Heat pipe-embedded tooling for sustainable manufacturing

Abstract Manufacturing is a broad terminology which comprises of various processes that convert raw materials into a finished product. Out of many such processes, machining is one of the primary processes that has been practiced by industries over ages. Even in this era of Nano technology and additive manufacturing, machining plays a vital role in production and contributes to nearly 70% in product development. In a raw material, the removal of unwanted portion and obtaining a finished part with the required size and shape is termed as machining and is performed by applying shear deformation by a machine and cutting tool. Generally, a rise in temperature and cutting force is observed while machining. These adverse effects contribute to the poor product quality and tool life such as rough surface finish, increased tool wear, higher rate of part rejections, etc. The major cause of these problems is attributed to the heat produced because of the tool and workpiece interface. Approximately 20% of the total heat that is produced stays with the cutting tool and remaining 80% is removed by the chips that are produced while machining. It has been a practice for decades to apply coolant and remove the excess heat near the tool-work interface, thereby maintaining the desired dimensional accuracy and surface finish. But this practice has originated other problems such as increase in overall production cost, increase in industrial waste, increase in land and water pollution, increase in health hazard of operators, etc. This is high time that the industries should concentrate on developing cleaner and sustainable techniques to tackle these problems without compromising on the product quality and tool life. Industries and researchers have tried Dry machining as an alternative for coolant-fed machining and obtained a certain amount of success. Nevertheless, Dry machining has its own adverse effects such as difficulty in machining soft alloys, reduced production rate, excessive heat which alters the metallurgical property of the workpiece, requirement for special cutting tool, etc. Hence, a requirement is needed for removing the excess heat at the tool-work interface applying sustainable techniques and machining should be carried out in dry condition which will lead to cumulative advantages of both coolant-fed machining and dry machining. The chapter deals with using heat pipes as one of the many sustainable techniques that has been practiced in various industries to remove heat effectively. Heat pipes are considered to be a simple and highly effective heat transfer device that can effectively remove heat from a source with the help of a higher thermal conductivity heat pipe material and a phase transition medium (generally water). This helps in keeping the source at lower temperature. It does not use any form of external energy to carry out this task. It is considered to be one of the clean and eco-friendly heat transfer mediums. Heat pipes embedded in cutting tools serve as an alternate to remove the excessive heat present at the interface between the tool and workpiece. The machining that is carried out using these tools is dry. At the same time, the temperature at the interface between the tool and workpiece is kept minimum with the aid of heat pipes that run through the tool and placed closer to the tool tip. This method of employing heat pipe-embedded tools has been designed, fabricated, and tested for numerous machining processes which include drilling, milling, and boring and found suitable for industrial usage. The chapter demonstrates the behavior of the heat pipe-embedded tools during machining, showing a sizeable reduction in the temperature at tool-work interface. The enhancement in the surface roughness of the produced parts and the tool life is also discussed. Interesting results such as reduction in cutting force while employing such tools are also dealt here. This chapter acknowledges the usage of heat pipe-embedded tools for future machining requirements, which is considered to be an effective technique and an alternate to conventional methods for removing heat while machining. The chapter also demonstrates the possibility of carrying out dry machining operation through sustainable technique.