Browsing by Subject "fused filament fabrication"
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Item Active - Z Printing: A New Approach to Increasing 3D Printed Part Strength(University of Texas at Austin, 2017) Khurana, Jivtesh B.; Dinda, Shantanab; Simpson, Timothy W.Research suggests that topology and build parameters in Fused Filament Fabrication (FFF) play a vital role in determining mechanical properties of parts produced by this technique. In particular, the use of 2D layers printed parallel to the build surface produces high anisotropy in parts making them the weakest when loaded perpendicular to the layer interfaces. We investigate a novel approach that uses non-planar 3D layer shapes - Active Z printing, to improve mechanical strength through alignment of localized stress tensors parallel to the deposition paths. Sinusoidal layer shapes are used with varying amplitude, frequency, and orientation. Design of experiments is performed to correlate effect of varying shape and orientation of sinusoidal layer shapes on flexural strength of parts. Based on this, the results are used to decide parameters to be studied further and characterize their effect on the strength of parts.Item Continuous Fiber Angle Topology Optimization for Polymer Fused Filament Fabrication(University of Texas at Austin, 2016) Hoglund, R.; Smith, D.E.Mechanical properties of parts produced with the Fused Filament Fabrication (FFF) process are known to be dependent on the printed bead direction, especially when short carbon fiber reinforcement is added to the filament. Given that many FFF filament suppliers now offer carbon-fiber filled products, a unique opportunity emerges in the design of polymer composite FFF parts since bead and fiber direction can potentially be prescribed to give the best structural performance. As FFF moves from a technology for rapid prototyping and the hobbyist to a viable additive manufacturing method, it is important to also have a design tool that takes advantage of the opportunities that present themselves when polymer composites are employed. This paper presents a topology optimization method for continuous fiber angle optimization approach (CFAO), which computes optimal material distribution (as in the well known SIMP method) in addition to a preferred fiber angle direction by minimizing compliance of statically loaded structures. Our computed results show the effects of variable orientation angle on fiber reinforced microstructure for the topology of two-dimensional FFF parts. Optimal fiber orientations are shown to align with the axis of structural members that form within the structure as expected. Example design problems are solved and then printed on desktop 3D FFF printers using the material distribution results and a simple infill method which approximates the optimal fiber angle results by a contour-parallel deposition strategy. Mechanical stiffness testing of the printed parts show improved results as compared to structures designed without accounting for the direction of the composite structure. Future work includes extension of the method to three dimensional structures for further application.Item Deposition Controlled Magnetic Alignment in Iron-PLA Composites(University of Texas at Austin, 2018) Watson, Nathan D.; Von Lockette, ParisBy manipulating the print plane, infill direction, and geometry of Fused Filament Fabricated (FFF) iron-PLA composite parts, the alignment of their magnetic axes can be influenced. FFF printing allows control of deposition direction, which affects the arrangement of the iron within the composite part in ways that induce preferred magnetic orientation, the so-called easy axis. Qualitative results show the direction of deposition of the composite iron-PLA filament has significant effects on the response of the printed parts to an external magnetic field. Results further show that across different geometries, the easy axis of a printed part can be prescribed by setting the print plane and infill direction parallel to the desired orientation. Expected part geometry effects, along with the print plane and infill influences, suggest the phenomenon can be modeled using multi-scale demagnetizing field theories to print magneto-sensitive devices that can perform localized, controlled actuation in a uniform magnetic field.Item Dimensional Analysis of Metal Powder Infused Filament - Low Cost Metal 3D Printing(University of Texas at Austin, 2019) Terry, Shane; Fidan, Ismail; Tantawi, KhalidThe process of Additive Manufacturing (AM) is the newest form of fabrication with the primary method being layer-by-layer production. The most common form of this technology is Fused Filament Fabrication (FFF), where material is deposited layer by layer to produce a highly customized part. When compared to subtractive manufacturing the production of waste is greatly reduced. This study presents some innovations on a new metal fabrication technique for FFF printing. By printing a PolyLactic Acid (PLA) compliant metal powder composite filament, a