'Micro-stoning' is the following type of operation:

SOLUTION

Explanation:

Roughing:

• It is a process by which the bulk of the material is removed as rapidly and as efficiently as possible while leaving a small amount of material on the work-piece for the finishing and super-finishing operation.

Finishing:

• Finishing operations are performed to obtain the final size, shape and surface finish on the work-piece.

Super-finishing:

• It is also known as micro-honing/micro-surfacing/micro-stoning.
• Here the focus is primarily on the improvement of surface finish and much less on the correction of geometric errors.
• Pressure and amplitude of oscillation applied during micro-honing are extremely small.
• The surface finish is of the order 0.05 - 0.1 μm R_a.

Polishing:

• Polishing is done to remove or smooth grinding lines, scratches, pits, mould marks, parting lines, tool marks, stretcher strains, and surface defects that adversely affect part appearance or function.
• It is performed with either a wheel or belt with abrasives bonded in it.
• Resulting polished surface has a surface finish of 0.4 μm R_a or less.
• Aluminium oxides (Al₂O₃) and silicon carbide (SiC) are the most widely used synthetic abrasives.