher than the convex perimeter, while the values of these parameters were 41–43% higher in the sand mold. Increasing the casting section size led to an increased graphite perimeter, with it being much higher for sand mold. The graphite particles’ shape factors, involving the maximum and minimum size, were at a lower level for metal mold solidification, while by involving the difference between Pr and Pc, is higher for the metal mold. The shape factor, including the graphite area and maximum size, had higher values in the metal mold, sustaining a higher compactness degree of graphite particles and a higher nodularity regarding metal mold solidification (75.5% versus 67.4%). The higher was due to the graphite compactness degree level (shape factor increasing from 0.50 up to 0.80), while the lower was due to the graphite nodularity for both the metal mold (39.1% versus 88.5%) and the sand mold (32.3% versus 83.1%). The difference between the metal mold and sand mold as the average graphite nodularity increased favored the metal mold.