Research On Extrusion Forming Technology Of Clasp Insulation Sheath And Optimum Design Of Mold

With the rapid development of power systems,many 110 kV and 220 kV simple overhead bare wires have serious effects due to lack of insulation protection measures,such as discharge,flashover,and repeated tripping in harsh environments.In order to solve the operation safety problem of the transmission line,the power department uses the insulating tape to wrap the package to insulate the bare wire,but the insulation performance of the tape is not good,and the installation is inconvenient,which requires manual work,time and labor.And the silicone rubber material is sheathed for insulation protection,but the production cost is high,the mechanical properties are poor,and it is easy to fall off due to long-term use.In recent years,the power sector has used the newly-launched polyolefin snap-on insulating sheath to insulate the bare wire.Due to it is an emerging product,the jacket lacks theoretical research and technical guidance in production,and needs to be perfected.It is necessary to improve extrusion process and optimize extrusion die to improve extrusion quality and performance.Therefore,this paper takes the snap-in insulation sheath as the research object,analyzes the extrusion molding process by studying the structural shape,material properties and mold structure of the jacket.And the structure of the extrusion die is improved and optimized by numerical simulation technology.Firstly,the structural shape and size parameters of the insulating sheath are studied,so that the sheath can be easily installed on the electric wire,and it can be fastened and not easy to fall off.Then the selection of polyolefin material for insulating sheath is analyzed and the material proportion is selection.Then the extrusion process of the insulating sheath is analyzed,and the appropriate extrusion processing equipment and process plan are found.Then the extrusion mold of the insulating sheath is designed,in which the design of the extrusion die is the main part,and the strength of the entire extrusion die is checked.Fluent software is used to simulates the flow process of plastic melt in the flow path of the extrusion die.The velocity distribution and pressure distribution of the melt in the flow channel are analyzed based on the uniformity of the melt flow velocity at the exit of the flow path.Changing the structure of the flow passage in the sector region and adding a damping block to make the melt flow uniformly in the flow passage and optimize the extrusion die.Finally,the insulating sheath was pilot-produced through experiments,and the insulating sheath was extruded to simulate the optimized mold structure.The electrical properties and physical properties were tested,the errors and defects in the experiment were analyzed,and the measures and methods for solving the problems were found.In this paper,through the research on the extrusion molding process and mold design of polyolefin snap-in insulation sheath,the production quality and performance of the insulation sheath are improved,which provides a theoretical reference for the development and research of similar products.