National Institute of Advanced Industrial Science and Technology （AIST） Advanced Manufacturing Research Institute

Research Results

Raw powders used for AM are required high flowability and high packing density to achieve high process efficiency and to offer high-grade AM products. The requirements bring high costs and to restrict the usable materials in AM. To overcome the issues, we are studying a spheroidizing technology of metal powders using DC arc plasma. Some of the keys of this study are to clarify the melting behaviors of metal powders depended on the type of materials and to control atmosphere and plasma properly based on the melting behaviors, consequently allowing to obtain high-grade metal powders that have suitable properties for AM.
Until now, applying this study to some alloy powders including non-spherical stainless-steel powder and tungsten carbide granulated powder that is known as cemented carbide, we have successfully shown that this plasma technology enabled not only to spheroidize the powders and to remove the surface moisture of them but also to reduce the inner defects such as inner porosities and gaps between primary particles by reheating and melting under inert atmosphere.
At present we are examining the advantages of the plasma treated powders by conducting AM processes using them. Furthermore, we are actively engaging in developing a technology that integrates AM processing with powder treatment processing for fulfilling a new concept of AM.