Theoretical Modelling of Subsurface Damage in Ultra-Precision Grinding of Fused Silica

Fused silica is a typically brittle material with high hardness and low fracture toughness. Ultra-precision grinding technology is an effective method to improve the machinability of fused silica with high surface quality. To achieve low damage grinding of fused silica, the grinding performance with different grinding parameters was investigated and the material removal mode was also presented after determining the critical cutting depth. The subsurface microcrack was analyzed using indentation fracture mechanics, and a mathematical relationship model between the subsurface damage depth
$\boldsymbol{h_{SSD}}$
and the maximum height of surface roughness
$\boldsymbol{S_{z}}$
was established. The relatively optimum surface quality of
$\boldsymbol{S_{z}=1.986\mu \mathrm{m}}$
and subsurface damage depth
$\boldsymbol{h_{SSD}=2.65\mu \mathrm{m}}$
was achieved. The theoretical values of the established model were found to agree well with the actual measured values, which indicates that the model can be used for non-destructive detection of subsurface damage depth.