Two current examples from research will provide an insight into the wide range of applications. One specific field of application from production is the automated production of cabin elements at suppliers. Due to their outstanding lightweight construction properties, these are largely manufactured in sandwich construction. In addition to 3D-formed cladding parts, flat sandwich panels with cover layers made of glass fiber reinforced plastic and a core made of aramid fiber paper in honeycomb structure are the most relevant.

Optimized sandwich production
With the approach developed in the Veronika project for optimized sandwich production, all component features that occur in practice can be produced using core filler (modified epoxy resin), reinforcements for the top layer and subsequent milling. The reduction of the necessary production steps enables automation of the entire process chain.

A robot takes over the laying of the individual sandwich layers, the cutting of smaller fiber mats for reinforcement and the insertion of the core filler. Automated generation of the robot paths increases flexibility compared to conventional production and frequent product changes can be implemented with little effort. Time-consuming preparation of areas to be filled (e.g. using costly templates or manual masking) is no longer necessary; the programs are created directly from design data using CAD/CAM software.

However, dosing the core filling material is not trivial from a process engineering point of view and is considered separately in the Robofill project. While the nozzle moves over the surface of the honeycomb core and presses the material into the individual cells, the air must be able to escape from the lower top layer and no material should protrude or be smeared after processing. The latter in particular can still be observed at manufacturers of dosing systems and leads to a manual post-processing step. With the help of research into the process model and simulations based on this, it will be possible in future to automatically generate the dispensing parameters and systematically design tools such as nozzles in order to optimize control of the overall process.

Blading of compressor and turbine stages
Aircraft engines represent the largest cost item in the field of aviation MRO. These are subject to regular maintenance intervals, during which engines are completely dismantled for inspection and repair. The subsequent assembly also represents a relevant proportion of the total cost. The blading of compressor and turbine stages in particular is a complex, manual process as, depending on the design, extensive adjustments have to be made to the blade sets. In addition to a balanced arrangement of the deviating blades, the gap dimensions on the individual stages must also be adjusted according to the manufacturer's specifications.

The Automok project therefore developed an automated solution for assembling the high-pressure compressor of a CFM-56 engine. The aim here was to reduce the effort required to adapt a blade set and the associated handling operations. This was achieved by upstream measurement of blade width and mass, which enables the selection of a suitable blade set and minimizes the need for further adjustments.

For this purpose, a measuring method was developed to determine the platform width of blades, on the basis of which the gap width is adjusted. A solution for automatically measuring the gap width was also developed in order to be able to check this after completion of assembly. The determination of the blade masses allows the determination of an optimum blade arrangement with regard to balancing. Blade handling during the measurement processes and assembly on the rotor are carried out by an industrial robot.

Equipped with grippers for the shovel foot and the shovel blade, as well as an additional gripping station, it is able to remove prepared shovels from their templates, feed them to the measuring systems or assemble them. The positioning inaccuracies that occur, as well as the tendency of the blades to jam within their groove, do not allow a purely position-controlled assembly process. By using force-torque sensors, the robot is able to compensate for positioning deviations based on the contact forces. Jamming of blades can also be reliably avoided by applying defined contact forces. M. Harnisch, M. Dammann, H. Eschen/as