Optimized Design of Twin Screw Extruders for High-Performance Material Processing

In modern industrial manufacturing, twin-screw extruders have garnered significant attention due to their exceptional performance and wide range of applications. As technology continues to advance and market demands evolve, Nanjing Granuwel Machinery, as a leading manufacturer of twin-screw extruders, is committed to optimizing equipment performance. We aim to help our customers meet complex processing requirements and provide robust support for the development of high-performance materials.

Optimization Design of Twin-Screw Extruders

1. Optimization Design of Screw Elements

Elementos de tornillo

The screw elements are one of the core components of twin-screw extruders, and their structural parameters significantly impact material conveyance and mixing efficiency. By optimizing design parameters such as pitch, channel depth, and helix angle of the screw elements, we can enhance material conveyance efficiency and mixing uniformity. For example, an unequal pitch design can achieve axial backflow and radial mixing of materials, improving dispersion effects. Nanjing Granuwel’s screw elements design employs high-precision manufacturing processes to ensure exceptional machining accuracy and durability, meeting the processing requirements of various complex materials.

Kneading Block Elements:

Kneading blocks possess strong shearing and dispersive mixing capabilities, making them suitable for mixing high-viscosity materials. By strategically arranging the number and position of kneading blocks, we can control the shear rate and residence time of the material, enhancing mixing quality. Additionally, using kneading blocks of different shapes and sizes allows us to meet the processing requirements of various materials. Nanjing Granuwel offers a variety of kneading block elements in different specifications and supports customized designs, ensuring that each customer can find the solution best suited to their process needs.

Toothed Elements:

Toothed elements exhibit excellent dispersive and distributive mixing capabilities, making them suitable for mixing powdered materials. By optimizing the number of teeth, tooth shape, and arrangement of toothed elements, we can enhance the dispersion effect and mixing uniformity of materials. Additionally, combining toothed elements with other components can achieve multiple mixing effects. Nanjing Granuwel’s toothed elements are precisely designed and verified through numerous experiments, providing exceptional performance in powder processing and high-precision mixing applications.

Screw Elements of Granuwel Twin-Screw Extruders

2. Optimization Design of Screw Configurations

Screw Configurations:

Different screw configurations can achieve various mixing and conveying effects. For instance, combining forward-threaded elements with reverse-threaded elements can facilitate axial backflow and radial mixing of materials; pairing forward threads with kneading blocks can enhance shearing and dispersive mixing. The selection and arrangement of different specifications of screw elements determine the equipment’s shear intensity and mixing capability for the material system. Typically, screw configuration optimization adopts a “convey-mix—convey-mix” approach, allowing materials to be dispersed and mixed in a balanced manner. Different plastics have varying requirements for screw configurations. For example, PE and PP require moderate shear intensity and an appropriately lengthened screw, while elastomers like TPE and TPR need strong shear intensity and longer screw lengths. PVC, being a heat-sensitive material, requires very low shear intensity and the shortest possible screw length. By selecting the appropriate screw configuration, we can meet the processing needs of different materials.

Feeding Methods and Side Feeding:

The method of feeding significantly impacts material mixing and conveyance. Common feeding methods include volumetric measurement and loss-in-weight measurement. Volumetric measurement is suitable for materials with good flowability, while loss-in-weight measurement is ideal for materials with poor flowability. Different material systems have varying requirements for the sequence of feeding, which is when we use side feeders to add from the rear section of the equipment. For example, in the case of PA+GF reinforced modification, PA and additives are added through the main hopper, while GF is fed from the side hopper at the rear (for short glass fibers) or from the top of the rear barrel (for long glass fibers). When the material system contains components with different melting points, adding them all through the main hopper can cause low-melting-point materials to lose their physical properties or decompose due to excessive temperatures. In such cases, high-melting-point materials should be fed first through the main feeder, and low-melting-point materials should be added later in the rear section, with the barrel temperature set lower in that section. Choosing the appropriate feeding method can improve feeding accuracy and stability while offering more options for diverse material mixing systems.

Ventilation Methods:

During the extrusion process, materials may contain small molecules or moisture, affecting product quality. Therefore, it is necessary to set up appropriate venting systems. Common venting methods include natural venting and forced venting. Natural venting is suitable for materials with low volatility, while forced venting is ideal for materials with high volatility. Choosing the right venting method can effectively remove gases from the material.

Custom Designed Screw Configurations of Granuwel Twin-Screw Extruders

Study on application of twin-screw extruders in processing high performance materials

1. Processing of Thermoplastic Elastomers (TPE)

Thermoplastic elastomers are materials that possess the elasticity of rubber and the processability of plastics, widely used in automotive, electronics, medical, and other fields. The Nanjing Granuwel twin-screw extruder offers the following advantages in TPE processing:

Good Dispersion:

The strong shear and mixing action of the twin-screw extruder can uniformly disperse fillers and additives in TPE, enhancing product performance.

Precise Temperature Control:

The twin-screw extruder can achieve precise temperature control to meet the temperature requirements of TPE processing.

Efficient Venting:

 The forced venting function of the twin-screw extruder effectively removes gases from TPE, preventing defects such as bubbles in the product.

2. Modification of Engineering Plastics

Engineering plastics have advantages such as high strength, high rigidity, and wear resistance. However, they also have some drawbacks, such as poor toughness and difficulty in processing. Modifying engineering plastics through the twin-screw extruder can improve their performance. For example, adding toughening agents can enhance the toughness of engineering plastics; adding fillers can reduce costs; adding stabilizers can improve the weather resistance of engineering plastics.

3. Preparation of Nanocomposites

Nanocomposites exhibit excellent mechanical, thermal, and electrical properties and are widely used in aerospace, electronics, automotive, and other fields. The Nanjing Granuwel twin-screw extruder offers the following advantages in the preparation of nanocomposites:

Good Dispersion:

The strong shear and mixing action of the twin-screw extruder can uniformly disperse nanofillers in the matrix material, enhancing the performance of nanocomposites.

Precise Temperature Control System:

The precise temperature control system of the twin-screw extruder meets the temperature requirements for processing nanocomposites.

Efficient Venting:

The forced venting function of the twin-screw extruder effectively removes gases from nanocomposites, preventing defects such as bubbles in the product.

4. Processing of Biodegradable Materials

Biodegradable materials are those that can decompose in the natural environment, playing a significant role in environmental protection. The Nanjing Granuwel twin-screw extruder offers the following advantages in the processing of biodegradable materials:

Gentle Processing Conditions:

The twin-screw extruder can achieve gentle processing conditions to avoid degradation of biodegradable materials during processing.

Precise Temperature Control System:

The precise temperature control system of the twin-screw extruder meets the temperature requirements for processing biodegradable materials.

Efficient Venting:

The forced venting function of the twin-screw extruder effectively removes gases from biodegradable materials, preventing defects such as bubbles in the product.

Granuwel Twin-Screw Extruder

In summary, the optimization design of twin-screw extruders and the application research in high-performance material processing is a continuously evolving and innovative field. As an industry leader, Nanjing Granuwel Machinery always adheres to the philosophy of “technological innovation and customer priority.” By continually optimizing the design of screw elements and screw combinations, as well as exploring the applications of twin-screw extruders in various high-performance materials, we further enhance the performance and processing quality of twin-screw extruders, thereby promoting the development and application of high-performance materials.