Papers by Keyword: Ultra-Precision

Abstract: Materials such as binderless tungsten carbide and silicon carbide have become ubiquitous in the fabrication of high-performance tooling and molding inserts. But while conventional grinding of these hard ceramics has been studied in depth, the theory underlying their super-fine finishing has been less extensively explored. In particular, the boundary in process parameters that delineates the brittle/ductile removal transition remains mostly undocumented. In this paper, we review some super-fine finishing methods for carbide materials, based on both bound and kinetic abrasive processes. The focus is then placed on modelling the interaction between material and abrasives under their respective process conditions, and deriving some useful criteria guiding the brittle/ductile transition.

Abstract: The optical structure has a large number of micro-structures, which has multiple arrays, complex free-form surface features. But those can not be achieved the requirements with traditional turning and grinding processing, it require to use high-frequency and micro-feed to get ultra-precision machining precision. After creating the 3D digital model of micro-displacement platform using Pro/Engineer, and analyzing the motion and the force, the paper studies the influencing factors about the rigidity and acceleration and explores the motion characteristics of the micro-displacement platform in the high-frequency control, and it the establishes the corresponding dynamics equation. The stiffness and linearity data is accessed after the micro-stage is simulated used by Admas and Ansys software. According to the above data, the structure of micro-stage is optimized in order to meet the ultra-precision machining accuracy and the quality of the workpiece. The research takes advantage of the favorable conditions of the Nanofabrication Laboratory, and it has completed the physical production of the micro-displacement platform supported by the introduction of innovative R&D team program of Guangdong Province, those provide a reliable experimental conditions for future in-depth study.

Abstract: It is difficult to balance long travel & high precision, especially in multi-coordinate machining. In ultra-precision cutting, grinding and non-traditional machining, aimed at tri-coordinate ultra precision machining, studies the ultra precision machining technology and theory in this paper. It attempts to seek the principle in ultra precision machining as well as construct a pilot antitype with the ultra precision tri-coordinate machining system machine.

Abstract: This essay briefly introduces a structure scheme design of a high diameter-length ratio rotary plate. This structure scheme is unique from any well-known schemes. In this scheme, there is only one flat act as the working flat for both main thrust bearing and aux thrust bearing. It minimizes the faces which need lapping. At the same time, this scheme minimizes the number of assembling parts. So, it will be easier for this scheme to achieve high accuracy. This essay includes the process of design: calculation for bearings and schemes compare.

Abstract: Ultra-precision machining is in the forefront of advanced manufacturing technology and also will become the basis of future manufacturing technology. Ultra-precision machining already has turned into the enabling technology to success in the international competition. Some new progresses in traditional ultra-precision machining processes including processing and measuring techniques, machining equipment, and analysis methods are introduced in this paper. Components with high form accuracy and good surface roughness are widely applied to precision apparatuses. Structured surfaces can be acquired by selecting reasonable machining parameters before mechanical process. The continuous growing markets will fuel many industrial sectors by ultra precision machining. We should pay great attention to the further developments of this technology.

Abstract: A finite element model of an ultra-precision grinding machine that can have high precision and high stiffness is constructed and structural analysis is done with equivalent stiffnesses of linear motion guides by after structural design and the deformation of the grinding machine is obtained. In order to reduce the deformation of the grinding machine that causes bad influence, structural complement is conducted by adding ribs at the lower part of the column. Also, the straightness of the grinding machine is improved by lifting that the base side of the column.

Abstract: X-Y positioning system subject to rapid development of high technique is becoming one of the core parts in modern industries. The requirement of motion control for such systems advances rapidly, such as ultra-precision processing, micro/nano manufacturing, packing and so on. In addition to the demand of positioning precision, coordinated movement is also specified. In this paper, a scheme of X-Y positioning platform based on ACS motion controller is proposed. Then, system configuration and parameter optimization are presented. Simulation results demonstrating the effectiveness of the accurate tracking for the desired trajectory are given.

Abstract: This paper introduces a new position method based on phase difference. The electrocircuits are designed to meet the position demand. The signal produced, phase demodulation, drive circuit are described. Lots of experiments are performed to test the linear error, hysteresis error, repeatability error and stability error. The uncertainty is synthesized based on testing data and the results show that the displacement error form electrocircuits is less than 11.2nm.

Abstract: In this paper, ultra-precision shaping and ultra-smooth polishing investigations have been done upon a high-purity quartz glass substrate with an aspheric surface in nanoparticle colloid jet machining, which is an ultra smooth surface processing technique utilizing surface chemical reaction between work surface atoms and nanoparticles to remove the uppermost surface atoms. The shaping and polishing characters of high-purity quartz glass in nanoparticle colloid jet machining has been researched. The surface profile of the high-purity quartz glass workpiece before and after shaping has been measured by surface profilometer. And the surface microscopic morphological characteristics of high-purity quartz glass surface polished by nanoparticle colloid jet machining have been observed by atomic force microscopy (AFM). The measurement results indicate that nanoparticle colloid jet machining has good shaping ability for surface shape correction in ultra-precision machining. And the AFM observation results show that the roughness of the high-purity quartz glass surface has been reduced from 1.919 nm RMS to 0.784 nm RMS by nanoparticle colloid jet machining.

Abstract: In this paper, ultra-precision shaping and polishing experiments have been done to research the shaping and polishing characters of nanoparticle colloid jet machining. A high-purity quartz glass sample with aspheric surface profile was employed as workpiece and polished by nanoparticle colloid jet machining. We utilized surface profilometer to measure the surface profiles of workpiece before and after shaping by nanoparticle colloid jet machining. The measurement results indicate that the nanoparticle colloid jet machining has good shaping ability to satisfy the demands for surface shape correction in ultra-precision machining. Atomic force microscopy (AFM) was utilized to observe the surface microscopic morphological characteristics of the workpiece surface polished by nanoparticle colloid jet machining. The observation results show that the roughness of the workpiece surface has been reduced from 1.919 nm RMS to 0.784 nm RMS by nanoparticle colloid jet machining. Based on the atomic force microscopy observation results, power spectral density analyses have been done to evaluate the polishing performance of the nanoparticle colloid jet machining.