An overview of the 56-year development route of broaching technology (1968–2023)

Since 1968, as the demand for the broaching process has grown along with the availability of new materials, scientists and engineers have taken a keen interest in exploring the process's many scientific and technical challenges. In the last 56 years, people have been committed to solve the existing difficulties, mainly including the high stiffness and lightweight structure design of broaching machine, broaching technology of complex contour and fir-tree slot of difficult-to-machine materials for engines, green manufacturing technologies, workpiece surface monitoring in broaching processes, tool condition monitoring and life prediction, and so on. In this review, we focus specifically on the comprehensive development of broaching processes and equipment design over the past 56 years. We first review the basic principles of broaching and analyze the breakthrough progress in various research directions in broaching. In addition, we provide a detailed overview and discussion of broaching by keywords, year, country, journal, author and citation using bibliometric analysis for the first time. It is found that faced with the challenges in the field of broaching, researchers remain enthusiastic and have made significant contributions in areas such as process monitoring, equipment design, traditional broaching studies, and green manufacturing. It also gives new insights on the future development direction of broaching machine tools, i.e., in terms of future broaching high precision, intelligence, high efficiency and sustainability. We advocate for a deeper exploration of the broaching process and machine tool technology through extensive research, aiming to create expanded opportunities for scholars and engineers in this field.