Extrusion International 6-2020

32 Extrusion International 6/2020 SHEET EXTRUSION, RECYCLING This also applies to the manufacture of ABS and PS sheet for technical applica- tions. The properties of thermoplastics such as PS and ABS are particularly well suited to recycling. Melt Filtration as the Key to Increasing the Proportion of RecycledMaterial When considering the use of recycled material in a process such as ABS and PS sheet for technical applications, it is important not only to consider the effect of the recycled material on the properties of the product, which has to achieve strict and stringent quality requirements. The process and the economics of the process itselfmustnotbecompromised by down time, variations etc. The Melt Filtration system is perhaps “the” key to enabling the use of recycled mate- rial without compromising production ef fi ciency whilst maintaining the high- the Gneuss RSFgenius Melt Filtration System in place of the original equip- ment screen changer which was sup- plied with the extrusion line. When selectingaMelt FiltrationSystem for a given application, it is important to consider not only the ability of the system to handle the contamination loadwhich the recycledmaterial brings - and to achieve the required fi ltration fi neness, but also the impact of the sys- tem on the process consistency. This is another area where the Gneuss Rotary MeltFiltrationSystemsofferamajorad- vantage: The Gneuss RSFgenius system for example, can operate with a guar- anteedpressure consistency of +/- 2 bar evenwhenprocessingheavily contami- nated recycled material. Thanks to the ef fi cient, electronically controlled high pressure purging system, the screen packs can be regenerated in situ up to 400 times. This can mean intervals be- Today, plastics processors feel a responsibility toward the environment and are always looking to optimise their production processes with regard to sustainability and energy ef fi ciency. This of course starts with careful use of the resource: plastic. Internal factory waste is seen as a valuable raw material, collected and recycled and in many cases virgin material is replaced as far as possible by secondary, repelletised material ABS and PS Sheet for Technical Components – Melt Filtration as the Key to Increased Efficiency and Recycled Content est possible product quality. However: whilst the typical screen changers usu- ally suppliedasoriginal equipmentwith extrusion lines are generally acceptable when processing only virgin material, theyquicklybecomeabottleneck in the production process as soon as recycled material is used in any quantity. A major German manufacturer of PS sheet for thermoforming to technical parts recognised this aspect early and equipped three extrusion lines with Gneuss RSFgenius Melt Filtration Sys- tems. By retro fi tting the extrusion lines with these systems, they were able to re-use all their internal waste: not only edge trim but also the skeletal waste and off cuts from the production of the thermoformed parts themselves. Anotherwell knownGermanmanufac- turer of ABS and PS sheet for technical applications (e.g. for vehicle interiors) retro fi tted their extrusion lines with