Abstract
The high requests for modern manufacturing processes have been proposed on high precision, low cost, short cycle time, and environment friendliness in the past decade. The intensive research on material behavior and evolution has become the foundation of processes with abundant achievements. Recent advances in material and manufacturing have introduced new technologies and fundamental investigation to study dynamic mechanical properties, history of microstructure variation, mechanisms for manufacturing, and overall effect of process parameters. Knowledge and understanding of material fundamentals have led to the development of new materials, new processes, new measurement methodology, and accurate physics-based models.
The papers selected for this special issue present the effort and achievement in this area. Although the selected topics and papers only focus on some specific issues and may not be comprehensive as representation of the area, they represent the versatile attempts and advances, that we have the pleasure of sharing with the readers.
This special issue contains seventeen papers. Three papers are related to microstructure evolution and other three papers focus on the mechanical performance of certain metal materials. Eight papers are regarding the effect of process parameters on final quality for precision machining and other manufacturing processes. Finally, three papers concentrate on the theoretical algorithm research on mechanical design, manufacturing, and industrial engineering.
In the first paper, titled “Effect of the co-depositionions on structural and tribological properties of electro-brush plated coating,” X. Cui et al. have investigated the effects of the codeposition ions on structural and tribological properties of electro-brush plated coatings. The microstructure and phase structure were also studied with SEM, XPS, and XRD. It was concluded that the hardness and tribological property of the coatings are improved obviously when proper chemical ion W or Cu codeposited with iron ion is added. The interface bond strength between the coating and the substrate is improved obviously for the Fe-W-Cu coatings.
In the second paper, titled “Austenite grain growth behavior of AISI 4140 alloy steel,” L. Wang et al. presents an algorithm to model the austenite grain growth in isothermal condition and elevated temperature. The experiments have been conducted to provide the data support and validate the model. Meanwhile, the standard error analysis has been done to assess and optimize the coefficients in the function of grain growth.
In the third paper, titled “Performance evolution of phytic acid conversion film in the forming process,” X. Cui et al. investigated the evolution of the microstructure, composition, roughness, corrosion resistance, nanomechanical property, and residual stress in the film formation process. It was concluded that, in the forming process, the changes of microstructure, mechanical property and corrosion property, are closely related to the variation of elements and residual stress. The determination of residual stress and cracking time is the key factor to optimize preparation techniques and control film quality.
In the fourth paper, titled “Dynamic mechanical behaviors of 6082-T6 aluminum alloy,” P. Yibo et al. have investigated the dynamic mechanical behaviors of aluminum alloy and a Johnson-Cook constitutive relationship has been regressed based on the designed tensile tests with a strain rate from quasistatic (10−3 s−1) to moderate (100 s−1), which has a good agreement with experimental data. The effect of strain rate and strain on the flow stress was discussed. It can be seen that more precipitates appear with an increasing strain rate through BSE graphic analysis, which may enhance the pinning effect on grain boundaries.
In the fifth paper, titled “Effect of detail design on fatigue performance of aircraft door frame,” K. Jianxiong et al. assess the fatigue performance of two designs, single-side and double-side door frames, by conducting the fatigue test. The finite element method was taken to examine the stress distribution. It was concluded that double-side design can reduce stress concentration around the bevel of specimen effectively, which resulted in a fatigue life of 18–21 times longer than that of single-side one. The fracture has been observed to analyze the generation and propagation of cracks.
In the sixth paper, titled “Numerical simulation of force enhancement by cellular material under blast load,” C. Qi et al. have developed finite element (FE) models of cellular material under blast load to analyze the force evolution. The comparison between the FE methods and one-dimensional analytical model has been conducted to verify the capability of FE methods. The relationship between blast load intensity and the length of the foam bar was analyzed. It was found that the time of momentum transfer between the compacted foam bar and the protected structure was very short compared with the total time of the blast event, which caused force enhancement.
In the seventh paper, titled “An experimental investigation of residual stresses in high-speed end milling 7050-T7451 aluminum alloy,” X. Huang et al. have studied the regularity of residual stress in high-speed end milling process of 7050-T7451 aluminum alloy. The effect of machining parameters on residual stress has been investigated by designing orthogonal cutting experiments and the significance of four parameters is ranked. It was concluded that the residual stresses in feed direction were higher than that in cutting direction, and that decrease of the cutting speed and increase of the feed rate led to significant increase significantly in compressive residual stresses on finished surface.
In the eighth paper, titled “Analysis of grinding force and elastic deformation in thread grinding process,” W. Wang and X. Feng present a dynamic numerical thread grinding model to analyze grinding force and dynamic contact arc length. The elastic deformation of workpiece was drawn by using force analysis. The effect of some parameters, for example, grinding speed and angle of helix, has been investigated. However, more experimental work needs to be done to validate the model.
