Extrusion International 4-2019

35 Extrusion International 4/2019 stantly updating database, conclusions regarding sources and causes of contamination are possible. On this basis, existing processes in the company or at suppliers can be optimized to ensure a comprehensive quality control. Application areas of the automatic light table The described automatic light table offers a broad range of applications. Flakes, micro granulates, films as well as extruded and injectionmolded parts with a sample height of up to 5 mm (.2”) can be inspected on the sample tray, that has a width of 295 x 210 mm (11.6 x 8.3”) (pictures 3 to 5). For instance, approximately 100 g (.22 lb) pellets can be inspected and analyzed per run. This corresponds to up to 3,300 pellets with a size of 4 x 4 x 4 mm (.16 x .16 x .16”). In addition to the possibility of analysis for deter- mining root causes and process control in classical labora- tory, the system is suitable for incoming goods inspection due to its quick automatic analysis within seconds as well as for outgoing goods in order to compare the quality with the customer requirements. Conclusion Quality requirements in the production and processing of plastics are continuously increasing whilst the complexity of the production processes is rising simultaneously. In ad- dition to a permanent online monitoring of the produc- tion process by inspection and sorting systems, periodic offline sample testing of the plastic material is required in order to ensure a consistent quality from the rawmaterial to the final product. Up to now, manual light tables as well as automated visual inspection devices with no allo- cation of the contamination and no follow-up inspection for quality assurance, are used as standard in the plastics industry. An innovative optical technology combines the advantages of the manual visual inspection with an auto- mated material sample control. The automatic light table system automatically detects and visualizes contamina- tion from 50 µm (2 mil) and evaluates them statistically. The contamination is clearly allocated and a follow-up inspection is possible at any time. The system is more pre- cise, faster, more reproducible and reliable than the hu- man eye at a light table. Therefore, it largely contributes to quality control and an efficient process optimization. SIKORA AG Bruchweide 2, 28307 Bremen, Germany www.sikora.net Picture 6: Automated light table systemfor offline inspection andanalysis of plasticmaterial