The polymer insulators manufactured by YIKUN ELECTRIC employ integral injection method and crimping technology between hardware fittings & glass-fiber core， checked by automatic flaw detection system. The metal fittings are sealed with four layers of high temperature silicone rubber to eliminate the brittle fracture fault caused by the sealing reason. By applying advanced equipment and strict production procedure, our polymer insulators can fully meet the technical requirements of GB/T19519 and IEC61109.