Improvement of Parameter Setting for Soft Gelatin Capsule Manufacturing Process

This paper demonstrates the application of Six Sigma “DMAIC” to reduce misshapen defects within a soft gelatin capsule manufacturing process. The paper follows the DMAIC stages to investigate defects, root cause, and provide a solution to reduce these defects. Firstly, the problem is identified with the Pareto diagram. Secondly, an attribute agreement system is assessed for accuracy and precision. Next, the causes for the misshapen capsule are analyzed by the why-why analysis diagram. Then, the causes are narrowed down by applying a hypothesis test. Three significant factors are affecting the soft gelatin capsule manufacturing process. Which are, injection temperature, cooling temperature, and die roll speed. Full factorial design experiments were conducted. The results suggested that their two factors and two-way interactions are significant. An optimal setting was identified with a response optimizer. The new setting has resulted in a defect rate from 5.40% to 0.35%