Modelling of simultaneous estimating the laser heat flux and melted depth during laser processing by inverse methodology

In the present study, a conjugate gradient method based inverse algorithm is applied to simultaneously estimate the unknown time-dependent laser heat flux and melted depth during laser processing based on available temperature measurements. It is assumed that no prior information is available on the functional form of the unknown laser heat flux and melted depth. While knowing the temperature history at the measuring positions, the laser heat flux and melted depth can be simultaneously determined. The methodology presented in this paper can also be applied to other various applications, such as to calculate the cutting forces in nanomachining by atomic force microscopy (AFM), to estimate the heat sources in X-ray lithographic process, or to determine the location of the solid–liquid interface and the temperature distributions of the two phases during microthermal machining by using scanning thermal microscopy.