How to Select Crusher and Shredder Configuration for Plastic Recycling

In recycling lines, improper front-end size reduction causes unstable feeding, high wear cost, and downstream washing inefficiency.

Start with material behavior

Different materials fail differently under load:

• PET bottles: brittle after de-labeling, easier to crush
• PP/PE film: flexible, likely to wrap shafts
• rigid mixed plastics: variable wall thickness and contamination

This is why one machine cannot be optimal for all streams.

When to use a shredder first

Use shredding as the first stage when:

• feedstock is bulky or baled
• you need controlled opening before washing
• contamination includes string, rope, or soft wrapping

A shredder improves feed consistency for the crusher and helps protect downstream units.

When direct crushing is enough

Direct crushing can work when:

• feedstock is already pre-sorted and size-consistent
• contamination is moderate
• line objective is simplified operation with lower capex

This setup is common in post-industrial rigid scrap projects.

Key configuration checkpoints

• rotor speed and knife geometry aligned with material hardness
• screen size matched to washing and separation requirements
• anti-wrapping strategy for film-heavy applications
• wear part access for fast maintenance

Common mistake

Oversizing motor power without process matching. Higher power does not guarantee better output if screen design, knife setup, and feeding logic are wrong.

Practical recommendation

For most mixed projects, a staged architecture works best:

1. pre-shredding for volume reduction
2. controlled crushing for particle size consistency
3. contamination removal and washing

Rumtoo engineering evaluates this sequence based on feedstock photos/videos plus expected throughput to avoid expensive trial-and-error onsite.