Fraunhofer researchers have developed an extremely heat-resistant ceramic-based ink. This enables metal components processed in the automotive industry at temperatures over 1000 °C to be marked with a code.
Marking components so that each one can be tracked and traced is an important requirement for the digitalization of processes in the manufacturing industry. In metalworking industries, efforts in this area have previously failed because many metal components must be heated in individual process steps. Codes imprinted conventionally are destroyed when heated and can therefore no longer be read. Prof. Thomas Härtling, group manager for Optical Test Methods and Nanosensors, and his team at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS have now developed an ink that can withstand temperatures of over 1000 °C in the oven without being damaged. The ink consists of heat-resistant ceramic particles and a glass component. In the oven, the melting glass ensures that the marking is fixed to the metal and yet is still easy to read. This ink makes it possible to provide metal components — particularly those that are heated during production in the automotive industry — with a highly stable marking.
Heat-resistant ink for metal
Take the following application scenario: during a spot check in an automotive production plant, a worker discovers a defective metal component. Its geometry does not meet the specifications and the part has not been shaped correctly. The component has a marking, known as a data matrix code, which uniquely identifies it via a serial number. The worker can read out this code using a scanner. On the display, a database opens and shows all the parameters for the component’s manufacturing process, such as the temperature and dwell time in the oven, geometric data and press pressure. It is now easy to identify the problem: the press pressure was not high enough during a particular process step. With just a few clicks, the worker can view all the other components that were processed with the incorrect press pressure and that are therefore defective. These are then quickly discarded — if necessary, a robot can do this fully automatically. The time-consuming work of inspecting all the components that may have been affected and manually removing rejects is a thing of the past, and the production process can continue straight away.
As the next step, the Fraunhofer researchers are working on how to imprint curved or shaped metal components. Further developed image recognition algorithms will then be able to read out codes precisely even on irregular or curved metal surfaces.