Single step shimming solution for automated aircraft assembly

This paper describes a method for filling individual joining gaps in the automated assembly of large aircraft primary structures in the factory of the future. High manufacturing tolerances lead to unique gaps between large Carbon Fibre Reinforced Polymer (CFRP) parts. These gaps must be filled with liquid or solid materials, which are called shim materials in the aircraft industry. Under a specific threshold gap size defined by aviation certifications of the utilized materials, liquid shim is applied. Above this value solid shim must be used and therefore individually manufactured. Until now in industry all steps are done manually by workers, within the last years research has shown that these processes can be automated with the use of smart manufacturing processes. This paper shows that an extension of processes like joining surface scanning, virtual assembly of scanned parts and 3D gap calculation between parts with processes like shim decision and shim application leads to a significant reduction of process time. The algorithm for deciding which type of shim must be applied and the process flows for liquid and solid shim application are described. The method is evaluated and tested in a one-to-one scale assembly cell for large CFRP primary structures.