Process instability in laser welding of aluminum alloys at the boundary ofcomplete penetration

Intrinsic instabilities in the depth of penetration achieved when laser wel ding aluminum alloys were investigated in this article. Four types of weld pool configuration, resulting in different welds, were identified, only two of which are associated with full penetration. A simple phenomenological e xplanation of the unstable welding process at the boundary of complete pene tration was proposed. The nature and cause of the instabilities were discus sed and suggestions were offered for process control. (C) 2001 Laser Instit ute of America.