A COMPARISON OF POWDER PARTICLE-SIZE MEASURING-INSTRUMENTS

Eight different powders commonly employed in powder injection molding were used as the basis for examing the effects of powder characteristi cs on particle size measurement. Several different techniques were app lied to measure particle size, including: laser diffraction with the p owder dispersed both wet and dry, aerodynamic time-of-flight, electric al zone sensing, dynamic light scattering or photon correlation spectr oscopy, and optical image analysis. After reviewing the particle size data obtained from these different techniques, it is concluded that ac curacy is dependent strongly on dispresion of the powder in the carrie r fluid. With adequate dispersion analogous particle size information is obtained independent of instrument type.