In this article, an overview of granule production methods has been provided. Before delving into these methods, an important point to consider is that granules refer to the bead-like forms of polymers and are not a specific type of polymer themselves.
1. Strand Type Granulation:
- This method involves the production of granules in a strand-like manner. - The extruder device is used for the passage of molten plastic pieces. - Subsequently, plastic pieces emerge from the device in a strand-like form and pass through a plastic mill to become dry. - This method is less suitable for producing fresh materials and often results in granules with sharp edges that may lower the quality of the final products.
2. Hot Die Face Cutting Granulation:
- In this method, shredded plastics, after melting in the extruder, exit through fine holes and are rapidly cut by blades. - They then enter a larger reservoir where, by creating a pressure difference, heavier granules settle at the bottom of the reservoir. - This method requires more precise machinery and has a higher production cost. However, the produced granules closely resemble those of primary materials, exhibiting more stable plastic properties.
3. Water Ring Cutting System:
- This method bears great resemblance to dry granule production, with the difference that, after cutting, granules adhere to a reservoir's periphery using centrifugal force and take on a lentil-like shape. - This system is mainly employed for breakable compounds.
4. Underwater Cutting System:
- In this system, materials such as strands, after melting and passing through a sieve, are directed underwater, where they are swiftly cut. - This method is typically used for high capacities (e.g., one ton per hour) and is suitable for most thermoplastics. The high maintenance cost is one of the reasons why it is usually employed for high-volume granule production.
In summary, this article provides an overview of four granule production methods: Strand Type Granulation, Hot Die Face Cutting Granulation, Water Ring Cutting System, and Underwater Cutting System. Each method has its own characteristics, advantages, and drawbacks.
- Strand Type Granulation: This method seems less suitable for producing fresh materials, and its sharp edges may impact the quality of the products.
- Hot Die Face Cutting Granulation: This method requires more precise machinery and comes with a higher production cost. However, the produced granules exhibit more stable plastic properties.
- Water Ring Cutting System: Primarily suitable for breakable compounds.
- Underwater Cutting System: Suited for high capacities, but maintenance costs are relatively high.
The choice of the best method depends on specific needs and desired features. For instance, if stability in plastic properties is crucial, Hot Die Face Cutting Granulation stands out. Conversely, if high capacity with lower maintenance costs is a priority, the Underwater Cutting System might be a suitable option.