Colour Rapid Prototyping Based on SLS Process 227

Currently, the colour of parts made by the Selective Laser Sintering (SLS) process depends on the colour of the material used. SLS cannot make multiple coloured prototypes because only homogeneous powder (or powder composites) can be used during the process. In this paper, an ink-jet based mechanism is designed to print multiple colours onto the prototypes. The surface tension of conventional ink used in bubble jet printers is so high that it cannot penetrate into the SLS powders. To reduce the surface tension, ethanol is added to it. The ratio of ink to ethanol for necessary penetration is determined by experiments. This paper will go on to describe how the ink affects the structure of SLS materials. The effect of temperature on the penetration of ink into powders will also be discussed.