How to Choose the Right Screen Changer Solution?

2023-10-26 | Technical Blog | By Janine Cheng |

Plastic pelletizing machines provide cutting, extruding, and pelletizing processes in one machine. Within the extrusion process, the degassing and filtration systems play a pivotal role in enhancing plastic quality. In this article, we will focus on the filtration systems that POLYSTAR provides and explain the differences.

Commonly seen plastic wastes and the sources

Types Forms Sources
  • PE
  • PP
  • PS
  • ABS
  • PU
  • EPS
  • Others
  • Printed and non-printed films and bags
  • Laminated films
  • Multilayered films
  • Raffia, woven and non-woven sacks
  • Hard plastics from injection molding, blow molding, and others
  • Production line scraps
  • Defective products
  • Landfill

Plastic types have significant impacts on the viscosity, flow rate, pressure, throughput rate, and more. Different screen changers provide different levels of efficiency in removing larger or finer impurities. Let’s explore each screen changer solution in detail:

1. Fan-type screen changer

Fan type screen changers feature a smaller screen channel and larger hole sizes that effectively capture relatively larger impurities. The rotary fan blade design is particularly well-suited for plastics with low viscosities, allowing for easy passage through the screen. Due to the smaller filtering area, the screen changing frequency is higher and the durability of the mesh screens are lower.

This system is only applied on our Mini-type in-house plastic pelletizing machine. This model is specifically designed for processing in-house PE films and bags, which typically exhibit minimal contamination levels.

Mini type plastic recycling machine
(Mini-type plastic pelletizer)

2. Slide-type screen changer

Compared to the fan-type screen changer, the slide-type screen changer is designed with a stationary screen plate so that it offers stability for processing plastics with medium viscosity. Moreover, smaller mesh holes enable it to capture finer impurities.

This filtration system is suitable for processing a wide range of impurity levels and viscosities. It reduces the frequency of screen changes, consequently reducing overall maintenance costs. The slide type screen changer can be applied on all of our water-cooled plastic pelletizing machines, catering to a variety of materials.

Shredder plastic recycling machine
(Water-cooled Plastic Pelletizing Machine – Shredder Integrated Plastic Pelletizer)

3. Dual-piston screen changer

Dual-piston screen changers and slide type screen changers share certain capabilities, such as managing high viscosity materials and effectively filtering larger impurities. However, dual-piston screen changers offer bigger filtering area and higher mesh hole density, resulting in prolonged screen durability. They also provide additional benefits including reduced operational interruptions and enhanced final product quality.

The dual-piston screen changer can be seamlessly integrated into all our water-cooled plastic pelletizing machines to maximize recycling performance.

Two stage plastic recycling machine
(Water-cooled Plastic Pelletizing Machine – Two-stage Plastic Pelletizer)


Fan-type Slide-type Dual-piston
Suitable materials Low to Medium Viscosity Plastics Medium to High Viscosity Plastics Medium to High Viscosity Plastics
Application Lower Impurity Levels Medium to High Impurity Levels Medium to High Impurity Levels
Filtration Efficiency Effective for Larger Impurities Effective for Various Impurities Effective for Various Impurities
Maintenance More Frequent Screen Changes Moderate Screen Changes Reduced Screen Changes

With these screen changer systems, you are able to enhance and stabilize the quality of the recycling process and the final recycled pellets. However, it's important to bear in mind that although these technologies make your recycling project smoother and more effective, your plastic should undergo washing and drying procedures to achieve the optimal results.

Contact us now to receive solutions for your plastic waste.

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About the Author
Janine Cheng

POLYSTAR Marketing Assistant

Janine creates engaging content for POLYSTAR’s social media presence, including keeping social media channels updated and brand-focused and seeking ways of connecting with plastic producers and recyclers.

You can find Janine on LinkedIn.