A double-point moving source model for predicting seam geometry in laser welding

A theoretical double moving point source model, based on the superposition principle, is proposed for predicting the weld seam geometry produced by a CW Nd:YAG laser in a constrained overlap configuration on a martensitic stainless steel in a transitional regime between pure conduction and keyhole welding. This intermediate regime is modelled by varying the power balance between the two point sources along with their relative distance. Tests show that the main geometrical features of the weld bead (penetration depth and resistance length) are comparable to the predicted values (error less than 5%). Finally the model can be also profitably used in order to predict the temperature field around the molten pool.