Development of low cost mql system and investigation of drilling aisi 304 using commercial mql oil and used cooking oil

Abstract

Despite lots of research in Minimum Quantity Lubrication (MQL), and the acceptance of its positive effects on tool life, workpiece quality and the environment, MQL is yet to be adopted in small and medium-scale manufacturing industries. The initial cost of the MQL system, the cost of commercial MQL oil and the failure of the research community to take the technology to these industries are the main reasons for this slow adoption of MQL in machining industries. Developing low-cost MQL systems and application of used cooking oil/waste cooking oil generated in restaurants/homes (which poses a health risk if it enters the food chain again) as feedstock for MQL applications can help in increasing the adoption of MQL by these industries. A simple MQL system that works only on compressed air is developed and tested. The spray characteristics (droplet size and velocity) of the MQL aerosol are analysed using CFD to arrive at an optimum nozzle design and the nozzle spray characteristics are studied using Phase Doppler Particle Analyser (PDPA). Drilling of AISI 304 (Stainless steel 304) plates of 10 mm thickness with the developed MQL system with commercial MQL oil and used cooking oil is carried out in two different cutting speeds 90 m/min (high-speed) and 45 m/min (nominal speed) with the same feed rate of 0.11 mm/rev. The high performance (HP) drill used for high-speed drilling has special tool geometry to drill stainless steel specifically, while the drill used for nominal speed drilling is a general purpose (GP) drill which can also be used for drilling other materials along with stainless steel. The drills were chosen so as to prove the performance of the developed MQL system for different industries. The HP drill while costs more than twice that of the GP drill is used in advanced aerospace applications which the more affordable GP drill may find applications in small and medium scale industries newline