Sustainable Machining

This chapter elaborates on the attractiveness of the notion of sustainability in machining and points out needs for its improvement. It explains that the chief areas of further improvement in sustainability of machining operations are improvement in modeling of the cutting process and thus in the design of practical machining operations; system considerations of measures to enhance sustainability of machining; and development of proper metrics for sustainability assessment. As such, the proper modeling of machining operation plays the most important role as it allows realizing the idea of virtual machining as a keystone of machining sustainability. The chapter argues that one of the most common mistakes made in known an attempt to improve sustainability of machining operations is a nonsystem approach to the analysis of the result. The latter was exemplified by considerations of errors made in implementation practices of dry and near-dry machining as well in the reduction of the volume of the work material being removed by machining, i.e., the use of near-net-shape blanks.

Cutting fluids are popularly used in machining to reduce cutting forces, temperatures and thus prolong the tool life. However, cutting fluids are complex compounds containing different ingredients some of which are toxic. Constant exposure to these fluids causes severe health hazards to the workers. Further, the disposal of the cutting fluids adds to the cost due to the required chemical treatment. Hence, the concept of using minimum quantity lubrication (MQL) has come into picture. Further, to make the fluids more benign, vegetable-based compounds are being used to replace the toxic ingredients. This is done in different levels, i.e., either only the mineral oil in the fluid is replaced by vegetable oil or even the emulsifier is replaced by a vegetable alternative. The present chapter discusses MQL and vegetable-based cutting fluids for sustainable machining. Results obtained during the application of vegetable oils are presented.

This chapter presents an experimental approach for quantifying the effects of traditional cutting parameters and innovative cryogenic and hybrid cooling methods on specific energy consumption in addition to tool damage and productivity. The chapter also puts forward the application of fuzzy modeling on the experimental data for optimizing the machining process in respect of various combinations of minimizing specific energy consumption and maximizing productivity as well as tool life. The machinability levels of two commonly used industrial alloys, when cut under cryogenic and hybrid environments, have also been comparatively analyzed.

Nowadays, the consideration of sustainability aspects in manufacturing sector is on utmost priority. Globally, the manufacturers are compelled to follow the stringent environment regulations which encourage to minimise the diverse business risks inherent in any manufacturing operation while maximising the new opportunities that arise from improving processes and products. It implies to all the important segments of manufacturing sector from extraction of raw material to supply chain. Ice jet machining is an important sustainable variant of abrasive water jet machining (AWJM) which ensures the environmentally friendly cutting, finishing, cleaning, and deburring of a variety of materials. It differs from conventional AWJM in the aspects as the frozen water; i.e., ice particles are used in place of abrasive particles to facilitate the machining. Replacement of abrasives by ice particle ensures lower cost, better machining capability, waste management, recycling and operator’s safety, and thereby overall sustainability. Ice jet machining is recognised as a clean, green, and lean technology. This chapter introduces ice jet machining technology and describes its working principle, process parameters, and mechanism. The significant benefits of using ice jet machining over other conventional processes as well as some important work done utilising this technology so far are also discussed.