This study aims to improve traditional Chinese medicine (TCM) tablet manufacturing efficiency by optimizing die filling to improve tablet uniformity. It comprehensively investigates the filling performance of 23 fermented Cordyceps powder batches to evaluate batch-to-batch variation effects. Powder flow properties were measured, and die filling behaviour was analysed using a custom system with high-speed imaging, assessing performance via critical filling velocity (Vc). A predictive model correlating flow properties with Vc was established. The powders exhibited cohesive behaviour and limited flowability. Statistical analysis revealed minor variations in bulk density, tapped density, hausner ratio, particle size distribution span, and stability index, and major principal stress, but significant inter-batch differences in D10, D50, D90, size distribution width, permeability, cohesion, and flow function. Close examination identified a distinctive "blocky intermittent flow" phenomenon during filling. Variable Importance for Projection (VIP) analysis identified particle size distribution indicators, flowability indicators, and packing indicator as the critical material attributes governing inter-batch filling performance. This study establishes that a multivariate statistical model can effectively predict key material characteristics governing batch filling dynamics in TCM powders, enabling control to improve solid dosage form quality.