Papers by Author: Xing Xin Xu

Abstract: The CVD diamond films have a series of excellent performances, so it has a wide range of applications in the cutting tools, wearable devices, electrochemical electrodes and other fields, and it has a very substantial market prospects. In this study, The diamond films with a layer of uniform and smooth were deposited on the surface of the complex surface YG6 carbide end mill by using the hot filament CVD method, the quality of diamond films was detected by using the scanning electron microscopy and the laser Raman spectrometer. The cutting performances of diamond coated end mill were evaluated from the workpiece surface quality and tool life two aspects by cutting silicon carbide aluminum reinforced composites, and compared with the uncoated carbide tools. The experimental results show that because of the cutting tool was pretreated that make tool surface coarsening, leading the surface quality was machined by diamond coated tools is lower than the carbide cutting tools. However, the coating can protect the tools, increase the wear resistance of the coated tools and make the life of the diamond coated tools increase 3-5 times than the carbide cutting tools.

Abstract: The surface of the carbide YG6 milling insert was roughened by using three different pretreatment crafts, the diamond films was deposited on the substrate surface, after deposition, the morphology and quality of the diamond films were detected by using the scanning electron microscopy and the laser Raman spectroscopy, the adhesion strength of the membrane-based was discovered by using the method of indentation test. The results showed that: the surface of the substrate had the lower surface roughening with the hydrochloric acid aqueous solution and methanol solution pretreated, in addition the surface of the films had cracks, obviously, the adhesion strength of the membrane-based was unsatisfactory; However, the surface of the substrate had the higher roughening degree with the sulfuric acid hydrogen peroxide solution pretreated, and with good adhesion strength between the film and substrate.

Abstract: The diamond thin films was deposited by hot filament CVD method in the Cemented Carbide (YG6) substrate. The surface morphology and quality of the diamond film coating was detected by scanning electron microscopy and Raman spectrometer. The internal stress of the diamond thin films and Cemented Carbide substrate, exerted by load, was calculated by the method of finite element numerical analysis. The analysis result shows that the internal stress of the film is tensile stress. The maximum appear in the blade and the tip place, the stress distribution more evenly in the middle area of the film. The stress is a zonal distribution and reduced gradually from the matrix surface to bottom in the Cemented Carbide, the results of the finite element analysis can provide the reference for the other methods to determin the diamond film stress and improve the stress between the membrane and substrate.

Abstract: By analyzing the chart data and formulas in the traditional design of the roller chain, together with the SolidWorks modeling features, a fast modeling method of roller chain drive is presented on the basis of the main parameters in the chain drive design. In virtue of the Curve Driven Array, the chain modeling is executed in parts environment, with the track dimension property changed and the dimension driven mathematical formula established to correct the error between theoretical calculation and practical graphics, which ensures a successful array and provides an effective way for the rapid 3D model establishment of chains and the chain drive assembly.

Abstract: With the rapid development of manufacturing technology, high speed, high efficiency and high performance have been the characteristics of metal cutting. And cutting technology has been faced with a lot of opportunities and challenges. But at the same time, cutting parameter optimization has gradually been one of the most outstanding bottle-necks that restrict the rapid enhancement of cutting technology. Since the essences of cutting process, such as cutting force and temperature, are invariable, force and heat constraint are performed here to optimize milling parameters of titanium alloy. Influences of cutting edge strength and cutting temperature on milling parameters are analyzed. Finally, feasible region of milling parameters are obtained.

Abstract: With the rapid development of aviation at home, particle reinforced metal matrix composites (PRMMCs) has been widely applied recently. But at the same time, the difficult machining has gradually been one of the most outstanding bottle-necks that restrict the rapid enhancement of productivity. Here, in virtue of the self-developed ultrasonic drilling equipment, hole-making experiments of common and ultrasonic vibration drilling are performed on SiC particle reinforced aluminum-matrix composites （SiCp/Al）with different content of SiC by using two types of tungsten carbide drill. Drilling characteristics of machining composites with ultrasonic vibration are analyzed from such respects as the composites crush, drilling force, drill wear and hole surface quality. Studies show that, during the ultrasonic vibration drilling process, SiC particle in the composites is prone to break along the crystal connection boundary or suffer ductile fracture under the dynamic ultrasonic impulse, in which the cutting resistance could be reduced and the tool edge could be protected. Thereby, drilling locating precision and hole surface quality could be enhanced, wear of the drill chisel edge effectively improved, and the drilling torque reduced about 30%.

Abstract: From the definition of logarithmic spiral and its particular characteristics, logarithmic spiral is discussed and adopted as the tooth back curve of the relieving shaped milling cutter under the new manufacturing conditions. Thus, the relief angle of each point on the cutting edge keeps instant after regrinding the cutter and thereby makes for preserving the machinability stability. Besides, cutter structure parameters determine coefficient values in the equation of logarithmic spiral tooth back curve. Based on the objected-oriented thought, a CAD system for the relieving shaped milling cutter with logarithmic spiral tooth back is developed in virtue of the language of VBA embedded in AutoCAD, which achieves the automatic generation of logarithmic spiral, realizes the cutter parametric design, shortens the whole cycle and improves the design quality.

Abstract: In recent years, particle reinforced metal matrix composites (PRMMCs）has been widely applied because of its excellent mechanical performances. But the machining is very difficult due to the rigidity of reinforced phase in it, thus the popularization of PRMMCs is restricted much. Here, a method of ultrasonic vibration drilling is presented to the hole-making of Aluminum-matrix composites based on cutting force analysis between common and vibration machining. In virtue of the self-developed ultrasonic drilling equipment, experiments of common and ultrasonic vibration drilling are performed on SiC particle reinforced Aluminum-matrix composites with different content of SiC by using two types of tungsten carbide twist drill. Since the tool life can be represented directly by drilling force, especially the torque, the study of drilling force is very important for the surface roughness, the design and life of drill. Drilling force and its variation in the machining process are analyzed by comparison of common and vibration drilling. It shows that the eviction of drilling chips can be meliorated to some extent, and the drilling torque can be reduced about 30% during the ultrasonic vibration drilling process.