1:30 pm – 6:30 pm:
M10-Additive Manufacturing Materials
(Moderators Ray Pearson and Jason Lyons)-Room S320E

1:30 pm – 2:00 pm:
3D Printing Feedstock from Recycled Materials

Nicole Zander, US Army Research Laboratory
Nikki Zander is Research Chemist in the Macromolecular Science and Technology Branch at the US Army Research Laboratory (ARL) in Aberdeen, MD. Her current primary research interests are additive manufacturing using recycled and indigenous materials, nanofiber research in areas such as tissue engineering, antimicrobial materials and filtration, brain injury mechanisms, and understanding bacterial adhesion mechanisms. She received a Ph.D. in Chemistry from the University of Delaware in 2012.

2:00 pm – 2:30 pm:
Assessing the Performance of Continuously Reinforced Acrylonitrile Butadiene Styrene with a Thermotropic Liquid Crystalline Polymer in Fused Filament Fabrication

Mubashir Ansari, Virginia Tech
This work is concerned with the processing of wholly thermoplastic and continuously reinforced filaments in Fused Filament Fabrication (FFF), a form of extrusion based Additive Manufacturing (AM). Acrylonitrile Butadiene Styrene (ABS) was continuously reinforced with a Thermotropic Liquid Crystalline Polymer (TLCP), composed of terephthalic acid (TA), 4-hydroxybenzoic acid (HBA), hydroquinone (HQ) and hydroquinone derivatives (HQ-derivatives), using a novel dual extrusion system. The processing conditions for FFF were determined by performing dynamic mechanical analysis on the pure TLCP. Rectangular specimens were printed using the reinforced filaments with all the roads aligned in one direction. Tensile testing was performed on the filaments as well as the printed specimens to determine improvement in the mechanical properties.

2:30 pm – 3:00 pm:
High Impact Strength Polycarbonate Filament for Additive Manufacturing

Sarah Grieshaber, SABIC
Sarah Grieshaber is a Sr. Scientist at SABIC with 6 years of experience in product development for a variety of industries including additive manufacturing. Her background is in chemistry with a Ph.D. in Materials Science and Engineering from the University of Delaware.

3:00 pm – 3:30 pm:
Bonding Strength in Additively Manufactured Multi-Material Plastics Parts

Jakob Onken, Institute of Plastics Processing at RWTH Aachen University
2015: Masters in Mechanical Engineering at RWTH Aachen Unversity, Germany Since 2015: Research assistent and doctoral student at the Institute of Plastics Processing at RWTH Aachen University, coordinating the team “Materials Selection, Part Design, Injection Moulding, CAE”

3:30 pm – 4:00 pm:
Crystallization Kinetics During Materials Extrusion Based Additive Manufacturing of Polycaprolactone

Kalman Migler, NIST
Filament-based additive manufacturing processes extrude molten polymer through a printer nozzle at high shear rates (> 100 s-1) prior to cooling and crystallization. Although the phenomenon of flow-induced crystallization is well-known in general, the effect of nozzle flow on the crystallization kinetics of polymers are unknown for extrusion based additive manufacturing. In fact, there is no method available to quantitatively measure crystallinity during the AM process. To address this issue, we demonstrate that fiber optic probe based Raman spectroscopy can be used to conduct in situ measurements of the crystallinity kinetics of extruded polycaprolactone during additive manufacturing. We then quantify crystallinity as a function of distance away from the nozzle.

4:00 pm – 4:30 pm:
Processing Considerations: Cellulose Nanocrystal Thermoplastic Urethane Filament Production

Jacob Fallon, Virginia Polytechnic Institute and State University
Cellulose nanocrystal (CNC) thermoplastic urethane (TPU) nanocomposites offer a wide range of unique thermal and mechanical properties. This paper focuses on solution mixing and melt processing considerations for producing cellulose nanocrystal (CNC) thermoplastic urethane nanocomposite filaments which can subsequently be printed using a fused filament fabrication (FFF) machine.

4:30 pm – 5:00 pm:
Structure and Property Relationships of Additively Manufactured Polyphenylene Sulfide with Carbon Fiber Reinforcement

Peng Liu, Oak Ridge National Laboratory
The objective of this work is to investigate the microstructure of carbon fiber (CF) reinforced polyphenylene sulfide (PPS) resulted from extrusion-based large-scale additive manufacturing (AM) process. This study attempts to establish a fundamental understanding on the role of AM process in transferring a set of intrinsic material properties to the macroscopic properties of the final part. Questions on development of morphology focus on polymer crystal orientation and carbon fiber alignment in proximity to the interface of successive layers. Our findings demonstrated that PPS at the interface has lower crystal perfectness compared to the layer region; the carbon fiber shows higher level of preferred orientation at the interface. Successive layers along the building z-direction present lower storage modulus as it is demonstrated in the dynamic mechanical analysis (DMA).

5:00 pm – 5:30 pm:
Strength Analysis of Fused Filament Fabricated Continuous Carbon Fiber Composite Test Samples

Rogelio Herrera, University of Wisconsin – Madison
With the use of the Ansys® Workbook program, Markforged® Mark Two fused filament fabrication (FFF) composite samples were subjected to three-point flexural testing, using ASTM D790 standards. The results of flexural testing and the provided data of the mechanical properties of the composite materials were used to develop finite element analysis (FEA) models. The samples were composites of Markforged’s proprietary continuous carbon fiber filament and nylon filament. In comparison between the test results and the FEA models, both composite model methods and isotropic FEA modeling methods resulted in stronger and less flexible mechanical attributes if the proprietary material specifications were used. Through the development and analysis of micrograph samples of the Markforged’s carbon fiber filament (CFF), found that the CFF was only composed of 22.31% a fiber volume content (FVC). With the new FVC data, a more accurate model was possible for a limited range of flexural displacement.

5:30 pm – 6:00 pm:
Improving the Electrical Conductivity of PC/ABS Printing Filament for Fused Filament Fabrication Using Carbon Nonstructers

Nicole Hoekstra, Western Washington University
A study was conducted to show the effect of polyurethane coated carbon nanostructure (CNS) loading on the electrical volume resistance of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) blends. Formulations containing estimated 0.5, 3, 4 and 5 wt% CNSs were created using twin screw extrusion at various screw speeds and an efficient, repeatable method for characterizing electrical volume resistance was developed to compare the resistivity of manufactured samples. Screw speeds of 400 rpm, a material feed rate of 7.11 g/min and an actual CNS loading of 4 wt%, filament samples exhibited an average volume resistance of 74 ohm.

6:00 pm – 6:30 pm:
Rheological Characterization and Quality Assessment of Commercial ABS Filaments for Fused Deposition Modeling

Adam Miller, Shawnee State University
Acrylonitrile-butadiene-styrene (ABS) is the most commonly used thermoplastic used for Fused Deposition Modeling (FDM) due to its low cost and good properties. The viscoelastic behavior of five commercial ABS filaments was investigated and compared to quality features of a two-piece printed part. The results that the commercial ABS filaments differ not only with respect to viscosity, but also to relaxation time, recoverable deformation, morphology/composition, and thermal stability. Filaments with lower recoverable deformation tend to present better surface finish regardless the viscosity and relaxation time. Filaments with lower viscosities and faster relaxation times resulted in tight fit due to disproportional variations in the critical dimensions of the printed part.