The effect of processing temperature on wedge peel strength of CF/PA 6 laminates manufactured in a laser tape placement process

Abstract

High-performance thermoplastics such as PEEK have been most commonly studied for thermoplastic ATP. Engineering thermoplastics such as PA6 have comparatively low melt viscosities and different processing behaviour. The effect of processing temperature on the quality of CF/PA6 laminates manufactured with a near-infrared laser ATP system is investigated. The inter-laminar bond strength is characterised by wedge peel tests on samples manufactured at different process temperatures from 200 °C to 460 °C at a placement rate of 100 mm/s. Thermal degradation of the polymer was investigated by DSC and DMA. Optical microscopy of cross-sections revealed significant squeeze-out of the matrix for process temperatures exceeding 320 °C, corresponding with a rapid decrease of wedge peel strength. No significant thermophysical changes were detected for temperatures up to 380 °C. Reduction of wedge peel strength at high temperatures was attributed to matrix squeeze-out caused by the low melt viscosity of the polymer and not thermal degradation of the PA6.