On the Optimized Design of Broaching Tools

Abstract

Among the cutting tools that are utilized in industry broaching tools are the most expensive ones. Unlike other machining operations such as milling and turning in which a cutting tool can be used for producing a variety of shapes, the broaching tools are uniquely designed depending on the desired profile to be produced on the workpiece. Consequently, the shape of broaching tools may be altered from one case to the others. This shape can be a simple keyway or a complicated fir tree on a turbine disk. Hence, a proper design of the broaching tools has the highest priority in broaching operation. Every single feature of these expensive tools must be accurately designed to increase productivity, promote part quality and reduce manufacturing cost. A geometric model of the cutting tool and a predictive force model to estimate the cutting forces are two fundamental requirements in simulation of any machining operation. This paper presents a geometric model for the broaching tools and a predictive force model for broaching operations. The broaching tooth is modeled as a cantilevered beam and the cutting forces are predicted based on the energy spent in the cutting system. A design procedure has been also developed for identification of the optimized tool geometry aiming to achieve maximum metal removal rate (MRR) by considering several physical and geometrical constraints.