EFFECTS OF THE EDM PARAMETERS ON SURFACE ROUGHNESS OF TITANIUM ALLOY TI-6AL-4V

Irapuan Santos¹; Milton Luiz Polli¹; Dniel Hioki¹

¹ UTFPR

doi:10.20906/CPS/COB-2015-0657

Resumo

Electrical discharge machining (EDM) is a manufacturing process which has the capacity of manufacturing complex formats and machining high-hardness materials. Ti-6Al-4V has poor machinability due to its low thermal conductivity and high strength at high temperatures. By applying EDM technology, these materials may be able to be machined efficiently. This paper investigates the effects of peak current, tool electrode polarity, pulse on time, and duty time in EDM of titanium alloy Ti-6Al-4V with graphite electrode on surface roughness. The experimental results showed that surface roughness increases as the pulse on time increases, especially when high amounts of discharging energy are involved. This is related to the depth and size of the generated crater on workpiece surface. Higher peak currents represent greater amounts of discharging energy what generates large and deeper craters on the surface resulting in greater surface roughness. Duty time variation did not exert significant influence on surface roughness for the tested range. Surface roughness values are considerably lower for the positive tool polarity when compared with the negative tool polarity all over the tested TON range. Probably because the discharge crater generated on the workpiece surface with positive tool polarity is smaller than that of negative tool polarity.

Palavras-chave: Electrical discharge machining; titanium alloy; surface roughness