Forming characteristics of thin-wall aluminium alloy tube by laser beam

Comparing with laser forming sheet metal, the heated zone of metal tube subject to the greater deformation resistance during laser forming process, the formed shape of the metal tube is depend on the distorted degree of tube wall. Because of the higher heat expansion coefficient of aluminium alloy, its tube wall is very easy to distort by the laser irradiations than other metals and exhibit the prominent characteristics. In this paper, the forming characteristics of thin-wall aluminium alloy tube scanning by CO₂ laser beam are experimentally and numerically investigated. The research results indicate that the deformation of tube wall takes on two patterns: two-sides thickening and outward buckling, the scanning circles and beam diameter are the primary factors changing the deformation patterns. By analyzing the stress distribution of tube wall, a better explanation for the deformation mechanism of tube wall during laser forming process is presented.