Structural quality of parts processed by fused deposition

Abstract

Commercial solid freeform fabrication (SFF) systems, which have been developed for fabrication of wax and polymer parts for form and fit and secondary applications, such as moulds for casting, etc., require further improvements for use in direct processing of structural ceramic and metal parts. Defects, both surface as well as internal, are undesirable in SFF processed ceramic and metal parts for structural and functional applications. Process improvements are needed before any SFF technique can successfully be commercialized for structural ceramic and metal processing. Describes process improvements made in new SFF techniques, called fused deposition of ceramics (FDC) and metals (FDMet), for fabrication of structural and functional ceramic and metal parts. They are based on an existing SFF technique, fused deposition modelling (FDM) and use commercial FDM systems. The current state of SFF technology and commercial FDM systems results in parts with several surface and internal defects which, if not eliminated, severely limit the structural properties of ceramic and metal parts thus produced. Describes systematically, in detail, the nature of these defects and their origins. Discusses several novel strategies for elimination of most of these defects. Shows how some of these strategies have successfully been implemented to result in ceramic parts with structural properties comparable to those obtained in conventionally processed ceramics.

Thermal properties of 3-D printed polylactic acid-metal composites

“…As described by Agarwala, layering effects of the printing process develop compounding un-intentional pore formation [34]. Pore phases (porosity constituents) are effectively thermal insulators.…”

Mechanical Characterization of Additively Manufactured Parts by FE Modeling of Mesostructure

“…The FDM processed part will have pores, which are inherent to the process. Also, the size and shape of the pores influence the mechanical properties of the part [6]. The effect of size and shape of the voids on the mechanical properties is also investigated for different architecture of mesostructures in the present work.…”

“…The effect of process parameters and building strategies on the mechanical properties of a part have been the main focus in research so far. The right printing strategy and optimum process parameters improve the mechanical properties of the part [6]. The filling strategy affects the strength and stiffness of a part due to the extent of bonding within layer as well as between layers [7,8].…”

“…The bond formation among the roads is driven by thermal energy of the extruded material [9]. Researchers [2][3][4][5][6][7][8][9][10][11][12][13] discussed the various process parameters of FDM such as raster orientation, air gap, bead width and temperature effect on the mechanical properties of the final fabricated part. The raster angle was observed to have more influence on the mechanical properties than other parameters.…”

“…The elastic moduli for FDM processed layers (orthotropic material) are found experimentally by Casavola et al [27] and then classical laminate theory is employed to characterize the mechanical behavior of the FDM processed parts. So far, most studies [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] presented experimental work. However, there has been relatively little literature available on numerical modeling to find the elastic moduli of a material of the FDM processed part.…”