Micro Discharge Welding and Joint Reinforcement by Non-contact Welding Method

Abstract

Newly developed manipulator using microprobe has a function of welding for small metal particles. The welding is carried out by contact discharge welding method and non-contact discharge welding method. High voltages are applied to the probe when the probe touches the particle with the former method, while it is applied when the probe is positioned at 20μm above the particle with the latter method. The welded particle is detached, and the fractured joint is observed by an SEM. The fractured joint is less than 5μm in each side of square cross section with the contact discharge welding regardless of the welding time. Followed by the contact discharge welding, the non-contact discharge welding is carried out to increase the welding interface. When nitrogen gas is introduced toward the surface during the welding, the discharge flare generated at the tip of the probe extends along the surface of the particle to the joint. Molten metal is piled around the joint and the welding interface is increased.