Preliminary investigation on flexible cutting technology for rotating shaped cutter

Abstract

The wear and impact failures of polycrystalline diamond compact cutter seriously limit its lifespan and efficiency. The flexible rotating shaped cutter is a new idea that transforms traditional rigid cutting into flexible cutting while combined with rotary cutting and plowing. The cutting test verified the feasibility of flexible cutting technology that the cutting force and its fluctuations of flexible cutting were reduced by more than 23.25% and 22.41% compared to rigid cutting. It owes to the bit-cutter elastic interaction and the cutter axial translation freedom created by the disc spring elastic element. By compressing the elastic element, buffering and vibration absorption are achieved. As the number of disc springs increases, the buffering effect improves. Driven by the shaped surface and side rake, the cutter has circumferential rotation freedom, which enables its entire circumference to participate in rock cutting, which could improve the utilization rate and reduce wear rate of the cutter. The rotation is reflected in the experimental rock scratch, the rotary speed decreases as the number of disc springs increases, increases as the side rake and depth of cut increases. The experimental results indicate that the cutting forces' magnitude and standard deviation of the flexible rotating shaped cutter increase with the increase of side rake and depth of cut. The cutting forces' coefficient of variation have a small value around 10° side rake and 1.5 mm depth of cut, which means that the fluctuation is relatively small. Therefore, the 10° side rake is the appropriate working angle and 1.5 mm is the recommended depth of cut. This investigation demonstrates that the flexible rotating shaped cutter could effectively improve the impact and wear resistance, thus preventing failures and improving the service life of drill bit cutter.