Low cost camera based sensor system for advanced laser heat treatment processes

Industrial laser processes need to be reliable and well controlled. Infrared pyrometers are standard systems for contact-free temperature measuring at laser heat treatment. These system are hardly to use for precise measurement at processes where large rectangular or linear laser spots are applied since they integrate the infrared emission over a circular spot with a certain size. It is impossible to use just one infrared Pyrometer for multi-spot applications. The presented system is based on a CCD-camera which has a larger field of view than the laser spot size, but contains over 400.000 single infrared sensitive measuring points. With help of several image analysis and variable fields of view it is possible to measure very localized as well as highly integrated like a standard infrared pyrometer. Relative movement between laser hot spot and measuring spot especially near edges and other critical shapes at 3D-applications does not influence the temperature measurement. In contrast to standard infrared camera systems, which are mostly overqualified for controlling heat treatment processes over 800 °C, the price for the presented system is only about 20% of those.