If we machine ductile materials in general what kind of qual

If we machine ductile materials, in general, what kind of quality issues can happen?

Solution

answer :

During continuous machining of ductile materials the uncut layer of the work material just ahead of the cutting tool (edge) is subjected to almost all sided compression.The force exerted by the tool on the chip arises out of the normal force, N and frictional force, F.

Due to such compression, shear stress develops, within that compressed region, in different magnitude, in different directions and rapidly increases in magnitude. Whenever and wherever the value of the shear stress reaches or exceeds the shear strength of that work material in the deformation region, yielding or slip takes place resulting shear deformation in that region and the plane of maximum shear stress. But the forces causing the shear stresses in the region of the chip quickly diminishes and finally disappears while that region moves along the tool rake surface towards and then goes beyond the point of chip-tool engagement. As a result the slip or shear stops propagating long before total separation takes place. In the mean time the succeeding portion of the chip starts undergoing compression followed by yielding and shear. This phenomenon repeats rapidly resulting in formation and removal of chips in thin layer by layer