Study on High Speed Machining (No.14)

On Machinability of Materials Cut

Abstract

In the previous report, the fundamental machinability formula was presented both theoretically and experimentally based upon the theory of tool-chip contact area. The machining characteristics defined by cutting force, shear angle and chip-thickness-ratio could be clearly analysed by the formula. Consequently tool-chip contact area had been proved to be a basic factor of machining characteristics defined as above.
It is a very interesting phenomenon that each material has its own machinability characteristic although the cutting conditions are the same. Machinability of materials also could be analysed through the same principle mentioned above, that is, the machining theory based upon tool-chip contact area. Here in this experiment, various materials such as aluminium, copper, brass, mild steel, alloy steel and Meehanite cast iron are machined under definite cutting conditions to investigate each tool-chip contact area and chip formation, of which results are compared with the individual material testing data. As a result, the slope of the shear test curve near the rupture point has been verified to be closely related with the tool-chip contact area in machining and cosequently with the machinability of the material.