Papers by Author: N.Q. Wu

Abstract: This article first presents the performance of Electrorheological Fluid (ER fluid). Thus, a new-style machining technique based on ER effect to form a tiny grinding wheel is developed for superfine machining. By adding abrasive particles to ER, an array of stable chains of ER particles can be shaped when an electric field is applied and abrasive particles are fixed to these chains structure. When the tip of tool is rotated, the abrasive particles rotate with the flow and a superfine grinding process come into being. This process is expected to be applicable to the aspheric surface machining of micro miniature components made of optic glass or other hard-brittle materials.

Abstract: As a special instantaneous bond, particle-dispersed Electrorheological-fluid (ER fluid) is used to cohere abrasive particles in the ER fluid so as to form dynamical tiny grinding wheel in grinding. This technique eliminates the dimension restriction of traditional concretion abrasive grinding wheel and is applicable in optics glass polishing to meet machining demands for micro-apparatus within millimeter or sub-millimeter microstructure. By regulating some parameters such as voltage, ingredient, volume rate of ER fluid, machining time, as well as distance between cone-tool and workpiece etc, the size, rigidity, and abrasive mutual combine-intensity of the micro grinding wheel can be controlled in order to achieve an expected machining effect. Experiments have been carried out by using SEM to analyze the characteristics in applying this technique.

Abstract: The profile accuracy of the workpiece is mainly determined by the accuracy of abrasive wheel in the form-grinding process. Thus, the shaped wheel dressing becomes one of the key points in the form-grinding process. In order to grind the revolving curved surfaces grooves whose cross-sectional profiles are steep and smooth, a new NC dresser with three NC axes is developed by adding a swing axis on the basis of NC external cylindrical grinding machine. A wheel of any desired convex profile can be dressed when using the Diaform single-diamond dresser and the possible geometrical interference between the single-diamond dresser and wheel can be eliminated. By analyzing the influence of installation accuracy on the profile accuracy, a method of comprehensive error compensation is presented. The comprehensive errors can be diminished greatly to improve the profile accuracy by means of error compensation. It is proved in the experiments that the precision requirements of grinding the formed surfaces grooves can be met.