What is a barrel screw used for?

1. Plastic Extrusion Process: 

In plastic extrusion, raw plastic material is melted and formed into a continuous profile by pushing it through a die. The screw barrel is a key part of the extruder, where the plastic material is melted, mixed, and then forced through the die to create the desired shape.

2. Melting and Mixing: 

The barrel screw has a helical screw design that rotates within a heated barrel. As the plastic pellets or granules are fed into the barrel, the rotating screw applies heat and pressure to melt the plastic while simultaneously mixing and compressing it. This process ensures uniform melting and mixing of additives, if any, which are often used to modify the properties of the plastic.

3. Transporting: 

The rotating screw also serves to transport the molten plastic material along the barrel towards the die. The depth and pitch of the screw's threads are designed to provide the necessary pressure and conveyance of the molten plastic.

4. Die Extrusion: 

Once the molten plastic reaches the end of the barrel, it is forced through a shaped opening called a die. The shape of the die determines the cross-sectional profile of the extruded product. For example, the die might produce a round tube, a flat sheet, or a complex profile depending on its design.

5. Cooling and Setting: 

After exiting the die, the molten plastic is rapidly cooled and solidified to maintain its shape. This cooling process can involve air cooling, water cooling, or other methods depending on the specific requirements of the product being manufactured.