Journal of Manufacturing Processes最新文献

This study employed Friction Stir Extrusion (FSE) on the LM13 aluminum alloy to fabricate tubes using three distinct tool head designs: cylindrical, 30° taper, and 60° taper profiles. A comprehensive analysis of the microstructures and mechanical properties of the resulting samples was performed. A numerical study was conducted to model the process dynamics, focusing on temperature and strain distributions, material flow patterns, and the evolution of force, torque, strain, and strain rate. Findings indicated that the axial force with the cylindrical tool was 4–5 times greater than with tapered tools, while forces for the 30° and 60° taper tools were comparable. The 30° taper tool generated the highest strain value of 280 mm/mm, which significantly enhanced the mechanical strength of the pipe up to 139 MPa while it was 85 MPa in the base metal. However, the cylindrical tool had a much higher average strain rate of around 40 1/s, compared to below 10 1/s for the tapered tools, yet it was less effective at reducing porosity and breaking Si particles due to insufficient strain. Additionally, material flow patterns differed: with the cylindrical tool, flow moved from the periphery to the center, while tapered tools directed flow from the center toward the pipe wall.

In the quest for seeking aluminum alloys with high printability, AlSi10Mg alloy has been sought as one of the most promising candidates for the laser powder bed fusion (LPBF) technique. Despite the extensive research conducted in LPBF AlSi10Mg, the development of printing parameters to obtain a combination of low porosity and roughness, as well as the desired combination of strength, elongation, and fatigue properties, is considered as one of the most significant difficulties to meet the minimum requirements specified in the standards. Due to the high surface roughness observed in the printed samples using standard printing parameters, this research aims to obtain a combination of low roughness and porosity, as well as excellent tensile and fatigue properties through the development of printing parameters including layer thickness, laser power, scan speed, and hatch distance. Among the developed parameters, decreasing the layer thickness from 60 μm to 50 μm considerably mitigated the surface roughness with the laser power (360 W), scan speed (1550 mm/s), and hatch distance (150 μm). In addition, the optimal stress relief heat treatment at 285 °C for 240 mins was determined for the proposed 50 μm layer thickness to meet the tensile test requirements.

Haynes 230 is widely used in high-temperature regions in the aerospace field. However, the long-term exposure to high-temperature environments results in catastrophic structural failures. Therefore, how to make the heat evacuate quickly and efficiently has become an urgent problem to be solved. Here, we have investigated for the first time the use of Cu-Mo30Cu-Ti composite foil as a thermal interface material to join the C_f/C composite and Haynes 230 in the form of brazing to attain stable operation of the component. The results show that the Cu-Mo30Cu-Ti composite foils form a metallurgical joining with the matrix materials and construct a heat transfer channel between them. When the brazing parameter reaches 1220 °C for 10 min, the thermal conductivity (29.9–34.8 W·m⁻¹·K⁻¹, testing in the range of 600–900 °C) of the joint is improved by 500 % ~ 600 % compared with that before brazing (4.5–5.5 W·m⁻¹·K⁻¹). Our work provides some references to promote the application of C_f/C composite and Haynes 230 in future high-temperature thermal management.

Aiming at the lack of theoretical calculation formulas for inner and outer spinning force in the asymmetric counter-roller spinning process, and the difficulty of direct measurement or conversion of indirect measurement of spinning force under the active rotation condition of rollers, as well as the time-consuming simulation analysis, a theoretical calculation method for asymmetric active counter-roller spinning (AACRS) force by combining strain electrical measurement and simulation is proposed. The initial theoretical calculation model of the inner and outer spinning force for the AACRS process is established based on the energy method. Then, the method of combining the indirect electrical measurement with dynamic simulation analysis (IEM&DS method) is proposed, and the equivalent section coefficient S_WE is used as the pivot to obtain the actual spinning force value equivalently. On this basis, the dynamic and static strain analysis test platform is built, and the modified theoretical calculation formula of spinning force under the counter-roller spinning process is obtained based on the dynamic strain test results. The results show that the theoretical calculation method can directly calculate the inner and outer spinning force values more accurately. The relative error between the corrected outer spinning force and the equivalent measured value is only 6.38 %, improving the accuracy by 49.65 % and 3.46 % compared with the uncorrected theoretical calculation and simulation values, respectively. This method effectively enhances the accuracy of spinning force acquisition while reducing the simulation time and experimental costs.

This paper investigates the impact of a novel Flexible Abrasive Jet Polishing (FAJP) method on the edge preparation of profile cutting tools based on Hertz contact theory. FAJP employs flexible rubber particles encapsulating diamond micro-powders as abrasives for air jet polishing. The results indicate a significant improvement in material removal rate with FAJP compared to traditional drag finishing methods, along with superior surface quality near the tool edge. The duration of abrasive usage has the greatest impact on FAJP, depending on the specific requirements of the tool edge, with options ranging from 400 to 200 h. There exists a correlation between jet pressure and jet time, with a recommended jet pressure of 225 kPa, and different coating effects achievable by adjusting the jet time. A tool speed of 280 rpm is recommended.

