2024 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2024): Process Development: Material Extrusion
Program Organizers: Joseph Beaman, University of Texas at Austin
Wednesday 8:00 AM
August 14, 2024
Room: 615 AB
Location: Hilton Austin
Session Chair: Raihan Quader, North Dakota State University
8:00 AM
The Development of a Precise Quick Response Apparatus for Functional Grading in Reactive Extrusion Additive Manufacturing: Brandon Yu1; Hongtao Song1; Mohammad Zamani2; Zoubeida Ounaies2; Carolyn Seepersad1; 1Georgia Institute of Technology; 2Pennsylvania State University
Reactive Extrusion Additive Manufacturing (REAM) is a process in which a multi-part thermoset resin is layered by a motion-controlled nozzle mixer. The initial liquid state of the material allows for the addition of magnetic particles into the neat resin which can be functionally graded in the final part. The functional grading unlocks the ability for shape actuation, via magnetic field stimuli, after the curing process is completed. The main challenge of functional grading is the large dead volume within the passive mixing system, which prevents rapid and accurate particle grading. To reduce this volume an active mixing nozzle, designed for the rapid mixing of neat and particle filled resin with the catalyst, is employed for more rapid, precise grading. The effectiveness of mixing and the accuracy of functional grading are tested by printing multiple geometries with their compositions validated through VSM analysis.
8:20 AM
Novel FFF Processes for Fiber-Enabled Designs: William Johnston1; Bhisham Sharma1; 1Michigan Technological University
While current fused filament fabrication (FFF) processes are effective at producing rigid objects, many fibrous structures found in nature remain difficult to create, including bristles and human hair. In this work, we introduce two new processes to incorporate such fibers into existing FFF workflows: the bridging and extrude/pull methods. By modifying printing G-code to control the nozzle’s speed and extrusion, we add hair-like fibers to any existing design. Further, we demonstrate methods to tailor each fiber’s placement, thickness, and angle orientation. We showcase the print dimensional accuracy of these fibers and highlight their enhanced sound absorption performance at low frequencies. These novel processes allow us to produce fiber-enabled designs suitable for a plethora of applications, including fibro-porous sound absorbers, tensegrity-assisted inflatables, bio-inspired quiet propeller blades, and membrane-type metamaterials. Our processes demonstrate a promising future toward enhancing the design customization of FFF workflows.
8:40 AM
Multi-Nozzle Cooperation for Micro-Cold Spray: Ronnie Stone1; Michael Gammage2; Junmin Wang1; Michael Cullinan1; Desiderio Kovar1; Zhenghui Sha1; 1University of Texas at Austin; 2Army Research Lab
While the multi-robot systems (MRS) paradigm has been successfully applied in fused deposition modeling (FDM) processes for cooperative 3D printing, one of its core goals is the development of a framework that is adaptable to different types of additive manufacturing (AM) technologies. Processes that benefit from multi-material and multi-resolution capabilities and are notoriously difficult to scale up both in size and speed are of particular interest. Micro-cold spray (MCS) has been historically limited to systems with single-nozzle configurations, which restrict the range of viable printing applications due to the invariability of particle density and thermal conductivity during the process. A multi-nozzle, MRS-inspired configuration would allow independent control of deposition parameters and feature sizes, widening the horizon of MCS applications. In this paper, we develop a computational MRS framework as the first step in enabling multi-nozzle cooperation for MCS. Specifically, we focus on rules for slicing, motion planning, and process scheduling.
9:00 AM
A Real-Time Monitoring Framework for Cooperative 3D Printing: Cole Mensch1; Anuj Swaminathan1; Zhenghui Sha1; 1University of Texas at Austin
This paper presents a real-time process monitoring framework designed for cooperative 3D printing (C3DP), capable of detecting common errors that occur in FDM 3D printing and providing corrective feedback in a closed-loop system. C3DP is a primitive instance of swarm manufacturing (SM) that integrates swarm robotics and additive manufacturing to build large parts to overcome the scalability issues present in traditional 3D printing. Our prior work has established the C3DP framework, with steps such as geometric partitioning, scheduling, placement, and path planning. However, C3DP cannot achieve full autonomy unless its capabilities include live monitoring of the manufacturing environment and feedback-driven error correction. The proposed system utilizes various computer vision techniques, including object tracking, object classification, and image similarity comparisons, which are merged into a holistic decision-support system for real-time monitoring and closed-loop control of C3DP. We demonstrate its effectiveness by running multiple test prints with various combinations of built-in errors.
