Transient temperature behaviour and dynamic process models in laser surface melting of clay tiles

It is well known that there are many process parameters which influence the results of laser melting. Some parameters should be kept within certain tolerance limits to ensure the expected quality of the mark; hence, a closed-loop control system is required during the laser melting process for quality control. For this, accurate dynamic models are required. This paper describes two dynamic experimental models relating processing parameters and melt pool temperature during laser melting of clay tiles. The models were determined by process identification. The observable signal considered was melt pool temperature, measured on-line with an infrared pyrometer. The input quantities investigated were laser power and traverse speed. Good agreement between the data measured and the model outputs were achieved by an ARX (2,2,1) auto-regression model. The models were validated with experimental data and proved to be extremely accurate (errors less then 1%).