EFFECT OF PRE-FABRICATED KERF SIZE ON THE DIRECTIONAL PROPAGATION AND SURFACE QUALITY OF CRACKS DURING CONNECTING ROD FRACTURE SPLITTING

Abstract

3D Fracture Splitting (FS) is a new technology used as an alternative to the traditional machining process of splitting a connecting rod’s big-end in an
automotive engine. The 3D concave-convex matching surface after fracture replaces the 2D planar mating surface of the traditional method. Through this 3D
mating surface, the two halves of the connecting rod’s big-end can be easily and accurately positioned in the subsequent assembly process. This article focuses
on the operation of pre-fabricating kerf by using laser cutting and the directional fracture splitting process of connecting rods made of A356.0 cast aluminum
alloy, with deep research on the influence of the geometric dimensions of the pre-fabricated kerf on 3D-fractured surface quality (e.g., the occurrence of
mechanical defects such as plastic deformation, metal defects, branching, etc.). Experimental results show that, for medium-sized connecting rods made of
A356.0 cast aluminum alloy, a pre-fabricated kerf size of width l = 0.3mm and depth d = 0.5mm offers a reasonable surface quality and good appearance.