Roller compaction scale-up using roll width as scale factor and laser-based determined ribbon porosity as critical material attribute

摘要

Due to the complexity and difficulties associated with the mechanistic modeling of roller compaction process for scale-up, an innovative equipment approach is to keep roll diameter fixed between scales and instead vary the roll width. Assuming a fixed gap and roll force, this approach should create similar conditions for the nip regions of the two compactor scales, and thus result in a scale-reproducible ribbon porosity. In the present work a non-destructive laser-based technique was used to measure the ribbon porosity at-line with high precision and high accuracy as confirmed by an initial comparison to a well-established volume displacement oil intrusion method. The ribbon porosity was found to be scale-independent when comparing the average porosity of a group of ribbon samples (n = 12) from small-scale (Mini-Pactor (R)) to large-scale (Macro-Pactor (R)). A higher standard deviation of ribbons fragment porosities from the large-scale roller compactor was attributed to minor variations in powder densification across the roll width.