part can be made with approximately 90% metal composition and sintered. The sintering process removes the PLA bonding leaving a 100% metal part fabricated on a low cost FFF printer. Overall, this study reports the initial findings on dimensional changes in low cost metal 3D Printing process.Item Distributed Optical Fiber Testing for Additive Manufacturing(University of Texas at Austin, 2023) Hlifka, Brian M.; Kinzel, Edward C.This paper explores optical fiber's use for in-situ inspection of additive manufacturing. Single-mode SMF-28 optical fiber can be placed on the build plate to monitor the printing process or embedded in the part. Distributed measurements using optical backscattering reflectometry (OBR) resolve the strain along the optical fiber and the temperature. OBR-enabled sensing is demonstrated for the fused filament fabrication (FFF) process. The small diameter (0.125 mm) of SMF-28 lends itself to embedding in FFF prints. This enables laying the fiber into the part, which provides continued sensing for the details in use. Knowledge of the process and the fiber arrangement allows heating from the deposition head to be distinguished from stress-driven strain. Calibration of the fiber arrangement is discussed, as well as a comparison with process modeling.Item The Effect of Polymer Melt Rheology on Predicted Die Swell and Fiber Orientation in Fused Filament Fabrication Nozzle Flow(University of Texas at Austin, 2017) Wang, Z.; Smith, D.E.Short carbon fibers suspended in the polymer feedstock enhances the mechanical performance of products produced with Fused Filament Fabrication (FFF). As the melted filament is extruded and deposited on a moving platform, the velocity gradients within the polymer melt flow orientate the fibers, and the final orientation has a direct effect on the mechanical properties of printed bead. This paper numerically simulates an FFF nozzle flow, including the extrudate material beyond the nozzle exit. Finite element simulations of the extrusion process are performed with Generalized Newtonian Fluid (GNF) models and a viscoelastic rheology model, included in ANSYS Polyflow, to evaluate the polymer melt velocity field and predict die swell. Fiber orientation tensors are computed along streamlines using the Fast Exact Closure and Folgar-Tucker isotropic rotary diffusion. The predictions indicate that shear thinning behavior reduces the die swell but viscoelastic rheology significantly intensifies the extrudate swell. Orientation tensor values calculated from the flow results of the viscoelastic model yields lower principal alignment in printed beads than those computed with GNF models.Item Effect of Printing Parameters on the Internal Geometry of Products Manufactured by Fused Filament Fabrication (FFF)(University of Texas at Austin, 2023) Moreno-Núñez, Benjamin A.; Trevino-Quintanilla, Cecilia D.; Esponiza-Garcia, Juan Carlos; Uribe-Lam, Esmeralda; Cuan-Urquizo, EnriqueThe internal geometry of a 3D-printed product determines its mechanical properties. In Fused Filament Fabrication (FFF) the filaments that build up the internal geometry suffer from variations that have not been sufficiently studied. This research focused on identifying the parameters that most affect the filaments and finding the optimum values to reduce their variations. A fractional factorial design of experiments was used to detect the printing parameters of FFF that most affect the width of extruded filaments, these results were also statistically analyzed. A response optimization was done to obtain the values of the printing parameters that will give the closest width of extruded filaments to the nozzle of the 3D printer used. Results showed layer height has the largest impact on filament width variation.Item Effect of Process Parameters and Shot Peening on Mechanical Behavior of ABS Parts Manufactured by Fused Filament Fabrication (FFF)(University of Texas at Austin, 2017) Kanger, Cody; Hadidi, Haitham; Akula, Sneha; Sandman, Chandler; Quint, Jacob; Alsunni, Mahdi; Underwood, Ryan; Slafter, Cody; Sonderup, Jason; Spilnek, Mason; Casias, John; Rao, P.; Sealy, M.P.The goal of this research was to understand how shot peening affected the tensile strength and elongation of ABS polymer parts between three process parameters: layer height, infill angle, and outer shell quantity. Experiments were conducted using a Hyrel 30M fused filament fabrication (FFF) printer to produce ASTM 638D-IV samples. This is an important area of research because 3D printed polymers have typically been limited to prototyping applications due to low strengths and stiffness. Traditional means of improving a polymer’s mechanical properties are changing the structural or chemical makeup. However, shot peening, a surface treatment commonly used to improve mechanical properties of metals, was hypothesized to have a statistically significant effect on the tensile strength and elongation of polymer parts. Results showed that shot peening had a significant effect on decreasing the tensile strength. Although