Process 1: Raw Material Inspection and Preparation
Raw material quality is the foundation of qualified hollow capsules, so this process focuses on strict inspection and scientific proportioning of raw materials. The main raw materials include gelatin (for animal-derived capsules) or hydroxypropyl methylcellulose (HPMC), pullulan (for plant-derived capsules), plasticizers (such as glycerin, sorbitol), and purified water.
Process 2: Gelatinization and Dissolution
This process aims to fully dissolve and gelatinize the proportioned raw material mixture to form a uniform, transparent, and stable glue solution, which is crucial for ensuring the uniformity of the capsule shell's thickness and texture.
Process 3: Dipping and Forming
Dipping and forming is the core process of forming the capsule shell, which relies on specialized dipping equipment and precise temperature control to ensure that the glue solution adheres uniformly to the mold and forms the desired shape.
Process 4: Primary Drying
After dipping and forming, the capsule shells attached to the mold pins are in a semi-solid state with high moisture content (about 40-50%). Primary drying aims to rapidly reduce the moisture content to a certain level, making the capsule shells initially solidify and maintain their shape.
Process 5: Secondary Drying (Fine Drying)
Secondary drying is a fine-tuning process to further reduce the moisture content of the capsule shells to the standard range, ensuring their stability and mechanical properties. The moisture content of the final capsule product is a critical indicator-too high moisture will lead to softening, sticking, and microbial growth; too low will make the capsule brittle and easy to break.
Process 6: Demolding and Trimming
After the capsule shells are fully dried and solidified, they need to be separated from the mold pins (demolding) and trimmed to the standard length to ensure the consistency of the capsule's size.
Process 7: Cap-Body Fitting and Visual Inspection
This process involves fitting the trimmed capsule caps and bodies together and conducting preliminary visual inspection to remove products with obvious defects.
Process 8: Final Quality Testing and Packaging
This is the last barrier to ensure product quality, involving comprehensive performance testing of the qualified capsules after visual inspection, followed by standardized packaging.