Processing methods

Different processing methods are used for different polymer types.

Here, we have described the three processes that we use at The Flipflopi Project.

Shredding

Machine: Shredder
How it works: Uses blades to break down materials into smaller pieces
Output: Flake
Works well with: PET, HDPE, PVC, PP, PS, OTHER

Considerations:

Requires three-phase electricity
Crushing PET is more energy intensive than PP or HDPE
To get the right flake size for your needs, you need a correctly sized sieve
Blades can be easily damaged by metal (screws, small metal pieces can go undetected during sorting)

Benefits of shredding:

Large volumes can be stored in small spaces
Easy to transport
Flakes are easy to recycle
Attracts a higher price on the market

Drawbacks of shredding:

Blades are expensive and need to be sharpened and replaced frequently (especially when crushing PET)
Maintenance is high and takes time

Efficiency additions: Conveyor belt

Baling

Machine: Baler
How it works: Compresses materials into smaller volumes
Output: Bale
Works well with: PET, LDPE, PP (flexible packaging)

Considerations:

Requires three-phase electricity (hydraulic)
Baled materials do not attract a high price in the market
You can bind your bale using straps or binding wire – there are cost considerations for both. Ensure your wire/strap is thick enough to reduce the length of binding you will use (if you use a thick binder, you bind fewer times)

Benefits:

Large volumes can be compressed for storage
Minimum dust and waste produced
Low energy usage compared to crushing
Simple to maintain

Drawbacks:

Baled material still needs to be crushed/agglomerated to be used in an extrusion, injection, or pelletising machine
Baled material takes more space than flakes during transport (nearly twice as much)
Attracts a lower price on the market

Efficiency additions: Strapping machine (if using straps rather than binding wire)

Agglomerating

Machine: Agglomerator
How it works: Uses blades to shred materials, and heat to melt them together into small balls
Output: Agglomerate
Works well with: LDPE, PP (flexible packaging)

Considerations:

Requires three-phase electricity
Blades can be easily damaged by metal (screws, small metal pieces can go undetected during sorting)

Benefits:

Provides a usable material for extruding (soft plastics would otherwise be too lightweight to effectively extrude)

Drawbacks:

Packaging needs to be cut before being fed into the agglomerator (this can be done manually with a knife or using a machine)
Constant supervision is required to ensure that the material doesn’t melt and form into one large ball