Fractal phenomena in powder injection molding process
(1. State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China;
2. School of Mathematical Science and Computing Technology,
Central South University, Changsha 410083, China;
3. School of Materials Science and Engineering,
University of Science and Technology Beijing, Beijing 100083, China)
Central South University, Changsha 410083, China;
2. School of Mathematical Science and Computing Technology,
Central South University, Changsha 410083, China;
3. School of Materials Science and Engineering,
University of Science and Technology Beijing, Beijing 100083, China)
Abstract: The complicated characteristics of the powder were studied by fractal theory. It is illustrated that powder shape, binder structure, feedstock and mold-filling flow in powder injection molding process possess obvious fractal characteristics. Based on the result of SEM, the fractal dimensions of the projected boundary of carbonylic iron and carbonylic nickel particles were determined to be 1.074±0.006 and 1.230±0.005 respectively by box counting measurement. The results show that the fractal dimension of the projected boundary of carbonylic iron particles is close to smooth curve of one-dimension, while the fractal dimension of the projected boundary of carbonylic nickel particle is close to that of trisection Koch curve, indicating that the shape characteristics of carbonylic nickel particles can be described and analyzed by the characteristics of trisection Koch curve. It is also proposed that the fractal theory can be applied in the research of powder injection molding in four aspects.
Key words: powder injection molding; fractal theory; chaos; Navier-Stokes equation