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Search Publications by: Jonathan Seppala (Fed)

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Displaying 26 - 50 of 73

Effects of Environmental Temperature and Humidity on the Geometry and Strength of Polycarbonate Specimens Prepared by Fused Filament Fabrication

October 3, 2020
Author(s)
Lichen Fang, Yan Yishu, Ojaswi Agarwal, shengyu Yao, Jonathan Seppala, Sung Hoon Kang
It is widely known that the printing quality of fused filament fabrication (FFF) is heavily affected by environmental temperature and humidity, as the case of warping and porosity. However, there is little understanding about the quantitative relations

3D printed optical concentrators for LED arrays

July 19, 2020
Author(s)
Behrang H. Hamadani, Jonathan E. Seppala, Clarence J. Zarobila
Additive manufacturing methods based on photopolymerization offer a great potential for fabrication of high quality, highly transparent optical components. One appropriate use of these technologies is related to fabrication of parts that can be used in

Outcomes and Conclusions from the 2018 AM-Bench Measurements, Challenge Problems, Modeling Submissions, and Conference

February 13, 2020
Author(s)
Lyle E. Levine, Brandon M. Lane, Jarred C. Heigel, Kalman D. Migler, Mark R. Stoudt, Thien Q. Phan, Richard E. Ricker, Maria Strantza, Michael R. Hill, Fan Zhang, Jonathan E. Seppala, Edward J. Garboczi, Erich D. Bain, Daniel Cole, Andrew J. Allen, Jason C. Fox, Carelyn E. Campbell
The Additive Manufacturing Benchmark Test Series (AM-Bench) was established to provide rigorous measurement test data for validating additive manufacturing (AM) simulations for a broad range of AM technologies and material systems. AM-Bench includes

Compressive deformation analysis of large area pellet-fed material extrusion 3D printed parts in relation to in situ thermal imaging*

February 8, 2020
Author(s)
Eduardo M. Trejo, Xavier Jimenez, Kazi M. Billah, Jonathan Seppala, Ryan Wicker, David Esplain
In large area pellet extrusion additive manufacturing, the temperature of the substrate just before the deposition of a new subsequent layer affects the overall structure of the part. Warping and cracking occur if the substrate temperature is below a

Measuring & Predicting Crystal Morphology in Fused Deposition Modeling

June 19, 2019
Author(s)
Claire McIlroy, Jonathan Seppala, Anthony Kotula
Semi-crystalline polymer melts are commonly used in fused deposition modeling. Although flows have a profound effect on polymer crystallization, the relationship between typical fused deposition modeling (FDM) deformation rates and printed-part crystal

Polymer Additive Manufacturing: Confronting Complexity

June 19, 2019
Author(s)
Anthony P. Kotula, Jonathan E. Seppala, Chad R. Snyder
Since its development and commercialization in the 1980s, polymer additive manufacturing (AM) has become a disruptive technology. In this chapter we describe the ever-increasing demands for polymer AM in industry, academia, and government, as well as the

Preface

June 19, 2019
Author(s)
Jonathan E. Seppala, Anthony P. Kotula, Chad R. Snyder

Weld formation during material extrusion additive manufacturing

August 11, 2017
Author(s)
Jonathan E. Seppala, Seung Hoon Han, Kaitlyn E. Hillgartner, Chelsea S. Davis, Kalman D. Migler
Material extrusion (ME) is a layer-by-layer additive manufacturing process that is now used in personal and commercial production where prototyping and customization are required. However, parts produced from ME frequently exhibit poor mechanical