Have you ever heard the name "extruder" before? Perhaps you might be wondering, what is an extruder?

An extruder is essentially an industrial device used in the processing and shaping of granular materials. It guides the materials with both motion and heat, leading them into the machine and, upon exit with pressure from the end of the device, produces a product in the form of a dough or ribbon. These products are used in various sectors of the rubber and plastic industries.

Extruders are composed of three main areas: the compression and compression zone, the feeding zone, and the measurement zone.

Types of extruders:

The most common types of extruders are divided into two categories: single-screw and twin-screw.

Single-screw extruder: A method for shaping plastics, extrusions, consisting of a single screw. This model can perform the extrusion process without tolerance, optimizing material and energy consumption. Other features of this device include a long lifespan, high production capacity, and desirable product quality.

The key components of a single-screw extruder are divided into five main parts, as shown in the figure:

1. Drive system
2. Feeding system
3. Cylinder (screw, shell, and heating system)
4. Mold and head assembly (die)
5. Control system

Operation of a single-screw extruder:

The raw materials, in the form of granules or soft powder, enter the screw through the hopper. Then, due to the heat generated by the device's barrel heaters and the cutting resulting from the movement on the edges of the screw, the material is heated. As the material passes through the passage depth, the length of the screw decreases, resulting in material compression.

In the end, where the output is located, the molten material passes through various molds to achieve the desired shape for the final product. Single-screw extruders are primarily used for the production of various polyethylene pipes.

Twin-screw extruders:

Among other types of extruders, the twin-screw extruder utilizes two screws in opposite directions or some in the same direction. This type of extruder typically has three times the production capacity of single-screw extruders.

Operation of a twin-screw extruder:

In the counter-rotating system, the materials are cut and compressed between two rollers with different rotations. In the co-rotating mode, materials are transferred from one screw to another with the same rotation. This method is suitable for heat-sensitive materials.

Applications of extruders:

Depending on their intended use, extruder products can be classified into six main groups:
1. Rods and profiles
2. Pipes
3. Films and sheets
4. Monofilaments
5. Extrusion coatings
6. Wire and cable coatings

Shaping methods using extruders:

Extrusion is a highly flexible method that can produce a wide range of products using suitable dies. Some commonly used methods include:

1. Production of granular shapes
2. Profile production
3. Production of very thin sheets by the calendering method
4. Thermoforming molding