Modelling surface roughness improvement in grinding

Grinding is a precision machining process used to improve workpiece surface roughness. This paper demonstrates that spark-out is the most important stage of a plunge grinding cycle for achievement of a low value of roughness. The nature of the spark-out process is investigated including the effects of machine stiffness, system deflection, wheel sharpness and plastic deformation on improvement of surface roughness. Experiments and a comparison with predictions from a computer simulation programme demonstrate the effects of the fundamental factors. It is demonstrated that the time constant for roughness is more than twice the time constant for system deflections.