With over 70 years of experience, ZERMA is one of the leading manufacturers of high-quality size reduction equipment. The extensive range of machines covers the entire spectrum of size reduction technology. Starting with beside the press granulators to soundproof granulatorshigh performance granulators to heavy duty shredders. The product range is rounded off by special machines, pulverizerssuitable accessories and spare parts.

As a result, ZERMA is able to offer solutions for the recycling of most recyclable materials.
ZERMA = shredding and processing of all kinds of plastic waste!


The slow speed granulators of the GSL series and the GST granulators series are designed to recycle rejects and scrap in injection and blow molding applications. Various hopper and discharge designs allow a flexible and customised implementation of the machines.

GSL 180 mainly used in injection and blow molding processes as beside the press machines to grind runners and sprues
GSL 300 can be used as low noise central granulators for small throughput requirements as well
GST 250 suitable for blow-molding waste

Our beside-the-press granulators


The slow-speed granulators of the GSL series operate at a low rotor rpm ensuring a minimal noise level and the highest quality virtually dust free regrind. The specially designed rotor knives can be resharpened several times and due to their unique design do not require any adjustment when installing in the granulator after sharpening. The material to be processed is introduced into the machine via a light-weight sound dampening hopper built in sandwich construction. The screen mounted at the bottom of the cutting chamber regulates the final size of the granulated material.

The regrind is collected in a stainless steel bin, which can be emptied with normal vacuum systems.

  • Specially designed rotor knives simplify maintenance and reduce downtime
  • Tool-less access to the machine for maintenance and cleaning
  • Low noise emission due to slow speed and sound dampening hopper
  • Modular design allows for customisation

All machines are designed according to latest statutory safety standards to avoid operation while the cutting chamber is accessible.

Easy maintenance and cleaning

Access to the cutting chamber and screen is quick and easy without the need for tools. Seals and high precision manufacturing ensure a clean machine environment.

Unique knife design simplifies maintenance

The rotor is equipped with specially designed knives. The curvature of the knives ensures a constant cutting gap even after sharpening without the need to readjust the rotor knives.

Sturdy rotor

The rotor shaft is supported on both ends by heavy duty bearings. Due to the modular design of the rotor the shaft is sized for the widest machine ensuring performance and longevity across the whole range. The staggered design of the rotor means that a maximum of 2 blades cut at any one time thus reducing the stress on the rotor.

Sound dampening hopper

All GSL granulators are equipped with lightweight sound dampening hoppers featuring sandwich construction of a thick layer of sound dampening material between the inner stainless steel and external aluminium. The standard hoppers allow feeding by hand or robot.

Quick-Snap system

The proven ZERMA quick-snap system allows a quick and easy opening of the machine and removal of the front plate to gain access to the screen. This allows simple cleaning when changing colour or material. Safety switches avoid starting of the machine when the cutting chamber or rotor are exposed.

Sound proofing

Optionally the GSL granulators can be equipped with complete sound proofing cabin and doors to further reduce the operational noise.

GSL 180 Series

GSL 180 Series closed GSL 180 Series open
closed open

The slow speed granulators of the GSL 180 series feature a closed 180 mm diameter rotor with width range options from 120 mm to 430 mm. The rotors are comprised of single discs arranged on an oversized drive shaft connected to the gear motor. This allows for efficient and low maintenance power transmission. The material can be fed manually, by conveyor or by robot into the large sound dampening hopper. Typically the machines are placed on a low frame with integrated heavy duty casters. Discharge of the material is accomplished via vacuum system from the integrated stainless steel material collection bin.


The slow speed granulators in the GSL 180 series are specifically designed for the processing of runners, sprues and rejects in injection molding processes. The safe, easy access to the cutting chamber allows for quick changeovers in case of material or colour changes. The low rotor speed allows processing of pliable as well as rigid materials and ensures high quality regrind with low dust.

