9. Non-contact Micro- and Nanowelding

Micro- and nanoscale welding or joining processes are needed in miniaturisation or microsystem fabrication such as microelectromechanical systems (MEMS) and carbon nanotubes (CNTs). The constant strive for miniaturisation that necessitates that products are manufactured smaller and more lighter comes with the challenge of having smaller parts that require to be joined or assembled at a micro- or nanoscale level. The ability to weld at micro- and nanoscale levels is key to the efficient and effective fabrication of miniaturised components and products. This need has necessitated the development of welding processes that have the capability to join these delicate and fragile parts. The conventional joining process could cause heat damage to the welded part because of the large input from such processes. Also, the tools of these conventional welding processes may even be larger than the miniaturised parts that makes them unsuitable in fabrication of parts at micro- and nanoscale levels. Micro- and nanowelding are performed under powerful microscope. In this chapter, non-contact micro- and nanowelding processes are discussed. Two types of these advanced welding processes discussed are the advanced non-contact fusion welding and solid-state welding processes. Laser micro/nanowelding and electron beam micro/nanowelding are the two fusion-state micro/nanowelding processes that are presented in this chapter. For the solid-state micro/nanowelding processes, ultrasonic micro/nanowelding and resistant micro/nanowelding are presented. In micro- and nanowelding processes, the main challenge is the tight operational tolerance that needs to be met and the processing parameters are found to play an important role in achieving the desired results. The focus of this chapter is on the research developments in this field. The working principles, advantages, limitations and areas of application of these welding processes are explained in Chaps. 7 and 8.