not statistically significant, samples did show an increase in elongation after shot peening.Item Effect of Process Parameters on the Vibration Properties of PLA Structure Fabricated by Additive Manufacturing(University of Texas at Austin, 2021) Xue, Fangkai; Robin, Guillaume; Boudaoud, Hakim; Cruz Sanchez, Fabio A.; Daya, El MostafaAdvances in Fused Filament Fabrication (FFF) enable the design and manufacturing of multi-material and multi-functional structure that can potentially be used to develop light weight and high damping structures for vibration control. However, very few studies mention the vibration characteristics of FFF printed structures. This paper investigates the effect of four process parameters, raster angle, nozzle temperature, layer height and deposition speed, on the vibration properties of FFF printed Polylactic Acid (PLA) structure through modal analysis and design of experiment. The effects of all four parameters show a good agreement on the first fives modes of resonance. It was found that raster angle significantly affects both resonance frequency (16.6%) and loss factor (7.5%). Meanwhile, the impact of the other three parameters is relatively low (less than 4%), which is different from previous research results on static mechanical properties. All these results provide a guidance for further application of FFF in vibration field.Item Effects of In-Situ Mechanical and Chemical Polishing on Surface Topography of Additively Manufactured Fiber-Reinforced Polymers(University of Texas at Austin, 2021) Nigam, Aman; Tai, Bruce L.Additive manufacturing of fiber-reinforced polymers (FRPs) has revolutionized fused filament fabrication (FFF) by producing polymeric parts with enhanced mechanical properties. However, FFF suffers from poor surface quality and dimensional accuracy, particularly for FRPs, due to their abrasive and rheological nature. This examines an in-situ polishing scheme for FRPs in the FFF configuration. Glass-fiber-reinforced Nylon was used as the study material. Three polishing schemes, mechanical, chemical, and a combined thereof, were adopted along with various parameters in each case. The results show significant surface improvements in all cases, and the combined process can further reduce the Ra value to around 2 μm and the dimensional error to 0.2 mm and less. The combined process also enhances surface uniformity (i.e., similar Ra in all directions). In particular, with the combined approach, the in-situ polishing scheme is expected to improve the quality of 3D printed FRPs significantly.Item Electrical and Mechanical Properties of Fused Filament Fabrication of Polyamide 6 / Nanographene Filaments at Different Annealing Temperatures(University of Texas at Austin, 2019) Tate, J.S.; Brushaber, R.P.; Danielsen, E.; Kallagunta, H.; Navale, S.V.; Arigbabowo, O.; Shree, S.; Yaseer, A.Polyamide 6 (PA 6) nanographene composites are viable engineered nanocomposite materials with high potential for electrostatic discharge applications. This can be attributed to the ability of the nanographene particles in reducing the electrical resistivity of the parent polyamide 6 and in turn creating a conductive network for a controllable discharge of static electricity. In addition, PA 6 nanographene composites can also exploit the good mechanical properties of the parent polyamide 6, a structural thermoplastic ideal for 3D printing via fused filament fabrication (FFF). Hence, 3, 5, and 7 wt.% of NGP were blended with PA6 using co-rotating twin screw extruder to produce 1.75mm diameter for FFF using Lulzbot TAZ 6 3D printer. Scanning Electron Microscopy (SEM) was used to evaluate the degree of exfoliation of the nanographene and tensile and electrical resistivity test samples were manufactured via fused filament fabrication. The polyamide 6 nanographene composites were further subjected to annealing treatment at 80ºC, 140ºC, 200ºC and a comparison study was carried out on the observed tensile properties and electrical resistivity values of both annealed and not annealed treated.Item Evaluating the Effect of Z-pinning Parameters on the Mechanical Strength and Toughness of Printed Polymer Composite Structures(University of Texas at Austin, 2021) Bales, Brenin; Smith, Tyler; Kim, Seokpum; Kunc, Vlastimil; Duty, ChadTraditional Fused Filament Fabrication methods create a mechanically anisotropic structure that is stronger in the deposition plane than across successive layers. A recently developed pinning process deposits continuous pins in the structure that are orientated in the build direction across multiple layers. Initial studies of this technique have demonstrated the ability to increase inter-layer strength and toughness. The current study evaluated various z-pinning parameters for carbon fiber reinforced polylactic acid (CF-PLA) structures, including infill percentage, pin length, and deposition pattern. Each of these was found to affect the ability of the z-pin to mechanically bond with the existing lattice structure and had a resulting impact