SYSTEM DESCRIPTION FOR
SYSTEM DESCRIPTION FOR COLD ROLLING MILLS / PROCESSING LINES Ellipsometry Measuring System Breaking Barriers through Optimisation SYSTEM DESCRIPTION FOR COLD ROLLING MILLS / PROCESSING LINES The ellipsometry measuring method is based on the measurement and evaluation of polarisation properties. For this, linear polarised laser light is directed at the material at a defined angle. The light passes through the layer that is to be measured and is reflected by the substrate. While the laser light illuminates the layer, the polarisation properties change. Using suitable detectors, these changes are measured and converted by a calibration to a layer thickness or a mass per area unit value. The method allows non-contact and non-destructive measurement of layers ranging from 0 to 100 nm. Using a suitable optical system, the passive angle tolerance is fixed at ± 0.5 ° and the passive distance tolerance at a measuring distance of 48 mm at ± 0.6 mm. If the distance changes by up to ± 4 mm, a servomechanism intervenes and repositions the optical system. The optical system and signal processing electronics are housed in a robust aluminium housing and protected against external influences. The measuring head needs a 24V power supply, a supply of air to keep the optical system clean and a network connection to the control system. The measuring system boasts high sensitivity and a high measuring rate and is suitable for industrial processes with high material speeds up to 800 m/min. Calibration is more or less completely automated and requires little manual work. IMS measuring systems are used in rolling mills in the harshest of environmental conditions and are renowned for their very high availability. By using modern X-ray technology and fast, high-precision detectors, IMS measuring systems achieve extremely high measuring accuracies at very low measuring time constants, establishing their rightful place in the range of hightech systems used in industrial metrology. Together with optimised process models and precision control technology, the measuring meth ods and technologies described are essential pre-requisites in the attainment of the high level product quality required in high-speed continuous production processes. An inter-plant quality management system enables inter-process optimisation. New goals are achieved through permanent ongoing development. What is technically feasible today may be accepted as every day practice tomorrow, and possibly replaced completely by new technologies the day after. You profit from our experience! Due to the high resolution of the measuring method, it is possible to measure even the smallest of coat changes of various types. The measuring system therefore consists of a combination of a base measurement before the coating process and a main measurement. In this way it is possible to minimise the influence of disturbances from upstream processes. The system is able to measure both relative coating changes as well as absolute values on various base materials such as steel, stainless steel, aluminium, copper and brass. The applications for this method lie in the measurement of organic and inorganic coatings (e.g. oils, alternative oiling on tinplate), the determination of phosphate layers and in measurement of oxide layers. The measuring system is also suitable for measurement of residual contamination (e.g. in temper mills). 18 19
