The production of lightweight composite products in large series is increasingly influenced by the demand for diversification and individualisation of the products. The demand for customised, functionalised components at low prices causes challenges for the manufacturers in the fields of component development, process flexibility and part costs. For functionalised thermoplastic composite (TPC) components, the common manufacturing route is forming and back injection moulding of TPC sheets. However, the production of individualised products as well as small, variable series in this manufacturing route is economically challenging due to the cost-intensive mould technology. In order to increase process flexibility and extend the range of application for TPC components, an innovative combined forming and joining process has been developed at the Institute of Plastics Processing (IKV) at RWTH Aachen University within the BMBF funded project LightFlex together with eleven partners from industry and science. In this process, functionalised TPC components are individually produced by forming and joining of continuous fibre reinforced, load optimised TPC sheets to additively manufactured functional structures (e.g. ribs, fastening elements) in one process step. One key element of the combined forming and joining process is the geometry independent preheating of the functional structure with a laser scanning system. Thereby, the surface of the additively manufactured structure is locally melted. After the preheating of the structure the melted TPC sheet is formed onto the structure using a one sided diaphragm based forming process. In this paper, the functionality of the laser scanning system for the preheating of additively manufactured structures is described. Results of investigations regarding the bonding strength between the TPC sheet and the additively manufactured structure are presented and discussed for different materials of the structure.