Air entrapment is a primary cause of tablet lamination, yet the quantitative impact of specific tooling variables remains underexplored. This study investigates the influence of tapered dies and compaction position on lamination type 1 using two distinct formulations: a plastic MCC-based blend (FMCC) and a brittle Mannitol-based blend (FMann). Tablets were manufactured using a compaction simulator mimicking high-speed rotary press kinematics, varying die geometry (straight vs. tapered), punch-die clearance, and compression position. Lamination propensity was quantified by identifying the compression pressure threshold at which defects occurred, which is termed lamination pressure. Results demonstrated that facilitating air escape, either through increased clearance or by compressing higher in the die, increased the lamination pressure. While the tooling effects were limited for the plastic formulation, the brittle formulation showed significant sensitivity to these parameters. Notably, compressing high in the die was found to be more effective than using a tapered die, as tapered dies offered no additional benefit when the compression position was already optimized. Results indicate that optimizing compression position is an industrially more significant solution for air entrapment than the use of tapered dies.
Madi et al. (Sat,) studied this question.