News

Trade news

Company news

FAQ

Process conditions for extrusion in a rubber extruder

Time：

2018-09-14

When operating a rubber extruder, the primary factors to monitor are temperature and speed. Proper temperature control ensures smooth extrusion, boosts production output, and enhances the quality of the extrudate—resulting in a smooth surface, dimensional stability, precise dimensions, and a low expansion ratio. If the extrusion temperature is too low, the extrudate may exhibit a rough surface, increased cross‑sectional dimensions, and higher electrical load; conversely, excessively high temperatures can lead to scorching and foaming. Therefore, an appropriate temperature profile should be employed throughout the extrusion process. Typically, different sections of the extruder require distinct temperature settings: the barrel is set at a lower temperature, while the die head operates at a higher temperature; moreover, the barrel may be divided into one or multiple zones.

When operating a rubber extruder, the key parameters to monitor are temperature and speed. Proper temperature control ensures smooth extrusion, boosts output, and enhances the quality of the extrudate—resulting in a smooth surface, dimensional stability, precise dimensions, and a low expansion ratio. If the extrusion temperature is too low, the extrudate may exhibit a rough surface, increased cross‑sectional dimensions, and higher electrical load; conversely, excessively high temperatures can lead to scorching and foaming. Therefore, an appropriate temperature profile should be employed throughout the extrusion process. Typically, different sections of the extruder require distinct temperature settings: the barrel is set at a lower temperature, while the die head operates at a higher temperature. The barrel itself may be divided into one or more temperature zones, with the screw temperature consistently maintained above that of the barrel.

　　The feeding section of a rubber extruder typically operates at a relatively low temperature, which facilitates feeding and enhances extrusion uniformity. For most rubber compounds, a temperature setting of 43–60°C is sufficient; for harder compounds, the temperature can be slightly increased to 49–60°C.

　　High temperatures at the die and die‑land of a rubber extruder offer two advantages: first, they reduce the swell ratio of the extrudate; second, they lower die pressure, thereby helping to increase extrusion output.

　　A lower barrel temperature in a rubber extruder can increase the compound’s viscosity. Therefore, in practical operation, maintaining a barrel temperature lower than the screw temperature is beneficial for boosting production. However, the temperature difference between the extruder barrel and the screw should be kept within an appropriate range. If this differential is too large, although it may enhance output, it can degrade the quality of the extrudate, leading to defects such as micro‑porosity and spiral marks; conversely, if the differential is too small, production rates will decline.