Study On Some Technologies In Diamond Cutting Of Microstructured Surfaces With FTS

The microstructured surfaces are widely used and have good prospects in lots of military and civilian industries applications, as their special and unique engineering functions, such as optical, conglutinative, tribological, lubricative, anti-abrasive characteristics and so on. Diamond cutting based on FTS featured high dynamic response and high positioning resolution is a popular microstructured surfaces manufacture technology. Some precision microstructured surfaces fabricated with FTS have been used industrially in many advanced countries. However the research on FTS diamond cutting of microstructured surfaces technology is at start stage in our country. In this dessertion, some works have been done to reduce the gap between our country and foreign countries in the research on ultra-precision machining of microstructured surfaces.High-precision tool path is a precondition for obtaining high quality microstructured surfaces which were formed by the position of spindle, X slide and FTS system. A special tool path generating method should be adopted in order to obtain high precision tool path for machining microstructured surfaces as the special cutting process. In addition to, the microstructured surfaces with large amplitude cannot be finished with FTS because of its shorter stroke. In this dissertation, the method of large amplitude microstructured surfaces tool path generation and allotment was studied base on freeform decomposing and reconstructing principle. A strategy of tool path drive points has been proposed. The compensation arithmetic of tool reference point position error caused by tool geometries and setting error was deduced base on vector mathematics. The methods and arithmetic mentioned above have been proved by trail results. The experimental results showed that the machined surfaces quality and form accuracy of microstructured surfaces manufactured with cpmpensated tool path have an obvious improvement.Tool geometries and tool wear are two key factors of affecting microstructured surfaces quality. A phenomenon of over cutting will appear with unreasonable tool geometries. The application of diamond cutting in practice for manufacturing microstructured surfaces is often limited by the rapid wear of diamond tools. In the dissertation, a general tool geometries design principle to avoid over cutting was proposed according to the 3D profile of microstructured surfaces. The wear of sharp point tip diamond tool was investigated by a series of sinusoidal microstructured surfaces cutting tests. The experimental results showed that the patterns of micro diamond tool include smooth wear with a low feed rate and catastrophic fracture with a high feed rate. The wear mechanism is believed that the diamond on the tool edge and tool tip has been transformed into graphite under the effect of the alternating cutting force loads, cutting thermal loads and micro impact loads in the cutting of microstructured surfaces. The wear of diamond tool with different geometries also was studied experimentally. The experiment results afford a foundation to design and employ diamond tool in diamond cutting of microstructured surfaces.The depth of cut changes along the profiles of microstructured surfaces in the diamond cutting process. The position and velocity of diamond tool movement is not smooth as the existence of sharp corner and step profiles which can cause fluctuation of cutting forces, excite cutting system vibration and make cutting process unstable. Therefore the task of FTS control system is not only to eliminate non-linearity characteristics of piezoelectric actuator but also to decrease effects of disturbances caused cutting force and un-modeling factors. In this case, a variable-structure sliding-mode control with combination approach arithmetic was proposed. The comparison with exponential approach arithmetic was fulfilled experimentally.In order to reduce cutting parameters optimization tests and obtain high quality machined surfaces, a simulation model was established with Matlab/Simulink for diamond cutting process of microstructured surfaces with FTS. Tool path generation and compensation, diamond tool geometries design, control system characteristics, machine tools dynamic response and surfaces generation were integrated in the model. Some linear and non-linear factors also were considered. The simulation model was validated with sinusoidal microstructured surfaces cutting tests. The effects of spindle speed and feed rate on the machined surfaces quality of micro square-pit non-rational symmetric surfaces were investigated by the simulation model. The square-pit non-rational symmetric surfaces were manufactured with the optimization cutting parameters which obtained with the simulation model.