Plastic Extrusion Process Principles

Extrusion Process Principles

Extrusion process is very common in the plastic industry. It is used for high volume plastic production. In extrusion process the color pigments along with other performance enhancing additives are combined with resin which is then pushed through the rotating screws. The heat and pressure generated within the barrels of screw is dispersed and melts the plastic elements. Thus a homogeneous mixture is produced. A cool die is usually placed at the end of the mixture. After passing through the die the mixture is ready to experience the finishing operation which may include pelletizing, calendaring or other processes. 

The arrangements shows a motor which runs the gear box. The speed is used by this gear reducer box. Which then moves the screw. The metal ingredients is poured through the hopper. The feeding of metal is done in the feeding zone. Then with the increased pressure and temperature of the screw melts the elements in the melting zone. The next part is the melt pumping zone which increases the pressure of the liquid. This pressurized liquid is then pushed through the filter. Then the molten metal flows through the die and cooled. The thermocouple is set at different points to measure the temperature. The figure of the whole process is shown below. Click on it to have a better view . 

Advantages of Plastic Extrusion Process

One of the main advantages of the extrusion process is it can produce pipes of any length. It is continuous. High production volumes with very low cost per pound. The melting is very efficient. The mixing of the ingredients is very good. Different types of raw materials can be used. It uses thermoplastics which can be reused.

Disadvantages of Plastic Extrusion Process

Highly complicated parts are very not suitable for production in extrusion process. It can only produce the parts which have uniform cross sections. 

Please Read : 

• Different Types of Plastics and Their Advantages and Disadvantages
• A complete Guide to Casting Process