9:20 AM
Novel Approach to Manufacture Soft Magnetic Core with MIM (Metal-Insulation-metal) Structure
via Dual-Nozzle Material Extrusion (MEX) Technology: Taehyeob Im1; Kwiyoung Lee1; Jonghyeok Ahn1; Suyeon Kim2; Juyong Kim3; Dongju Lee2; Jai-Sung Lee1; Jongryoul Kim1; Caroline Sunyong Lee1; 1Hanyang University; 2Chungbuk National University; 3Reprotech R&D center
In this study, Dual-Nozzle Material Extrusion (MEX) printer has been developed to manufacture Soft Magnetic Core with MIM (metal-Insulation-metal) structure to minimize Eddy current loss by increasing its resistivity. To achieve this, layers composed of Fe-6.5wt.%Si layer/ MgO-based insulation layer/ Fe-6.5wt.%Si layer were designed to be extruded alternatively using Dual-Nozzle MEX printer as Fe-6.5wt.%Si is reported to have minimum coercivity. The insulation layer was printed between the Fe-6.5wt.%Si layers at its thicknesses of 0.1, 0.2, and 0.5 mm to find out its optimum thickness to minimize core loss. Finally, we have used spark plasma sintering (SPS) for the final component to achieve a high density of the part. The Microstructure at the interface between insulator and metal, resistance, apparent density, and BH analysis were observed for comparison. Therefore, we have proposed new method to suppress core losses by printing MIM structures based on Fe-6.5wt.%Si layers using dual-nozzle MEX technology.
9:40 AM
Optimization of SiC Colloidal Ink for Direct-Write Additive Manufacturing via Dual-Polyelectrolyte Ratio Method: Michael Odunosho1; James Smay1; 1Oklahoma State University
Robocasting is being extensively explored for fabrication of silicon carbide (SiC) components for a variety of applications. Many of the previous works have only been able to print low-to-moderate volume solid loadings (φ=0.33-0.44) and with larger nozzle sizes (600-1500μm) because high-solid loadings are difficult to extrude. However, printing low-moderate solid loadings and larger nozzles usually lead to poor surface finish and excessive shrinkage upon sintering of printed part. Therefore, optimizing SiC ink would be beneficial for printing high-solid loadings with smaller nozzles. In this study, a systematic approach towards the optimization of SiC by dual-polyelectrolyte ratio method was explored. A viscoelastic study revealed that lower concentration of flocculant is more suitable for SiC colloidal gel used in robocasting while higher flocculant concentration led to over-flocculation, thereby causing a transition from a strong gel initiated by bridging flocculation to a weak gel due to steric stabilization overcoming the bridging flocculation.
10:00 AM
Developing In-Situ Process Monitoring Capabilities for Material Extrusion Additive Manufacturing: Zachary Renda1; Jan Petrich1; Callie Zawaski1; Joseph Bartolai1; 1Pennsylvania State University
A machine agnostic framework for in-situ data collection during Material Extrusion (MEX) Additive Manufacturing (AM) builds with user-defined anomaly tagging is presented. To enable the use of Machine Learning (ML) algorithms for detection and identification of MEX build anomalies, a large set of training and test data is required. The tagging framework is integrated into a data collection system that includes infrared imaging, visible light imaging, accelerometer data, homography-based telemetry data, temperature, and environmental conditions. This data is registered both in time and 3D space, allowing the build anomaly data to be traced to a specific location on the as-built part. The presented framework allows users to create a database by identifying anomalies during a MEXAM build and automatically marks data around the anomaly time step across all collected sensor modalities. This tagged data can then be used as ground truth for ML training and validation.
