AUTOMATED GENERATION AND ANALYSIS OF POWDER COMPACTION DIAGRAMS

The compaction diagram is a useful characterization tool for measuring the strength of powder agglomerates (e.g. granules) and characterizing the microstructural development of powder compacts in dry forming operations. The current work describes a new method for the rapid measurement and analysis of compaction diagrams. A computer-controlled testing machine was used to collect crosshead versus load data during powder compaction in a uniaxial die. The net crosshead translation during loading included the permanent compaction of the powder plus the combined elastic deflections of the powder compact and the testing apparatus. In order to compensate for the elastic deformation in the testing apparatus, baseline data were collected by compressing an empty die and were subtracted from the net crosshead position. At the high pressure endpoint, the elastic deformation in the powder compact (i.e. springback) is the difference between the adjusted crosshead position and the thickness of the pellet after ejection from the die. At intermediate pressures, mathematical models were used to estimate the springback. This approach resulted in improved accuracy, significant time savings and an expanded scope of analytical capability compared to other methods of generating compaction diagrams.