Heat-sealing/welding of inflatable PTFE radomes

Heat-sealing of inflatable PTFE radomes typically employs hot-press welding; the details are as follows:

1. Hot-Press Welding

1.  Principle: Two sheets of PTFE—characterized by high molecular weight and excellent thermal stability—are heated to a specific temperature (generally above 327°C) within a specialized mold. Under applied pressure, the surfaces of the two sheets are fused together, resulting in a bond with high shear strength and a specific level of peel strength. 
2.  Applications: This method is used to fabricate linear components and connected small-diameter branch pipes. In the manufacture of inflatable PTFE radomes, it is utilized to join PTFE materials to one another and to weld PTFE films to PTFE fabrics. 
3.  Weld Quality: When the welding temperature reaches (385 ± 5)°C and the pressure is 1–2 MPa, the weld seam strength is approximately 90% of the base material's strength, and the peel strength reaches about 1.5 MPa. If a layer of PFA film is applied to the weld interface to act as a hot-melt adhesive, the required welding temperature and pressure can be reduced, while the peel strength of the weld at room temperature can exceed 1.5 MPa.