Ball burnishing of additively manufactured parts

In recent years, additive manufacturing (AM) technologies have been developed significantly and can be considered an important revolution in the field of advanced manufacturing processes. Due to the remarkable ability of this family of technologies in the manufacture of parts with complex geometry, their demand in various industries, especially advanced sectors such as aerospace, medicine, and automobile, amongst others, is increasing. However, AM faces significant challenges in order to be used as a mass production method in various industries [1]. One of the most important challenges that AM technologies face is the surface quality of the parts produced by them. In fact, the high surface roughness and internal defects of the parts manufactured by AM are known as their main disadvantages. Surface roughness is recognized as one of the most important factors of surface quality of any part that plays an important role in the life and performance of the part [2]. In fact, surface roughness is known as stress focal points that can lead to cracking and growth, reduced fatigue life, and ultimately failure of the part. Therefore, in order to reduce surface asperities in particular and enhance the surface integrity, it is necessary to perform post-processing operations on the parts, such as heat treatments or polishing [3]. The burnishing process is known as one of the finishing methods in which using plastic pressure applied by a hard ball or roller on the surface of the part, plastic deformation is done under hard working conditions, which increases the surface integrity. The burnishing process as a finishing operation can reduce roughness, increase hardness, and improve wear and corrosion resistance. It also causes compressive residual stresses in the part, which helps to improve the fatigue life of the part [4]. Due to its cheapness, availability, and also positive effects of this process on surface integrity, it can be used as a potential post-processing process for AM components.