**1. Introduction**

The manufacturing field has developed tremendously in the last decades. Today, transforming raw materials into useful parts or products (by using different manufacturing processes) is nearly unlimited. The manufacturing research is always focusing on developing and using manufacturing processes with lower cost and waste, and higher production rate. Currently, there is fast and high variation in the design of products, and very high market competition because of global competition. Design for Additive Manufacturing (DFAM) is one of the important methods for obtaining this global competition in terms of manufacturing.

Additive Manufacturing (AM), is a type of printing (3D printing) method used to create three-dimensional products by laying the fused material layer by layer.

AM is the current and dominant future manufacturing method [1]. AM processes are considered easier as compare to subtractive processes represented by machining and other manufacturing types. This is because of producing a part through one AM process is more effortless than producing the same part through several subtractive manufacturing processes (such casting then machining). Subtractive manufacturing processes often require millions of dollars, while using AM processes can offer the same manufactured parts at a fraction of the cost, and in less than half the time [2]. In addition, manufacturing the part in one process eliminates the need for several skilled workers (which subtractive manufacturing requires), in lieu of a single knowledgeable worker.

AM is the future face of the industry, not just in manufacturing field—printing technology has even been used to construct buildings in recent years. However, the MAM process for producing small and medium size metallic parts also present difficulties and issues. These difficulties may be inherent to the MAM process itself, such as selecting the right MAM process, adjusting support materials, building direction, geometry (complexity) of the part, and printing orientation. All these difficulties might lead to some issues and defects in MAM products, such as porosity, variation in mechanical properties, microstructure evolution, residual stress, fatigue, and crystalline phase and more. In the next section a recent comprehensive literature review is presented to explain the main issues and difficulties facing MAM processes, in the production of small and medium size parts.
