Roller Compaction Scale-Up Made Simple: An Approximate Analytical Solution to Johanson's Rolling Theory.

Area of Science:

• Powder Technology
• Mechanical Engineering
• Pharmaceutical Sciences

Background:

• Johanson's rolling theory is a foundational model for understanding powder compaction during roller compaction.
• Accurate prediction of densification is crucial for process scale-up and ensuring consistent product quality.
• Existing models often require complex material characterization, limiting their practical application.

Purpose of the Study:

• To derive an approximate analytical solution to Johanson's rolling theory.
• To identify a dimensionless parameter for scale-up and equipment transfer in roller compaction.
• To simplify the prediction of powder densification by reducing reliance on specific material properties.

Main Methods:

• Derivation of an approximate analytical solution based on Johanson's rolling theory.
• Identification and validation of a single dimensionless parameter.
• Benchmarking model predictions against pilot-scale roller compactor data and literature data.

Main Results:

• A single dimensionless parameter was identified, invariant during process scale-up and equipment transfer.
• This parameter effectively relates densification factor to process, geometric, and material properties.
• Model predictions showed good accuracy for ribbon density, even when material properties were calibrated from uniaxial die compression, and notably did not require nip angle data.

Conclusions:

• The derived analytical solution offers a simplified approach to modeling roller compaction.
• The identified dimensionless parameter facilitates robust process scale-up and equipment transfer.
• The model's reduced dependency on complex material characterization enhances its practical utility in powder processing.