Research On The 'Trap' Effect Of The Semi-Fixed Abrasive Plate And Its Influence Factors

Abrasive machining is the primary method of precision or ultra-precision processing for advanced ceramic materials.At present, the requirements of machining presicion for advanced ceramic materials become higher and higher. How to improve the machining precision and decrease the surface damage at the same time is the most important problem. In this paper, semi-fixed abrasive machining technique is proposed and it can reduce or eliminate the surface damage caused by large abrasive gains, which will improve the efficiency of precision or ultra-precision processing.The mechanisms of typical abrasive machining methods are reviewed. The concept and range of semi-fixed abrasive machining are discussed.The relationships of 'trap' effect and semi-fixed, chip storage, embeded grain are analyzed.Referencing to the mechanisms of advanced ceramics material removal, the preliminary theory of semi-fixed abrasive plate (SFAP) design is proposed. Ordinary grinding wheel and manufacturing are summarized, SFAP is manufactured successfully in this paper. The parameters: hardness and micro-structure of SFAP have important influence to 'trap' effect, which are tested in this paper.The 'trap' effect of SFAP and its influence factors are analyzed and studied, using damage free single crystal silicon as workpiece and using Rv, Ra as evaluating parameters. The effects of hardness of SFAP, concentration, size and hardness of large grains, machining processing are discussed. As a result, with the increase of SFAP hardness and large gain size and hardness the 'trap' effect decreases, because it is more difficult to embed in the SFAP for large grain when the SFAP is harder or the size of that grain is larger. The concentration of large grain has little influence on the 'trap' effect, however, there is one threshold of the number of large grains to be accommodated by SFAP, when the number of large grains is no more than the threshold, all large grains embed into SFAP; otherwise, a part of large grains can not embed into SFAP and bear the processing load, leading to an increase of surface defects. The 'trap' effect decrease with the increase of processing load, because the normal load acted by single abrasive grain or large grain on the workpiece is increased. The rotating speed of SFAP has little influence on 'trap' effect, for the variation of rotating speed of SFAP speed does not change the load of large grain or abrasive grain acted on the workpiece. While the frequency of single grain passing through the workpiece surface during unit time increases with the increase of rotating speed of SFAP, leading to an increase of surface roughness. In order to study the influence of large grains shape on the 'trap' effect, discrete element simulation and indenter experiment are carried out. The simulation results are consistent with the experiment: The 'trap' effect decrease with the increase of large grains' apex angle.Semi-fixed abrasive machining experiments are carried on single crystal silicon, stainless steel, to validate the performances of high efficiency and precision of SFAP which is manufactured in this study. The effects of processing load and rotating speed of SFAP on the surface roughness and material removal rate of workpiece are discussed.This research provides theory instructions for manufacture technology of the SFAP and semi-fixed abrasive techniques.