IMPROVED METHOD FOR ADDITIVE MANUFACTURING

A method of using of a focus lens (630) in additive manufacturing for forming a three-dimensional article through successive fusion, with a high energy beam (605), of parts of at least one layer of apowder bed (660) provided on a work table, which parts correspond to successive cross sections of the three dimensional article, said method comprising the step of using said focus lens (630) for varying a spot size of said high energy beam (605) on said powder bed as a function of an already fused thickness of said three-dimensional article below said powder which is to be fused. 种在增材制造中使用聚焦透镜（630）来形成三维物件的方法，所述三维物件通过利用高能射束（605）对在工作台上所提供的粉末床（660）的至少个层的各部分连续熔合而形成，所述部分对应于三维物件的连续截面，所述方法包括使用所述聚焦透镜（630）进行以下操作的步骤：作为所述三维物件的在要被熔合的所述粉末下方的已熔合的厚度的函数，改变所述粉末床上的所述高能射束（605）的光斑尺寸。