A study on ultrasonic elliptical vibration cutting of tungsten carbide

Abstract

Sintered tungsten carbide (WC) is a versatile metal matrix composite (MMC) material widely used in the tool manufacturing industries. Machining of this material with conventional cutting (CC) method is a real challenge compared to other difficult-to-cut materials. Ultrasonic elliptical vibration cutting (UEVC) method is a novel and non-conventional cutting technique which has been successfully applied to machine such intractable materials for the last decade. However, few studies have been conducted on cutting of WC using single point diamond tool (SPDT) applying the UEVC technique. This paper presents an experimental study on UEVC of sintered WC (∼15% Co) using polycrystalline diamond (PCD) tools. Firstly, experiments have been carried out to investigate the effect of cutting parameters in the UEVC method in terms of cutting force, flank wear, surface finish while cutting sintered WC. The tests have revealed that the PCD tools in cutting of WC by the UEVC method results in better cutting performance at 4 μm depth of cut (DOC) as compared to both a lower DOC (e.g. 2 μm) and a higher DOC (e.g. 6 or 8 μm). Moreover, the cutting performance improves with the decrease in both the feed rate and cutting speed in the UEVC method like conventional turning (CT) method. A minimum surface roughness, R_a of 0.036 μm has been achieved on an area of about 1257 mm² with the UEVC performance. The CT method has also been employed to compare its cutting performance against the UEVC method. It has been observed that the UEVC method results in better cutting performances in all aspects compared to the CT method. Theoretical analysis on the UEVC method and analysis of the experimental results have been carried out to explain the reasons of better surface finish at 4 μm DOC and better cutting performance of the UEVC method.