An analytical model for the elastic stress field during scratching an isotropic hard brittle material is presented. A critical function for crack propagation for single grit scratching an isotropic hard brittle material is developed. The effects of original crack density on the surface, strain rate and grinding coolant are considered in the function. Controllable grinding mechanisms of surface micro cracks on fused silica are investigated based on the critical function for crack propagation. The grinding mechanisms variates from ductile mode to low-load semi brittle mode, full brittle mode and high-load semi brittle mode in sequence with the increasing single grit scratching depth. When the workpiece feed rate is low to 1 mm/min, fused silica is removed by crack-free ductile grinding, but the material removal efficiency is too low for practical fabricating of fused silica lens. While full-brittle grinding is a feasible precision process for its shallow subsurface damage, high efficiency and good self-sharpening of grinding wheel.
YAO Peng
,
WANG Wei
,
HUANG Chuanzhen
,
ZHU Hongtao
. Analytical Model for the Elastic Stress Field during Scratching and Controllable Precision Grinding Mechanisms of Fused Silica[J]. Journal of Mechanical Engineering, 2018
, 54(21)
: 191
-204
.
DOI: 10.3901/JME.2018.21.191
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