Novel Method for Assessment of Critical Powder Packing During Powder Forming

Abstract

Powder forming of a successful product requires initial selection of powder with appropriate packing characteristics. Packing estimations from particle characteristics are erratic, and estimations from apparent density and tap density measurements are only moderately good because of poor powder flow as a result of inter particulate friction. Use of a wetting fluid in the torque measurement method avoids friction and allows particle rearrangement, but the monitoring of torque or viscosity changes with powder binder mixing requires costly equipment. A simpler method for the assessment of the critical packing volume concentration (CPVC) of a given powder by monitoring temperature during mixing is proposed. The CPVC values of different powders are measured with the new method. The effects of powder characteristics and operational parameters on the CPVC estimation are studied. The packing values arrived at by this method are found to agree with those from the torque measurement method. PM/0703