Лако-красочные материалы — производство

In modern aircraft manufacture, the bonding process starts with a chemical surface preparation of the components to be joined (see above). On completion of the final back-washing step, the surfaces are dried and then coated (as immediately as possible) with an anticorrosive primer, either by spray application or by using an electrostatic coating process. Before the assembly process, the primer is cured at 120 °C (see Section 5.10); this allows the surface conditions obtained to be preserved for several weeks until the bonding takes place. The components to be bonded are then joined using tools that may be very costly (such as clamping pins) to position the adhesive films, which have been pre-cut, between the adherents. As the epoxy resin adhesive films, which are able to cure without any application of pressure, would not adequately wet the primed surfaces, a foil that is sealed towards the border of the tool covers the joined and fixed components. The space between the foil and the tool is evacuated, and the whole tool is placed in a heated autoclave; the curing process is then initiated by the application of external pressure and heat. Clearly, this process is very labor-intensive and, indeed, in many other fields of industry such a system would not be used due to its associated high expense and time consumption. Yet, in aircraft manufacture the high-quality standards of bonding are met almost exclusively by this process. Although a reduction of the high manufacturing costs associated with this method represents an important future task, it must also be realized that riveting — a high-precision, largely automated method — is also very expensive.