Investigation of Tool and Workpiece Interaction on Surface Quality While Diamond Turning of Copper Beryllium Alloy

Abstract

Among all the materials, diamond turning of heterogeneous materials like copper beryllium (CuBe) poses serious machining challenges as the heterogeneity in the workpiece affects the quality of generated surface. Therefore, the present study is aimed to understand the effect of tool–workpiece interactions on the surface characteristics of heterogeneous CuBe workpiece material. Experiments and molecular dynamics simulation (MDS) were carried out to analyze the various surface and subsurface interactions during cutting. Results from the experiments on both the materials for whole cutting length show that the average roughness values on CuBe-machined surface are found to be ∼48% higher than those of copper (Cu). Scanning electron microscopy (SEM) results show that while deterministic lay pattern is obtained in the case of Cu, the CuBe-machined surface possesses near-random lay pattern, which is also reflected by the fast Fourier transform (FFT) spectrum of surface roughness profiles. Experimental and MDS results reveal that the hard precipitate suffers cracks which propagate vertically as well as radially and as the tool travels from Cu-rich phase to Be-rich phase, ductile to brittle transition in cutting mechanism is observed. Furthermore, it is observed that diamond-turned Cu and CuBe surfaces are contaminated by the oxides of C and Cu. MDS results verify the mechanisms involved in the surface and subsurface interactions during diamond turning.