Influence of tool path strategies on the residual stress development in single point incremental forming

摘要

The prevailing residual stress state in a formed metal component highly affects its mechanical properties. The single point incremental forming (SPIF) process allows a flexible adjustment of the process parameters during the forming process to influence the residual stress state. A selective induction of compressive residual stresses in the component can improve product properties, such as the fatigue strength. The effect of the dominant forming mechanisms on the residual stress state of the manufactured component is analyzed. Linear grooves are formed into aluminum alloy 5083 sheets and their resulting residual stress state is measured by means of X-ray diffraction (XRD). The grooves are manufactured in a multiple-stage process to ensure the transferability of the results to the incremental forming process of complex-shaped components. Different unidirectional and bidirectional tool path strategies were used to analyze the residual stress development. To set the dominant forming mechanism, the process parameter step-down incrementΔzwas adjusted, the other process parameters were kept constant. The dominant forming mechanisms were evaluated numerically. The results suggest that the influence of the tool path strategy on the resulting residual stress amplitude is unincisive. Distinctive residual stresses can be observed in bending-dominated regions. In case of shear domination, the resulting residual stress state is less pronounced.