The key processes for the manufacture of composite insulators are: umbrella material selection and processing technology, mandrel material selection and sheath processing technology, metal breakage selection and end connection, sealing processing. The characteristics of the three production technologies are as follows:

    1. Single umbrella set bonding plus flower sleeve Baohua plus vertical filling type: After the outer core is molded by the core rod, it is introduced into the umbrella string bonded by room temperature vulcanized silicone rubber, and the gap vacuum is filled into the polymer filling. The glue is finished after the end is connected with the fittings. This kind of technology is an early process, with many processes and large dispersibility. It is difficult to ensure the fullness of the voltage level of 220KV and above in mass production. Due to the deflection of the mandrel, the glue gap is small, and the contact between the mandrel and the inner wall of the umbrella string is likely to cause blockage of the half of the rubber channel, resulting in partial no filler and forming insulation defects.

    2. Squeeze sheath and sticky umbrella disc type: After the core rod is brushed by the brushing process, it is made into a sheath by the extrusion machine, and the vulcanized umbrella piece is flashed at room temperature after being vulcanized. The vulcanized silicone rubber is bonded and finished by connecting the end fittings to the fittings and sealing treatment. The technology has high production efficiency, because the domestic extrusion machine has a low outlet temperature, and the core rod and the sheath are mainly bonded by secondary vulcanization, and the bonding surface of the disc and the sheath is small.

    3. Segmentation or one-shot injection form: After the core rod is brushed by the brushing process, it is injection molded in the mold by an injection molding machine. After the insulator with high voltage level is formed by segmental injection molding, it is completed after secondary vulcanization and fitting. The mandrel and the sheath of the process are thermally connected, the bonding effect is good, the inner insulation has only one layer interface, and the interface is small, which is a relatively new production technology.