Patent ID: 7537722

Claim:
A device for manufacturing a three dimensional product, comprising: a work table on which said three dimensional product is to be built; a powder dispenser arranged to lay down a thin layer of powder on the work table for the formation of a powder bed; a ray gun for giving off energy to the powder whereby fusion of the powder takes place; members for controlling the beam released by the ray gun across said powder bed for the formation of a cross section of said three dimensional product through fusion of parts of said powder bed; a controlling computer storing information about successive cross sections of the three dimensional product, said successive cross sections build the three dimensional product, the controlling computer controlling said members to guide the ray gun across the powder bed according to a running schedule forming a cross section of said three dimensional body, said three dimensional product being formed by successive fusion of successively formed cross sections from powder layers successively laid down by the powder dispenser; and means for sensing the temperature distribution of a surface layer at the powder bed, wherein the surface layer of the powder bed is divided into three categories including: areas in which fusion is taking place through machining by the ray gun where a melting temperature is measured, areas already fused, and which are thereby cooling where a cooling temperature is measured, and areas not machined by the ray gun, where a bed temperature is measured, said controlling computer is arranged to affect said running schedule for the ray gun based on information about the temperature distribution of the surface layer of the powder bed from said means for sensing of the temperature distribution, said means for sensing temperature distribution of a surface layer at the powder bed includes a camera, said temperature distribution of a surface layer constitutes a temperature distribution matrix that is stored in the controlling computer, the temperature distribution matrix comprising a plurality of temperature values corresponding to the three categories that the surface layer of the powder bed is divided into, the controlling computer compares the plurality of temperature values of the temperature distribution matrix with desired values corresponding to the three categories to determined any deviation, and for any deviation, the controlling computer makes a determination as to whether the deviation exceeds an allowed limit for the corresponding category.