We cannot say that present day machining processes are clean. Current trends in the manufacturing sector will not be acceptable in the future. This will an arise need for extensive research and development work necessary to meet the environmental concern. Although research on promising green energy technologies manage to supply partially for current machining systems; the high energy-efficient machining systems that demand less energy remain important and highly desirable. The energy-efficient machining system requires a comprehensive understanding as well as optimization of energy consumption. This paper focuses upon the energy requirement during actual metal machining. The first part explains about the basics of energy in machining and the flow of energy in a production line. In the later part, two energy models are described that shows dependence of energy consumption in machining process upon the operating parameters and set-up parameters. Effects of these different parameters on specific energy consumption are also summarized. Finally, a brief introduction to few energy optimization techniques is given.

Keywords: Machining, Specific energy consumption, Energy models, Energy optimization.