Combining PMEDM with the tool electrode sloshing to reduce recast layer of titanium alloy generated from EDM

Titanium alloy has been widely applied in industrial fields because of its excellent material properties. Electrical discharge machining (EDM) is commonly technology for processing titanium alloy. When titanium alloy was processed by EDM, a recast layer was inevitably be produced on its surface, which can adversely affect the surface quality and working life. Focus on the above problem, this paper proposed to add B4C powders into the spark oil and cooperate with the tool electrode sloshing for powder mixed electrical discharge machining (PMEDM) of titanium alloy, which can reduce the thickness of the recast layer and thereby improve the quality of the machined surface. Firstly, B4C powders were mixed in the spark oil and the PMEDM of the titanium alloy was carried out. In this step, the thickness of recast layer was preliminarily reduced and the quality of machined surface was improved. Secondly, when the PMEDM of the titanium alloy was nearly completed, the tool electrode sloshed along the machine tool spindle within the EDM gap. Combining PMEDM with the tool electrode sloshing, the recast layer on the machined surface was further eliminated and the quality of machined surface was further improved. By adding 3000 mesh B4C powders into the spark oil, the paper carried out the PMEDM of titanium alloy combining with the tool electrode sloshing. Under the action of appropriate process parameters, the micro-groove structure with surface roughness Ra of 0.205 μm was obtained in the titanium alloy and the recast layer on the machined surface was almost invisible.