In
the present work, an attempt has been made to monitor the tool
condition status during microturning of aluminium alloy (AA 6061) using
multiple sensors such as cutting force dynamometer, acoustic
emission (AE) and accelerometer. The tool wear (nose wear) is correlated
with surface roughness (Ra), chip width, thrust force (Fx), tangential force (Fy), feed force (Fz), AERMS and vibration signals. It is observed that Ra, chip width and cutting forces are increased with increase in the tool wear. Among the cutting forces, the tangential force (Fy) is found to be more sensitive to the tool wear status compared to that of the thrust force (Fx) and feed force (Fz).
From the signal analysis, it is observed that during machining with
good tool condition, the dominant frequency of the AERMS and vibration
signals are found to be 81 kHz-110 kHz and 2.07 kHz-3.84 kHz
respectively, whereas with the worn out tool the dominant frequencies
are shifted to higher levels. Chip morphological studies indicated that
favourable type of chips are formed upto 40th minute and unfavourable chips are observed from 41st minute to 60th minute.