A method for forming at least one three-dimensional article through successive fusion of parts of a powder bed, which parts correspond to successive portions of the three-dimensional article, said method comprising the steps of: providing at least one model of said three-dimensional article, moving a support structure in a Z-direction at a predetermined speed while also rotating said support structure about a Z-axis at a predetermined speed, applying a powder layer on said support structure, and directing a first energy beam from a first energy beam source at a first selected location of said powder layer and a second energy beam from a second energy beam source at a second selected location, said first and second energy beam sources causing said powder layer to fuse in said first and second selected locations according to said model to form respective first and second portions of said three-dimensional article, wherein: a first portion of said powder layer is applied simultaneous with a fusing of a second portion of said powder layer, a first cover area of said first energy beam on said powder layer is arranged at a predetermined minimum distance from and non-overlapping with a second cover area of said second energy beam on said powder layer, the first and second cover areas are each respectively smaller than an area of said support structure, and the first cover area is covering an outer ring of the work table and the second cover area is covering an inner circle after a full lap of rotation, where the outer ring and the inner circle are at least one of partially overlapping each other in an overlap region, abutting each other, or separated relative to each other when said support structure is rotated a full lap. providing at least one model of said three-dimensional article, moving a support structure in a Z-direction at a predetermined speed while also rotating said support structure about a Z-axis at a predetermined speed, applying a powder layer on said support structure, and directing a first energy beam from a first energy beam source at a first selected location of said powder layer and a second energy beam from a second energy beam source at a second selected location, said first and second energy beam sources causing said powder layer to fuse in said first and second selected locations according to said model to form respective first and second portions of said three-dimensional article, wherein: a first portion of said powder layer is applied simultaneous with a fusing of a second portion of said powder layer, a first cover area of said first energy beam on said powder layer is arranged at a predetermined minimum distance from and non-overlapping with a second cover area of said second energy beam on said powder layer, the first and second cover areas are each respectively smaller than an area of said support structure, and the first cover area is covering an outer ring of the work table and the second cover area is covering an inner circle after a full lap of rotation, where the outer ring and the inner circle are at least one of partially overlapping each other in an overlap region, abutting each other, or separated relative to each other when said support structure is rotated a full lap. a first portion of said powder layer is applied simultaneous with a fusing of a second portion of said powder layer, a first cover area of said first energy beam on said powder layer is arranged at a predetermined minimum distance from and non-overlapping with a second cover area of said second energy beam on said powder layer, the first and second cover areas are each respectively smaller than an area of said support structure, and the first cover area is covering an outer ring of the work table and the second cover area is covering an inner circle after a full lap of rotation, where the outer ring and the inner circle are at least one of partially overlapping each other in an overlap region, abutting each other, or separated relative to each other when said support structure is rotated a full lap.