Automation in the aviation industry
A challenge for the production and maintenance of aircraft is the machining, assembly, and coating of components of very differing size, ranging from just a few millimeters to 20 meters or longer. The dimensional stability of large components presents a further challenge. The load-bearing components of aircraft naturally have very small tolerances. Permissible deviations from the design optimum are often just ± 0.2 mm, and sometimes even less.
Manual work procedures are currently predominantly used for the assembly and coating of aircraft. Tolerance management often involves fine modification of the component shape and position using manual force. Shimming is also used for tolerance management in assembly: This involves filling the often non-uniform gap between overlapping components with a precise amount of a 2-component epoxy resin adhesive. At many places, including for example on the leading edges of wings, sealant is used to fill gaps of differing width and depth and around the heads of rivets in order to create flat surfaces that meet aerodynamic requirements.
The decoration and surface protection of aircraft and other large structures is generally carried out manually and is a costly and manpower intensive process.
The comparatively small production batch sizes in the aircraft manufacturing industry would at first sight seem to make complex process automation unattractive. However, production rates on the work floor are ever increasing and efficiency improvement via automation has economic benefits.
Individual automation solutions
From a technical point of view, automated tolerance management for the manufacture and assembly of large components must address the issue of how production systems can satisfactorily detect individual deviations in tolerances and respond effectively to these. Fraunhofer IFAM, in addition to its work in the area of materials development and process optimization, offers automation solutions as versatile technology building blocks. It also develops automation solutions to meet the specific needs of customers. This involves in particular the development of specially adapted tools for the automated process such as nozzles and devices for adhesive and sealant application, application systems, and overspray-reducing application techniques. The work also involves the development of auxiliary production equipment to facilitate manual processes. All these aspects help to optimize the precision of the production process. Furthermore, the use of adapted sensor systems for quality assurance (cameras, lasers, inductive and capacitive sensors) in combination with industrial robots and handling systems is standard in the process design.
Flexibility via automation
The extensive portfolio of Fraunhofer IFAM in the area of automation covers the treatment of components, geometry-independent component pick-up that optimizes the gap to be joined via shape and positional correction of the substrates, and rapid, contactless measuring and referencing techniques for the use of robotic end-effectors. For robot-controlled processes and also for portal systems a range of technologies is available for guaranteeing the required positional and path accuracies. The automation solutions of Fraunhofer IFAM meet the required tolerances for machining, joining, sealing, coating and printing, in each case with automated quality assurance. The processes of adhesive bonding, sealing, coating, lacquering, and functional printing are often preceded by cleaning or surface treatment, and automation is also offered here.
Of particular interest for large components are robots that use linear axes, autonomous guided vehicles (AGVs), or a second positioning robot to extend their work range without affecting their precision.
A further facet of the development work concerns mobile robotic systems of all sizes that work side by side with people in the production: human-robot cooperation and human-robot collaboration. All the mentioned technologies support digital data management in accordance with Industry 4.0.
It should be pointed out that partial or full automation is not beneficial for all work procedures in the aircraft manufacturing industry. Some manual processed are favored, especially those whose efficiency can be increased with electronic equipment and seamlessly integrated into the data flow along the whole production chain.