Adhesive bonding technology and surface technology

In industrial component manufacturing, release agents are used in many areas, e.g. injection molding in plastics production, die casting in the production of aluminum components or in the production of fiber composite materials. In order for such components to be further processed, the often obstructive residues of release agents must be adequately removed. Fraunhofer IFAM has extensive expertise in dealing with release agent residues, particularly in the areas of adhesive bonding technology and surface technology, and can therefore provide support in all questions regarding the detection of release agents and suitable cleaning concepts.

Surface analysis as a basis for cleaning

Release agent residues have the effect of reducing adhesion in adhesion-specific manufacturing processes such as adhesive bonding and coating. For example, adhesive bonds can fail immediately after manufacture or prematurely in use. In the case of coatings, for example, release agent residues can lead to large-area coating delamination or to punctiform wetting disturbances such as paint craters.

For a quality-assured process, the type and quantity of release agent residues on the surface must be determined. For this purpose, our experts use surface-sensitive analysis techniques that determine the chemical composition of the component surfaces in detail. These include, for example:

• Photoelectron spectroscopy (XPS)
• Time-of-flight secondary ion mass spectrometry (TOF-SIMS)

Thus, the respective surface qualities can be evaluated in order to subsequently select a suitable cleaning process on this basis and to qualify it with analytical support.

Long-term stable manufacturing process due to qualified cleaning

Based on the knowledge gained from the surface analyses, suitable cleaning processes can be selected in a targeted manner. These can either remove the release agent residues or chemically transform them to such an extent that they no longer pose a problem with regard to the adhesion properties. Among other techniques, these cleaning methods are possible:

• wet chemical processes
• plasma cleaning
• flame treatment

With the aid of surface analysis, a qualified cleaning process can then be developed in which the respective process parameters can be optimally matched to the chemical structure and concentration of the release agent residues. With this cleaning process, a long-term stable manufacturing process can finally be established.

The Surface and Nanostructure Analytics group, headed by Dr. Thorsten Fladung, is concerned with the chemical and topographical characterization of interfaces. With the help of surface-sensitive analysis techniques, interface-based phenomena such as adhesion and corrosion can be investigated in detail and the corresponding material properties can be specifically optimized on this basis.