10:20 AM Break
10:40 AM
Toward Real-Time Adaptive Material Control in Large-Scale Robotic Additive Manufacturing: Walter Glockner1; Peyton Weisbeck1; Jakob Hamilton1; 1Iowa State University
This work presents a modular, open-loop control scheme for deployment in large-scale additive manufacturing (AM) systems. While AM offers unique material and design capabilities, it suffers from the inability to produce components predictably from experimental feedstock materials. Our approach addresses this issue by allowing for on-the-fly toolpath and parameter modification to maximize quality and consistency of custom materials. Control of motion and peripherals are combined into a singular workflow, simultaneously simplifying operational instruction and data handling. A key advantage of this approach is the real-time feedback provided to operators and integration of additional sensors and signal processing tools without significant modifications to an OEM system. An exemplar system is built atop a six-axis robotic pellet-extrusion AM system to demonstrate modularity and scalability. This work builds toward automating large scale printing for material-critical applications with reliable and predictable quality.
11:00 AM
Controlled Distribution of Composition within Extrusions as Enabled by an Active-mixing Hotend: Ian Rybak1; Daniel Hernandez1; Roger Gonzalez1; Joshua Green1; 1University of Texas at El Paso
Local control of composition in additive manufacturing has great potential for improving properties and multifunctional characteristics of printed materials. Dimensional resolution of such composition control in fused filament fabrication is usually limited to the geometry of a single extrusion. To achieve microstructural control within extrusions, an active-mixing hotend was configured to extrude with various proportions of mixing rod rotation and material flow. Distribution control was investigated through optical characterization of extrusion cross-sections at steady state using various polymers, colors, and composites. When at low proportions relative to extrusion, rod rotation affects material phase shape and location. Resultant phase distributions are specific to the extruded material combinations and are affected by extrusion heights and widths. These mechanisms for controlling microstructures can be controlled in situ through software enabling fabrication of multifunctional materials with a wide variety of strength, stiffness, thermal and electrical conductivity, solubility, corrosion resistance, and more.
11:20 AM
Design and Fabrication of a Multi-directional Aerial 3D Printer: Jacob Garifalis1; Alex Pan1; Otgondulam Boldbaatar1; Elijah Olowokere1; Lucas Vergara1; Alaina Villanueva1; Suyog Ghungrad1; Jonathan Komperda1; Azadeh Haghighi1; 1University of Illinois Chicago
Aerial 3D printing is an emerging technology that aims to overcome several limitations of traditional additive manufacturing platforms, specifically constraints associated with print size and accessibility (e.g., at high altitudes). An aerial 3D printer integrates an Unmanned Aerial Vehicle (UAV) with the additive manufacturing technology for targeted deposition of material, enabling automated manufacturing, maintenance, and repair at hard-to-access locations such as high-rise buildings and bridges. However, the existing state-of-the-art aerial 3D printers cannot accommodate multi-directional material deposition, e.g., for conformal printing over complex or angular surfaces. To address this gap, this work presents the design and fabrication of a first-ever multi-directional aerial 3D printer. Various design alternatives for the deposition head were considered and analyzed with respect to weight, functionality, and rigidity metrics. Finally, successful multi-directional material deposition using an expanding foam has been demonstrated with the fabricated prototype.
11:40 AM Cancelled
Strengthening Polylactic Acid and Thermoplastic Elastomer Blends through Thermoforming to Reorient Extrusion Paths: Pamela Campos Valles1; Roger Gonzalez1; Joshua Green1; 1The University of Texas at El Paso
Fused filament fabrication is compatible with thermoplastics which are commonly used for thermoforming. Structures printed through fused filament fabrication are often weaker along the build direction due to the interface bond strength between layers. In contrast to conventional printing methods, thermoforming can alternatively be used to reorient extrusion paths and increase strength relative to a particular load direction. Through use of a fused filament fabrication printer with an active-mixing hotend, sheets with rectilinear infill were printed with a variety of uniform blends of polylactic acid and thermoplastic polyurethane. The sheets were then thermoformed to reorient extrusions relative to the printer’s build orientation and stretch the material as is common in thermoforming applications. Tensile tests were performed to compare the effects of thermoforming as compared to specimens printed in the same orientation. Results indicate an ability to favorably modify tensile properties through thermoforming rather than orientation of print direction alone.
