Thin-walled Beam Mirco-milling Process Of Flexible Component

Micro flexible components with thin-walled beams and high aspect-ratio characteristics are important parts in pendulous accelerometers and vibrating beam accelerometers for its advantages of small volume, high precision and good sensitivity. But thin-walled parts is difficult to be clamped for the micron scale. There are also some key problems, such as thin wall deformation, micro burrs formation, surface roughness and work hardening on the surface layers. To solve the above problems, this paper focus on the mechanisms of deformation and burrs formation, then the machining processes were improved in order to reduce the roughness.Firstly, mechanics model and deformation characteristics of thin-walled beam in micro milling process was studied, the flexible deformation curve of thin-walled beam was analyzed, which showed that the weak stiffness of thin-walled beams is the key factor for its deformation. Building auxiliary supporting structures to control thin-walled beams formation and deformation, its selection requirements also were proposed. The experimental tests verified the feasibility of this method.Secondly, The micro burrs formation mechanisms in micro milling was analyzed. It was found that the radius of the micro tools and weak rigidity of workpiece surface play critical roles in micro burrs formation. Building sacrificial layer to control and inhabit burrs formation was proposed. The sacrificial layer was removed after micro milling process, then components with burr-free were obtained.Thirdly, The factors affecting the surface quality of flexible thin-wall beam in micro milling was studied. Tool diameter, spindle speed, depth of cut and feed per tooth were took into account to study the influence degree on surface roughness of micro flexible components. The optimization cutting parameters were obtained by orthogonal tests.Finally, machined surface features of beryllium bronze were studied after the micro milling process. The mechanisms for machining hardening were analyzed, then machining experiments were performed to explore different cutting tool edge radius for the influence of microhardness. The microhardness mechanisms also were analyzed.