This paper introduces a novel high-velocity impact welding process: the standoff-free vaporizing foil actuator welding (standoff-free VFAW). This technique employs a new type of driving mechanism, overcoming the geometric placement constraints between the flyer plate and the target plate inherent in conventional impact welding processes. It enables welding without requiring an initial standoff distance between the two plates. The feasibility and general applicability of the proposed process were validated through experiments. The welding performance was evaluated using shear tests, peel tests, and microstructural analysis. The results indicate that the proposed process can successfully weld T2 copper to 304 stainless steel and AA5083-H112 to 304 stainless steel. Additionally, this study verified that the proposed process can achieve progressive welding, making it possible to utilize standoff-free VFAW for large-area metal welding. Furthermore, microanalysis revealed the presence of a typical wavy interface characteristic at the joint. Key parameters influencing the welding results were also explored through experiments and finite element modeling, which suggest that the boundary constraints of the workpiece play a key role in the success of standoff-free VFAW. This implies that the initiation of the small and dynamic gap between the flyer and target plates could be the potential mechanism for the proposed process. In summary, standoff-free VFAW presents simplicity and efficiency as its advantages. Moreover, the insights gained from this technique are not limited solely to vaporizing foil actuator welding (VFAW) but could also provide reference points for other high-velocity impact welding techniques.

Due to titanium and aluminum alloys having the characteristics of low mass density and high specific strength, the welding of both has a unique advantage in the aerospace field. However, traditional friction welding is mainly used for casting and forging materials, and there are few studies on friction welding between Ti and Al alloys fabricated by laser powder bed fusion (L-PBF). Because L-PBF is a kind of rapid solidification methods, the microstructure evolution in rotary friction welding joints should be further studied. In this study, L-PBF was used to prepare Ti6Al4V and AlSi10Mg samples, and rotary friction welding (RFW) was used to prepare rod-shaped welding samples. OM, SEM, and XRD were employed to study the morphology and microstructure of the welding interface, and EDS was used to study the intermetallic compounds (IMCs) of the welding interface. Finally, the microhardness and other mechanical performance of the solder joints were investigated, and the optimal process parameters were obtained. The results showed that the interface grain size of the welded sample prepared by L-PBF and RFW is small, and the IMC produced is TiAl and TiAl₃. It is found that the diffusion of Al-Ti elements is hindered by Si enrichment. When the ratio between friction to forging force of welded specimens was less than 2, the maximum tensile strength could reach 278 MPa, a 50 % improvement over using RFW directly. Moreover, SEM and EDS characterization results showed that the fracture mode of the welded end face was a typical brittle fracture, and the IMC was significantly reduced. This is because the formation of the Si particle networks at the interface inhibits the mutual diffusion of Ti and Al, and the microhardness increases. Therefore, in this research, L-PBF and RFW are combined to produce Ti-Al alloy with high mechanical performance, which provides a feasible strategy for welding dissimilar materials.

This study introduces a novel Laser-Induced Plasma (LIP) technique for the non-contact, rapid removal of nano and microparticles from through-holes in Additive Manufacturing (AM) components. This method is crucial for high-value applications, such as medical devices, compact heat exchangers, and aerospace engineering, which require efficient cleaning of intricate parts with holes and channels to address high failure costs. The technique leverages shockwaves generated by LIP to target and clean these complex geometries. The research focuses on two main areas: (i) characterizing the effects of shockwaves in semi-cylindrical channels to understand interactions with complex geometries, and (ii) quantitatively analyzing the removal of Fe-271 microparticles from semi-cylindrical channels of silicon (Si) wafers, selected for their consistent surface properties compared to the rough textures of AM-produced surfaces. Utilizing the experimental set-up Laser-Induced Plasma LIP Cleaning for Additive Manufacturing (LIPCAM), the study demonstrates that complete microparticle removal is achievable up to 20 mm from the plasma source with variable laser pulses. The results indicate that particles larger than 27 μm are entirely removed after a single pulse, and particles larger than 21 μm are removed after 50 pulses. These findings highlight the method's effectiveness in achieving high particle removal efficiency across different distances and particle sizes, thus ensuring thorough decontamination of complex internal structures. The study underscores the potential of this method to enhance the reliability and safety of critical AM builds, making it a viable solution for industries where precision and cleanliness are paramount.

Both continuous and discontinuous non-proportional loadings occur in multi-stage automotive stamping processes. Discontinuous loading is widely studied, but due to requiring sophisticated experimental procedures, continuous loading has been studied less. This study explores the impact of continuous loading on DX54 steel utilising an innovative experimental setup that enabled cruciform samples to undergo uniaxial to biaxial strain path change continuously without unloading. A similar two-stage discontinuous loading from uniaxial to biaxial with unloading in between was generated in DX54 to understand the differences in macro-strain, micro-strain, microstructure, and micro-texture evolution between the continuous and the discontinuous loadings. The stress state of the material during continuous loading was different to that during discontinuous loading. In this study, the occurrence of ‘pseudo-localisation’ was observed during continuous loading, and the observed rotation of high-strain bands differed between continuous and discontinuous loading. The discontinuous loading induced a higher strain, hardening rate, and increased elongation compared to the continuous loading. These results suggest the potential for higher formability during the discontinuous loading compared to the continuous loading.

Innovative press concepts with multiple degrees of freedom such as the 3D Servo Press (3DSP) allow the implementation of incremental forming processes, thus the production of previously unfeasible workpiece geometries. This publication demonstrates that elliptical double-sided collars can be formed out of sheet metal through closed-loop control of the ram pose and controlled ram tilting. For this purpose, a new tool has been developed that enables the process of flexible hole rolling on a 3DSP. We show that the geometry of produced parts can be influenced by adapting the tool path trajectories and present a compensation approach that ensures the highly accurate insertion of the collars into the sheet metal. The geometries as well as the resulting courses of the collar height over the circumference of the hole, are analysed using experimental and FEM-based simulation results.