Selective laser sintering is a solid freeform fabrication method which is capable of fabricating complexly shaped objects directly from computer models. The method is commercially available, and builds objects in a layer by layer manner, using laser to selectively fuse powder particles. While conventional selective laser sintering technology allows a user to create variation in material composition along the build direction by layering powders of different compositions, presently there are no solid freeform fabrication technologies that can build objects with functionally tailored heterogeneous or varying material compositions.
University of Michigan researchers have developed methods to produce a heterogeneous product having a true 3-dimensional composition gradient based on selective laser sintering. The new method deposits multiple materials in prescribed patterns through a nozzle array, whose design is based on the fluid mechanics and control of granular matter in miniature hoppers and narrow tubes under gravity flow or gas assisted flow conditions. Once the desired powder or micro- to nano-scale material has been deposited, laser sintering is used to selectively consolidate the deposited materials. Sintering may be followed by a planarization step by laser milling to obtain a consolidated layer of uniform thickness, or by laser micromachining to resolve fine features. This process is repeated layer by layer to complete the multifunctional device.
Applications and Advantages
- medical implants
- biomedical devices
- drug delivery and controlled release
- customizable composition and architecture
- single step fabrication method
- applicable to a variety of composite materials-nl-including combinations of polymer,-nl-ceramic, metal, and biological molecules