Experimental comparative study on Near-dry wire-cut electrical discharge machining process using moistened wire

Abstract

Abstract The disturbance of flushing to the electrode wire exists in conventional top and bottom flushing process and the machined surface easily being burned in the dry process, a novel dielectric fluid feeding method (moistened wire method) with near-dry high-speed reciprocating wire electrical discharge machine (HS-WEDM) was proposed. A dielectric fluid was poured onto a drum to achieve a moistened wire and packed into the discharge gap by a high-speed running molybdenum wire, and form a gas-liquid double-layer dielectric for discharge machining, cooling and cleaning for the working material. The effect of four processing (conventional top and bottom flushing with emulsion, the dry with atmospheric, the moistened wire with emulsion and moistened wire with emulsion-SiC nanofluids) during the finishing process on the kerf width, average cutting speed, surface roughness, surface morphology, and corner accuracy of the Cr12MoV die steel was studied. Compared to the conventional top and bottom flushingprocess, the moistened wires with emulsion and emulsion-SiC nanofluid processes maintained the high cutting speeds and obtained smooth machined surfaces. The Ra values decreased by 39.8% and 45.8%, the inner circle radius decreased by 4.1% and 4.9%, and outer circle radius decreased by 3.4% and 10.3%, respectively. The results showed that the moistened wire process improved the machined surface quality and corner accuracy of 90° profile without sacrificing the average cutting speed due to their moderate discharge gaps. Compared with the moistened wires with emulsion process, the moistened wires with emulsion-SiC nanofluid process further improved machined quality with lower surface roughness and corner error.