Consolidation of carbon fiber reinforced Polyamide 6 tapes using laser-assisted tape placement

Carbon fiber reinforced plastics – and especially those with thermoplastic matrices – may significantly contribute to future light-weight concepts. Pre-impregnated tapes with thermoplastic matrices enable economic manufacturing processes. The most important step during processing of pre-impregnated thermoplastic tapes is consolidation. This thesis aims at deepening the understanding of consolidation processes of carbon fiber tapes with Polyamide 6 matrix (CF/PA 6) by laser-assisted automated tape placement (LATP). For this thesis, CF/PA 6 tapes were characterized with respect to thermo-physical properties and properties that are used for modeling of consolidation (i. e., viscosity, fiber-matrix viscosity, and surface roughness). Furthermore, the interactions between process parameters of the LATP process and the process responses that are crucial for consolidation (i. e., pressure, time, temperature) were investigated. The two fundamental mechanisms of consolidation – intimate contact development and autohesion – were explored in various experiments. The effective mechanical bond strength was quantified by wedge peel tests and double cantilever beam (DCB) tests. For the efficient design of LATP processes analytical models were derived by Design of Experiments with computer experiments. The thesis’ results can be used for improving tape placement with in-situ consolidation of thermoplastic tapes. The improvements may include more precise consolidation models for process simulation and optimization, consolidation at higher placement rates, as well as options for a model-based process control that allows manufacturing of complex shaped parts by LATP.