The Effect of The Variation of Tool End Geometry on Material Removal Mechanisms in Nanomachining

The selection of effective and optimal machining parameters is a major challenge for the
manufacturing industries. The tool-work interactions may be affected by many process parameters
including depth of cut, cutting speed, feed rate, cutting tool geometry et cetera. Proper selection of
these parameters is critical in material removal processes. The effect of different geometric end
shapes on the phenomena of rubbing and ploughing in nanomachining was investigated by using the
Molecular Dynamics (MD) simulations. The shapes used were flat, pointed, spherical and trapezoidal.
The tools in increasing order of sharpness are the following, namely; the tool with the flat end (least
sharp), the tool with the spherical end, the tool with the trapezoidal end and the tool with the pointed
end (sharpest). The tools show the initiation of ploughing in that order. The tool with the flat end
geometry shows a fast initiation of ploughing, because it has the largest surface area to engage more
atoms. The total energy is lowest for the tool with the pointed end and highest for the tool with the flat
end. All the tools clearly show the phenomena of rubbing and ploughing in the depth of cut range of
0.05 to 0.5 nm. The tool with the pointed end has the lowest average cutting force and the tool with the
flat end has the highest average cutting force. It is important to note that in nanomachining the tool
with sharpest end may not necessarily cause the greatest material removal! The different tool ends
may be suitable for different semiconductor and metal machining applications.