Titanium Ti6Al4V alloy is a commonly used material in modern aerospace industry due to its excellent mechanical properties and corrosion resistance. However, its low heat conductivity often results in a steep temperature gradient at the tool-chip interface especially in high speed machining applications such as milling operations. This high level of temperature generated during the cutting process is one of the key factors that limits the machining process optimisation.
However, developing a temperature measurement system to monitor the tool-chip interface for milling applications is not a straightforward task. There are many issues that need to be taken into account. The main factors that need be considered when selecting a temperature measurement method are: temperature range, sensor robustness, temperature field disturbances by the sensor, signal type/sensitivity to noise, response time and uncertainty. In addition to this, the positioning of the sensor is crucial for an accurate estimation of the temperature at the area of interest i.e. the tool-chip interface. Furthermore, in order to successfully use the sensors inside the machine tool, a degree of protection from the hostile machining environment must be provided for the sensor. The presence of coolant, swarf, as well as electrical interference from the high powered spindles can all impair the ability of the sensor to successfully acquire data. Finally, the wiring of the sensors inside the machine tool also presents a major challenge. The majority of sensors require hard wiring to transmit data to the data acquisition (DAQ) system which is normally placed outside the cutting zone. This presents a major issue in their use in moving components, requiring a complex slip ring arrangement. However, in some machine tools, it is often not possible to manipulate the wires through the machine enclosure. In these cases, the DAQ may need to be placed closer to the cutting zone, such as within a tool holder and must be able to transmit the temperature data wirelessly.
In this project, it is envisioned that the candidate improves the current readily available temperature measurement system developed at AMRC for a more robust measurement method for on line temperature measurement in milling processes for solid carbide tools and Ti6Al4V alloys. The work will be conducted in close collaboration with the AMRC, AFRC and the University of Sheffield Electronic Engineering Department. AMRC and AFRF host numerous industrial milling machines and have experienced operators. The student will have access to all thses facilties and resources throughout the lifecycle of the project. In addition to this, the AMRC will provide data acquisition equipment. The equipment includes National Instruments hardware, inductive based wireless system and temperature sensors.
The CDT in Advanced Metallics is a partnership between the Universities of Sheffield and Manchester and the I-Form Advanced Manufacturing Centre, Dublin. CDT students undertake the CDT training programme at all three locations throughout the 4-year programme.