Underwater pelletizing system SPHERO 100 from Maag.
Underwater pelletizing system SPHERO 100 from Maag.

Soredi S.p.a. is a manufacturer of thermoplastic compounds such as polypropylene Niplene. For this compound to provide the optimum stiffness or hardness levels to the thermoplastic, the granules or pellets need to be the perfect size and shape. An underwater pelletizing system the SPHERO 100 model brought substantial improvements to the type of granule produced and reduced the amount of waste produced.

“We have a strong presence in several markets, including electrical, automotive, lighting, household items and furniture,” said Giorgio Ghidini, General Manager of Soredi S.p.a. “Currently, 65% of our products are used in the domestic Italian market with 35% exported, but we want to grow our export capabilities. We have confidence that our competitive advantages of flexibility in our production processes, along with the high quality of our products, will help us make our hoped-for expansion into additional global markets and regions a reality.”

To make this goal a reality, as well as helping to satisfy growing production demands, Soredi has built on an area of 20,000 m2 (65,600f2), 11,000 m2 (36,000 ft2) of which are covered. Within those facilities, Soredi has completely automated all of its production cycles, including a battery of 18 silos for the storage of the raw materials, and also the use of modern software that manages all processes and operations, which gives Soredi the utmost control of product quality and quantity until delivery to the end-user.

In its operations, Soredi works with a number of polymer-based feedstocks that are used to create specific thermoplastic-compound end-products, such as polypropylene (PP), acrylonitrile butadiene styrene (ABS), SAN, HIPS PC and PC/ABS blends, polybutylene terephthalate (PBT), PA 6 and 66, polyoxymethylene (POM). In all, 

Polypropylene Niplene

Soredi produces 15 different thermoplastics products at its manufacturing facility. One of the more popular products that Soredi makes is polypropylene Niplene, of which it produces 23 different varieties. Polypropylene Niplene is a thermoplastic that contains resins that are used as fillers or reinforcing agents. The injection of these resins, or polymers, which are usually glass fibers, talc or calcium carbonate, or mixed fillings between glass fiber and different mineral fillers, produces a techno-polymer that offers greater stiffness, hardness and dimensional stability under heat to the user for several application in automotive, appliances, design furniture and electrical parts.

“We produce polypropylene Niplene glass fibers, mineral fillers like talc and calcium carbonate, and/or fillings that can be mixed together, and are available in various percentages, generally from 10% to 70%,” explained Ghidini”.

Specifically, Soredi produces four grades of standard-quality Niplene that is reinforced with glass fibers (Niplene F15-Niplene F30); six grades of Niplene that is reinforced with glass fibers that are chemically coupled to the polymetric matrix (Niplene F15 AGR-Niplene F50 AGR); two grades of Niplene that is reinforced with glass fibers that are chemically coupled to the polymetric matrix for use in high-flow processes (Niplene F25 AGR HF-Niplene F30 AGR HF); one grade of Niplene that is reinforced with glass fibers that are chemically coupled to the polymetric matrix for improved impact resistance (Niplene F30 AGR HI); four grades of Niplene that are filled with calcium carbonate (Niplene C20-Niplene C70); four grades of Niplene that are filled with talc that are suitable for injection molding (Niplene T10-Niplene T40); one grade of flame-retardant Niplene for use in injection molding (Niplene T20 FR V0); and one grade of flame-retardant Niplene that has a UL 94 V0 at 1.6 mm flame-safety rating (Niplene V2).

In order for the polypropylene Niplene to provide the optimum stiffness or hardness levels to the thermoplastic, the granules or pellets, the injection of which are an essential intermediate stage in the thermoplastics production chain, need to be the perfect size and shape, or else the final product may be compromised. To produce the polypropylene Niplene granules, company’s like Soredi employ pelletizing systems that take difficult-to-handle melts and powders, which are the foundation of compounds like polypropylene Niplene, and turn them into the granular resins that are needed to produce the final end-product.

Dry-cut pelletizing systems

Since its founding 30 years ago, Soredi has traditionally used dry-cut pelletizing systems for the crucial granule-making process. It was not until the last few years, however, that Soredi discovered a more effective technology for this process: an underwater pelletizing system.

