An extruder screen, also known as a screen pack or screen changer, is a device used in the plastic extrusion process to filter out impurities and contaminants from the molten plastic before it is extruded through a die.

The extruder screen is typically made of woven wire mesh or perforated metal and is placed in the melt flow channel of the extruder. It acts as a barrier, preventing any foreign particles such as metal, paper, or dirt from entering the final extruded product.

The screen is designed to have a specific mesh or perforation size, which determines the size of particles it can filter out. The choice of screen size depends on the desired quality and purity of the final product.

Over time, as the extruder screen collects impurities, it can become clogged and cause a decrease in output or quality of the extruded material. To prevent this, some extrusion systems are equipped with a screen changer, which allows for easy removal and replacement of the screen without interrupting the extrusion process.

Overall, the extruder screen plays a critical role in ensuring the quality and purity of the extruded plastic product by filtering out impurities and contaminants.