Innovative Design of New Laser Based Thickness Gauge for Inline Measurment of Strip Thickness

by Dr. Axel Schultz, Mr. Jeff Mitchell

Publisher - LAP GmbH Laser Applikationen

Category - General Novel

Traditionally, there were two accepted types of gauges to measure thickness on flat rolling mills and process lines: radiometric (X-ray, isotope) and contact gauges. Systems based upon other technologies such as ultrasonic and eddy current have also been used but these are not widely accepted in the industry. In the 1980’s and 1990’s laser based systems were introduced to measure a variety of properties on flat rolled materials, including thickness, but they tended to be used on thicker materials like slab and plate. Advances in laser triangulation technology now enable users to consider laser thickness gauges as a viable alternative to radiometric and contact gauges in many applications, even in cold mills and processing lines. Comprehensive studies have shown that the new laser-based systems achieve the same or often superior levels of performance than existing systems in certain thickness ranges and applications. They work entirely independently of strip properties. Therefore, it is not necessary to input any chemistry and density data for the strip or maintain such information in a database, as required by most radiometric methods. The LAP CALIX systems measure at such high rates that thickness variations are captured extremely reliably, without “average effect”. The high measuring frequency makes the systems suitable to be integrated into fast acting gauge control. Other advantages include the lack of radiation protection measures, low maintenance (because of very little hardware), no high voltages, and lower costs when compared to conventional systems. While LAP Laser custom engineers many different types of systems, this paper will focus on a specific new stand alone type of thickness gauge called the CALIX

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