Method and apparatus for short arc welding

Abstract

A short circuit arc welding system is disclosed. The control scheme uses a current command signal comprised of a long-term current command that sets the long-term current command level and a real-time or short-by-short current command to drive the output current. Feedback is used to determine if the desired arc length is present and to adjust the long-term command. The short-by-short current command is derived from real-time arc current feedback and is used to control the burn-off rate by adjustment of the current command. The short being about to clear is detected in real time. When the process is ending a very low current level is provided to avoid forming a ball. If a short is created, after the low current level, a burst of energy is provided to clear of burn off the short. After the short is cleared, very low current is again provided to avoid forming a large ball, until the wire stops and the process ends.

Dependencies are inferred from the claim text.