Quality Evaluation of Powder for Metal 3D Printer: Shape Analysis by Dynamic Image Analysis Method

Introduction

The properties and homogeneity of metal powders for use in metal 3D printers affects the quality of the molded products. One particle property is the spheroidicity of the particles. As the shape of the particles becomes more spherical, fluidity increases and packing density can be obtained. On the other hand, the existence of irregularly-shaped particles can become a cause of defects, poor mechanical properties, and poor external appearance of molded products. Although scanning electron microscopy (SEM) can be used in evaluations of the shape of powders with sizes on the order of several 10 μm, the narrow field of observation by SEM is a problem, as the measurement time is long and it may be impossible to secure an adequate number of measurements. In contrast, the dynamic image analysis (DIA) method is suitable for the purpose of conducting rapid shape evaluations, as it is possible to acquire images and quantitative information for a significant number of particles in a short time. The Shimadzu iSpect™ DIA-10 dynamic particle image analysis system (Fig. 1), which is based on the DIA method, is an instrument which acquires images of particles in liquid samples and measures the particle size distribution, particle concentration, and particle shape. It is possible to analyze tens of thousands of particles in only minutes with an optical system that misses very few particles (image acquisition efficiency: 90 % or higher). This article introduces an example in which the circularity of SUS 316L stainless steel powder before and after spheroidizing treatment was evaluated by using the iSpect DIA-10.

January 27, 2021 GMT