TECHNOLOGY | GRANULATORS
Above: Lower half of
composite image shows Hellweg’s Smart Control System
maximum throughput. Another major advantage of the cut is that even with fast material discharge, the regrind is smooth-edged with an extremely low fines content of around 0.01% for PP and 5% for very brittle materials such as PBT-GF. Managing Director Mark Hellweg said: “Our
work in recent years has focused, and will continue to focus, on applying the possibilities of artificial intelligence to plastics recycling and, in particular, to granulating production waste. Our digital Smart Control system paves the way to greater energy efficiency in granulators, extended service life of all system components, and ultimately increased process sustainability. At the same time, regrinds and granules of higher, more uniform quality are obtained.”
Right: Wittmann G-Max 23 granulator installed at Keeney Holdings’ facility in Winchester, New Hamp- shire, US
Regrind quality Keeney Holdings, a US manufacturer and distribu- tor of drainage products, contacted Wittmann USA when looking to upgrade its injection moulding operation in Winchester, New Hampshire. With the increased use of regrind in its moulding operations, it was concerned with the overall quality. After an initial meeting, Wittmann USA ran a granulator trial where it obtained Keeney’s material, did a grinding test with screenless and conventional granulators, and performed a regrind quality analysis using a multi-stage sieve test where the regrind is passed through a series of sieves with progressively smaller holes. After the trial, the percentage of dust and fines was calculated and compared. Denis Metral, Wittmann’s International Granula- tors Sales Manager, said: “With the increased push towards recycling and sustainability in our industry, the question has always been and continues to be,
38 PLASTICS RECYCLING WORLD | September 2024
www.plasticsrecyclingworld.com
can we use regrind to make good, finished prod- ucts? The answer is usually ‘yes’ but it’s important to prove-out the concept to our customers in advance.” Following the trials, Keeney purchased seven new G-Max 23 granulators, bringing its total number of Wittmann granulators to 15, which are now up and running in the Winchester plant. Advanced Plastics Machinery (APM), the New England Representative of Wittmann USA, pro- duced customised upper feed chutes for the granulators. “The sprues and runners on Keeney’s products are often quite large, and sometimes do not have a consistent drop out of the moulding machine,” said Bruce Beckmann of APM. “The customised upper feed chutes we designed provide a much larger landing area to the runners, so that they funnel into the granulator without difficulties and directly down into the cutting chamber.” Also at Fakuma, Wittmann displayed its new S-Max Dual 6 granulator, which replaces the Junior Double 6 model. The main difference is that the two 2.2kW motors are now arranged vertically to enable the smallest possible footprint. The S-Max Dual 6 is described as the ideal granulator for central scrap reclamation, and can also be used for inline recycling of sprues from injection moulding machines. It has been designed for a throughput maximum of 40 kg/h and is equipped with two counter-rotating cutting rotors as standard, with six blades and eight toothed rollers in total, and a cutting chamber with dimensions of 530 × 467 mm. The design allows for easy and safe cleaning of the cutting chamber. The speed of rotation is 27 rpm, ensuring
IMAGE: HELLWEG
IMAGE: WITTMANN
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