Development of Aluminum Foil Longitudinal Wrapping Mold for Longitudinal Watertightness Coaxial Cables

To meet stringent requirements for high frequency transmission and longitudinal watertightness in coaxial cables for deep sea special equipment, a longitudinally applied adhesive coated aluminum foil wrapping mold that operates synchronously with a braiding machine was developed. By precisely wrapping adhesive coated foil onto an insulated core during dynamic production, seamless electromagnetic shielding and reliable longitudinal water sealing were achieved, and seamless integration with subsequent tinned copper wire braiding was realized to form a dual layer shielding structure. Subsequently, cable samples were tested for longitudinal watertightness using a dedicated deep sea pressure simulation test device and for high frequency transmission performance using a high performance vector network analyzer, respectively. Results showed that low loss transmission of 20 GHz high frequency signals and long term reliable operation at depths of 500 m or greater were simultaneously achieved by cables manufactured with this mold, providing a critical cable solution for underwater equipment.