Method and apparatus for increasing the resolution in additively manufactured three-dimensional articles

摘要

A method for increasing the resolution when forming a three-dimensional article through successive fusion of parts of a powder bed, said method comprising providing a vacuum chamber, providing an electron gun, providing a first powder layer on a work table inside said vacuum chamber, directing an electron beam from said electron gun over said work table causing the powder layer to fuse in selected locations to form a first cross section of said three-dimensional article, providing a second powder layer on said work table, directing the electron beam over said work table causing said second powder layer to fuse in selected locations to form a second cross section of said three-dimensional article, reducing the pressure in the vacuum chamber from a first pressure level to a second pressure level between the providing of said first powder layer and said second powder layer.

主权项

1. A method for increasing the resolution when forming a three-dimensional article through successive fusion of parts of a powder bed, which parts corresponds to successive cross sections of the three-dimensional article, said method comprising the steps of:
providing a vacuum chamber, an electron gun, and a first powder layer on a work table inside said vacuum chamber; directing an electron beam from said electron gun over said work table causing said first powder layer to fuse in selected locations to form a first cross section of said three-dimensional article; providing a second powder layer on said work table; directing the electron beam over said work table causing said second powder layer to fuse in selected locations to form a second cross section of said three-dimensional article, wherein said second layer is bonded to said first layer; and reducing the pressure in the vacuum chamber from a first pressure level to a second pressure level between the providing of said first powder layer and said second powder layer, preheating the powder bed at least partially with said first pressure level, wherein a mean pressure level during the preheating is higher than a mean pressure level during the fusion of the selected locations.