Abstract
Anisotropy of mechanical properties is characteristic of components printed using processes like extrusion deposition additive manufacturing, wherein the properties along the print direction (x-direction) are superior when compared to the corresponding properties in the build direction (z-direction). This effect, influenced by the bond strength in the z-direction, can be more pronounced for components with longer layer times, as the bottom layers tend cool below the glass transition temperature (Tg) of the material, thereby restricting thermal fusion between the printed layers. The work discussed here builds on the previous work by the authors, demonstrating infrared preheating as a technique to actively control the bond temperature during printing to improve the mechanical properties (z-direction) of parts printed on a large-format extrusion AM system. IR preheating was used on the surface of printed layers just prior to the deposition of the next layer to increase the surface temperature closer to the glass transition temperature. The current study explores the effect of variation in bead surface temperatures (indicative of variations in layer times) prior to and after pre-heating on the mechanical properties in z-direction.
| Original language | English |
|---|---|
| Pages | 1576-1582 |
| Number of pages | 7 |
| State | Published - 2019 |
| Event | 30th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2019 - Austin, United States Duration: Aug 12 2019 → Aug 14 2019 |
Conference
| Conference | 30th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2019 |
|---|---|
| Country/Territory | United States |
| City | Austin |
| Period | 08/12/19 → 08/14/19 |
Funding
The authors gratefully acknowledge Dr. Donald Erdman at Oak Ridge National Laboratory for the use of lab facilities for mechanical testing and Techmer ES for providing the materials used in this work. Research was sponsored 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. Extrusion deposition additive manufacturing, the process where the feed material is melted and deposited layer-by-layer on a build platform, is now being used to print components using a variety of polymers and composite materials on print platforms with build volumes ranging from ~ 10 cm3 up to ~130 m3 [1, 2]. Despite several advancements in the development of new materials and printers based on this process, one of the challenges that still exists is the inability to obtain printed components with isotropic mechanical properties [3-5]. There exists a certain level of This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-publicaccess-plan).
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | |
| Advanced Manufacturing Office | DE-AC05-00OR22725 |
| Office of Energy Efficiency and Renewable Energy |
