Feasibility of micro quantity internal cooling (MQuIC) of cutting tools

Machining of space age materials like Ti-6Al-4V is associated with thermally activated wear mechanisms which lead to rapid tool failure and considerable machine downtime. The high strength and low thermal conductivity of Ti-6Al-4V can reduce tool-life to less than a minute at high cutting speeds, further adding to the per-unit cost. A new concept, Micro Quantity Internal Cooling (MQuIC) is proposed in this research to extend the tool-life and/or enable higher cutting speeds, while machining materials such as Ti-6Al-4V. The concept involves introducing flow (water) in a micro-duct placed inside the tool and close to the cutting edge, thus bringing the cooling source close to the heat source (chip-contact area).; Two different techniques are utilized in developing and applying the proposed concept. The first uses finite element analyses (structural and thermal) to evaluate the impact on the structural strength of the tool due to the micro-duct and to examine the effect of flow on tool temperatures. These analyses lead to an experimental setup-specific analyses, in order to converge on the final operating parameters. Physical testing employing coolant consumption of less than 5% of the current industry standard has proven the viability of the concept by demonstrating a 100-200% increase in the tool-life. The testing also proves the application of the MQuIC concept to enable higher cutting speeds than the current industry standard for machining Ti-6Al-4V.; Further, a lab based technique with a focus on commercial realization has been developed to fabricate tools based on this concept. The developed tools have been successfully tested to validate their performance. A few other concepts for further reducing tool temperatures and extend the benefits of MQuIC are also presented in this dissertation. Conclusions drawn from this research are used to recommend possible future work to further enhance the MQuIC performance during real time machining of difficult to machine materials.