Experimental investigation on reduction of broaching forces by active external vibrations

Abstract Broaching is very efficient for machining complex-shaped slots in turbine disks made of high thermal resistant super-alloys. However, large cutting forces and high thermal flux lead to high tool wear. To reduce the broaching forces, this paper proposes a vibration assisted broaching system, including the main components of a hydraulic horizontal internal broaching machine, an electrohydraulic vibration exciter, a 2-dimensional valve and a control unit. A force measuring structure and vibration signal acquisition module are designed and integrated into the system. By changing the frequency of the active vibration, cutting forces are obtained and analyzed by fast Fourier transformation method. The experimental results show that through the additional imposed vibration, static and dynamic broaching forces are significantly reduced.