A Nonlinear Heat Conduction Model for Laser Irradiated Printing Plates

A nonlinear heat conduction model was developed on the basis of the FINITE DIFFERENCE METHOD to calculate temperature distributions in laser irradiated printing plates. The basis of the numerical model is the assumption that the laser heated zone in the material represents a semi infinite slab subdivided in finite spatial cells. By employing a step by step iteration algorithm referring to space and time, the temperature dependent character of the thermophysical parameters of the laser exposed material such as specific heat capacity, heat conduction and density as well as the optical material parameters such as absorptivity and reflection are taken into account. Particularly in the case of gravure or flexography, melting and vaporization processes can be included in the numerical calculation.