Validation - Material removal in electric discharge process

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Reference: Numerical simulation of titanium alloy machining in electric discharge machining process 

Authors: XIE Bao-cheng, WANG Yu-kui, WANG Zhen-long, ZHAO Wang-sheng

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Consider the 2D Axisymmetric geoemtry with dimensions 60x60um

Material Name: Ti-6Al-4V

Material Properties:

• Density, ρ=4500 kg/m3
• Specific heat capacity, cp(t)=505−624 J/(kg·°C) in the range of 300−800°C
• Thermal conductivity, k=7.4−16.5 W/(m·°C) in the range of 300−800 °C
• Ambient temperature, T0=25°C; melting point temperature, Tm=1660°C

Equivalent Heat Input Radius is assumed as a function of the duration of the spark (Ton) and the current (I): R = 2.04e-3*I^0.43*Ton^0.44

Fig. 1 - Gaussian distribution

Heat input to workpiece is Gaussian distribution.

where n is the percentage of discharge energy transferred to the workpiece; U is the discharge voltage; I is the discharge current.

Consider in 2 scenarios:

1. Scenario 1: Change the value of I and Ton
   • I = 0.84A, Ton = 100us
   • I = 0.42A, Ton = 50us
   • I = 0.21A, Ton = 20us
   • I = 0.11A, Ton = 10us
2. Scenario 2: Change the value of n (20%, 30% and 40%)

Results

1. Scenario 1

Temperature distribution in 4 cases of change the value of I and Ton

Fig. 2 - Temperature distribution

Fig. 3 - Effect of current and pulse duration of temperature distribution

1. Scenario 2:

Fig. 4 - Temperature distribution

Fig. 5 - Effect of percentage of energy on temperature distribution

Material removal rate (MRR)

Comparison of predicted results