Prospects of producing aluminum parts by wire arc additive manufacturing (WAAM)

Abstract

In contrast to subtractive manufacturing processes, such as machining, and forming processes, additive manufacturing (AM), which is also called 3-D printing, direct digital manufacturing or free form fabrication, is a process of joining materials to make objects from 3D model data, usually layer by layer. Although additive manufacturing was mainly used in the production of prototypes from polymeric materials initially, the production of metallic parts with this manufacturing technology has attracted great interest in recent years. This innovative technology is commonly referred to metal additive manufacturing (MAM) and is presently being applied in various industries such as aeronautics-space, energy, automotive, medicine, various tools and customer goods. Metal parts are produced in three different ways by MAM methods. These are powder bed fusion, powder feed fusion and wire feed fusion systems. In the first two of these additive manufacturing methods, metal or alloy powders are used as raw materials, while in the third method, the filler wire made of metals or alloys is the starting material. However, metal powders, especially alloy powders, are quite costly. This in turn makes the production of metal parts using filler wire very attractive. Another advantage of wire feed additive manufacturing systems, particularly of wire arc additive manufacturing (WAAM), is its potential to produce small- and medium-sized metallic parts economically with high deposition rate. Nowadays, this innovative manufacturing technology is being considered as a promising fabrication technology for manufacturing several products from various engineering materials including aluminum and its alloys. In this paper, studies on WAAM of Al-alloy parts will be discussed. In addition, the most common defect (i.e., porosity) encountered in Al-alloy parts produced by WAAM will be considered as well as the precautions taken against its formation.