U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Jonathan Seppala (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 73

Online Measurement for Parameter Discovery in Fused Filament Fabrication

April 3, 2024
Author(s)
Jake Read, Jonathan Seppala, Filippos Tourlomousis, James Warren, Nicole Bakker, Neil Gershenfeld
Abstract To describe a new method for the automatic generation of process parameters for fused filament fabrication (FFF) across varying machines and materials. We use an instrumented extruder to fit a function that maps nozzle pressures across varying

Characterization of Die-Swell in Thermoplastic Material Extrusion

July 5, 2023
Author(s)
Austin Colon, David Kazmer, Amy Peterson, Jonathan Seppala
Die-swell is a flow effect that occurs in polymer extrusion whereby the material experiences rapid stress and dimensional changes upon exiting the nozzle orifice. Material extrusion additive manufacturing is no exception, and this effect influences the

Steady Melting in Material Extrusion Additive Manufacturing

July 5, 2023
Author(s)
Austin Colon, David Kazmer, Amy Peterson, Jonathan Seppala
Purpose One of the main causes of defects within material extrusion additive manufacturing is the non-isothermal condition in the hot end, which leads to inconsistent extrusion and weld healing. This work validates a custom hot end design intended to melt

Simulated stress mitigation strategies in embedded 3D bioprinting

August 30, 2022
Author(s)
Leanne Friedrich, Ross Gunther, Jonathan Seppala
Extrusion-based 3D bioprinting is a powerful tool for fabricating complex cell-laden constructs. Embedded Ink Writing (EIW) is an extrusion-based printing technique wherein a nozzle embedded into a support bath writes continuous filaments. Because it

Suppression of filament defects in embedded 3D printing

July 5, 2022
Author(s)
Leanne Friedrich, Ross Gunther, Jonathan Seppala
Embedded 3D printing enables the manufacture of soft, intricate structures. In the technique, a nozzle is embedded into a viscoelastic support bath and extrudes filaments or droplets. While embedded 3D printing expands the printable materials space to low

Solvent-cast 3D Printing of Biodegradable Polymer Scaffolds

October 22, 2021
Author(s)
John Tolbert, Diana Hammerstone, Nathaniel Yuchimiuk, Jonathan Seppala, Lesley Chow
Three-dimensional (3D) printing is a popular technique to fabricate scaffolds for tissue engineering because of its ability to produce complex tissue-like architectures. Scaffolds are often 3D printed using biodegradable polymers like poly(caprolactone)

Simulated filament shapes in embedded 3D printing

July 22, 2021
Author(s)
Leanne Friedrich, Jonathan Seppala
Embedded 3D printing, wherein fluid inks are extruded into a bath, has enabled the manufacture of complex, custom structures ranging from cell-laden tissue analogues to soft robotics. This method encompasses two techniques: embedded ink writing (EIW)

Fabrication of 3D Printed Hydroxyapatite Composite Scaffolds for Bone Regeneration

May 19, 2021
Author(s)
Yoontae Kim, Eun-Jin Lee, Albert Davydov, Stanislav Frakhtbeyen, Jonathan Seppala, Laurence Chow, Tagaki Shozo, Stella Alimperti
Additive biomanufacturing has been adapted in a wide variety of biomedical and tissue engineering applications, including orthopedics. The ability to print biocompatible, patient-specific geometries with controlled porosity, mechanical strength has made

Estimations of the effective Young's modulus of specimens prepared by fused filament fabrication

April 5, 2021
Author(s)
Lichen Fang, Yishu Yan, Ojaswi Agarwal, Jonathan Seppala, Kalman D. Migler, Thao D. Nguyen, Kevin Hemker, Sung Hoon Kang
The elastic response of homogeneous isotropic materials is most commonly represented by their Young's modulus (E), but geometric variability associated with additive manufacturing results in materials that are neither homogeneous nor isotropic. Here we

AMB2018-03: Benchmark Physical Property Measurements for Material Extrusion Additive Manufacturing of Polycarbonate

October 29, 2020
Author(s)
Daniel P. Cole, Frank Gardea, Todd C. Henry, Jonathan Seppala, Edward Garboczi, Kalman D. Migler, Christopher M. Shumeyko, Jeffery R. Westrich, Sara Orski, Jeffery L. Gair
Material extrusion (MatEx) is finding increasing applications in additive manufacturing of thermoplastics due to the ease of use and the ability to process disparate polymers. Since part strength is anisotropic and frequently deviates negatively with