Gessenharter, A., Van Koppen, B., and Graf Bethusy-Huc, M., "Optimization of Assembly Processes by Heated Air Technology," SAE Int. J. Aerosp. 6(2):378-382, 2013, doi:10.4271/2013-01-2133.
In today's assembly of large complex Carbon Fiber Reinforced Plastics (CFRP) components, e.g. vertical tail planes (VTP) of modern passenger aircrafts, liquid resin-based materials are used for several applications. Commonly, liquid resin-based materials are used to close gaps between the CFRP single parts during assembly (shimming) or to smoothen outer surfaces to fulfill aerodynamic requirements (aerodynamic sealing).Curing times of standard resin-based materials vary between eight to twelve hours at room temperature under normal shopfloor conditions regarding air humidity. In running aircraft production such long curing times are definitely waste in the sense of lead time. By heating these resin-based materials the common curing time can drastically be reduced down to two hours. By using heated air - instead of e.g. heating lamps - the curing process can reliably be controlled, without any risk of overheating and destroying the sealant or shim material.Both, the heated air technology as well as the newly developed dedicated heated air toolings are presented in this technical paper. The first example is the aerodynamic sealing of a VTP. Curing time of the aerodynamic sealant can be reduced by eight to ten hours using the newly developed heated air technology. The second example described in this paper is the shimming of gaps between a VTP center box and metallic parts attached to this center box.