Extrusion International 4-2019

33 Extrusion International 4/2019 Combination of Light Table and Automatic Sample Testing for Offline Inspection and Analysis Quality standards in the plastics processing industry present great challenges for plastic manufacturers as well as the processing industry. Inspection and analyzing of raw material before it enters the production process is thus industrial standard. In order to ensure the highest quality of the material and of the final product, plastic manufacturers use online inspection and sorting systems. They inspect the material, detect contaminants, coloredanomaliesand inhomogeneities intheongoingproductionprocessandautomatically sort out contaminatedmaterial. Furthermore, systems for sample testing or incoming goods inspection and analysis of plastic material are used. This offline inspection and analysis provides material manufacturers and processors with key information on contamination, the causes of contaminants as well as on their own production processes and is, therefore, essential in future-oriented production lines MEASUREMENT TECHNOLOGY of the Smallest Contamination in Plastic Material Increasing quality requirements in the plastics industry Plastics, as they are used in the medical sector or in aero- space and automotive industries, require the highest qual- ity standards as well as a reliable control and processing of rawmaterials. Contamination may occur during the differ- ent process steps for the production of plastic products. During pellet extrusion, for example, cracking in the form of black specks can occur in the material due to tempera- ture peaks. If they enter the further production process, the absolute purity of the final product is no longer guar- anteed – sometimes with severe consequences. At the pro- duction of medical tubes, contaminants in the raw mate- rial lead to a full loss of production. Before production may start again, the whole production line has to be cleaned. Conventional technologies for offline inspection and analysis of plastic material On the market established technologies for sample testing inspection and analysis of plastic material are subsequently described. A distinction is made between manual light tables and automated optical inspection systems. Picture1: Color camera imageof pellets onmonitor: Detected contaminants aremarkedand selected pellets arehighlighted in color and zoomed in