Additive Manufacturing of Tungsten Carbide Hardmetal Parts by Selective Laser Melting (SLM), Selective Laser Sintering (SLS) and Binder Jet 3D Printing (BJ3DP) Techniques

Additive manufacturing is a process of transforming 3D CAD models into a finished part by adding layers of material. The technology is being used for more than three decades to make prototypes using polymer powders. Over the years, the technique has evolved, which currently allows the industries to manufacture functional parts out of different metals that have high complexity and limited lot size. Tungsten carbide (WC-Co) is a refractory metal with a very high melting point of around 2900 °C and is difficult to manufacture by conventional methods. Hence, tungsten carbide hardmetal parts are made by powder metallurgy technique, wherein tungsten carbide and binder metal powders (cobalt, nickel, iron or alloys of these metals) are pressed into the desired shape and sintered. However, due to the recent advancements, researchers have proven that complex tungsten carbide parts can be made by additive techniques. Hence, the article aims to summarize the three major techniques, Selective Laser Melting (SLM), Selective Laser Sintering (SLS), and Binder Jet 3D printing (BJ3DP) used in the manufacturing of tungsten carbide hardmetal parts. The process variables, metallurgical and mechanical characteristics, and challenges in manufacturing are presented which would serve as a knowledge pool for prospective researchers.