Analysis of Influence Factors for Density of Compressed Powder Products during High Velocity Compaction

The density and its uniformity were crucial parameters which affected the mechanics properties of high velocity compacted powder products. The distribution and variation of densities in powder compaction processes were obtained by using Drucker-Prager Cap model and transient explicit dynamics finite element method. Four parameters， i.e.， sidewall friction coefficient， height-to-diameter ratio， energy per unit mass and initial relative density were analyzed quantitatively to study their effects on the density and its uniformity. The sensitivity of these factors were studied by orthogonal tests. The main conclusions are drawn as following： the non-uniformity of the density mainly concentrates on the top and bottom surfaces， and the density difference increases with the compact processes. The non-uniformity of density is more obvious along the sidewall locations. The major factor that has the greatest impact on density is the energy per unit mass， while the improvement of lubrication conditions of sidewall， height-to-diameter ratio， initial relative density do not affect the density obviously. The major factors that have the greater impact on density non-uniformity are sidewall friction coefficient and energy per unit mass. The density increases with the energy per unit mass. Once the energy per unit mass reaches its critical value， the average density does not increase any more， but the density uniformity keeps improved. © 2018, China Mechanical Engineering Magazine Office. All right reserved.