Papers by Author: Chuan Zhen Huang

Abstract: The interaction between abrasive waterjet and target is studied by computational fluid dynamics (CFD) and finite element method (FEM). The flow field inside and outside abrasive waterjet (AWJ) nozzle is obtained by CFD software. Then the pressure distribution of the fluid on the target is plotted, which is in well agreement with the force distribution of the AWJ impacting on the target and leads to the material deformation. The interaction between the AWJ and target and the fluid-solid coupling is happened. The cloud figure of the target’s deformation and stress are obtained by FEM software. The AWJ parameters such as the flow velocity, off-set and abrasive volume factor have a great effect on the material deformation and the stress distribution. The study results provide a new method to study abrasive water jet machine mechanism and help to optimize process parameters.

Abstract: Laser-assisted waterjet micro-machining can significantly reduce the thermal damages to the workpiece as compared to the traditional laser machining process, and hence can overcome the problems associated with laser machining, such as the formation of heat-affected zone, which is a serious issue for thermal sensitive and functional materials. An experimental study on micro-grooving of monocrystalline silicon wafers is reported in this study to explore the effects of process parameters on the groove depth and width as well as the heat-affected zone (HAZ) width. Predictive models based on dimensionl analysis are then developed for estiamting the groove characteristics.

Abstract: Single crystal silicon carbide (SiC) is a new semiconductor material that has a great potential to be widely used. However, SiC is a kind of difficult-to-machine material due to its extreme hardness and brittleness. The present study investigated the machinability of single crystal SiC using dry laser and three different water-laser co-machining processes. The results indicate that using the hybrid laser-waterjet micro-machining to micro-groove single crystal SiC can derive the clean and straight edges and thermal damage-free grooves.

Abstract: The milling of AISI 321 stainless steel which has wide engineering applications particularly in automobile, aerospace and medicine is of great importance especially in the conditions where high surface quality is required. In this paper, L16 orthogonal array design of experiments was adopted to evaluate the machinability of AISI 321 stainless steel with coated cemented carbide tools under finish dry milling conditions, and the influence of cutting speed ( V ), feed rate ( f ) and depth of cut ( a_p ) on cutting force, surface roughness and tool wear was analysed. The experimental results revealed that the cutting force decreased with an increase in the cutting speed and increased with an increase in the feed rate or the depth of cut. The tool wear was affected significantly by the cutting speed and the depth of cut, while the effect of the feed rate on the tool wear was insignificant. With the cutting speed increased up to 160 m/min, a decreasing tendency in the surface roughness was observed, but when the cutting speed was further increased, the surface roughness increased. The effect of the feed rate and the depth of cut on the surface roughness was slight.

Abstract: Gear grinding is expensive and difficult to research due to its complex kinematics and meshing theory. In the paper, a simplified method based on the meshing model of spiral bevel gear system is presented. With the relative speed and normal curvature of tooth surfaces and grinding wheels on meshing point deduced from differential geometry theory and grinding parameters, the spiral bevel gear grinding can be simplified to fundamental grinding process like surface, cylindrical and internal grinding, which may be utilized to perform experimental investigation on mechanism of gear grinding.

Abstract: A new processing technology is used in micromachining silicon nitride ceramics for improving the processing efficiency. Laser-assisted waterjet machining technology with near damage-free plays an important role in reducing the heat-affected zone (HAZ). In order to understand the effects of process parameters, such as pulse energy, waterjet offset distance and water pressure, on microgrooving of silicon nitride ceramics and the machining performance, a full-factorial experiment with the comparison experiment has been carried out in this study for analyzing and discussing the groove geometry, the surface quality and HAZ width. It can be concluded that the laser-assisted waterjet processing technology can expel more material removal with near damage-free.

Abstract: The cutting edge radius and cutting thickness as well as feed rate are in the same order of magnitude in micro-cutting. So it will appear a situation that the chip cannot be formed when the cutting thickness is less than a certain value which is the minimum cutting thickness. It is possible to find a method that can determine the minimum cutting thickness in the finite element simulation of micro-cutting according. In this paper, a series of finite element simulations of different workpiece materials in micro-cutting are carried out and several different minimum cutting thicknesses are obtained. It is shown that the minimum cutting thickness is related to the workpiece material in micro-cutting. When the workpiece materials are different, the minimum cutting thicknesses obtained are also different in micro-cutting.

Abstract: In this work, two kinds of Al₂O₃-TiC-TiN ceramic cutting tools (AC2U and AC2UN2) were developed by hot-pressing sintering techniques. The mechanical properties were measured and the cutting performance was investigated. The workpiece used in the cutting experiment was quenched carbon tool steel T10A, and the tool material for comparison was LT55. The wear resistance and the main wear patterns of the ceramic tools were analyzed at the high speed of 300m/min. The results indicated that the novel Al₂O₃-TiC-TiN ceramic cutting tools showed better cutting performance than LT55, and AC2UN2 was better suitable for machining quenched T10A. When the cutting condition was v=300m/min, f=0.1mm/r and a_p=0.1mm, the adhesion wear and abrasive wear of the novel ceramic tools were slighter than those of LT55, the diffusion wear resistance of AC2U was better and the oxidation resistance of AC2UN2 was better.

Abstract: In order to fulfil the actual request of machining process to the machining database system, according to the characteristics and requirements of machining process, the fuzzy technology and case-based reasoning method were introduced to the design of machining database system. The reasoning process of case-based reasoning method and three main aspects of the fuzzy model were discussed. The match of cases and fuzzy comprehensive evaluation were introduced. The function of high-speed machining database was analyzed and the structure of the database was described. The users can use the database to acquire the overall solutions about high-speed machining.

Abstract: The cutting performance, failure mechanisms and reliability of Al₂O₃/TiC micro-nanocomposite ceramic tools with different geometry parameters in continuous machining of austenitic stainless steel were studied. The results showed that the largest metal removal amount was got at the cutting speed of 80 m/min, the feed rate of 0.15 mm/r and the cutting depth of 0.1 mm. The failure modes of the tool with small chamfering width and corner radius were mainly cutting edge fracture and tool materials peeling off, which was due to the subcritical crack growth. The life of the tool with small chamfering width and corner radius well followed the Gamma distribution.