Materials Science Forum Vols. 626-627

Abstract: Glass possesses poor machinability in diamond cutting due to its high hardness and high brittleness. In order to investigate the effect of cutting fluids on the machinability of glass, this paper first conducted soda-lime indentation experiment, and then examined the resulting indentation by optical microscope. Based on this, turning tests were carried out to evaluate the influence of the cutting fluid properties on the machinability of glass. Boric acid solutions were selected as cutting fluids in the tests. The surface processing quality of soda-lime was assessed based on the observations of the micro- morphology of the turned surfaces utilizing AFM. Experimental results indicated that compared with the process without cutting fluid action, the machinability of glass soda-lime can be improved by using boric acid solution as the cutting fluid.

Abstract: The characteristics and principle of deliquescent polishing technology for potassium dihydrogen phosphate (KDP) crystals are introduced, and the performance requirements of deliquescent polishing fluid for KDP crystals are proposed. The main components of the deliquescent polishing fluid for KDP crystals were selected according to these performance requirements. Through uniformity experiment, stability experiment and fluidity experiment, uniformity, stability and fluidity of deliquescent polishing fluid for KDP crystals prepared using the selected components were tested. Through deliquescent polishing experiment of KDP crystal, polishing performance of deliquescent polishing fluid compounded using the selected components was tested. The material removal rate of the KDP crystal in the deliquescent polishing experiment was 6.03μm/min, and the surface roughness of the KDP crystal after deliquescent polishing was 4.857nm. The experimental results show that the compounded deliquescent polishing fluid for KDP crystals has good polishing performance and can reach the requirements.

Abstract: According to the theory of axiomatic design, to process function decomposition and grey cluster analysis of high speed milling cutter with indexable inserts, found the design matrix of cutter, and propose the design method of cutter based on high speed milling safety, stability and efficiency. High speed face milling cutter for machining aluminum alloy was developed according to design method and design matrix of cutter, experiment and fuzzy object element evaluation for cutting performance of cutter was accomplished. Results showed that there was not design loop which existed in the development of cutter, design process was simplified effectively, cutting energy of high speed milling cutter using axiomatic design method was dispersed, it held higher safety, cutting stability and efficiency, comprehensive cutting performance met the design requirement of high speed milling cutter.

Abstract: This paper deals with the effect of cutting speed on chip fracture strain in high speed cutting. Firstly, a chip-fracture-strain-measuring device is designed and made according to chip breaking principle. Secondly, experiments are performed by the chip-fracture-strain-measuring device. The experiment results show that chip fracture strain increases first and then diminishes as cutting speed increasing in high speed cutting while feedrate and depth of cut are constant values. Lastly, the effect of cutting speed on chip fracture strain is theoretically analysed from three main factors which affect chip fracture strain. The study above lays a theory and basis for future investigation of chip fracture strain of the other metals and for future investigation the mechanism and chip breaking forecast system of 3-D groove insert in high speed cutting.

Abstract: The tool-chip contact length, as an important parameter controlling the geometry of tool crater wear and understanding chip formation mechanism, is widely investigated in machining. The aim of this paper is to study the influence of chip curl on tool-chip contact length by means of experimental observations with high cutting speed. The relationship between tool-chip contact length, chip radius of curvature and uncut chip thickness was investigated. Experimental results show the effect of increasing spiral chip radius on tool-chip contact length with low uncut chip thickness in high speed machining.

Abstract: Separating the workpiece velocity on the plane of grinding wheel, it is helpful to analyze Quick-point grinding mechanism. There are some relations among wheel’s deflective angle, workpiece feed velocity and tangential velocity. In this research, the resultant workpiece speed, grinding contact zone and material removal mode is analyzed. And a model is established which is helpful to analyze the tendency of component grinding forces and force ratio. It is found the grinding force is influenced by the factors such as cutting depth, wheel velocity, grinding angle as well as equivalent diameter, respectively. Finally, a theoretical basis for actual processing is provided.

Abstract: In the light of the strongly coupled and nonlinear characteristics of a power magnetic bearing, a new control algorithm, which can integrate the vector control of torque windings and the independent control of levitation windings, is proposed to solve the coupled relationship between torque windings and levitation windings effectively. Additionally, a good speed regulating performance and stable levitation capability can also be obtained by using the algorithm. Finally, a simulated model is built according to the essential method of the algorithm and MATLAB/Simulink is adopted to analyze the control system quantitatively and qualitatively.

Abstract: A design proposal for developing a high-precision timer of the real-time digital copying control system is put forward by analyzing the real-time characteristics of Windows 2000 operating system. Proposals of using information systems timer—WM_TIMER, multimedia timer, VxD and hardware to achieve high-precision timing in Windows operating system are analyzed and compared. Based on computer high-frequency timer and multi-thread technology, timing function provided by Microsoft Visual C++ is used to achieve a high-precision software timer of the system. Finally, the researched timing method is tested in Advantech IPC-610 host with Intel Pentium 4 processor, and the maximum timing error is less than 5μs which meets the system timing requirements.

Abstract: The purpose of this paper is to show the investigation on a type of unitary piezoelectric four-component cutting dynamometer. Based on piezoelectric effect of quartz crystal, such as torsion effect, transverse effect, lengthways effect and shearing effect, horizontal moment and three-direction orthogonal forces carried on the dynamometer during cutting process can be measured simultaneously. The dynamometer can be used to measure forces and horizontal moments in drilling, grinding, milling, turning. A secondary purpose is to optimize structure parameters of the dynamometer by ANSYS. The dynamometer has good performance with high sensitivity, good linearity and repeatability and low crosstalk after optimizing.

Abstract: While using natural diamond tool to cut stainless steel alloy, the cutting parameters have a great impact on tool life. The impact of cutting parameters on influencing cutting tool life was studied through experiments on using ultrasonic vibration to cut special stainless steel alloy. The experiments were conducted with various cutting speeds, different tool feed rates, altered cutting depths and adapted vibration parameters. Consequently, the relative curve between cutting parameters and tool life was obtained. The experimental results indicated that in the ultrasonic vibration the diamond tool can manufacture stainless steel alloy precisely and made surface quality well. The tool life depended on the spindle speed of machine tool as well as the amplitude and frequency of ultrasonic vibration to a large extent. Among the parameters which affect the processing quality, cutting speed was utmost, followed by feed followed, and the influence of back cutting depth was insignificant.