Filling machines for soft gelatin capsules are specialized pieces of equipment used to encapsulate liquids, suspensions, or semisolids within a gelatin-based shell. The process of making soft gelatin capsules involves several steps, and the filling machine is central to the encapsulation process.


Here's a breakdown of the components and functions of filling machines used for soft gelatin capsules:

1. Basic Components of the Filling Machine:

  • Gelatin Tanks and Spreaders: The gelatin solution is prepared in heated tanks and is spread as a thin film.
  • Rotary Dies: The machine uses a pair of rotating die rollers. These dies form the capsules by creating a continuous strip of gelatin, which is cut and shaped during the process.
  • Fill Material Hopper: The fill material (liquid or paste) is loaded into a hopper, which feeds it into the capsules.
  • Pump and Injection Wedge: A pump is used to inject the fill material into the gelatin sheets. The injection wedge is heated and positioned between the die rollers to inject the fill material precisely at the point where the two sheets of gelatin meet.
  • Cooling Drum: After the capsules are formed, they pass over a cooling drum to ensure the gelatin solidifies around the filling.

2. Working Process:

  1. Gelatin Film Preparation: Two thin sheets of gelatin are extruded from heated gelatin tanks, which are kept at a temperature suitable to maintain the gelatin's consistency.
  2. Capsule Formation and Filling: The two gelatin sheets pass over the rotary dies, which contain depressions of the desired capsule shape. As they meet, the fill material is injected into the gelatin sheets by a calibrated pump. The fill material is precisely dosed to ensure uniformity.
  3. Sealing and Cutting: As the rotary dies rotate, they shape, fill, and seal the capsules simultaneously. The heat and pressure from the dies form the capsule shape and seal the edges to enclose the fill material.
  4. Tumbling and Drying: Once formed, the capsules are soft and need to be dried to reach their final consistency. They pass through a tumble dryer to remove some moisture, followed by drying trays or a drying tunnel where the remaining moisture is reduced to an appropriate level.

3. Types of Filling Materials:

The filling material can be:

  • Liquids: Oils, solutions, or suspensions.
  • Pastes: Semisolid formulations, such as those containing dissolved or suspended active pharmaceutical ingredients.

4. Key Features:

  • Precision: The machine allows precise dosing of the fill material to ensure consistency across capsules.
  • High Speed: It can produce thousands of capsules per hour, making it suitable for industrial-scale production.
  • Quality Control: The encapsulation process is tightly controlled to maintain product quality, including thickness of the gelatin shell and fill volume.

5. Uses in Industry:

Filling machines for soft gelatin capsules are used widely in the pharmaceutical, nutraceutical, and food industries. They are ideal for products that require an accurate dose and a convenient, easy-to-swallow delivery form.