Extrusion International 3-2020

48 Extrusion International 3/2020 MEASURING TECHNOLOGY The cause is often sought in the machines and processes, while the raw material is rarely included in the analyses. Risks resulting from contamination are breakdowns in high voltage cables and damage to the mold in injection molding systems. In this respect, a continuous quality con- trol in the production process that fulfills a 100 % con- trol of the amount of pellets to be processed is essential. SIKORA AG has developed a special online inspection and Black specks and color deviations often lead to increased scrap rates in the production of plastic injectionmolded parts, but also in themanufacture of profiles, cables and pipes. The same applies tometal inclusions in the pellets, which leave traces in the end product and the processingmachines and cause costs. As far as black specks are concerned, this type of material contamination is often caused by thermal overload, whereas metallic contamination often originates in the cutting tools of the pelletizing plants Inspection and Sorting of Plastic Pellets as a Guarantee for Visually and Functionally Perfect Products Examples for plastic contamination (left): The optical cameras detect visual defects on the pellet’s surface as well as color deviations (center). With an X-ray camera, metallic contamination inside the pellet can be detected (right) Cross sectionof anextra-highvoltage cablewithdischarge