Due to their excellent performances such as mechanical,thermal,chemical,optical and electrical properties,polycrystalline diamond(PCD) are widely used in many fields.However,having high hardness and high wear resistance,PCD compacts are very hard to be machined.Electrical discharge and ultrasonic-assisted mechanical combined machining is an ideal method for PCD processing.On the basis of analyzing the principle of the combined method,the electrical discharge and ultrasonic-assisted mechanical combined machining process was realized by using bronze-bonded diamond grinding wheel.The relevance of the machining effects and the parameters of the combined machining method were studied.The experiment results show that parameters of pulse width,pulse interval,peak current,ultrasonic amplitude and open-circuit voltage affect the machining effects distinctly.

Some of the critical and practical issues regarding the problem of condition monitoring of mobile equipment have been discussed, and an anomaly detection method without priori knowledge has been proposed. The method involves setting amplitude benchmark via spectrum amplitude in normal condition and obtaining the maximum entropy value in abnormal condition. The condition identification is achieved through estimating the amount of anomaly information in spectrum, and a measure of anomaly condition is given by the anomaly degree derived from entropy value dividing the maximum value. The sensitivity, stability and computation load of the method have been also discussed, and the method is validated on an experimental test-bed that the test bearings with different fault diameter support the motor shaft.

Polycrystalline diamond, (PCD) is currently used in the industry for cutting tools of difficult-to-machine materials because of its superior characteristics such as hardness, toughness and wear resistance. But the PCD material is difficult to machine due to its above properties. Before making the PCD blank in varies tools, the lapping process is essential and necessary. The lapping quality depends heavily on the parameters. Therefore it is of great significance to study the path and velocity of lapping process for ensuring the lapping quality and uniform wear of abrasive disk. In this paper, on the basis of kinematics and geometry principle, the path equation was established. The complicated lapping process can be converted into two rotation movements, i.e. the movement of part against the center of lapping disk and rotation of fixture around its center. The relative path and relative velocity of random point of the part against abrasive disk were also analyzed and calculated. The computer simulation software was developed for figuring the path curves and instantaneous velocity of the lapping process. The results show that the abrasive disk can wear uniformly and the lapping quality can be raised. The application of computer simulation software provides the possibility to analyze the lapping principles, which is a simple, convenient and effective method.

A velocity blending method is devised for micro-segment line high-speed machining. The model is constructed for blending velocity, and the blending curve equation is established under the constraint of maximized contour error. According to MATLAB simulation, the proposed model and its solving algorithm can achieve the high-speed linking between micro-segment lines, and the efficiency is promoted distinctly.

Movement relationship of the horizontal ultrasonic machine for processing polycrystalline diamond wire drawing dies was analyzed and the trajectory equation between tool and wire drawing dies was formulated. The movement trajectory of the tool relive to the wire drawing dies was studied by using computer simulation technology, on the basis of which the processing parameters were optimized. The results indicated that processing trajectory was a function of the parameters such as the motor speed of the chuck (N) and the eccentric wheel (F) and the location of the lever rotation center (a). The processing trajectory was seriously uneven when N=zF/n (z, n is positive integer). When n was a definite value, processing trajectory would be more uneven with the decrease of the value z.computer simulation technology can optimize the trajectory of the horizontal ultrasonic machining of polycrystalline diamond wire drawing dies and provide effective guidance for the further optimization of the mechanical structure of the horizontal ultrasonic machine.

Metal microwires mean the metal wires with diameter less than 0.10 mm.The metal microwires have not only the characteristics of metal materials but also the special performances of nonmetal materials such as good electric conductivity,good thermal conductivity,high strength,high elasticity,good wear resistance and anti-corrosion,high temperature resistance,heat stability,better screening,antimagnetism,radiation protection,less electrostatic effect,and so on.Therefore the metal microwires are widely used in the various departments of the national economy.The development of the modern technologies urges the metal microwires to progress towards the high precision and minuteness,which puts forward higher request to the precision of diamond dies for drawing the metal microwires.The precision of the dies made in China is much lower than that of Japan and Germany products.The micro-ultrasonic machining of diamond dies for drawing the metal microwire was studied on the basis of the authors′earlier researches.High precision dies were developed with the dimension error of 0.42 μm and the roundness error of 0.18 μm.