An investigation of die wall friction during the compaction of powders

Abstract

Crystalline aspirin, hexamine, sucrose, and sodium chloride, and simple granulations of hexamine and of sucrose, have been compressed and the die reaction determined using a “moving-die” technique. The shear strength of the ejected compacts has been measured under zero load conditions, and when compressed to theoretical density, using a punch penetration test. Calculated values of die reaction based on friction theory have been compared with experimental measurements. Correlation between the two is best for aspirin and hexamine crystals when the compact approaches theoretical density and shear strength values for compacts of zero porosity are used in the calculations; for sodium chloride, correlation is best when shear strength values under zero load conditions are used.