on the mechanical strength and toughness. Initial studies showed an increase in ultimate tensile strength in the Z-axis of around 3.5x. Upon expanding the pinning settings, further studies showed increases of over 35% from the X and Z axis ultimate tensile strength and improved mechanically isotropic behavior.Item EXPERIMENTAL CHARACTERIZATION OF THE MECHANICAL PROPERTIES OF 3D PRINTED BÉZIER-BASED LATTICE BEAMS(University of Texas at Austin, 2023) Álvarez-Trejo, A.; Cuan-Urquizo, E.; Roman-Flores, A.Architected materials are widely used in additive manufacturing to reduce weight. The controlled arrangement of material allows to tailor their mechanical properties by tuning their geometrical parameters. A parametrization based on cubic Bézier curves is employed here to generate lattice beams by changing the position of a free control point. Two topologies with the same volume fraction and base curve for the lattice constituent elements at different positions are studied and compared. Lattice beams are manufactured via Fused Filament Fabrication of polylactic acid. The effective stiffness and yield stress of these lattice beams is analyzed experimentally using three-point bending tests. Adjusting the control point location leads to tailoring the effective mechanical properties of the lattice beams. This methodology leads to the synthesis of architected topologies with customized mechanical properties.Item Failure Detection of Fused Filament Fabrication via Deep Learning(University of Texas at Austin, 2019) Zhang, Zhicheng; Fidan, IsmailAdditive Manufacturing (AM) is used in several fields and its utilization is growing sharply in almost every aspect of daily life. The focus of the current studies in the AM field is generally focused on the development of new technologies and materials. In addition, there is a limited number of research studies on the troubleshooting aspects of the AM processes. For the most commonly used Fused Filament Fabrication (FFF) process, the waste of material and time due to the printing errors are still an unsolved problem. The typical errors such as nozzle jamming and layer mis-alignment are inevitable during the printing process, and thus cause the failure of printing. It is a challenging task to clearly understand the physical behavior of FFF process with uncertainty, due to the phase transition and heterogeneity of the materials. Therefore, to detect the printing error, this research proposes a deep learning (DL) based printing failure detection technique. In this study, DL is utilized to monitor the printing process, and detect its failures. This newly developed DL framework was beta-tested with a commercially available FFF setup. The beta testing results showed that this technique could effectively detect printing failures with high accuracy.Item Fused Filament Fabrication on the Moon(University of Texas at Austin, 2021) Zhang, J.; Van Hooreweder, B.; Ferraris, E.Additive manufacturing (AM) techniques possess the capabilities to rapidly produce complex and customised parts, typically in low-volume and with reduced material us- age and preparation tools . These attributes magnify their indispensability when the availability of materials and equipment is limited. It can be such a case for off-Earth manufacturing, e.g. in manned lunar explorations. This article presents a preliminary discussion on the possibility of performing fused filament fabrication (FFF) on the Moon from the perspective of heat transfer in printed parts. It makes use of experimen- tal data and simulations to quantify the significance of each heat transfer mechanism taking place during printing. The quantification then enables us to investigate how the lunar environment affects the cooling in the printed parts. Finally, FFF on the Moon is predicted to be feasible. Yet, apparent differences in the process window and types of applications are pointed out as compared with the counterpart printing activities on the Earth. The full paper may be found in a special issue of the TMS publication JOM, March 2022.Item In-Situ Verification of 3D-Printed Electronics Using Deep Convolutional Neural Networks(University of Texas at Austin, 2021) Ahlers, DanielPrinted electronics processes are becoming more stable and evolve into first industrial applications. These industrial applications require proper quality assurance to get a mostly autonomous production process. In this work, we present a new approach to inspect printed electronics and ensure their quality. Our hardware setup extends a fused filament fabrication (FFF) printer with an extruder for direct dispensing of conductive paste, a pick and place unit, and two cameras. The cameras take multiple images during printing. A trained neural network analyzes these pictures to separate the electronic wires from the plastic background. All separated images of a layer are combined to get a full view of the layer. Our algorithms then examine the detected wires to identify printing flaws. The algorithms currently detect connection