The use of short fibre-reinforced thermoplastics in engineering applications has considerably increased in the last few years. The ease of processing combined with high mechanical properties make this composite an ideal material for injection moulding. The orientation of the fibres in the reinforced product have a strong effect on the mechanical properties. If during injection moulding, two or more melt fronts meet, the junction of the material is hindered and forms a so called weld line. The fibre orientation within this weld line is typically perpendicular to the flow direction. Consequently, mechanical properties such as tensile or bending strength in the weld line region will be significantly lower compared to the rest of the product. For non-fibre reinforced injection moulding it is already known that the use of rapid heat cycle injection moulding can significantly improve the junction of weld lines. However, the effect of rapid heat cycling on weld line regions within fibre reinforced products is still unknown. This study investigates the influence of rapid heat cycling within the weld line region for different fibre concentrations. The fibre orientations in this region are determined using CT-scans, and the mechanical properties are evaluated using tensile tests, impact tests and three-point bending tests. Preliminary results indicate that an increasing mould temperature leads to a higher tensile strength but, rather unexpectedly, to a lower impact strength.