Model of wire-to-plane electric arc

Publisher Website
Google Scholar
Abstract
A simple model of the wire-to-plane electric arc based on energy and charge conservation is developed and solved numerically for discharges simulating those used for ball formation in the wire bonding process. Energy conservation balances heat generated by electrical dissipation against that conducted away and that stored. For the conditions of interest here, radiation and convection are negligible. Charge conservation is used to solve for the electrostatic potential. The electric field is static for the conditions of interest here. Electrical and thermal conductivities and the specific heats for air and argon are fit as functions of temperature (and pressure) to the best available data. The results show peak arc temperature in air and argon near 11 000 K. Calculated currents and voltages are consistent with measurements we have made on a 100× upscaled apparatus (3.2-mm wire). 5%–10% percent of the total energy in the discharge is transferred to the wire to heat and melt it. The remaining energy is transferred to the planar electrode or conducted away to the ambient gas.