In the ninth paper, titled “Vertical spindle grinding of Si and granite with a new abrasive disk,” Y. Yu et al. have presented a fabricating process of an ultrafine abrasive tool for vertical spindle grinding on Si wafer and granite. Sol-gel was applied to granulate ultrafine abrasives in order to reduce the aggregation of ultrafine abrasives and disks were dressed to expected flatness by using a brazed diamond pad. Based on the experiments on a high precision vertical spindle grinding machine, it was found that the brazed diamond abrasives could dress the grinding disks with high efficiency and satisfactory flatness and the new ultrafine abrasive disks had the ability to process silicon wafers and granite slabs with an acceptable performance.
In the tenth paper, titled “The experimental analysis of forming and strength of clinch riveting sheet metal joint made of different materials,” J. Mucha et al. have presented the design of the pressed joint processes using forming process. The design of rivets has a significant influence on the forming quality. The joint performance was characterized with a comprehensive examination of the morphology of joint cross section, shear force, failure mode of joints, microhardness, and metallurgy.
In the eleventh paper, titled “Affecting the ageing behaviour of injection-mouldedmicro parts using variothermal mould tempering,” S. Meister and D. Drummer have investigated the ageing behavior of injection-moldedmicro parts in dependence on the process conditions by using a variothermal injection mold. The results have confirmed that the mold temperature affects the inner properties and the resulting mechanical behavior. The effect of morphology on physical and chemical ageing has been compared and it is concluded that a more intense physical ageing happens with unpropitious morphology. Furthermore, a process induced favored morphology can attenuate the ageing effects and enhance mechanical properties.
In the twelfth paper, titled “Gas-assisted heating technology for high aspect ratio micro-structure injection molding,” S.-C. Chen et al. have designed a gas-assisted mold pre-heating process for injection of plastic material. The effect of preheating temperature and mold gas size on filling efficiency has been investigated. It was concluded that hot gas heating could enhance the filling capability with a filling percent of 91% for high aspect ratio small grooves because the temperature uniformity was improved with the hot gas.
In the thirteenth paper, titled “Mathematical and simulation modelling of moisture diffusion mechanism during plastic IC packages disassembly,” P. Mou et al. have researched the moisture diffusion behavior during PCB disassembling process with a diffusion model. The effect of parameters, for example, baking temperature and time, on result of moisture removal has been investigated by using experiments and simulations. It is found that the resistance to moisture diffusion mainly came from the internal part of the IC packages.
In the fourteenth paper, titled “Numerical simulation of the moving induction heating process with magnetic flux concentrator,” F. Li et al. have developed FE model to investigate the mechanism of the moving induction heating with metal powder bonded magnetic flux concentrator. Effect of process factors on temperature field of workpiece has been analyzed with the proposed model that has been validated with experimental results on AISI 1045 steel.
In the fifteenth paper, titled “Melt pressure signature tracking using an adaptive Kalman filter in microinjection molding,” H. Liu et al. have proposed an adaptive Kalman filter algorithm based on F-distribution for real-time tracking of the melt pressure in microinjection process. The proposed method can improve the convergence of the filtered signal during the tracking process and track the moments that sudden changes occur in the pressure signature. The experimental work provided the evidence for use in the mass production of microinjection moldings.
In the sixteenth paper, titled “Modeling and optimizing energy utilization of steel production process: a hybrid petri net approach,” P. Wang et al. have presented a new method for the process based on hybrid petri nets (HPN) to model energy flow within the real steel production process. A real steel production process from one typical integrated steel plant has been analyzed as a case in which the steel production, energy efficiency, and self-made gas surplus were set as the main optimized goals. A fuzzy linear programming method was carried out to obtain the multiobjective optimization results. Based on the analysis, some suggestions were given to improve the low efficiency and high cost.
In the seventeenth paper, titled “Mesh regeneration method for jig-shape optimization design of the high-aspect-ratio wing,” S. H. Huo et al. have proposed a mesh regeneration method for the jig-shape optimization design of a high-aspect-ratio wing. Three different cases on jig-shape optimizations based on the method were carried out and the designed jig-shapes have a good agreement with the expectation under the impact of static aeroelasticity. Lift coefficients of all the three jig shape optimization were proven to be larger than that of the original design.
Footnotes
Acknowledgment
We would like to thank the authors for their excellent contributions and patience in assisting us. Finally, the fundamental work of all reviewers on these papers is also very warmly acknowledged.