Diode laser forming of stainless steel tubes

In this study, complex tube bending operations were carried out by means of laser forming. Bending of slotted tubes was discussed as well as enlarging of one tube end. Experimental tests were performed on AISI 304 stainless steel tubes with a thickness of 1 mm and an outer diameter of 20 mm. A high power diode laser (HPDL) was used in focalization condition. In order to design the new processes, a finite element (FE) model was developed, which allowed the tube deformation under laser processing. The numerical model was experimentally validated and was used to study the physical phenomena occurring during the forming process. The thermo-mechanical problem was decoupled and solved sequentially in two phases: a transient thermal analysis to obtain temperature distribution that was input as body load for the following static analysis. HPDLs are very efficient laser sources for tube forming due to their large laser spot.