Design and Development of Double Spiral Shaped Flexural Feed Stage for Micro-drilling Workstation

Abstract

Flexure based system is class of compliant mechanisms which allows motion by bending the load elements. Accurate linear motion is one of the features of the flexure based systems. Due to these advantages flexural based mechanisms are used in various applications demanding micro and nano-positioning accuracy. The established high positioning accuracy of flexural mechanisms sets the motivation and promise for its utility in development of economical micro-drilling work station. This paper presents development of flexural guideways for micro-drilling workstation. Flexural systems are light in weight, possess low friction and require no lubrication. Use of spiral shape flexural guideways is the key element for accurate linear motion in feed direction in the developed system. In this paper, proposed spiral shape flexural mechanism is analyzed for its linear motion and strength using finite element analysis. The linear motion of the flexural feed stage is observed under feed force and undesirable lateral forces. The low axial stiffness and high radial stiffness is required to provide accurate linear motion even under presence of the undesirable lateral forces. Based on finite element analysis, the flexural design is converged and then accordingly fabricated for its implementation. The experimental results have shown that the flexural mechanism is capable of providing linear motion within ±5 µm accuracy. Further implementation of flexural stage could reduce the positioning errors. The inherent accuracy in linear motion of the flexural guideways has enabled to make micro-drilling up to 50 µm with ease and simplicity in design.