Sustainable Machining of Metal Matrix Composites Using Liquid Nitrogen

Machining of composite materials is difficult due to the high abrasiveness of reinforcing constituents. This creates friction between work piece-tool-chip interfaces resulting in high temperatures. The risk of developing elevated temperatures can be controlled by coolants, however, they are known to cause environmental problems. In the interest of ecological and environmental safety the global focus is towards achieving sustainable manufacturing. In the present study, a pressurized liquid nitrogen (LN2) feeding system is developed to supply LN2 over the tool edge-work piece interface. Comparative experiments are carried out during cutting of Al-5%TiCP under cryogenically chilled air (CCA), LN2, wet and dry conditions. It is found that LN2 reduces surface roughness, tool wear and cutting temperatures. Further, there is a reduction in built up edge formation. LN2 assisted machining has shown to improve machinability of composites while achieving sustainable manufacturing.