Details and options
of the GSL series

Screen of the GSL series

Screen of the GSL series
GSL series rotor

GSL series rotor



rotor knives

The GSL rotor knives
GSL as a compact unit

GSL as a compact unit
Easy accessibility

Easy accessibility

GSL 300 Series

GSL 300 series closed GSL 300 series open
closed open

The slow speed granulators in the 300 series feature a 300 mm diameter rotor with widths ranging from 400 mm - 800 mm. The rotor is directly driven by a geared motor. This ensures smooth operation even when processing challenging materials. The low rotor speed generates less noise and a high quality, low dust regrind. The specifically designed rotor knives can be sharpened multiple times and can be installed in the machine without readjustment of the cutting system.

The Quick-Snap system and large knobs allow fast and easy access to the cutting chamber without the need for tools. The material is introduced into the machine via a sound dampening hopper. The machines can be customised depending on the application with different hoppers and discharge options.


The slow speed GSL300 series are well suited for the processing of production scrap as well as voluminous parts. They can also be used as central granulator for low volume production or in laboratory environments. The sturdy construction and high torque of the GSL300 series allows processing of heavier, thick walled and other challenging materials.

Our granulators suitable for blow moulding waste

GST 250 Series

GST 250 series closed
GST 250 series open

In a comprehensive redesign, the best features from the proven GST serie have been integrated, with particular emphasis on weight, size, handling, and energy efficiency. These compact granulators are equipped with complete sound insulation, resulting in an extremely quiet operation. The granulators are available with a rotor diameter of 250 mm and widths of 300, 450, and 600 mm. As with all ZERMA granulators, rotor and stator knives are adjustable outside the machine to reduce maintenance downtime.

The strongly curved, tangential back wall of the cutting chamber, combined with the aggressive open rotor design, ensures reliable material infeed and minimises the risk of bridging in the hopper.


The compact granulators are ideal for use in blow moulding operations. Due to their low infeed height these machines are easily loaded with material manually or using a small infeed conveyor. The low noise emission and compact footprint make this granulator range a perfect solution for inline recycling applications.

ZERMA Messestand K 2022


Granulators suitable for blow moulding waste

In a comprehensive redesign, the best features from the proven GST series have been integrated, with particular emphasis on weight, size, handling, and energy efficiency.

Check out our latest video about the GST series:


Visit us at the PLASTICS & RUBBER THAILAND 2024 exhibition in Bangkok, Thailand! As ZERMA Machinery Thailand, we proudly present our new product range the GST granulators and our GSL slow speed granulators.

Date: May 15-18, 2024
Location: BITEC, Bangkok

Our team looks forward to introducing you to our state-of-the-art slow speed granulators. Come by and find out how our solutions can optimize your production processes.

We are looking forward to your visit!

SAVE THE DATE / 22 April 2023

We would like to thank you for visiting us at the official opening of ZERMA Machinery Thailand. It was our great pleasure to have you as part of our celebrations.

Your interest in our products and services is of great importance to us and we are proud to present you with innovative solutions for the plastics and rubber industry.

We value your trust in ZERMA Machinery Thailand and look forward to continuing our cooperation in the future. Don't hesitate to contact us with any questions or concerns. We are always ready to help you.

Thank you again for your visit. We look forward to having more opportunities to work together in the future.


ZERMA Machinery (Thailand) Co., Ltd.

450 Sukhumvit Road, Tambon Huaypong, Amphur Muang Rayong,
Rayong 21150, Thailand
Phone: +66 3301 3589

Offical Sales Offices

For Europe: ZERMA Machinery Thailand GmbH

Buchenring 8 - 10
21272 Egestorf (Germany)
Phone: +49 4175 3739969

For UK: Summit Sytems Ltd.
Tame Park Wilnecote
Tamworth Stafforshire
B77 5DY England
Phone: +44 1828 265 800

We are looking forward to helping you with your application or question.