Method and apparatus for additive manufacturing

A method for forming a three-dimensional article through successive fusion of parts of a powder bed, which parts correspond to successive cross sections of the three-dimensional article, said method comprising the steps of:

• providing a model of said three dimensional article;
• applying a first powder layer on a work table;
• directing a first energy beam from a first energy beam source over said work table, said directing of said first energy beam causing said first powder layer to fuse in first selected locations according to said model, so as to form a first part of the first cross section of said three-dimensional article;
• and
• directing a second energy beam from a second energy beam source over said work table, said directing of said second energy beam causing said first powder layer to fuse in second selected locations according to said model, so as to form a second part of the first cross section of said three-dimensional article,
• wherein said first and second locations of said first powder layer are at least partially overlapping each other in a first overlapping zone.