Design of A Micro Machine Tool with Double-Toggle Mechanisms

摘要

Micro machining plays an important role in manufacturing the miniature products which are made of various materials with complex 3D shapes and tight machining tolerance. In this paper, a new design of CNC micro machine tool with double-toggle mechanism is proposed. The machine has the characteristics of low cost, ultra-fine feed resolution, and high accuracy. With the double-toggle mechanism and regular driving components including AC motors, ballscrews, and a PC-based controller, the micro machine tool can perform good micro machining for miniature components. Because of the geometrical drive function, the errors of the machine are reduced by the double toggle structure without using high-end driving components and controller. In addition, the design of the structure avoids the drawback of the regular toggle mechanism which cannot have stable feed resolution for the full travel range. The kinematics model and characteristics of the machine were derived and analyzed. Modal analysis and dynamic compliance analysis were also conducted to evaluate stiffness and dynamic characteristics of the machine. A prototype of the machine was built, and the accuracy calibration results showed the machine can reach a positioning accuracy of 470 nm.