Layered laser vaporization of PMMA manufacturing 3D mould cavities

This paper deals with an innovative technique concerning CO2 laser machining in order to create 3D cavities to be used as moulds for the casting of polymer resins, vaporizing PMMA layer by layer. The removal of a single layer is achieved using multiple overlapping straight grooves. The groove profile (depth and width) has been predicted by theoretical models which investigate the influence of cutting sequence, number of passes, laser beam scanning speed and radiant flux. The removal depth varies proportionally with the number of layers, while the surface roughness, influenced by the grooves spacing and the orientation of the scanning direction between successive layers, cannot be decreased under a minimum value.