| 摘要 |
<p>A multiple beam laser sintering device includes a sintering beam (64) having a focal point at a powder bed (68) and at least one defocussed laser beam (116) incident on a region near the focal point of the focussed beam (64). The sintering beam (64) raises the temperature of the powder (84) to the sintering temperature. The defocussed beam (116) raises the temperature of the material surrounding the sintering beam (64) to a level below the sintering temperature, thereby reducing the temperature gradient between the sintering location and the surrounding material. Thermal radiation may be measured from one or both beams and used to control the power of one or both beams and the power of one or both beams may be controlled to maintain the temperature at a desired level. Alternatively, a plurality of defocussed beams may be used to provide either a plurality of thermal gradient steps, or to control the temperature of each region around the sintering point independently.</p> |
