Targeting homogeneous granulate
“We investigated several different granulators at the fair and carried out grinding tests with our own material at the respective suppliers”, explains the injection mold-ing department manager. At Wittmann’s technical lab in Nuremberg, the sprue from our plugs was ground on an S-Max 2 granulator. The result proved convincing. This granulator delivered a highly homogeneous granulate with grain diameters ranging from 3.5 to 4 mm, and the proportion of dust development was below that of other granulators we had tested.”
“The S-Max 2 screenless granulator series is designed for processing engineering plastics and parts which are hard to grind”, says Wolfgang Prütting, Regional Sales Manager at Wittmann Battenfeld Germany. The grinding tools have a long service life even with high fiberglass content.
Compact design and integrated sound insulation are further advantages showing their positive effect most distinctly when the granulators are not run in a separate room, but directly in the production hall instead.
Direct onward forwarding of granulate
S-Max 2 granulators come equipped with a filling level sensor as standard. As soon as the collecting container is full, the grinder stops. To enable continuous operation, Wittmann has designed a special solution for this particular customer. Instead of switching off the grinder, the signal from the filling level sensor is used to switch on an integrated vacuum conveyor unit. In this way, the material is transported directly from the granulator’s collecting container into a material bin.
The bin is then passed on to the central materials handling system with a lot of dry-ers, material loaders and a coupling station located on the floor above the storage room. Forklifts are used to lift the bins filled with granulate to the upper level and there connected with Gravimax blenders - which have also come from Wittmann. The gravimetric blending system enables gram-accurate metering of the granulate to be blended in with the virgin material.
Virgin material consumption significantly reduced
Since start-up of the in-house recycling project, the consumption of virgin material has gone down continuously, with an immediate effect on unit costs to improve the manufacturer’s competitiveness. Most recently, several patents have expired, result-ing in intensified competitive pressure. “Using recycled materials is our only way to achieve competitive unit costs”, says the processor. “The new granulators have al-ready amortized themselves within only six months.”