breaks, shorts, find points that have not been reached, and evaluate the width of the printed wires.Item Increasing the Interlayer Bond of Fused Filament Fabrication Samples with Solid Cross-Sections using Z-Pinning(University of Texas at Austin, 2019) Duty, Chad; Smith, Tyler; Lambert, Alexander; Condon, Justin; Lindahl, John; Kim, Seokpum; Kunc, VlastimilThe mechanical properties of parts made by fused filament fabrication is highly anisotropic, with the strength across layers (z-axis) typically measuring ~50% lower than the strength along the direction of the extruded material (x-axis). A z-pinning method has been developed in which material is extruded in the z-direction to fill intentionally aligned voids in the x-y print pattern. In previous studies that involved a sparse rectilinear grid cross-section (35% infill), the z-pinning approach demonstrated more than a 3.5x increase in strength in the z-direction. The current study expanded these efforts to evaluate the use of z-pins in a printed sample with a solid cross-section. Although a solid cross-section is more common in structural components, it is much less forgiving of instabilities that may occur in the z-pinning approach (such as over-filling). Even though this study utilized a low pin volume (~43% fill factor), the pinning approach demonstrated a 40% increase in z-direction strength for solid samples that had similar printing times.Item Influences of Printing Parameters on Semi-Crystalline Microstructure of Fused Filament Fabrication Polyvinylidene Fluoride (PVDF) Components(University of Texas at Austin, 2018) Momenzadeh, Niknam; Berfield, Thomas A.Piezoelectric polymers have garnered wide interest for sensing, actuation, and energy harvesting applications due to their unique combination of high strain tolerance and electro-mechanical coupling. Compared to other piezoelectric polymers, polyvinylidene fluoride (PVDF) and its copolymer and terpolymer variations demonstrate some of the strongest piezoelectric responses. One of the primary challenges associated with PVDF is that its piezoelectric response is highly dependent on its microstructure, which varies greatly with manufacturing-associated stresses. This work investigates Fused Filament Fabrication (FFF) of PVDF polymers, and the effects of processing parameters such as layer thickness, infill pattern, infill density and nozzle diameter on its microstructure development. Fourier Transform Infrared Spectroscopy (FTIR) measurements are used to assess the relative phase content of the semi-crystalline microstructure arrangement primary related with significant piezoelectric response in PVDF (β-phase).Item Lost-PLA Casting Process Development Using Material Extrusion with Low-Weight PLA(University of Texas at Austin, 2023) Ali, Mohammad Alshaikh; Huseynov, Orkhan; Fidan, Ismail; Vondra, FredThe goal of this research is to develop a baseline procedure for lost-PLA casting process of aluminum. Traditional Manufacturing techniques and Smart Manufacturing techniques have their advantages and disadvantages. Integrating the traditional and modern aspects of manufacturing enhances the capabilities of manufacturing. In this study, low-weight PLA is used in a Material Extrusion (MEX) machine to fabricate sacrificial patterns for an aluminum lost-casting process. Different process parameters, after a calibration process, are tested for the MEX process The MEX process parameters tested are: infill pattern, and top/bottom solid layers. The MEX process parameter investigation allows to draw conclusions to establish a standard for which parameters are ideal for the casting process. For this research, casting process parameters are set constant. The preliminary studies show that the lost-PLA casting process is successful in producing dimensionally accurate aluminum parts by a direct-pour casting process using the suggested MEX process parameters.Item A Low-Cost Approach for Characterizing Melt Flow Properties of Filaments Used in Fused Filament Fabrication Additive Manufacturing(University of Texas at Austin, 2019) Chen, Jingdong; Smith, Douglas E.Users of Fused Filament Fabrication (FFF) can choose from a wide variety of new materials as filament producers continue to introduce new polymer and polymer composite filament into the marketplace. This paper describes a low-cost device capable of measuring the rheological properties of off-the-shelf polymer filament. In this approach, measurements are taken during filament extrusion which are combined with a pressure drop model based on simple shear flow within the FFF nozzle to perform inverse analysis that computes parameters for the power law generalized Newtonian fluid (GNF) model. The applicability of our FFF-filament rheometer is demonstrated with four commercially available polymer filaments by comparing the results to those obtained from a commercial rotational rheometer. A filament characterization approach similar to Melt Flow Index (MFI) is also proposed to assess the extrusion characteristics of materials specific to FFF.