Abstract Cemented carbides (WC-Co) are difficult to be processed by conventional machining processes. Electrical discharge machining (EDM) appears as an efficient technology to manufacture WC-Co products with high accuracy. In EDM literature no research works investigating the influences of different grades of CuW electrodes on geometrical characteristics when ED-machining the same cemented carbide was found. This work presents an investigation on ED-Machining of cemented carbide (WC-Co) with 10% Co using two grades of coper-tungsten (CuW) electrodes with 65% and 85% of tungsten. ED-Machining experiments were carried out under rough, semifinish and finish regimes with input variables discharge current ie, discharge duration te and pulse interval time to using analysis of variance (ANOVA) based on design of experiments with complete factorial 32. Output variables evaluated were WC-Co workpiece geometrical characteristics 3D surface roughness and round cavities circularity measures. Results showed that ED-Machining regime is the most significant parameter on both WC-Co workpiece circularity and surface roughness measures. Electrodes grades CuW65 and CuW85 presented similar results on workpiece circularity and 3D surface roughness.

Wire Electrical Discharge Machining (WEDM) is one of the most important production technologies to manufacture very accurate small components and tools on any electrical conductive material. Titanium and its alloys have been widely used in automobile and aerospace industry as well as in medical engineering field. Small components and tools with complex geometrical shapes are difficult to be produced on titanium alloys by both conventional and nonconventional machining technologies. In this work an experimental investigation on the influences of wire electrode type and electrical variables when WEDM a thin plate of Ti6Al4V alloy has been carried out. Uncoated brass wire and copper wire with a diffused zinc coating were used for the experiments. Interval time, wire run-off speed, discharge duration and dielectric inlet pressure were evaluated in order to achieve adequate process parameter settings. Characteristics of surface integrity were also investigated. The best technological results for all tested WEDM parameters were attained for copper wire with a diffused zinc coating. The recast layer of the samples WEDMachined with the copper wire presented a smaller thickness and more compact than that obtained with uncoated brass wire. For WEDM with both types of wire, the existence of thermal cracks was observed.

At present, due to their properties, the tungsten carbide-cobalt (WC-Co) composite materials are in huge demand by industry to manufacture special tools, dies/molds and components under erosion. The powder metallurgy is the usual process applied to obtain WC-Co products, but in some cases this process is unable to produce tools of very complex shapes and highly intricate details. Thus, additional conventional and non-conventional machining processes are required. In this context, the electrical discharge machining (EDM) is an efficient alternative process. However, the EDM parameters have to be properly set for any different tungsten carbide-cobalt composition and electrode material to achieve an appropriate level of machining performance. In this work, a special grade of tungsten carbide-cobalt was used as workpiece and a copper-tungsten alloy as electrode. Experiments on important EDM electrical and non-electrical parameter settings with reference to material removal rate, electrode wear ratio and surface roughness were carried out under typical rough and finish machining. This paper contributes with an attempt to provide insightful guidelines to optimize electrical discharge machining of WC-Co composite materials using CuW alloy electrodes.