International Journal of Advanced Manufacturing Technology最新文献

Abstract

The integral blisk has been widely used in aerospace, and its structural performance is inextricably linked to the blade surface quality. To improve the surface integrity of polished surface, ultrasonic vibration assisted belt flapwheel flexible polishing (UBFP) is proposed. In this study, the polishing principle of UBFP and the effects of vibration on surface generation are investigated, and kinematic analyses and trajectory simulations are performed. Furthermore, the influences of the main processing parameters on the polishing force and surface roughness in UBFP are explored experimentally, and the sensitivity of the main parameters is distinguished by multi-parameter relative sensitivity analysis based on Monte Carlo simulation. The results show that the ultrasonic vibration contributes to the polishing process primarily through kinematic state changing and trajectories interlacing of abrasives. Compared with conventional belt flapwheel flexible polishing, the polishing force decreases by 15.72% and the surface roughness decreases by 17.39%. The compression depth is the most sensitive parameter in the process of UBFP. This study demonstrates the feasibility of UBFP and provides a theoretical and experimental reference for improving the polishing surface quality of the blisk blade.

During the pulsed laser cladding process, complex thermal accumulation occurs between powder and beam due to the pulsed laser periodic change. The selection of process parameters affects the cladding layer quality, and the correlation between the parameters is high. It is of great significance to obtain high quality cladding layer to determine the influence of the powder-carrying gas nitrogen velocity, powder feeding port diameter, and powder feeding angle on the powder flow, as well as the optimal powder shading rate and the mechanism of powder interaction with pulsed laser beam. In this paper, a gas–solid coupling model during the pulsed laser cladding process of three-beam coaxial powder feeder was established, and the rotating Gaussian heat source function of pulsed laser was written to calculate the temperature, flow velocity, and concentration distribution considering the interaction between laser and powder. The orthogonal test method was used to optimize the process parameters in order to reduce the shading rate of powder and improve the laser energy utilization. On this basis, a full cycle three-dimensional multi-field coupling numerical model for pulsed laser cladding process was established, and the temperature, flow, stress fields, and multi-component heat and mass transfer behaviors were calculated under different powder shading rates. The flow temperature of powder was collected by infrared thermometer and compared with the numerical results, the reliability of the model was verified. This study provides a significant theoretical basis for the full-cycle optimization of process parameters and the improvement of cladding layer quality during pulsed laser cladding.

This study investigated the mechanism of UVAD using numerical and analytical techniques. Silicon wafers possess challenging cutting properties due to their inherent brittleness and susceptibility to cracking along specific crystal orientation. Hence, non-traditional cutting methods like UVAD hold promise for precision micro-hole drilling in silicon wafers. In order to comprehend the mechanism of UVAD, the numerical technique utilized a direct brittle micro-cracking model within a 2D finite element (FE) method. This facilitated a comparative analysis between conventional drilling (CD) and UVAD, with a specific focus on understanding the micro-cracking mechanisms during the mechanical process. This study examined primarily the cutting force, micro-fracture analysis, and cutting energy. The numerical technique effectively predicted micro-cracks within the brittle regime, a task that is challenging to accomplish using analytical methods alone. In parallel, an analytical technique was developed to predict brittle-ductile transition (BDT) lines by analyzing the thrust force and specific cutting energy (SCE), combined with the numerical technique. Various feed rates per revolution were tested to validate the analytical force predictions. The analytical results demonstrate that the force profile corresponds to the transient cutting depth, while the numerical results indicated that the direct brittle micro-cracking model effectively demonstrated the fracture mechanisms, particularly at greater depths of cut. The SCE graph can predict the formation of a ductile regime on the cutting surface of the drilled micro-hole, although predicting micro-fractures on the side edges of the drilled micro-holes remains challenging. Additionally, UVAD demonstrated a reduction in micro-fractures on the sides of drilled micro-holes, particularly at very low feed rates per revolution.

