Th. Nayfeh et al., AN INTEGRATED ULTRASONIC SENSOR FOR MONITORING GRADUAL WEAR ONLINE DURING TURNING OPERATIONS, International journal of machine tools & manufacture, 35(10), 1995, pp. 1385-1395
The condition of the tool and the cutting process are essential inputs
to any productivity improvements through process optimization in conv
entional and unmanned machining. Tool replacement and tool wear compen
sation strategies, which are based on prior experience and/or tool his
tory are, in general, under performing. Currently, the methods of tool
condition monitoring are either time consuming, as in the case of off
-line direct measurements of the tool, or are modestly successful, as
in the case of the on-line indirect measurements, such as forces or ac
oustic emissions. This in part is due to the lack of suitable sensors
and/or exact dynamic models, which relate the indirect measurements to
the actual tool condition. This paper describes a promising ultrasoni
c method for on-line direct measurement of gradual wear in turning ope
rations. An integrated (transmit and receive) single ultrasonic transd
ucer operating at a frequency of 10 MHz is placed in contact with the
tool. The change in the amount of the reflected energy from the nose a
nd the hanks of the tool can be related to the level of gradual wear a
nd the mechanical integrity of the tool. The experimental results show
that under laboratory conditions, a correlation exists between the ul
trasonic measurement and gradual wear and that it is tool dependent.