An extruder is a machine used in manufacturing processes to shape and form materials by forcing them through a die. It is commonly used to process plastics, but can also handle other materials such as rubber, ceramics, and food products. The extruder works by continuously pushing the raw material, usually in a granular or pellet form, through a heated barrel using a screw - driven mechanism. As the material moves through the barrel, it is heated and softened, and then forced through a die at the end of the barrel to form a continuous profile with a specific shape.
The concept of extrusion dates back to the 18th century, but the modern extruder as we know it began to take shape in the early 20th century. The early extruders were relatively simple and were mainly used in the rubber and food industries. As the plastics industry grew and new polymer materials were developed, the extruder became a crucial tool for plastic processing. With advancements in screw design, heating technology, and die - making, extruders have become more efficient, versatile, and capable of producing a wide range of products with precise shapes and dimensions.
An extruder operates based on the principle of screw - driven conveyance and heat - induced plastic deformation. The material is fed into the hopper of the extruder and is then picked up by the rotating screw. The screw rotates within the heated barrel, causing the material to move forward. As the material progresses through the barrel, it is heated by the barrel's heating elements and the friction generated by the screw's movement. The combination of heat and pressure causes the material to soften and become a viscous fluid. This fluid - like material is then forced through the die at the end of the barrel, where it takes the shape of the die opening and solidifies as it exits, forming the extruded product.