plastic partsSince the mid-1980s, Selective Laser Sintering has been utilized as a prominent additive manufacturing technology to meet the needs associated with obtaining 3D parts. However, as the search for faster printed parts with higher resolution increased, an alternative cost-efficient process was desired to meet such demands. With all in mind, Behrokh Khoshnevis invented the Selective Inhibition Sintering process for plastics.



sisplasticAs shown in Figure 2, the SIS process is as follows:

    1. It starts by laying a thin layer of powder slightly above the previous layer, by sweeping a roller over both a powder supply tank and the build tank.
    2. Then, the areas of the powder bed selected for sintering inhibition are wetted by a printer.
    3. A radiation-minimizing frame is positioned to prevent areas of the powder layer which lie outside the part envelope from sintering.
    4. The entire layer is then sintered with a blast of thermal radiation from an infrared heater.
      In the end, a solid polymeric block remains that is totally sintered except for those areas wetted by the inhibitor liquid.

      • As implemented on the alpha machine, the heater is a coiled nichrome wire that is mounted on a carriage. This allows the heating element to be passed over the surface of the powder bed. Steps A-D are repeated until the part is completed.
    5. The final part can be easily extracted from the surrounding material.