Thermoforming process is a technique widely used in the plastic industry. This process involves three stages: i) sheet heating, ii) forming, and iii) cooling and solidification. A crucial problem occurring during this process is the non-uniform distribution of the energy flux intercepted by the plastic sheet during infrared heating. To circumvent the occurring of this phenomenon, the approach that we followed is first model the heat process as an optimization problem. Then, two meta-heuristic algorithms, simulated annealing and migrating bird optimization algorithms, are applied and compared so as to meet as much as possible the corresponding objective function. An experimental study is then conducted to evaluate the quality of the solutions produced by both algorithms. Results are presented and analysed.