“…However, based on numerous studies it has been determined that upon powder compaction friction coefficient tends to vary and is a function of several process parameters, such as powder density, normal stress, sliding velocity, temperature, displacement, tool surface-roughness, and material hardness [10, 13, 19, 21, 31, 86, 88-90, 113, 114]. Most importantly, in the case of an instrumented-die, only a mean friction coefficient value may be derived; however, the local friction coefficient value varies over the height of the compact [3,10,13,19,21,31,85,89,90,111,113,114].…”