Air bubbles in softgel capsules can affect capsule appearance, filling consistency, and sealing quality. When this problem occurs during rotary die encapsulation, the troubleshooting process should focus on the filling material, filling parameters, die pressure, and the condition of the forming components.
1. Optimize the Filling Process
First, check the condition and consistency of the filling material. For powder-based formulations, the material should be properly screened to maintain a uniform particle size and prevent foreign matter or oversized particles from affecting the filling process.
The filling speed should also be properly controlled. Excessive filling speed may increase the possibility of air entering the capsule together with the material. Adjusting the pump speed and filling timing can help reduce air entrapment.
During the sealing process, the gelatin ribbons must be properly formed and bonded around the filling material. Incomplete sealing or unstable ribbon feeding can also contribute to air pockets and leakage.
Hansheng Automation can manufacture custom precision components for filling and sealing systems based on customer drawings, including pump components, nozzles, shafts, bushings, guides, and other non-standard parts that require accurate dimensional control.
2. Adjust Roller Pressure
The forming roller pressure should be checked and adjusted according to the capsule specification and gelatin ribbon characteristics. Appropriate pressure helps the gelatin ribbons close properly around the filling material and reduces the formation of internal air pockets.
However, excessive roller pressure may increase die wear or negatively affect capsule appearance. Operators should therefore make incremental adjustments while monitoring the actual forming quality.
The condition of the roller dies should also be inspected. Worn or damaged die surfaces may lead to uneven forming pressure and incomplete sealing. When significant wear is found, the relevant components should be repaired or replaced according to the equipment manufacturer's specifications.
3. Check the Die and Feeding System
Air bubbles may also result from unstable feeding or poor synchronization between the filling system and the rotary dies. Check whether the filling pump, injection nozzle, and die rotation are properly synchronized.
At the same time, inspect the gelatin ribbon thickness, temperature, and feeding stability. Uneven ribbon thickness or inappropriate forming temperature can make it more difficult to completely seal the filling material inside the capsule.
For precision mechanical components such as die shafts, roller assemblies, pump parts, and positioning components, we support drawing-based custom machining and can manufacture replacement or application-specific parts according to customer requirements.
4. Confirm Process Parameters
The actual cause of air bubbles should be determined by considering multiple process parameters rather than adjusting roller pressure alone. Important factors include filling speed, pump stroke, injection timing, gelatin ribbon temperature, ribbon thickness, roller pressure, and die alignment.
A systematic adjustment of these parameters can help identify the source of air entrapment and restore stable capsule forming.
Overall, when softgel capsules contain air bubbles, the recommended approach is to inspect the filling material, filling speed, injection synchronization, roller pressure, die condition, and gelatin ribbon forming conditions in sequence. The exact adjustment values should follow the machine manufacturer's technical specifications and the actual formulation used.
