2023 Theses Doctoral

Inverted Laser Sintering

Whitehead, John

Existing laser sintering systems have several advantages over alternate additive manufacturing technologies but suffer from limitations inherent to the use of a single, self-contained powder bed. This powder bed design limits the ability of the machine to print multiple materials in a single print cycle, obscures the part during printing which can lead to material waste, and presents significant obstacles to embedding during printing. I present here an additive manufacturing process that uses an upward-directed laser to fuse monolayers of material powder onto a substrate through a clear surface.

The powder on the glass can then be replenished or replaced, and new powder can be fused to the previous powder layer. This is repeated until a solid, multi-layer hanging print is formed. This process eliminates the need for a large powder bed as well as allows the sintering of different powders in a single layer. I demonstrate this method by using a 445 nm laser to fabricate a multi-material pattern of Nylon-12 and TPU as well as producing direct metal laser sintered (DMLS) copper components. I also demonstrated the ability of this technology to print hybrid powder/resin components and embed during the printing process.