Papers by Keyword: Ultra-Precision Manufacturing

Abstract: Off-axis aspheric surface is an indispensable optical device for the high precision measurement and manufacturing equipment, and the tool path generation is a very important factor for the manufacturing to obtain the surface with high precision form and nanometric surface finish. In this paper, the systemic description of tool path generation method about the off-axis parabolic surface with ultra-precision single point diamond turning is processed. Two effective methods of generating the accurate spiral tool path are proposed and compared. The proposed methods are mainly based on mathematical calculation directly from analytic surfaces, including the general process of tool path generation, cutting-tool compensation and avoiding tool interference. This work can provide the theoretical basis of choosing the cutting tool path for off-axis parabolic surface and can improve the efficiency and precision of machine. Finally, some cutting simulations are implemented to prove the proposed methods.

Abstract: This publication focuses on the ultra precision manufacturing of hardened steel parts with single crystal diamond tools for optical applications such as injection moulding. Nowadays optical steel moulds are nickel plated, in order to be able to machine the surface with single crystalline diamond tools. One technology that has proven its potential for replacing this procedure is the ultrasonic assisted diamond turning technique. This process allows direct machining of hardened steel with single crystal diamond tools, which is conventionally not possible due to the high tool wear. The ultrasonic assisted diamond turning process is applied in order to machine different steel alloys that are conventionally used for mould manufacturing in injection moulding. The goal is to analyze the influence of the steel alloy and the material microstructure on the machining results. The presented analysis show the capabilities of this new technology and opens the door for it to compete with established manufacturing processes, such as the manufacturing of nickel plated mold inserts.

Abstract: With the rapid development of modern optics and correlative science and technology, hard-brittle materials such as optical glass, optical crystal and glass ceramic have very important applications in the fields of military, space and aviation, electronics and so on. It is of great importance to research optical machining method for hard-brittle materials for the development of science and technology. Different kinds of ultra precision machining methods have been developed to meet different industry requirement. Such as chemical mechanical polishing, precession polishing and magnetorheological finishing, etc. Under most conditions the optical surface after ultra precision machining would have certain contaminant particles and this would affect its working ability in future use. Formerly the polished workpiece is cleaned by flowing water or ultrasonic cleaning and the contaminant particles couldn’t be totally removed. Laser cleaning is brought forward in this paper and good results could be anticipated.

Abstract: Based on the theory of kinematics for multi-body system, the relative motion constraint equation is deduced according to the structure layout and the error distribution of the ultra-precision lathe Nanoform200. By solving the constraint equation, the corrective NC code is derived that can compensate the geometric errors. The error compensation software is developed aimed at the ultra precision manufacturing of optics parts. The cutting experiments show that the method and model in this paper can improve the accuracy about 50% for the ultra-precision turning of optical parts.