In this study, mahogany seed oil was sourced and prepared, and the performances were compared with mineral oils. The extracted oil was characterized to recognize properties related to pyto-chemical, physio-chemical lubricity and thereafter used along with mineral oil for the formulation of cutting fluid using emulsifying agent, anti-corrosive agent, biocides, and anti-foam agent as additives. These additives were added to oil and water by using 2⁴ full factorial design to achieve the optimal combination. In addition, central composite design (CCD) was adopted for the experimental design, and the performance of the mahogany oil-based cutting fluid (MBCF) was investigated in terms of surface finish, cutting temperature, material removal rate, machine sound level, and chips formation and, thereafter, compared with conventional mineral oil (CBCF) in turning of AISI 304 steel under flood cooling technique. Experimental data were analyzed using analysis of variance (ANOVA) and grey relational analysis (GRA). The experimental findings showed that optimal multi-response performance of the MBCF can be achieved using spindle speed, feed rate and depth of cut of 1100 rev/min, 0.27 mm/rev, and 0.23 mm, respectively, while optimal multi-response performance of CBCF can be achieved with spindle speed, feed rate, and depth of cut of 900 rev/min, 0.62 mm/rev, and 0.23 mm, respectively.

The concepts of digital twins (DTs) have been widely studied to predict system performance, shorten design cycles, and implement preventive maintenance, but mainly, in large-scale enterprises. It is extremely beneficial to the whole manufacturing sector, since DTs can be readily implemented in small and medium-sized enterprises (SMEs) with basic computer aided engineering (CAE) tools; over 95% enterprises are SMEs. This paper aims to prove the feasibility of using commercial CAE tools, such as SolidWorks Simulation, to design air-quenching processes for SMEs. SMEs can benefit to explore new business opportunities, reduce system design cycle, and improve existing air-quenching processes. To our knowledge, it will be the first work of adopting DTs in conceptual design of an air-quenching process in sense that (1) the need of simulating an air-quenching process before physical implementation is discussed thoroughly; (2) heat transfer processes are classified, governing mathematical models for various heat transfer behaviors are introduced to present an evaluation model of a heat transfer process; (3) main process variables of air-quenching are identified; (4) a DT of an air-quenching process is developed and simulated to verify the capabilities of commercial SolidWorks Simulation; (5) case studies are developed to show how a CAE tool can be used in DTs. The findings from the reported work are summarized with a debrief of our future work.

Compacted graphite iron (CGI) is increasingly used in industrial production due to its excellent mechanical property, especially in the field of high-performance automotive engine manufacturing, and has become a substitute for gray cast iron (GCI). However, the hard-to-machine problem caused by its excellent physical properties was the main issue affecting the surface quality of the CGI workpiece. As a new type of tool, the wiper insert could effectively improve the surface quality. In order to develop a long lifespan and high-stability wiper insert tool for CGI milling, this study conducted a series of experiments, including tool design and simulation, coating preparation and testing, and tool cutting performance testing. In the optimization of simulation analysis of tool geometric parameters, it was found that the numerical value of curved cutting-edge radius had a more significant impact on the cutting performance of wiper insert. In the coating test, AlCrN-coated wiper insert C with a coating thickness of 2.84 µm had the best load bearing and fracture toughness performance in the coating mechanic test and had the best coating bonding performance in the scratch test. In the milling experiment with a cutting speed of 125.7 mm/min, a feed rate of 0.15 mm/r, and a cutting depth of 0.5 mm, the coated wiper insert C had the longest tool life and the best machined surface quality of the workpiece. Compared to other coated tools, the tool life was extended by at least 15.7%, and the effective cutting area was increased by 20%, which means it was the most suitable tool for machining CGI.

