An investigation on the microstructure of the fine-blanked sprocket

Abstract

A sprocket is a profiled wheel with teeth that meshes with a chain, track, or other perforated or indented material. Instead of conventional machining methods, the fine-blanking process has been increasingly adopted to manufacture sprockets recently. On the basis of advantages of the fine blanking, the quality and the dimensional precision of the sprocket can surely be improved, especially those of the cut surface. In this paper, an investigation has been made on the microstructure of the sprocket tooth surface, since the microstructure is a significant factor affecting the performance of the part. Examinations by optical microscopy and SEM revealed microstructures at different locations of a sprocket tooth. In addition, numerical simulations of the fine-blanking process have been conducted by using a coupled thermo-mechanical finite element model. Based on results of the simulations, the distributions of temperature, strain, and metal flow velocity have been obtained to explain the microscopic phenomena. Moreover, the formation of the flown line and the die-roll, as well as the initiation and the propagation of the crack, has also been discussed in this work. Both of the numerical and experimental results were in good agreement with the mechanism of fine blanking.