Recycling machine produces high-quality pellets

Plastic production is focused – primarily for cost reasons – on generating as little production waste as possible. However, in order to be integrated effectively in the material logistics process, the leftover material has to be pelletized. The Indian company Maris Associates Private Limited, which manufactures a complete range of polypropylene woven sacks and flexible intermediate bulk containers (FIBCs), has implemented a zero-scrap production system using a shredder-feeder-extruder combination system from Next Generation Recyclingmaschinen GmbH. Because the S:GRAN recycling system does not generate any temperature spikes in the plastic during recycling, uniform pellets are produced. The two to three percent waste that is produced in the plastics recycling process can be returned conveniently to the main production system thanks to this efficient material recycling process, and this in turn allows the company to generate further profits. The entire recycling process thus takes place in a single step.

Maris follows the Japanese production concept known as 5S workplace design, and the company organizes its lean production system around the principles of sorting, straightening up and ensuring workplace cleanliness, as well as making all arrangements into rules and complying with all requirements and improving.  One aspect of this approach is the in-house recycling of plastic waste, which is produced, for example, when making big bags and which can lead to significant cost savings: Prior to commissioning the S:GRAN system, the company could only sell the waste product at a fraction of the cost of the raw material. Now Maris is able to prepare the material and return it to the production process with the original material. At the same time, the new solution saves space, as no storage area is needed for the recycled plastic waste.

Preventing lump formation through uniform temperature

“Regardless of the feed material, whether thick-walled parts, film material such as in LDPE recycling or the raffia tapes that we use to weave our big bags – in a single process step, S:GRAN shreds the plastic material and generates high-quality pellets for further processing,” explains M.V. Sivaraman, owner and CEO of Maris. The one-step technology is based on a reliable shredder with small cutting blades. A conveyor transports the material into the cutting area, where it is shredded. The feeder supplies the extruder screw, where the plastic waste is finally heated and homogenized. The result is high-quality pellets that can be used for further processing.

The feeding process can take place discontinuously, since the NGR control unit regulates all the necessary elements: In the hopper, the material level is regularly checked and the material feed is adjusted accordingly. The shredder is configured so that the blades turn slowly, which prevents temperature spikes from developing in the material. High temperatures in the cutting area would further impact the material thermally.

Once the machine was configured, it adjusts itself automatically, regardless of the size, thickness or bulkiness of the feed material. For this reason, Maris, which is located near Tuticorin harbor, selected the S:GRAN system. The recipe management system, which is found directly on the control panel, can also be used to select predefined programs, depending on the material and its quality.

“Go Green” initiative through recycling of production waste

“In order to ensure that the quality of the pellets is consistently high, we regularly measure the mechanical properties and flow characteristics,” states Sivaraman. “The S:GRAN transforms production waste into valuable raw material and thus not only reduces costs but also plays an important role in conserving resources and protecting the environment.”

Maris procures waste material from other bag manufacturers in their state. A part of the regenerated granules are sold at premium and the rest kept to cater the local market. The raffia tapes, (for local market) contain some five to seven percent recycled material, up to half of the plastic used in LD liners comes from newly recycled pellets. Sivaraman reports that no differences in quality can be identified for the products made from 100 percent original material. Samples from the destructive material test support this assessment.

Further benefits for the Indian company include the automatic on/off switch, which enables a restart with filled hopper and filled extruder screw in less than two minutes after unplanned shutdown. “Because power outages are common on the subcontinent, this practical solution helps to ensure downtimes are as short as possible,” says Sivaraman.

Delivery and commissioning on all continents

Installation and commissioning of a recycling machine is performed directly at the customer site and takes about one week to complete. First NGR delivers the machine components to the customer with a plan for rough setup. Next, a technician from the Austrian company checks and reviews the layout and carries out performance tests. This takes place before delivery, that is, at the headquarters, as well as in the form of an acceptance tests on site. In addition, employees are trained thoroughly in the operation of the machine. According to Sivaraman, the machine was very easy to learn to use.

S:GRAN has been developed continuously since 1996. We have since then brought six further machine models to market, and a seventh model is being developed this year, all with the aim of providing solutions that meet different needs – depending on customer requirements. In addition, NGR is actively investigating all the options to enable customers to design their material logistics processes so that the recycling material can be incorporated directly in the logistics stream. Worldwide more than 720 solutions have been installed already in more than 70 countries. Thanks to a remote service module, customers on other continents can have NGR check their machine at any time. In addition, processing parameters are queried and this data is sent via internet to the main office in Feldkirchen, which can then explain the corrective steps to the customer. This ensures the customer benefits from a professional recycling solution with low operating costs.