Abstract
A method for designing a transportation plate includes defining a model plate as a basic model of the transportation plate that is configured to transport dross generated by irradiation of a laser beam on a workpiece, acquiring a basic deflection amount that is an amount of deflection of the model plate, defining a first deflection amount as an amount of deflection of the transportation plate, and designing the transportation plate based on the model plate such that the first deflection amount is smaller than the basic deflection amount. The deflection of the model plate occurs due to irradiation of a first laser beam on the model plate. The deflection of the transportation plate occurs due to the irradiation of the first laser beam on the transportation plate under a condition substantially similar to a condition for the irradiation of the first laser beam on the model plate.