Xianglong Zhu

Optimization of support location in mirror-milling of aircraft skins:

As a new technology of reducing thickness of an aircraft skin, the mirror-milling system is widely used. The objective of this study is to optimize the support location in mirror-milling of aircraft skins. The study analyzes the machining mechanisms of mirror-milling system and establishes a theoretical model to predict the milling forces. In addition, it develops a finite element model to simulate workpiece deformation so as to predict workpiece profiles in mirror-milling system. The results of the study show that with the optimized support location, the profile error of the workpiece is reduced by 73.5%, whereas machining efficiency is increased.

Research on topography control of two-spindle and three-workstation wafer grinder

Silicon wafers are widely used in integrated circuits. This article addresses an important aspect of flat wafer grinding: grinder design. An advanced grinder with two-spindle and three-workstation for ø300 mm silicon wafer based on the principles of in-feed grinding was successfully developed. A mathematical model on topography control was developed for the first time to provide a totally integrated solution for dressing chuck with given topography. The developed model was then applied to predict the chuck topography or to adjust the obliquity adjustment device according to the parameters of ground chuck. Finally, the pilot experiments on two groups of chucks, which demonstrate the correctness of topography control are included.

Development of Ultra-Precision Grinder for 300mm Wafers

This study presents design of an ultra-precision wafer grinder which incorporates state-of-the-art automatic supervision and control system. The wafer grinder is characterized by wafer surface shape control, grinding forces and wafer thickness monitoring systems. The design provides a totally integrated solution to the ultra-precision grinder that is capable of grinding silicon wafers with surface roughness Ra<3 nm and total thickness variation<2µm/300mm.

Multipoint support technology for mirror milling of aircraft skins

ABSTRACT Mirror milling is a new efficient and green technology of aircraft skin processing. Currently, the support head of mirror milling system is mostly a metallic sphere and the support area is smaller than the milling area, which results in the deformation error of workpiece. To solve this problem, a new multipoint support device is proposed. The purpose of this research is to optimize the support location of multipoint support in mirror milling of aircraft skin parts. The simulation and experimental studies indicate that the deformation of workpiece is reduced by increasing the support points. To obtain the good thickness consistency of workpiece, the distribution of the support points should make the rigidity distribution of the workpiece consistent with the change of milling force, not as close as the milling trajectory. The workpiece deformation error can be reduced only by changing the support locations.