Abstract:
This study presents the results of an investigation of machinability improvement in
turning of mild steel (0.25% C) by magnetic cutting. Turning experiments were done by using a
precision lathe both without application of magnetic field and with the application of magnetic
field. The external magnetic field was implemented using two different magnetic setups: one
created by permanent magnet another by electro magnet. Poor machinability results in surface
defects and dimensional inaccuracy of the work piece as well as reduction of useful tool life and
damage to machine. A recent and promising way to improve the machinability of steel is to
reduce the vibration effect of machine-tool-work system by applying external damping effect
using magnetic cutting technique. In this investigation the effect of external magnetic field (both
permanent magnet and electromagnet) was evaluated on machinability parameters such as tool
life, surface roughness, cutting temperature and cutting force. The characteristics of chip
produced during turning were also observed to further study the magnetic effect on cutting
mechanism. Improvements in tool life, reduction in average surface roughness, increase in
cutting temperature and decrease in cutting force were observed during the experimentation by
magnetic cutting. Certain changes of chip formation characteristics were also observed when the
mild steel was being cut. It has been observed that the chip serration nature has been changed
significantly in magnetic cutting. Experiments were carried out by changing cutting speed and
depth of cut to determine the optimal magnetic field to be applied which would translate into
greatest amount of benefits. Due to the limitation of feed variation within the existing facilities of
lathe, the feed value was kept constant at 0.095 mm/rev. The observations of effect of magnetic
field on machinability parameters, lead to the conclusion that magnetic cutting improves the
machinability factors of mild steel significantly and further enhance the possibility of using
magnetic effects to reduce machining costs.
