Study on the Behavior of Metal Powder in Selective Laser Sintering

The two methods of using CO₂ and YAG laser of different wave length for selective sintering are introduced. The authors researched the behavior of metal powder sintered by the two kinds of laser. The result shows that using different laser to sinter the same metal powder produces different effect When YAG laser is used to sinter the Co based metal powder, the spherical effect is serious and the metal powder is hard to get into shape continuously; when CO₂ laser is used to sinter the same powder, the result is greatly improved. Similarly while the same laser is used to sinter the different metal powder, the result is also different. When CO₂ laser is used to sinter iron powder, it is easier to lead to continuous shape-forming than to sinter lead powder. But when lead powder is sintered by YAG laser, it can easily form shape. The authors also analyzed the spherical effect produced by laser-sintering Co based powder and lead powder, and concluded that after laser-sintering, the wettability of melted powdered material plays the main role in the spherical effect, therefore selecting the metal powder of low melting point for sintering will help decrease spherical effect and enhance the accuracy of laser-sintering metal powder.