Clearance Analysis of 3D Printed Assemblies Using Fused Filament Extrusion

Publication Year:
2016
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Repository URL:
http://scholarworks.rit.edu/theses/8975
Author(s):
Luthria, Kshitij
Tags:
3D printed assemblies; 3D printing; Additive manufacturing; Design for additive manufacturing
thesis / dissertation description
3D Printing technologies have been around for the better part of 30 years now, and researchers today have a reasonably good understanding of how the different processes work. A focus for the next era of 3D printing will likely be to gain a deeper understanding of how these processes can be used in unique applications. One such unique application that can potentially change the way conventional manufacturing works involves 3D printing of assemblies. By printing assemblies ‘in-situ’, multiple assembly steps can be by-passed, thus increasing efficiency and decreasing costs. This research specifically seeks to develop an understanding of how clearances between mating surfaces in 3D printed assembly components should be designed based on the orientations of the surfaces and the 3D printing process used.A design of experiments (DOE) approach was used to identify significant process parameters affecting the clearances obtained between mating surfaces in a 3D printed assembly. Factors such as the surface angle, CAD clearance between mating surfaces, and 3D printer layer thickness were all considered. The experiments were carried out on a MakerBot Replicator 2X machine, although the experimental methodology applies to other processes as well. The samples obtained were examined using a Hirox 7700 digital microscope to quantify differences between the CAD model design clearances and 3D printed clearances between mating surfaces in the assembly. The optimal ranges for experimental factors were thus derived.Based on results of the designed experiments, pin-hole assembly test samples were printed using the optimal range of parameter values. An unconventional method was then applied using a cylindrical pin-polygon assembly, which revealed that this method was more accurate in obtaining the desired clearances in a 3D printed moving assembly.