Parametric study on near-dry wire electrodischarge machining of polycrystalline diamond-coated tungsten carbide material

Abstract

Polycrystalline diamond (PCD)-coated tungsten carbide (WC) is a high-performance cutting tool material widely used in industry for cutting or ultra-precision cutting of advanced engineering materials, but it is difficult to machine using conventional machining techniques owing to its high hardness. However, wire electrical discharge machining (wire EDM) offers advantages in machining PCD-coated WC in terms of process reliability and flexibility to machine different shapes. To relieve pollution issues associated with traditional wet wire EDM, the present study investigated the feasibility of near-dry wire EDM of PCD-coated WC cutting tool material using deionized water and air mist. A parametric study on spark cycle and spark duration was carried out, and the effect of these two important wire EDM process parameters on machining performance in terms of material removal rate (MRR) and surface roughness ( Ra) was analysed. Compared with conventional wet wire EDM, near-dry wire EDM consistently produces better Ra values on the PCD-coated WC workpiece, but near-dry wire EDM produces lower MRR than wet wire EDM under some conditions.