With the development of technology and economy, ptfe has been applied in more and more fields, and has become an indispensable material to solve many key technologies in scientific research, military and civil fields and improve the production technology level. In order to continuously improve the production efficiency of polymer ptfe, we began to adopt the advanced production process, which is suitable for high viscoelastic material —— Ram-punch extrusion.
With the development of technology and economy, ptfe has been applied in more and more fields, and has become an indispensable material to solve many key technologies in scientific research, military and civil fields and improve the production technology level. In order to continuously improve the production efficiency of polymer ptfe, we began to adopt the advanced production process, which is suitable for high viscoelastic material —— Ram-punch extrusion.
According to the principle of “forging”, plunger stamping extruder mainly adopts plunger with small cross section area and high frequency stamping to push material into the barrel of extruder. Compared with traditional hydraulic column extruder, it has the characteristics of high stamping frequency, good melt plasticizing effect, good product quality, simple equipment and process.
According to the forming characteristics of Ram-punch extruder, the extrusion process is analyzed and studied. The physical model of the whole extrusion process of plunger ram extruder is established, which is divided into five sections: solid feeding section, melting section, shunt section, forming section and cooling section. The influence of die length and pressure vibration frequency on extrusion process was analyzed. Analysis results indicate that: although there are large fluctuation of pressure at the entrance of the melt, but on the whole pressure from inlet to outlet were reduced gradually, thus ensure the enough pressure to push the material extrusion, and the closer it gets to the finish mold outlet pressure and speed fluctuation is smaller, so it can ensure the continuity of extrusion, finally get good quality products. The length and stamping frequency of the die have certain influences on the extrusion pressure and speed. Due to the high viscosity of PTFE, a longer die should be selected, and the stamping frequency between 5-6hz is appropriate.
Ram plunger extrusion machining polymer PTFE are very new machining method, but in the process of material forming process, also cannot leave the material flow and deformation, rheological behavior and the law, understanding the process of molding process of reasonable selection, operation and optimization control and improve molding equipment has very important practical significance. Plunger stamping is not a steady-state machining method, and there is vibration in the stamping process. It is of great significance to study the behavior response of polymer under the action of vibration field, and to discuss how much impact the vibration field will have on the flow stability, so as to study the dynamic forming of polymer materials and optimize production.
Post time: Jul-30-2019