Fibre Bragg grating temperature sensors for high-speed machining applications
In high-speed grinding research, it is required to measure temperature within the workpiece. Present techniques are thermocouple based, and often suffer from excessive electrical noise on the signal. This thesis presents a number of novel and existing optical sensing devices that overcome this limitation and also, in some cases, offer greater performance. The optical sensors are fibre Bragg grating based and the optical techniques used to interrogate that sensor include DWDM, WDM, athermic grating, tuneable grating and coupler. Optical fibre devices are simpler to place in situ prior to the machining tests and they offer faster response and greater sensitivity than was previously possible. Results are presented from machining tests and the new devices are compared with each other and thermocouple based techniques. A method to relate internal measured temperature to machined surface temperature is also demonstrated in the context of high-speed machining.