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Overmoulding of consolidated fibre-reinforced thermoplastics - increasing the bonding strength by physical surface pre-treatments

: Liebsch, Alexander; Koshukow, Wikentij; Gebauer, Jana; Kupfer, Robert; Gude, Maik

Volltext ()

Procedia CIRP 85 (2019), S.212-217
ISSN: 2212-8271
Conference on Composite Material Parts Manufacturing (CCMPM) <2, 2019, Sheffield>
Bundesministerium für Bildung und Forschung BMBF (Deutschland)
Bundesministerium für Bildung und Forschung BMBF (Deutschland)
Bundesministerium fur Wirtschaft und Energie BMWi (Deutschland)
Zeitschriftenaufsatz, Konferenzbeitrag, Elektronische Publikation
Fraunhofer IWS ()
composite; surface modification; laser micro machining; joining; injection moulding; fibre reinforced plastics

Fibre-reinforced thermoplastic materials enable an automated and economical manufacturing of lightweight structures in series-production. By combining different material-configurations, highly stressable components can be designed. Previous studies have shown that the combination of continuous fibre-reinforced hollow profiles and injection moulding compounds is suitable even for crash-relevant automotive parts. During the overmoulding process, the pre-consolidated hollow profile must remain cold in order to withstand high injection pressures. However, this leads to a poor adhesion between the profile and the overmoulding material. To increase the bonding strength, the interface can be pre-treated using laser and plasma technology. In this work, fibre-laser and atmospheric pressure plasma treatment are applied to glass fibre reinforced polyamide 6 composite (PA6/GF) sheets. The resulting surface properties are investigated by wettability and microscopy analysis. Afterwards, single-lap-shear specimens and special rib specimens are manufactured by overmoulding the sheets with PA6-66/GF bulk material. The resulting bonding strengths are characterised in tensile shear tests as well as pull-off tests of the ribs. The effects of different pre-treatment parameters on the bonding strength are analysed. Additionally, the effect of sheet temperature on the bonding strength is investigated, also including specimens without pre-treatment. Finally, the results are discussed with regard to the surface treatment of composite hollow profiles, considering bonding strength, manufacturing environment and processing times.