2024 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2024): Application: End-Use Parts
Program Organizers: Joseph Beaman, University of Texas at Austin
Tuesday 8:00 AM
August 13, 2024
Room: 416 AB
Location: Hilton Austin
Session Chair: Kazi Md Masum Billah, University of Houston Clear Lake
8:00 AM
Application Driven: Process for Rapidly Fabricating Large 3D Printed Solid Parts: Callie Zawaski1; Christpher Smith1; Alexander Pique1; Joseph Bartolai1; 1Pennsylvania State University
Employing polymer additive manufacturing for rapid prototyping and fabrication has resulted in huge advantages for short project timelines. Printing large structures is more challenging than small parts due to their long print times and increased material use. This leads to fabricating a mostly hollow structure using infill percentages <10%. These low infill parts can be great in applications such as molding, where minimal strength is required, but can be concerning if the structure is expected to carry load. Ideally, these structures could be tested and modeled, nullifying the “rapid” advantage. To circumvent this, large structures were built with a low percentage gyroid infill and backfilled with a strong and light epoxy-based syntactic foam material. Parts were mechanically tested to determine strength and mode of failure. The mechanical property, time to completion, and cost trade space for low infill parts, solid infill parts, and syntactic foam filled parts is discussed.
8:20 AM
Continuous Wire Embedded 3D Printed Sorbent Structures: Ben Woods1; Phil Cox1; Alex Ferguson1; Tra-My Richardson2; 1Mainstream Engineering; 2NASA
CO2 and water vapor removal are critical for air revitalization on the ISS and other confined spaces. A combination of zeolite molecular sieves and silica is used to adsorb CO2, water, and other trace contaminants. These adsorbed contaminants are then expelled by heating the bed to regenerate it. These beds are currently fabricated of loose beads with cartridge heaters and fins for heating. In conjunction with NASA, Mainstream Engineering is developing a process of fabricating sorbent beds with an AM process. We have developed highly-loaded zeolite 13X and silica gel-based pastes that closely mimic the adsorbent capacity of the legacy sorbent beads. We can deposit these pastes into 2.5D and 3D layers optimized for pressure drop, breakthrough capacity, and overall sorbent bed SWaP. Additionally, our patent-pending continuous-wire embedding mechanism allows us to embed thin, high-resistivity wires directly into these printed roads; enabling highly uniform and SWaP-optimized heating of sorbent structures.
8:40 AM
Design for Additive Manufacturing Considerations for Compliant Constant Force Mechanisms: Sumant Dilip Rokade1; Nichloas Meisel1; Jared Butler1; 1Pennsylvania State University
Compliant Mechanisms (CMs) are a class of mechanisms that utilize bending to achieve motion. Compliant Constant-Force Mechanisms (CCFMs), a unique subset of compliant mechanisms, can deliver a constant force output over a fixed range of motion; these mechanisms are often planar systems driven by traditional manufacturing design principles and can be generated using a variety of methods. Some methods, such as rigid body replacement, are constrained to pins and linkages whereas those generated with topology optimization may possess more organic shapes. Traditional methods of manufacturing drive a wide variety of these designs. Applying principles dictated by Design for Additive Manufacturing (DfAM) may yield better designs for these complex applications. This paper develops a clear, concise framework that elucidates ways to design and manufacture CCFMs using Additive Manufacturing (AM). This is done by demonstrating the integration of DfAM considerations within a range of CCFM case study topologies.
9:00 AM
Evaluating the Impact of Printing Technology and Parameters on the Accuracy of Canine Maxillectomy Cutting Guides Produced by Additive Manufacturing: Satyanarayana Konala1; Sam Hernandez1; Marine Traverson1; Ola Harrysson1; 1North Carolina State University
Additive manufacturing (AM) is increasingly used to produce patient-specific surgical guides for complex procedures like canine maxillectomy. However, the accuracy of these guides can be significantly influenced by the choice of printing technology, process parameters, and material properties. This study investigates the impact of three factors - printer type (DLP, SLA, MJ), resin formulation, and build orientation - on the dimensional accuracy of maxillectomy cutting guides. Guides were designed based on CT data, manufactured using different combinations of printer type, resin, and orientation, and measured using coordinate metrology. Statistical analysis was performed to determine the main effects and interactions of the factors on guide accuracy. The results provide insights into the optimal selection of printing technologies and parameters for producing high-precision surgical guides, ultimately improving the predictability and outcomes of these delicate procedures.
9:20 AM
Additive Manufacturing of a Deployable Monolithic Camera Cover for Planetary Exploration: Maya Roman1; Christine Gebara1; Adrian Cheng1; 1NASA Jet Propulsion Laboratory
Camera covers are mechanisms commonly used to protect optical instruments during the launch and landing of a spacecraft. The mechanisms have two basic functions: protect optics from foreign objects and debris while stowed and move out of the camera’s field of view when deployed. Mechanisms of this sort are easily over engineered, with the final assembly consisting of dozens of piece-parts. This project presents a design that takes advantage of additive manufacturing to combine components, including flexures that deploy the cover. The proposed design would decrease part count and cost while maintaining the function and reliability of traditional camera cover mechanisms. As part of the development of the design, the performance of printed nylon and Ti-6Al-4V springs was tested and compared to analytical values.
9:40 AM Break
10:00 AM
Improved Design of Wings Built with Material Extrusion: Justin Valenti1; Joseph Bartolai1; Michael Yukish1; 1Pennsylvania State University
This paper details continued work on small wings built with material extrusion. Two features have been added to a previously published in-house code developed for this application: (1) an experimentally derived constraint on internal structure to mitigate manufacturing-process induced skin deformation and (2) flanges on toolpath intersections to improve adhesion between wing skin and internal structure. Point clouds were taken of as-built surfaces to show mitigation of process-induced skin deformation. Bend testing was performed on wings built with and without the process improvements. The improved wings exhibit improved bending stiffness and reduced variability in bending performance.
