A Review of the Metal Additive Manufacturing Processes

Abstract

Metal additive manufacturing (AM) is a layer-by-layer process that makes the direct manufacturing of various industrial parts possible. This method facilitates the design and fabrication of complex industrial, advanced, and fine parts that are used in different industry sectors, such as aerospace, medicine, turbines, and jewelry, where the utilization of other fabrication techniques is difficult or impossible. This method is advantageous in terms of dimensional accuracy and fabrication speed. However, the parts fabricated by this method may suffer from faults such as anisotropy, micro-porosity, and defective joints. Metals like titanium, aluminum, stainless steels, superalloys, etc., have been used—in the form of powder or wire—as feed materials in the additive manufacturing of various parts. The main criterion that distinguishes different additive manufacturing processes from each other is the deposition method. With regard to this criterion, AM processes can be divided into four classes: local melting, sintering, sheet forming, and electrochemical methods. Parameters affecting the properties of the additive-manufactured part and the defects associated with an AM process determine the method by which a certain part should be manufactured. This study is a survey of different additive manufacturing processes, their mechanisms, capabilities, shortcomings, and the general properties of the parts manufactured by them.

Effects of Shot Peening and Electropolishing Treatment on the Properties of Additively and Conventionally Manufactured Ti6Al4V Alloy: A Review

“…During the EBM process, an electron beam or focused laser is the heat source applied to melt the titanium powder. Layers are manufactured as follows: spreading the titanium powders on a base plate, preheating the powder, sintering the powder with a defocused beam, melting the powders by using a focused beam and then decreasing the building platform by the thickness of the layer [75,76]. Using the electron beam requires the powder to be sintered, or, in a different manner, the electrostatic forces lead to clouds of charged particles in the build chamber [77].…”

“…The consecutive layers are melted and frozen on each other until the process is completed. The whole process takes place in a chamber filled with inert gas when the laser method is used or in a vacuum environment when an electron beam is used [75,[90][91][92][93][94]. The scheme of building layers in DED technology using a laser is shown in Figure 10.…”

Additive Manufacturing: A Comprehensive Review

“…After one layer is melted and solidified, the build platform is lowered, and a new layer of powder is applied. This process repeats until the part is fully constructed [96]. The energy source, an electron beam, allows for rapid melting and solidification, making EBM distinct in its speed and the quality of the parts produced.…”

Development of a Novel Water Jet Polisher Using Soft Abrasives for Small Complex-Structure Heat Pipes of Aluminum Alloy Produced Using Additive Manufacturing

“…However, the design of the actual cooling system and the geometric structure of the served device often result in a complex spatial shape for heat pipes. Additive manufacturing technology provides new possibilities for manufacturing many complex structures [1][2][3][4][5][6]. The production of heat pipes using additivie manufacturing has garnered considerable attention due to its advantages in processing complex and highly customizable parts, integrated manufacturing with structural components, lightweight design, and high processing efficiency [7][8][9][10][11].…”