Paper Number
AM6 

Session
Additive Manufacturing and Composites

Title
Multi-material fused filament fabrication via core-shell die design

Presentation Date and Time
October 13, 2021 (Wednesday) 1:30

Track / Room
Track 3 / Meeting Room A-B

Authors (Click on name to view author profile)

1. Naqi, Ahmad (University of Delaware, Chemical and Biomolecular Engineering)
2. Mackay, Michael E. (University of Delaware, Materials Science and Engineering)
   Mackay, Michael E. (University of Delaware, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Ahmad Naqi¹ and Michael E. Mackay^2,1
1Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716; ²Materials Science and Engineering, University of Delaware, Newark, DE 19716

Speaker / Presenter 
Naqi, Ahmad

Keywords
experimental methods; additive manufacturing; applied rheology; composites; polymer melts

Text of Abstract
Additive manufacturing (AM), commonly referred to as 3D printing, promises avenues of rapid prototyping with enormous customization and cost savings in the development of new designs. Fused filament fabrication (FFF), also known as material extrusion (ME), is one of the emerging AM technologies that creates three dimensional objects by adding a melted polymer in a layer-by-layer manner based on computer-aided design (CAD) models. However, a key limitation for practical applications of FFF parts is the weak interlayer strength (aka, bond strength) due poor surface contact and limited molecular inter-diffusion at the interface between neighboring tracks. The use of composite core-shell filaments in FFF has shown a promising approach for increasing the extensibility and impact strength of printed objects as demonstrated by the work of Peng et al. [1]. In light of their findings, an annular coextrusion featuring a core and shell configuration has been design to fit directly into a desktop FFF machine. This new method advances the capability of FFF to extrude two different polymer melts simultaneously, using commercially available filaments, offering the advantage of producing composite filaments in a single step, which would otherwise necessitate multi-step operations. In this study polyethylene terephthalate glycol (PETG) and acrylonitrile butadiene styrene (ABS) will be used as the shell and core polymers, respectively. 3D printing results as well as mechanical testing of the printed objects will be discussed. In addition, rheological and thermal analyses are conducted to predict the development of healing over time, which is an important measure to quantify the interlayer welding quality, by using a non-isothermal healing model developed Yang and Pitchumani. References: 1. Peng, F., Jiang, H., Woods, A., Joo, P., Amis, E. J., Zacharia, N. S., & Vogt, B. D. (2019). 3D Printing with Core–Shell Filaments Containing High or Low Density Polyethylene Shells. ACS Applied Polymer Materials, 1(2), 275–285. https