10:20 AM
Design of Pneumatic Soft Actuators for Fabrication with High-viscosity Vat Photopolymerization: Roxana Carbonell1; Hongtao Song1; Martha Leach1; Carolyn Seepersad1; 1Georgia Institute of Technology
The field of soft robotics has grown with new applications for flexible, adaptable, lightweight robots in diverse fields. These applications motivate a shift in the design of soft robotics from exploratory proof-of-concept models to optimized designs with high levels of geometric complexity. However, many soft actuators are limited geometrically by the use of traditional molding processes. Vat photopolymerization (VPP) of true silicones is a promising alternative for the fabrication of geometrically complex elastomeric parts, but the high viscosity resins are difficult to process. A novel, large-format VPP system and an accompanying test bed enable VPP of high-viscosity silicone formulations with robust material and aging properties that are unattainable with other additive manufacturing systems. This system is utilized to fabricate a series of bending pneumatic unit cells. Based on these results and accompanying nonlinear finite element analysis, a process for designing VPP enabled soft robots with predetermined actuated trajectory is established.
10:40 AM
A Design and Additive Manufacturing Framework for Voxel-based, Multi-material, Thick-folding Origami: Evelyn Thomas1; Jared Butler1; Nicholas Meisel1; 1Pennsylvania State University
Origami has expanded beyond its paper-craft origins to solve problems related to volumetric constraints and deployment within fields such as aerospace, civil engineering, and biomedical engineering. While paper folding enables the design of complex mechanical systems, realizing these systems in thick, engineered materials requires additional design and manufacturing considerations when contrasted against traditional, thin origami. Methods to accommodate for thickness in origami-based systems require numerous processes and assembly steps. The material and functional complexity of voxel-based additive manufacturing can address the drawbacks inherent to traditional thick-folding origami. Design at the voxel level can allow for precise and continuous functionally graded material properties that enable novel behavior and improve the overall performance of thick-folding origami designs. This paper details a framework for designing voxel-based additive-manufactured thick-folding origami parts. This framework is demonstrated through two case studies that show the application of voxel-based multi-material additive manufacturing to thick-folding origami techniques.
11:00 AM
Nontraditional Electromagnetics: Fabricating RF Sensitive Sensors, Circuits, and Interconnects using Additive Materials and Techniques: Christopher Molinari1; Lucas Unger1; Michelle Connolly1; Jotham Kasule1; Basil Vanderbie1; Samuel Fedorka1; Shawn Kelliher1; Gary Walsh2; Corey Shemelya1; 1University of Massachusetts Lowell; 2U.S. Army DEVCOM Soldier Center
Additive manufacturing has revolutionized the realm of RF electronics, enabling the rapid prototyping and fabrication of electromagnetic structures using nontraditional materials. These materials, while allowing for significant flexibility in system form factors, present numerous design challenges such as substrate curvature, high surface roughness, and connection reliability. For example, the placement of discrete packages using conductive inks may result in wicking, causing unintentional shorting and poor component adhesion. This work demonstrates solutions to many of these issues, including the use of anisotropically conductive inks, printed press-fit PCB interconnects, RF-transparent protective coatings, and printed interposers for various package sizes. As a case study, we utilize these techniques to fabricate an RF detection system within a doubly-curved E-glass laminate, including printed antennas, vias, and transmission lines. Our work can offer unique and innovative ideas towards how additively manufactured RF circuits may be applied to meet novel design goals within existing systems.
11:20 AM
Planar and Non-planar Print Patterns in PEEK Flat Backup Rings to Increase Seal Performance Under High Pressure and Temperature: Joshua Green1; Ian Rybak1; Joseph McKee1; Chad Glaesman2; 1The University of Texas at El Paso; 2Halliburton Energy Services
Numerous industries use thermoplastics to meet the demanding requirements of high-temperature and high-pressure sealing applications. Flat backup rings, common components of sealing assemblies, can be additively manufactured using fused filament fabrication and can perform comparably to their conventionally manufactured counterparts. The load response which develops within the seals is largely driven by pressure and the geometry of the extrusion gap which is located opposite of the primary seal in the assembly. To better address this loading condition, flat backup rings were fabricated with conventional print patterns and compared to custom radial print patterns which were configured with planar and non-planar layer configurations. Specimens underwent pressure vessel tests to provide an estimate of seal performance at high-pressure and high-temperature. The observed relationship between test results and print orientation may inform tuning of sealing structures in numerous industries to further optimize seals for multiple objectives.
11:40 AM
Differences in Post-processing Techniques: Mary Louise Gucik1; Kasandra Escarcega Herrera1; Jay Taylor1; Michael Melia1; 1Sandia National Laboratories
Over the past decade, additive manufacturing has emerged as a competitive alternative to traditional fabrication; however, the as-printed surface roughness greatly degrades surface sensitive properties requiring a post-processing step before integration for the intended use. A crucial question then becomes, which post-processing technique is appropriate for the part in question? Herein, results from mechanical and chemical techniques will be shared and the differences highlighted. Media blasting was investigated on AM parts with high aspect ratio geometries; variations in surface feature removal were interrogated with different types of media. Conversely, the brightening, smoothing, and deburring of metallic AM parts was chemically investigated through electropolishing. Environmentally friendly baths were targeted for traditional wet electropolishing work in constant and pulsed potential regimes and the results will be compared to commercially available dry electropolishing systems. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. SAND2024-04969A