Papers by Author: D.W. Lee

Abstract: Flexure-hinge mechanisms are commonly used in the design of translational micro/nanopositioning stages. They can offer a drive system with negligible friction and no need for lubrication. Usually, a large motion range requires the use of a very long actuator which could interfere with a tight workplace. A lever which amplifies the input motion of a short actuator is an effective technique to solve the problem. This paper presents the methodology for the design of a lever-type magnified flexure mechanism used for the ultra precision fast tool servo (FTS) system. A lever type hinge mechanism is designed and utilized to guide the tool holder and to preload the PZT actuator. A low capacitance PZT actuator is adopted to match the given amplifier to achieve optimum performance of device displacement. A high resolution capacitive sensor is utilized to measure the natural displacement of the tool holder. An amplifier with a multiplying factor of 12 is utilized to magnify the drive signal for the expansion and retraction of the PZT actuator. Meanwhile, the motion range of the FTS system can reach up to 98.12 μm with a primary resonant frequency of about 460 Hz, and the amplification of the lever flexure mechanism is approximately 5 as calculated from the experiment.

Abstract: Recently, ultra-precision machining of components and dies for information and communication industries, such as fresnel mirrors, diffraction lens, and die for super high intensity reflective sheet is one of the major target. To machine three-dimensional micro patterns, such as super high-intensity reflective sheets, ultra-precision and mirror surface fabrication processes are required. It has been reported, however, that continuous cutting, such as turning or shaping, is more suitable to ultra-precision machining. Many researchers have studied the manufacturing process of reflective sheet dies to obtain high form accuracy and surface quality. In this paper, ultra-precision shaping system was developed to fabricate micro patterns mechanically. In order to estimate performance of the shaping system, micro V-shaped grooves and tetrahedron pattern arrays for a super high intensity reflective sheet was applied. Also, a new measuring technology to inspect form and machining errors of a machined tetrahedron patterns was proposed. The results show that shaping system has a positioning accuracy of x, y, z axis with 100, 10, 10nm resolution, respectively. Micro V-shaped grooves could be machined at various depths and micro tetrahedron patterns with a good quality were obtained as well.