Papers by Author: C. Zhao

Abstract: Based on milling experiment to explore the transformation and stress condition in the process of cutting of the thin-wall part made by aviation aluminum alloy, and then get data from the milling experiment through altering the axial cutting depth Ap=1 mm (a=1 mm), cutting radius Ae, spindle speed n and feed per tooth for milling force fz. Considering the milling force coefficient affected by each milling parameters, the orthogonal experiment of four factors and four levels are designed, and the milling coefficient is solved by MATLAB. The results indicates that the axial cutting depth Ap=1 mm (a=1 mm), the cutting force Fx increases with increasing in feedrate per tooth fz (c). the feedrate per tooth fz=0.03 mm (c=0.03 mm), the cutting force Fx increases with increasing in the axial cutting depth Ap. The discipline that the milling coefficient has an influence on milling force is obtained from the research which can provide the reference on the purpose of optimizing milling coefficient.

Abstract: Machining instability is often the limiting factor on metal removal rate. So the stability of cutting system is an important research in high-speed machining area. It is widely used in engineering practice. In this paper, the stability of high-speed milling was studied by the numbers aiming at the dynamic milling process model of ball-end mill. The dynamic model of high-speed milling process was established. On the basis of Altintas’s theory, the formula about the limit axial depth of cut was derived. Besides, the model parameters of the system were obtained and the accuracy of the stability lobes diagram was verified through the experiments. From this research, it was learned that structure parameters of machine tool-cutting tool system, cutting force coefficients, spindle speed and axial depth of cut were factors affecting the stability in high-speed cutting. And the obtained stability lobes diagram provided a reliable basis in selecting cutting parameters during tool path planning.

Abstract: In the development of a three-dimensional measurement system, binocular stereo matching is the most important and difficult. In the basis of introducing selective principles of matching algorithm, a new stereo matching algorithm for binocular vision is put forward that is named noncoded difference measuring distance. The algorithm effectively grapples with the problem of searching for the coincidence relation of raster and can efficiently and accurately obtain three-dimensional world coordinates of the entities. Experiment results show that this 3D measuring machine can effectively measure the 3D solid profile of free surface. During the evaluation test for accuracy, scan a standard plane. Fit all 3D points in one plane, and then the flatness value of this plane is obtained. The flatness value of the standard plane has been ultimately measured as: ± 0.0462mm, this measuring accuracy can completely satisfy the requirements of rapid prototyping or CNC machining, it as well as achieves the stated accuracy (± 0.05mm).

Abstract: The cutting force in manufacture process was observed with Kistler dynamometer. A special clamp was designed to simulate the real condition of blade cutting. Series of experiments were done. Cutting force reflected structure of the blade and movement of machine. Cutting force was changed with feed speed varied and the rotation of axis B & C. Resultant cutting force was uniform in back and basin of blade and increased with cutting speed went up. Resultant force was waved in edge of blade. Back and basin forces were lager than edge force in X direction. Force X invoked vibration.