Shulin Wang

Effect of Eu Doping on the Structural, Electrical, and Dielectric Properties of K0.5Na0.5NbO3 Ceramics for High-Temperature Capacitor Applications

The structural and dielectric properties of Eu-doped K0.5Na0.5NbO3 (KNN) ceramics were investigated as a potential candidate for use in high-temperature capacitors with working temperature beyond 200°C. x-Ray diffraction results showed that tetragonal and cubic structure distortions occurred for low- and high-concentration doping, respectively. With increase of Eu content, the dielectric anomaly of the tetragonal–cubic transition was depressed and shifted to low temperature, while the temperature of the orthorhombic–tetragonal transition remained unchanged. A dielectric relaxation associated with oxygen vacancies was detected in the paraelectric phase region. The activation energy of oxygen vacancies depended on the Eu concentration and the defect compensation mechanism. KNN doped with 3xa0mol% Eu (KNN3Eu) showed good dielectric temperature stability (±10%) with relatively high permittivity (>1800 at 225°C) over the temperature range from 119°C to 495°C, representing a good starting point for development of high-temperature capacitor materials.

The Imbalance Source of Spindle-Tool System and Influence to Machine Vibration Characteristics

Because of various errors in the process of special structural designing, manufacturing and assembLing, there are varying degrees of unbalanced residual content in machine spindle-tool system. This research presents some kinds of imbalance source of spindle-tool system, on the basis of classification, and then its components dynamic balancing quaLity grade influenced on the balanced state of entire system was demonstrated. By means of machine raising-speed idle running in CNC machine, three cases of testing machine vibration signal and analyzing its characteristics were investigated in turns, including spindle witHout assembLing tool system, the spindle with assembLing perfect balanced tool system and the spindle with various imbalance of tool system. The comparing results and conclusions will provide effective guideLine on the researching about spindle-tool systems imbalance influence to high speed machining stabiLity and processing quaLity.

Analysis on the Process of Induction Heating for Shrink-Fit Chuck

According to the principle of induction heating, the skin depth of shrink-fit chuck is determined and the mathematical model of induction heating is constructed. Then a finite element model of induction heating for shrink-fit chuck based on FEM software is set up and the electromagnetic field, temperature field and structure field are obtained. In the end, the paper discusses the influence of the position, current frequency and current density of the coil on the deflection of the clamping bore. Research work provides a theory reference for the design of shrink-fit tool holder and shrink-fit machine.

Stiffness of HSK tooling system in high speed machining

The stiffness of the HSK tool system directly influences the efficiency and the quality of high-speed machining. Based on the mechanics of materials and finite element method, theoretical analysis and digital simulation are done with the stiffness of the HSK tool system. An equation to calculate the deformation angle of the HSK shank is proposed. The basic change law of the stiffness of the HSK tool system is shown and it offers theoretical base for properly applying the HSK tool system to maximize benefit. It is important in theory and application area to develop new-style tool system with our own intellectual property.

Static Performance Parameters and Analysis of the Hydraulic Expansion Toolholder

Based on finite element analysis, the static transmitted torque of Hydraulic Expansion Toolholder is validated. When Hydraulic Expansion Toolholder is on the static state, the article does the analysis of the contact region deformation and contact stress under different structure sizes. The calculation and the analysis results can provide theoretical guidance for Toolholder application and structure design.

Determining Structural Modes of HSK Tool System Based on FEM and EMA

In this research, we computationally analyzed the structural modes of an HSK63E type tool system and verified the results with experimental modal analysis (EMA). The computation was implemented using the finite element method (FEM) based on a linear-elastic theory, with which we computed the natural frequency and obtained the modal shapes under both free and operating conditions. With the method of experimental modal analysis, we also obtained structural modal parameters including the natural frequency, modal shapes and damping ratio under the same free and operating conditions. The computational data were compared with the experimental findings. The reasonable agreement between the two data sets indicated the validity and provided a theoretical basis for using computational methods for determining the natural characteristics and influencing factors of HSK tool system. With this validated FEM model, further analyses were performed to evaluate the unique dynamic performance of the HSK tool system, and to apply dynamic optimum design to other types of HSK tool system.

The Effect of Clamping Force on Static and Dynamic Characteristics of Spindle-Tooling System

This paper investigates the effect of spindle clamping force on the static and dynamic characteristics of the spindle-tooling system through measuring the frequency response function of the tool end point in variable spindle clamping force. The research shows that the limited static stiffness increases accordingly and normal static stiffness changes little as the spindle champing force increases. The high spindle clamping force leads to reduce the modal damping of the spindle-tooling system while the natural frequency varies slight. The analyses of process stability indicates that the low spindle clamping force can improves the process stability because of the higher damping in some clamping force range.

Microstructure and Electrical Properties of Eu-Doped K0.5Na0.5NbO3 Ceramics

(K0.5Na0.5)1–3xEuxNbO3 (0≤x≤0.05) lead-free ceramics have been prepared by a conventional solid state reaction. XRD show that the ceramics possess a pure perovskite structure with orthorhombic symmetry. Dopant Eu restrains the grain growth, decreases the ferroelectric-paraelectric phase transition temperature and leads to a diffuse phase transition. With the increase of Eu, the observed remanent polarization (Pr) decreases while the coercive field (Ec) remains almost unchanged. Nevertheless, for the increase in relative permittivity, the sample with x = 0.005 exhibits the optimum piezoelectric properties, giving a large piezoelectric coefficient (d33 = 121 pC/N) and a high planar electromechanical coupling coefficient (kp = 0.41).

Determination of Capto C5 Shank’s Key Dimensions

Capto shank is widely used in high speed machining, especially in Turning/Milling center. Some of shank’s dimensions exert a tremendous influence on its working performance. In order to find out these key dimensions, finite element method is used to analyze how the change of Capto C5 shank’s nine dimensions affects its radial stiffness. Some key dimensions which have great effects on Capto shank’s properties are found. The research results provide theoretical basis for manufacturing and measurement of Capto shank.

The Property Comparison of Coating Prepared by Oxygen-Acetylene Spray Welding Technology and High-Frequency Induction Remelting Technology

Ni60A coating is obtained by oxygen-acetylene spray welding and high-frequency induction remelting process. Coating Surface, interface between matrix and coating, microhardness and wear resistance are investigated. The results show that both of the processes can achieve coating metallurgically bonded to matrix. But microhardness and wear resistance of Ni60A coating obtained by high-frequency induction remelting process are superior to those of Ni60A coating obtained by oxygen-acetylene spray welding process. At the same time, coating surface by high-frequency induction remelting process is of more brightness owing to less oxide skin. In order to more effectively prevent the hard phase from oxidation, the quartz glass pipe and inert gas should be considered to use in high-frequency induction remelting process.