Plastic extrusion is a large-scale manufacturing process that yields continuous products with uniform cross-sections. This technique involves melting thermoplastic materials and pressurizing them to force the melt through a die. A rotating screw’s interaction with the barrel walls generates pressure. As the melted plastic moves through the die, it gets shaped into the form of the die and emerges as an extrudate. Subsequent cooling methods like cooling rolls or water baths solidify the extrudate into its final form.
Plastic Extrusion
Advantages of Plastic Extrusion
Low Cost - Plastic extrusion has a low-cost relative to other moulding processes. This is due to the efficiency of the process.Flexibility - Plastic extrusion can be used to create a range of shapes in a variety of thicknesses, textures, colours, and sizes in a short amount of time.Post-Extrusion Alterations - When the plastic leaves the extruder, it’s still hot, which allows for post-extrusion manipulation.Plastic Extrusion Process
1. Material Preparation
Raw plastic, usually in the form of pellets or granules, is prepared for the extrusion process. You choose a material based on what properties you expect in the final product.2. Melting and Mixing
The plastic material is introduced into an extruder, a machine comprising a heated barrel and a rotating screw. The screw within its barrel rotates in a controlled manner.3. Extrusion Process
Following the thorough mixing and uniform melting facilitated by the extruder, the molten plastic is pushed through a specially designed die or mold located at the extruder's end.4. Cooling and Sizing
As the plastic material exits the die, it enters a cooling zone. Air- or water-cooling systems often assist during this stage. This removal of heat solidifies the plastic into its final shape.5. Hauling and Cutting
The extruded plastic material is pulled or "hauled" through the process using rollers or other mechanisms. This keeps the extrusion moving at the proper speed and tension. 6. Additional Processing
Some extruded items need additional processing. This could include: surface treatments, printing, markings, or attaching other components to the extruded profile.Plastic Extrusion Materials Comparison Table
Choosing a suitable material for your project is crucial to your extruded part’s overall functionality and longevity. In addition, the material can be a primary driver for manufacturability and cost. 