Investigating the performance of the pressurized injection lubrication technique in the turning process

Abstract

Efficient lubrication and cooling are crucial in machining operations to enhance tool life and workpiece quality. Sustainable methods like minimum quantity lubrication (MQL) and dry cutting often face limitations in cooling efficiency and chip evacuation, especially under high-speed conditions or when machining difficult-to-cut materials such as stainless steel. This study introduces the novel pressurized injection lubrication (PIL) technique designed to address these challenges by optimizing lubrication, cooling, and chip evacuation during the turning operations of stainless steel 304. Using flaxseed oil as the lubricant, the PIL system employs a 0.26 mm stream diameter at a pressure of 16 bar to provide the necessary cooling and lubrication to the cutting zone. Cutting temperature and surface roughness were selected as the primary responses. Experimental runs were designed using the Taguchi L9 method. Analysis of variance showed that the lubrication method significantly affected the cutting temperature, with a contribution percentage approaching 94%. The experimental results demonstrated that PIL reduced the cutting temperature by up to 55%, while MQL reduced it by about 48%, both compared to dry cutting at the highest utilized speed. The lubrication method was also found to be the most significant factor affecting surface roughness, with a contribution percentage of 72.8%. Experimentally, PIL improved surface roughness by a maximum of 16.2% compared to MQL. Additionally, PIL maintained low oil consumption (0.9 l/h) and energy usage (< 0.017 kWh). The cost-effective PIL setup, priced under 65 USD, underscores its potential as a sustainable and efficient alternative for machining processes. The system’s components are readily available, facilitating easy integration into existing metal-cutting machines. Finite element analysis (FEA) modeling was used to predict residual stresses under different lubrication methods. The FEA model indicated that PIL and MQL reduced residual stresses by about 81.2% and 76.6%, respectively, compared to dry cutting at a speed of 500 rpm. These findings suggest that PIL can significantly enhance machining performance and sustainability, offering a viable solution to modern manufacturing challenges.