Double focus technique: influence of focal distance and intensity distribution on the welding process

Abstract

Double focus welding is a proven technique to reduce or even to avoid blowholes and porosity in the welding process of aluminum. The application of two focal spots arranged close to each other offers advantages concerning process stability and quality, which is a result of a more stable keyhole geometry respectively of modified energy coupling and fluid dynamic conditions. The opportunity of designing a task-adapted intensity distribution opens possibilities for the bridging of gaps and the shaping of the weld seam geometry which means an increase of flexibility. This contribution will discuss the joining process and will show the connection between spot distance and intensity distribution on one hand and the welding result -- depth, efficiency and quality -- on the other hand.