by blades that direct the flow backwards. The convection pattern determines the amount of powder that is held in the blender as it is “pumped” forward by the blades. Smaller blades might also create larger stagnant regions in which the powder might not be flowing (conveyed) at all. Therefore blade configuration #5 was expected to yield the highest hold-up due to an increase in the recirculation created by the 1/2 alternating blade configuration as well as the reduction in the effective blade area available for powder convection.