An Investigation on Deburring Performance for Drilling Burr Removal using EDM

Burrs are formed during various machining processes. These burrs result in difficulty in assembling operations. Being sharp, burrs may injure operators, cause electric short circuit problem, poor aesthetics of component, etc. So, deburring is commonly required to remove burrs. In the present work, drilling burrs formed on low alloy steel workpieces are tried to be removed by electro discharge machining. Electrolytic copper of 16.88 mm diameter is used as EDM tool which is made cathode and workpiece as anode. Parameters varied are peak current and pulse-on time whereas parameters such as duty factor, sparking time, lifting time, sensitivity, anti arcing, sparking gap voltage are kept constant. Peak currents are varied in the range of 4A-10A, and 50 ps, 100 ps, and 200 ps pulse-on time are taken. Initially sparking is found to be concentrated in a small area since only the burrs are attacked by the tool. When sparking spreads to the whole periphery of the tool, it indicates complete burr removal. The time taken for complete burr removal and surface roughness of specimen after deburring operation is measured. Some thickness loss of specimen has also been observed. Deburring time is found to be reduced with increase in peak current and pulseon time. At smaller values of peak current and pulse-on time, surface roughness and thickness loss are lower, but deburring time increases due to low energy of spark, which results in less heat generation and lesser melting and evaporation of burrs. Small depth of crater formed at low peak current and pulse-on time may be responsible for lower surface roughness. Parameters are optimized in order to obtain minimum deburring time, thickness loss and surface roughness.