ABSTRACT
The goal in any blending operation is to have a properly blended powder mixture at the point in the process where it is needed, for example, during filling of the tablet die. This is not at all the same as requiring that all constituent powders in a blender be properly blended, since subsequent handling of a well-blended powder can result in significant deblending due to segregation. Segregation is as much a threat to product uniformity as poor or incomplete blending. An ability to control particle segregation during powder handling and transfer is critical to producing a uniform product. Understanding the flow behavior in bins and hoppers is a vital necessity for understanding segregation tendencies. Further consideration must be given to maintaining reliable flow of powder, since no flow or erratic flow can slow production or stop a process altogether.
