In PET bottle recycling, many customers ask: How small can a two-shaft shredder actually shred the bottles?
This article provides a detailed explanation and helps you understand its role in the overall recycling process.
1. Common Output Particle Size
A two-shaft shredder is a low-speed, shear-type machine. Its main function is "tearing + coarse crushing." The typical output particle size is:
30–120mm (irregular flakes/strips)
The specific particle size is affected by the following factors:
- Blade thickness and structure
- Material type (flattened bottles / whole bottles / baled bottles)
- Whether labels and caps are attached
- Equipment speed and torque
2. Why is the particle size uneven?
Unlike hammer crushers, single-shaft shredders, or four-shaft shredders, a two-shaft shredder:
- Has no screen to control size
- Relies on random tearing action
As a result, the output is typically coarse and irregular, but it offers good throughput and is less prone to clogging.

Two-shaft Shredder Cutter Box – Different Models
3. What process is it suitable for?
A two-shaft shredder is more suitable for:
- Coarse shredding of baled PET bottles
- Volume reduction
- Front-end / pre-treatment