Extrusion International 1-2017

26 Extrusion International 1/2017 MEASUREMENT Technologies for the measurement Manufacturer of hoses and tubes have been investing intensively in measuring and control technology as well as line control over the last years, aiming for an online quality control, process stability and cost reduction. Nowadays, online measuring devices with a connected control are a standard for extrusion lines. Used test devices include, amongst others, gauge heads that measure the inner and outer diameter, the ovality, eccentricity as well as ideally the sagging (“sagging” of the melt during the solidification at a too high viscosity) of the product during the extrusion process. The used measuring systems are based on varied technologies for different application areas. The following article provides an overview of conventional as well as innovative measuring technologies and discusses the advantages and limits of their usage in extrusion lines. of the diameter, wall thickness, eccentricity and sagging during the hose and tube extrusion