Using laser-induced breakdown spectroscopy (LIBS) to purify operating processes through inline solution
Traces of latex gloves or even hand sweat on cleaned electronic components or an oil film on a tire sheet: manufacturing processes, machining and the use of release agents can contaminate surfaces. To ensure stable bonding, however, surfaces must be enormously clean. Bonding is a so-called special process. This means that bonding processes cannot be 100% non-destructively inspected, therefore in-process quality assurance is essential. An important aspect here - in addition to the analysis of the adhesives - is the detection of surface contamination so that the adhesive forces are guaranteed.
Quality control with LIBS
Surface analysis, especially with regard to contamination detection to safeguard bonding processes, for example, is one of the core disciplines at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials. At the heart of this is laser-induced breakdown spectroscopy (LIBS), which can be used to analyze the elemental composition of surfaces in milliseconds. "Quality assurance, and therefore surface analysis, is enormously important. But it must be possible to integrate quality control into operational processes in the best possible way. With our research on the LIBS system, we at Fraunhofer IFAM are constantly developing a correspondingly simple and adaptable system," says Dr. René Neuholz. Without any further sample preparation, the LIBS system reliably and quickly indicates contamination - while providing a high level of information about the type and extent of contamination based on the elements measured.
The areas of application for the LIBS system are as diverse as the causes of the contamination. One example is the manufacturing process of fiber-reinforced composites: To ensure that fiber-reinforced composites can be released from the mold after curing, release agents containing silicon are used. The LIBS system is also used to prevent so called paint wetting disorders: in order to apply an even, glossy paint finish to a car door, the door must be clean. In addition to release agents, the LIBS system can also detect impurities, such as hand cream residues and oil films, among others.