Basics for In-Process Roundness Error Improvement by a Functional Workrest Blade

A centerless plunge feed grinding process can be conducted “below center” in order to increase process productivity. This statement results from the fact that the workpiece, in such a set up of the grinding gap, is fixed between grinding wheel, control wheel and workpiece rest blade, thus allowing higher feed rates of the grinding wheel support. But when grinding “below center”, the advantage of a higher productivity is accompanied by a negative effect, the arise of a polygonal workpiece form. Regarding only the geometrical rounding effect as one reason for this process characteristic phenomenon, different workpiece center displacements are examined and analytically described. The knowledge of relevant workpiece center movements within a centerless grinding application allows a quantified analysis of the influence of these displacements on the geometrical rounding effect. Deriving from such an analysis, a functional workrest blade is discussed, which influences the stability of the geometrical rounding effect.