On the Generating Mechanism of Surface Roughness : Forming Process of Single Asperity

It is clear that the pile-up phenomena on both sides of the grooves produced by means of abrasive grains have some effects on the roughness of finished surface. In this paper for the purpose of making the effect of the pile-up on the surface roughness clear the ratio of an actual generated asperity height to a geometrical asperity one, ηS for a conical cutting edge and ηSγ for a conical cutting edge with a spherical top could be estimated theoretically using the theory of plasticity. The theoretical values of ηS and ηSγ showed a good agreement with experimental ones. It is evident from the experimental results that the values of ηS are independent of the depth of cut and increase with the apical angle of conical cutting edge. It is also clear that the values of ηSγ decrease with an increasing apical angle of edge, depth of cut and coefficient of friction. And ηSγ decreases with a decreasing radius of top of conical edge but is scarcely influenced by the cutting speed and the cutting fluid.