Development of under-cut shape sprocket forming by CNC press

In standard P/M (Press-Sinter) technique, it is difficult to make under-cut shape parts. In this development, under-cut shape sprocket of whole circumference is made by CNC press and new designed die and tools. This paper describes the details of this development. (1) Features of CNC press and new designed die and tools for under-cut shape compacting. (2) How to eliminate cracks and barrs of this under-cut shape parts. (3) How to achieve the even density of this complex parts. (4) How to keep the dimension tolerance of this parts.