In order to improve the accuracy of the thermal error model of the electric spindle, a thermal error modeling method based on the optimized Elman neural network using the cuckoo algorithm is proposed. To analyze the thermal behavior of the electric spindle, an ANSYS analysis approach is utilized to create a temperature map. Based on the simulation analysis outcomes, an experimental platform is established to gather temperature data and thermal displacement data. The electric spindle temperature is optimized through the utilization of fuzzy cluster analysis and the Spearman rank correlation coefficient method in combination. The comparison between the established model and the Elman model and the GA-Elman model proves that the CS-Elman model has good prediction accuracy and stability.

Ball-end milling cutters are commonly used for precision processing of complex curved parts in CNC systems. However, the milling process often experiences chatter, leading to final surface damage. To solve the problem, the method of automatically adjusting the tool posture was proposed to avoid chatter problems during the milling process. Frequency response function varies along the processing path. The frequency domain control equation for ball-end milling cutter machining under different operating conditions was established in the feed coordinate system, and the stability of the system at the cutting point can be quickly determined by Nyquist. In order to accurately solve the control equation, a method for solving the Cutter Workpiece Engagement (CWE) boundary under different tool postures was designed. The feasible region for the tool axis was searched based on geometric and stability constraints at each original tool path position. In the feasible domain, the tool axis path was optimized and the tool position file was updated with the constraint of machine tool rotation axis smoothness. Milling experiments were conducted on AL7050-T745 workpiece. From the simulation and experimental results, it can be concluded that milling width and tilt angle have significant impact on the milling process. The method proposed in this article has been experimentally validated in a five-axis ball-end milling experiment.

The manufacturing technique known as investment casting has found extensive application in producing metal components featuring intricate geometries. The production efficiency of the wax patterns is an essential issue in the investment casting industry, especially for the mass production of wax patterns. A conformal cooling channel (CCC) performs the rapid uniform cooling process for injection molding. However, the significant pressure drop along the cooling channels is a distinct disadvantage of CCC. In this study, an innovative waterfall cooling channel (WCC) was proposed and implemented. The WCC cools the injected products by surface contact, replacing the conventional line contact to cool the injected products. The WCC was optimized using Moldex3D simulation software. Rapid tools with two kinds of cooling channels were designed and implemented. The cooling time of the molded part was investigated using a low-pressure wax injection molding machine. Considering a water cup characterized by a mouth diameter of 70 mm, a height of 60 mm, and a thickness of 2 mm, the experimental results confirmed that the use of WCC can save the cooling time of the product by about 265 s compared with the CCC. This result shows that the WCC can increase cooling efficiency by approximately 17.47% compared with conventional CCC.

The use of fused deposition modeling (FDM) in printing polymers for various applications has been ever increasing. However, its utilization in printing polymers for high-strength and superior surface finish applications is still a challenge, primarily due to process intrinsic defects, i.e., voids between the layers and the rough exterior arising from unrestrained deposition of molten polymer. This research hypothesizes that application of ultrasonic vibration (USV) post-fabrication could minimize these shortcomings. For this investigation, ASTM D638 Type IV samples were FDM-printed using poly(lactic) acid (PLA). Through screening experiments, an optimized set of ultrasonic parameters was determined. Then, the effect of both-sided ultrasonic application was characterized. Subsequently, the impact of USV on the samples’ physical, tensile, and morphological properties was examined by varying the layer height, infill patterns, and % infill density. Up to 70% roughness reduction was observed as a result of post-FDM ultrasonic application. Additionally, the tensile strength of the samples increased by up to 15.31%. Moreover, for some lower % infill samples, post-ultrasonic tensile strengths were higher than 100% infill control samples. Analysis of scanning electron microscopy (SEM) and X-ray computed tomography (CT) imagery indicated enhanced layer consolidation and reduced void presence in samples treated with ultrasonic. The combination of ultrasonic-generated heat and downward pressure promoted a synergistic squeeze flow and intermolecular diffusion across consecutive layers of polymers. As a result, increased tensile strength and surface finish were achieved while dimensional change was marginal.