Effects of Build Parameters on Compression Properties for Ultem 9085 Parts by Fused Deposition Modeling

It has been observed by various researchers that parts fabricated by the Fused Deposition Modeling (FDM) process have anisotropic properties. The research presented in the present paper was aimed to study the compression properties of FDM parts and to comprehend their dependence on build parameters. In this study Ultem 9085 was used as the material to fabricate both solid and sparse-build coupons with variations in build direction, raster angle and air gap. A full factorial experimental design was used to study the individual and combined effects of these build parameters on the mechanical properties of the coupons. The mechanical properties studied include compressive yield strength, compressive modulus, compressive strength/mass ratio, and compressive modulus/mass ratio. Besides the obtained test data, qualitative observation and reasoning was used to help understand how the compression properties are affected by the build parameters

Welding dynamics in an atomistic model of an amorphous polymer blend with polymer-polymer interface

We consider an atomistic model of thermal welding at the polymer-polymer interface of a polyetherimide/polycarbonate blend, motivated by applications to 3D manufacturing in space. We follow diffusion of semiflexible chains at the interface and analyze strengthening of the samples as a function of the welding time tw by simulating the strain-stress and shear viscosity curves. The time scales for initial wetting, and for fast and slow diffusion, are revealed. It is shown that each component of the polymer blend has its own characteristic time of slow diffusion at the interface. Analysis of strainstress demonstrates saturation of the Young’s modulus at tw = 240 ns, while the tensile strength continues to increase. The shear viscosity is found to have a very weak dependence on the welding time for tw > 60 ns. It is shown that both strain-stress and shear viscosity curves agree with experimental data

Modeling and Characterization of Fused Deposition Modeling Tooling for Autoclave Process

Additive manufacturing provides design flexibility, rapid tool development, material reduction, and reduced cost. Fused Deposition Modeling (FDM), an additive manufacturing process for fabrication of 3D parts by computer-controlled extrusion of thermoplastics, allows the produced tools to be utilized in the autoclave process. In the current study, an autoclave process was modeled using finite element analysis for FDM tools under elevated pressure and temperature. Solid and sparse-build tools manufactured with Ultem 9085 were studied. Material and build properties were characterized using compression testing at varying elevated temperatures. A Stratasys Fortus 400mc FDM machines was used to manufacture the Ultem tools, which underwent autoclave cycling with pressure of 100 psi and maximum cure temperatures of 180 °F and 250 °F. Tools were evaluated with dimensional analysis and surface roughness tests before and after the autoclave process. A finite element model examined the thermo-mechanical behavior of the FDM tools affected by an autoclave process