Elastic Impact of Abrasives for Controlled Erosion in Fine Finishing of Surfaces

Finishing of surfaces using free abrasive impingement is one of the constructive applications of erosive wear, well suited for complex shaped engineering components with difficult-to-access surfaces. Low velocity impact of abrasives in a fluidized bed is reported as a promising choice to impart fine finish on the target surface. An improved methodology to control the erosion and to achieve ultra fine finish through elastic impact of abrasives, using a carrier type-fluidized abrasive finishing, is discussed in this paper. Using the basic concepts of impact theory and contact mechanics, a revised mathematical model to express the depth of erosion as a function of material properties of target and erodent is proposed. Modification in erodent abrasive to introduce an elastic nature to the impact is described in detail using the theoretical model. This is substantiated through a particle-dropping experimental study. The effect of multiple impacts in a practical situation is also discussed through a detailed experimental study, clearly demonstrating the concepts of elastic impact erosion for surface finishing.