The Structural Design And Analysis Research On Precision Compensation Unit Of Piezoelectric Drive NC Milling

The feeding of ultra-precision machine is the key to the quality and the efficiency of the machining. In order to adapt to the development of ultra-precision processing technology and meet the high efficiency and precision requirements of the ultra-precision machine, the Z-axis feed mode of the ultra-precision machine tools with the ball screw and the micro piezoelectric compensation is researched and the flexible hinge structure associated with the piezoelectric structure is designed and analyzed in this topic. They provide reliable output protection of the force and the displacement for the piezoelectric actuators. This design opens up a new way that the piezoelectric actuator is used for the Micro-feed mechanism of machine tools which request low orders of magnitude in vertical direction. The paper's primary coverage is as follows:(1) Outlines the developing history and present situation of the Ultra Precision Machining, the Ultra Precision Machine Tools and the Machine Driven Approach (including stepping motor, rolling guide, hydrostatic sideways, linear electric motors and new intelligent material). The developing course and the unique advantages that applied to in the field driven of piezoelectric driven are systematically summarized. Then the main research contents of this paper are illustrated.(2)Introduces the basic principle of the piezoelectric effect and enumerate the important characteristic indexes of the piezoelectric stack. Mechanical characteristics of piezoelectric driven is derived from the two aspects of statics and dynamics. They lay a solid theoretical basis for the next step of flexible mechanism design and simulation analysis.(3) Determines the holistic frame construction of the ultra-precision machine tools finally based on argumentation of the piezoelectric micro-feed actuator project, and then the key components are selected according to the requirements of processing. The structure of piezoelectric actuator for compensation is mainly designed.(4)Selects appropriate type of flexible hinge through simulation analysis, and the mechanical characteristics of right-angle flexible hinge are derived. Designs the structure of the flexible hinge according to the design requirements of the machine tools, and analyzes the kinematics and the modal of the flexible hinge with the ANSYS software in order to lay a foundation for the further optimization.(5)Analyzes the structure of the flexible hinge model by the method of the Orthogonal Test, and then designs an orthogonal table which has five factors and four levels in accordance with the necessary test index (maximum stress, maximum strain and first-order natural frequency), gets the optimal solution based on the analysis of range about the sixteen groups of analytical result.(6)And then analyzes the kinematics and the modal of the flexible hinge with the ANSYS software again in order to verify the optimal solution with optimal effect in mechanics performance and dynamic characteristics. Actually processes the flexible mechanism with Wire-cutting technology, tests the linearity, resolution and stability of the piezoelectric drive unit with the laser displacement sensor and makes relevant conclusions.