Optical glass fabrication technology 2: Relationship between surface roughness and subsurface damage

For glass grinding conditions where fracture is the principal mechanism, a constancy is found between the depths of surface roughness and subsurface damage. For a range of experimental conditions we find the ratio of subsurface damage to surface roughness to be 6.2-6.4 for bound diamond abrasive grinding. This is larger than the value reported for loose abrasive grinding (3.7-4.0). The constancy of this value has great practical importance. From a measurement of the surface roughness one can obtain an accurate estimate of the damage layer thickness that must be eliminated by polishing or subsequent grinding operations.