Abstract
The development of large scale extrusion additive manufacturing systems such as the Big Area Additive Manufacturing (BAAM) system has enabled faster printing with throughput as high as 50 kg/h and the use of a variety of thermoplastics and composites with filler loading as high as 50%. The combination of high throughput and heavy reinforcements can give rise to a phenomenon known as “sharkskin” instability, which refers to extrudate surface distortions typically in the form of roughness or mattness, and is commonly observed in traditional extrusion processes. The onset of this instability depends upon the viscoelastic properties of the material and processing parameters such as throughput, shear rate, extruder die geometry, and temperature. For printed parts, such instabilities are undesirable and detrimental to mechanical properties. This work examines the effect of process parameters on the rheological properties of BAAM thermoplastics and composites to predict the occurrence of sharkskin during printing.
| Original language | English |
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| Pages | 1696-1704 |
| Number of pages | 9 |
| State | Published - 2020 |
| Event | 28th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2017 - Austin, United States Duration: Aug 7 2017 → Aug 9 2017 |
Conference
| Conference | 28th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2017 |
|---|---|
| Country/Territory | United States |
| City | Austin |
| Period | 08/7/17 → 08/9/17 |
Funding
Research sponsored in part by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office, under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The authors gratefully acknowledge Arkema Inc. for providing the materials used in this study. The authors also thank Ernest Rivera for his assistance with the experimental work.