In particular, Soredi began deploying the SPHERO 100 model of Underwater Pelletizing System from Automatik Plastics Machinery, a subsidiary of Maag, Oberglatt, Switzerland. Maag was established in 2010 through the merger of Maag Pump Systems AG with Automatik Plastics Machinery GmbH, Grossostheim, Germany, which is the world leader in developing pelletizing technology for use in the creation of thermoplastics compounds. In 2012, the newly created Maag became an operating company with the Dover Corporation’s Pump Solutions Group (PSG) Oakbrook Terrace, IL, USA.

“We became familiar with the Automatik dry-cut pelletizer technology when we formed our company back in 1983, and in 2009 we were introduced to the underwater cutting system,” said Ghidini. “After watching the Sphero 100 machine in action, we found that there was less wear to the equipment, it offered greater flexibility during production when we needed to change the color of the granules, the granules produced were of a perfect spherical size and there was a reduction in the amount of dust that was created during the cutting process.”

The Sphero 100 has been designed for use in compounding, recycling and master-batch applications and features a unique knife-head design and optimized water-flow conditions within the cutting chamber that combine to ensure the production of perfectly spherical pellets that are ideally suited for further processing. The system is also capable of producing high flow rates of up to 8,600 Kg/hr (19,000 lbs/hr) while the unit itself takes up minimal floor space.

Operational benefits

• A rugged design in which all components are arranged on a common supporting frame
• Optimized melt-flow channels that reduce the melt’s residence time and increase product quality
• Absence of an internal adapter, which results in a reduction of energy consumption
• A bolted-through diverter valve that connects directly to the valve plate, eliminating the buildup of polymer deposits
• Minimized cleaning, assembly and start-up times
• Lifetime cutting-tool performance
• Upgraded control panel with touch screen that provides fast start-up and maximum operational flexibility
• Single-handed opening and closing of the cutting chamber for quick, convenient and safe operation
• The availability of various die-plate options, including electric-heated, liquid-heated and thermally insulated SuperFlow designs

In conjunction to the Sphero 100 underwater pelletizing system, Soredi employs a DURO 2000 Belt Dryer from Automatik. The Duro 2000 gently and efficiently dries abrasive or brittle pellets, glass-fiber reinforced materials and other compounds with high chalk compositions, resulting in pellets that contain an extremely low level of residual moisture. This makes the Duro 2000 ideally suited for glass fiber-filled polymers, resulting in drastically reduced cost when compared to the operation of a centrifugal-style dryer. The Duro 2000’s small number of moving parts results in virtually no component wear, which also means quick and easy cleaning, especially during frequent product changeovers.

Main points:

• No movement of pellets against the dryer components
• Long life span of all parts that come into contact with the pellets
• Extremely gentle pellet-handling that ensures high product quality and keeps dust levels to a minimum
• Reduced energy consumption with no additional heating required

“We are extremely satisfied with the performance of the Sphero 100 cutting system and Duro 2000 belt dryer,” said Ghidini. “More importantly, our clients are very satisfied to receive the type of granules that we are now producing, which flow very easily during their production processes. From our perspective, the flexibility of the Sphero 100 and Duro 2000 reduces the amount of waste we experience during production changeovers while delivering high throughput and a lower need for system monitoring by the operator.”


The success of any company or operation is in large ways ultimately determined by the ability of its channel partners to deliver equipment and system solutions that fill the needs of the manufacturer. Soredi S.p.a. found one of these reliable partners back in 1983 when it began using dry-cutting pelletizing systems from Automatik Plastics Machinery. The performance and support that Maag has provided over the years to Soredi paid dividends when Soredi was looking for a better way to produce its polypropylene Niplene, and the company looked no further than Automatik for the solution: the Sphero 100 Underwater Pelletizing Systems and Duro 2000 Belt Dryer.

“For us, it’s important that not only does the equipment work, but that there is reliable local post-sales and technical support, and we get that in an excellent way from Maag, usually by Claudio Bonafede, After Sales Manager in Italy,” Ghidini said. “We recommend the use of Maag Automatik equipment for thermoplastic-compound production because of the efficiency and trustworthiness of the machines. We will certainly continue to use Maag Automatik Pelletizing Systems equipment in the future.”