12:00 PM
Thermal and Mechanical Characterization of Lightweight PLA Filaments for Material Extrusion: Mohammad Alshaikh Ali1; Ismail Fidan1; Shamil Gudavasov1; Vivekanand Naikwadi1; Mushfiq Mahmudov1; 1Tennessee Tech University
Recent advancements in Additive Manufacturing, particularly in Material Extrusion (MEX), have focused on lightweight (LW) PLA filaments. This study explores the thermal and mechanical properties of LW-PLA filaments to optimize the strength-to-weight ratio. Foaming additives, activated thermally to induce expansion, have been introduced to PLA. Three LW-PLA filaments are tested to assess their lightweighting capabilities. Using Thermogravimetric Analysis and Differential Scanning Calorimetry, degradation and glass transition temperatures are determined. Taguchi design is employed to analyze tensile strength, considering parameters like print orientation, nozzle diameter, and printing temperature. Initial findings suggest expanded LW-PLA exhibits decreased strength. The type of LW-PLA and print orientation significantly influence tensile strength, whereas nozzle diameter and printing temperature have minimal impact. Various weight-reduction settings are explored to identify the optimal strength-to-weight ratio. This research enhances understanding of LW-PLA properties and advances applications of MEX through strength-to-weight ratio optimization.
12:20 PM
Insights on Multi-Extrusion Filament Fabrication: Exploring the Impact of Seam Overlap and Ironing Process: Manuel Sardinha1; Luís Reis1; Joaquim Netto1; Nuno Frutuoso2; Marco Leite1; 1IDMEC, Instituto Superior Técnico, Universidade de Lisboa; 2FabInventors
Within additive manufacturing technologies, polymer extrusion has witnessed significant development in recent years. Nonetheless, the manufacturing of large-format parts remains a challenging task. Cooperative and independent extrusion systems show promise for the efficient fabrication of large components, but often introduce problems such as seams (bonding between material deposited by different extruders) that act as localized part weaknesses. Given that the diffusion of polymer molecules through a given interface depends on the available contact area and is greatly influenced by temperature, the authors hypothesize that increasing the contact surface and local temperature might improve part strength. In this study, the authors evaluate how overlapping seam areas affect the tensile properties of PLA samples produced with multiple extrusion systems. Besides overlapping, the effect of ironing (a thermal-based post-processing technique originally designed to smooth the top layers of parts) in overlapped areas is also studied. Results highlight the importance of overlaps and confirm that the fracture mechanism of heat-affected areas is different when compared with non-affected ones, suggesting that the mechanical properties of parts with seams can be improved, but further studies are needed. With this knowledge, the authors aim to help the process of designing large polymer parts using collaborative 3D printing.
12:40 PM
Effect of Thermal History on the Crack Propagation Rates in PA and PA/CF Samples prepared via Material Extusion Additive Manufacturing: Ava Lea1; Taylor Vance1; Jafor Md Abu1; Arief Yudhanto1; Trevor Fleck1; 1Baylor University
This study investigates the influence of thermal history on the mechanical properties of fused filament fabrication samples, specifically the fracture toughness and subsequent fatigue life performance. The thermal history of nylon and carbon fiber filled nylon is manipulated through nozzle temperature. Compact tension samples are fabricated and subjected to both static and fatigue loading to assess fracture toughness of the modified samples under different loading conditions. Thermal history analysis is conducted using thermography to determine the diffusion history of the samples. The experimental design allows for the systematic evaluation of how varying levels of nozzle temperature, and consequently different thermal histories, influence the resultant fatigue resistance and fatigue life. These findings contribute to advancing the broader application of additive manufacturing by enabling the production of components with reliable performance for functional applications.