Improved Density Distribution in Powder Metallurgy Parts with Filtering Methods
Powder Metallurgy (P/M) is mainly composed of four steps: powder feeding, compaction, ejection, and sintering. A feedshoe moves forward and backward over the die cavity to fill it with metal powders. Possible problem in this stage is the uneven supply of powder on the horizontal direction. It can cause tool breakage due to uneven density distribution. Unevenly-distributed powder also causes internal cracks during compaction or warpage during sintering. Another problem during powder feeding is the inclusion of air with powder. This changes the overall density of the part. Powder feeding mechanism is very important, because it is the first step in the process. If there is imperfection during powder feeding, the final part ends up with a bad part no matter how perfect the rest of the processes are. This paper describes the development of an advanced powder feeding mechanism, which allows well-distributed amount of powder to be delivered to the die cavity.
Young Won Chang, Nack J. Kim and Chong Soo Lee
M. S. Kim, "Improved Density Distribution in Powder Metallurgy Parts with Filtering Methods", Advanced Materials Research, Vols. 26-28, pp. 445-448, 2007