Why we recommend a shredder in front of a plastic recycling extruder

Advantages of a pre-shredding materials before extrusion

Plastic recyclers worldwide use a single-stage or two-stage size reduction system before material is fed into an extruder. This is not only beneficial for the capacity of the entire recycling line. Using a shredder reduces wear and power consumptions of the extruder and provides operators with much more flexibility when it comes input materials (e.g. changing from lumps to plastic films or fibers).

Worldwide references

These companies use a WEIMA shredding system upstream of their extrusion line
shredded, granulated and extruded fishing ropes in front of a weima shredder
Fishing nets
Healix, Netherlands
Recycling of fishing nets and ropes at HEALIX, with WEIMA W5.22 plastic shredder
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BOPP film
Diaxon, Greece
BOPP film shredding with a WEIMA S5.20 lift-up
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A crane that transports the PE blocks into the S7.20
PE lumps
Shredding of PE lumps with a WEIMA S7.20 shredder at Remondis Staffanstorp, Sweden
A WEIMA S7.20 single-shaft shredder shreds large and heavy PE lumps at a Remondis recycling plant in Staffanstorp, Sweden.
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View from above into an industrial hall, in the centre is an orange-red shredder, in the foreground you can see a forklift truck
LDPE film
RKW, Belgium
LDPE film recycling with a WEIMA shredder and NGR extruder
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A man and a woman wearing yellow high-visibility vests stand in front of a blue and white shredder that shreds IBCs.
IBC
Shredding of IBC containers with a W5.18 shredder at Dansk Emballage in Vamdrup, Denmark
A WEIMA W5.18 single-shaft shredder shreds IBC containers for further recycling at our customer Dansk Emballage in Vamdrup, Denmark.
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BOPP film & nonwoven
Thrace, Greece
Shredding of nonwoven and film with a WEIMA W5.22 and WLK 1500 shredder with roller feed.
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Film
True Plastics, USA
WEIMA WLK 20 Jumbo single-shaft shredder shreds plastic film.
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Romcarbon, Romania
A WEIMA WLK 1500 single-shaft shredder shreds big bags from production waste.
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You are convinced?

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Let's do the maths!

While the average extruder output without a shredder is 1.000 kg per hour, it can be increased to at least 1.200 kg per hour with shredding technology.

Projected to 8.000 operating hours per year, this means an additional 1.600 tons of material per year. This optimization improves economic efficiency and ensures a more stable, efficient production process.

WEIMA portfolio for shredding of material for extrusion

The right machine for every application
WEIMA WLK 1500 yksiakselinen murskain
Single-shaft shredder
WLK Series
Machines in the WLK series are ideally equipped for a wide range of plastics tasks. The machine design is characterized in particular by its durability and robustness. Thanks to the conveyor belt cut-out, all machines can be seamlessly integrated into any production line. They also offer a wide range of options in terms of drive and cutting geometry.
To the machine
Single-shaft shredder
W5 Series
With rotor lengths of 1,400 to 2,200 mm, the shredders in the W5 series shred large-volume plastic tanks and plastic garbage cans with ease. The hydraulically upward pivoting screen basket and the inspection flap allow foreign objects to be removed quickly and simplify maintenance. Large quantities of plastic flakes can be removed via the wide conveyor belt cut-out.
To the machine
Single-shaft shredder
S7 Series
The shredders in the S7 series stand for maximum stability, performance and versatility. With their robust design, various sizes and over 80 equipment options, they offer flexible solutions for the most demanding shredding tasks.
To the machine
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Sample calculation. Let's do the maths!

Average extruder capacity without shredder: 1,000 kg/hr
Average extruder capacity WITH shredder: at least 1,200 kg/hr
8,000 hours/year x 1,200 kg = 1,600 additional tons/year!

WEIMA x NGR partners in recycling

Shredding meets extrusion! WEIMA and Next Generation Recycling Machines (NGR) have been working together for years to develop first-class solutions for plastics recycling. A WEIMA shredder is an integral part of the NGR technical center and is available there for testing purposes.

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Your benefits at a glance

Combination of shredder and extruder
Fiberon plastic recycling line with WEIMA shredder
Reduced PCU cutting
With a shredder, the preconditioning unit (PCU) has significantly less work and therefore works more stably. Stable means fewer temperature fluctuations in the PCU, which leads to a consistently high feed/fill ratio of the extruder screw. Less chipping in the PCU = longer service life of the PCU knives = less downtime for knife changes and lower costs.
erema extrusion machine with expert recycling employee
More efficient extruder feeding for more flexibility
The hopper of the shredder acts as a buffer so that material has to be fed less frequently. The automatic stop/start system ensures even extruder feeding, which means that no additional full-time force is required for high throughputs. Feeding bulky material is also easier. Feeding is possible by forklift truck, wheel loader, feed belt or manually. The WEIMA discharge conveyor can be equipped with a magnetic roller to automatically separate small FE- particles automatically in front of the EREMA metal detector.
The extruder from NGR with water cooling system for the regranulates
Lower energy consumption, wear and maintenance costs
Pre-shredding means that the extruder works more efficiently as it no longer has to shred coarse material. This lowers the specific energy consumption, avoids peak loads and reduces electricity costs. At the same time, the mechanical stress on the screw, barrel and drive components is reduced, which minimizes wear, extends maintenance intervals and reduces unplanned downtimes. The optimized division of work between shredder and extruder thus ensures an energy-efficient, cost-saving and more durable production line.
Secondary plastic raw material granulates inside a palm of a hand
Material-friendly processing and higher pellet quality
Pre-shredding ensures a uniform material size, allowing the extruder to melt the plastic more efficiently and gently. Lower mechanical and thermal stresses prevent overheating and preserve the polymer structure. This results in high-quality recycled pellets with better mechanical properties, homogeneous coloring and a reduced reject rate - ideal for further processing or sale.
Sections of plastic pipes next to shredded plastic pipes
Wider range of materials and greater flexibility
A high-performance shredder makes it possible to process a wide range of plastic types - from bulky hollow bodies and start-up lumps to films and fibers. This means that even difficult-to-handle materials can be recycled efficiently, making the procurement of raw materials more flexible and cost-effective. The system also remains adaptable for future material changes and new business opportunities.
Separated foreign material (nails)
metal detection magnet on top of a shredder infeed conveyor
Avoiding the risk of foreign objects
The robust design of WEIMA shredders makes them less sensitive to metal contamination compared to an extrusion line and of course easier/cheaper to repair if foreign bodies get into the cutting chamber. In addition, the discharge conveyor can be equipped with a magnetic roller to automatically remove small FE particles in front of the EREMA metal detector.
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15-20 %
increase in capacity for the recycling extruder is possible by using a shredder upstream of a recycling extruder.
Portrait of Erik Hagen, Sales Director at WEIMA
You are convinced?

Request the right shredder for your recycling line now.

Request an individual quote