Environmentally conscious machining of difficult-to-machine materials with regard to cutting fluids

Machining difficult-to-machine materials such as alloys used in aerospace, nuclear and medical industries are usually accompanied with low productivity, poor surface quality and short tool life. Despite the broad use of the term difficult-to-machine or hard-to-cut materials, the area of these types of materials and their properties are not clear yet. On the other hand, using cutting fluids is a common technique for improving machinability and has been acknowledged since early 20th. However, the environmental and health hazards associated with the use of conventional cutting fluids together with developing governmental regulations have resulted in increasing machining costs. The aim of this paper is to review and identify the materials known as difficult-to-machine and their properties. In addition, different cutting fluids are reviewed and major health and environmental concerns about their usage in material cutting industries are defined. Finally, advances in reducing and/or eliminating the use of conventional cutting fluids are reviewed and discussed.

► A review of the issues and solutions for difficult-to-machine materials. ► Different types of coolants/lubricants are also reviewed and classified. ► The environmental and health issues of conventional cutting fluids are also studied. ► Advanced machining methods to remove or reduce the use of cutting fluids are identified. ► Studies related to dry, MQL, cryogenic and chilled air machining are reviewed.