A State-of-the-Art Review on Hemming: A Materials Processing Technology for Mechanical Joints

Abstract

Hemming is a material processing technology widely used in major sectors such as automotive and aerospace industries. As a mechanical joining process, hemming is applied to sheet metal components to build structural assemblies. In conventional hemming methods, dies and presses are used by designing product-specific tooling. In recent years, robot technologies have been integrated into this specific process to benefit from the advantages of flexible manufacturing systems. In this paper, a state-of-the-art review of the hemming process is presented based on a literature review. Since there is no background of collected works and systematic reviews, this work summarizes all the details and key points about hemming. This review fulfills the need for compiled knowledge at the right time because of two main reasons. First, there is no review currently on this issue to enlighten both industry and academia. Second, hemming technologies have been enhanced by the leading industrial companies without any contributions of written sources to the literature. In this work, the evolution of hemming technology is given from past to present. Deformation mechanisms in different hemming methods are presented. Effects of process parameters are discussed in terms of product quality, mechanics of materials, and manufacturing aspects. Lastly, recent developments in hemming technologies are given. Despite the availability of alternative joining methods, hemming remains at the forefront of metal joining processes due to its unrivaled simplicity.