Smart Molding International 2-2022

32 molding technologies smart_molding international 2/2022 Based on a legacy ENGEL duo injection moulding machine, the production cell for processing plastic flakes has a modular design. The production cell at the K show features a high-performance melt filter by ETTLINGER and a degassing unit W ith a new process, ENGEL makes it possible to pro- cess plastic waste as flakes in injection moulding directly after grinding. Since pelletising as a sepa- rate process step is eliminated, the innovation significantly improves the energy and cost efficiency in plastics recycling. At K2022, ENGEL is present- ing the new two-stage process for the first time as a live exhibit at a trade fair. Logistics load carriers with rollers, also known as dolly pallets, are being produced at the ENGEL stand at the Circular Economy Forum in the open air area. To be able to process flakes in injec- tion moulding, the recycling process breaks plasticising and injection down into two mutually tuned, but indepen- dent, process steps. In the first stage, the raw material, for example plastic flakes originating from post-consumer or post-industrial collection, is melted in a conventional plasticising screw. The melt is transferred to a second screw for injection into the cavity. Depending on the material and appli- cation, a melt filter and a degassing unit can be integrated into the process between the plasticising and injection units. This means that high-quality products can be created – even from contaminated plastic waste. Process- ing plastic flakes directly significantly improves the energy and CO2 footprint compared to processing regranulate. Typically, plastics from post-consum- er and post-industrial collection are first ground, and then, after sorting and cleaning, compounded, filtered and pelletised, and finally fed into the injection moulding process as re- granulate. This means the plastic has to be melted twice. Pelletising the re- cycled material is an energy-intensive process which typically also involves logistics overhead. The need for this step is removed completely in the two-stage process. Based on calcula- tions by ENGEL, the energy required for manufacturing the product is re- duced by 30 percent. One focus of the new process is on large-volume moulded parts, many of which, such as pallets, transport box- es and waste containers, are already made from recycled materials today. Integrated degassing extends the us- age spectrum to applications in the packaging and automotive industry. New degassing unit improves product quality The ENGEL developers focused on the degassing unit in particular. Degas- At K2022, ENGEL is presenting the new two-stage process for the first time as a live exhibit at a trade fair. Now it is possible to process plastic waste as flakes in injection moulding directly after grinding. High recycling quality directly from plastic flakes