Fabrication of hollow, 3D, micro-scale metallic structures by micro-powder injection moulding

Architectures of current micro-scale metallic structures are unable to meet some requirements of micro-component designers, particularly when a design calls for truly three-dimensional internal micro-geometries. Such complex geometries are particularly important for emerging microsystem applications such as high-performance microfluidics for analytical applications, or micro-engines for power generation. Here we report on a strategy by which miniaturized metallic structures with 3D cavities can be fabricated. We show results for a particular form of the strategy in which fabrication of sub-millimetre cavities with radii of 150 μm is achieved in 316L stainless steel. Fabrication of the cavities is achieved by a method which uses micro-polymer insert moulding, micro-powder over-moulding, catalytic debinding and sintering. This work establishes for the first time the feasibility of micro-moulding based fabrication routes for the production of 3D internal geometries in miniaturized metallic structures.