Conventionally, for moving part assemblies, the individual parts are fabricated separately and are later assembled together. But in 3D printing, with little consideration, the entire assembly can be fabricated in one single go.
There are technologies in 3D printing viz. Fused Filament Fabrication/Fused Deposition Modeling, Stereolithography etc., where supports structures are generated during part fabrication. In such technologies, moving part assemblies are not possible as the clearance between the moving members gets filled with support structures which hinders the relative motion between them.
But there are technologies in 3D printing viz. Selective Laser Sintering, Color Jet Printing etc. wherein there is no support structure generation. These are powder based technologies where the unsintered powder itself acts as a support structure. This unsintered powder can later be cleaned, leaving behind an assembly which is functional. Moving part assemblies are best suited in such technologies.
Fig. a, shows a benchmark for moving part assemblies. The clearance distance was varied from 0.05mm to 1mm. It was observed that for a clearance lesser than 0.5mm, the members fused together. Whereas a clearance greater than 0.5mm resulted in a loose fit. We thus came to the conclusion that moving part assemblies function as desired for a clearance value of 0.5mm.