How To Evacuate The Air of Reusable Silicone Vacuum Bags for Glass Lamination During Processing

In the process of producing laminated safety glass, reusable silicone vacuum bags are a critical tool for ensuring proper lamination of interlayers such as PVB (polyvinyl butyral) or EVA (ethylene-vinyl acetate) between glass sheets. A key step in the lamination process is evacuating air from inside the vacuum bag, which ensures that no bubbles or delamination occurs during heating. Proper air removal not only guarantees product quality but also prolongs the life of the silicone bag. Here's how to effectively evacuate air during the lamination process.

1. Prepare the Glass Stack and Bag Properly

Before placing the glass stack inside the silicone vacuum bag, make sure that all materials are clean and free of dust, debris, or moisture. Layer the glass, interlayer film, and top glass precisely to prevent misalignment during vacuuming. Place the stack centrally inside the bag to allow even pressure distribution.

2. Seal the Bag Securely

Proper sealing is essential. Make sure the bag’s edge and sealing bar are clean and intact. Position the silicone bag’s open end into the sealing groove, and apply even pressure or use mechanical clamps to close the seal completely. Avoid wrinkles along the seal, as they can cause air leaks.

3. Connect to a Reliable Vacuum System

Attach the vacuum port of the bag to a high-quality vacuum pump capable of achieving at least -0.095 MPa (or -950 mbar) vacuum pressure. Ensure all vacuum hoses and connectors are tightly fixed and leak-free. Start the pump and monitor pressure levels closely.

4. Perform a Leak Test

After achieving the desired vacuum pressure, let the system hold for a few minutes with the pump off to verify the seal. If the vacuum drops quickly, inspect the bag for tiny pinholes or check the seal again. Small leaks can be repaired using silicone patch material.

5. Begin Heating Process

Once the vacuum is stable, begin the heating and laminating cycle according to the material requirements. The vacuum ensures that trapped air is removed, allowing the interlayer film to bond evenly with the glass surfaces.

Conclusion

Evacuating air effectively from reusable silicone vacuum bags is crucial to achieving bubble-free, high-quality laminated glass. Through careful setup, tight sealing, and proper vacuum application, manufacturers can enhance product consistency while maximizing the performance and lifespan of the silicone bag.