Abstract
Additively manufactured parts made with polymer extrusion techniques can be 50–75 % weaker in the z-direction (across layers) than in the x- and y-directions. This has been attributed to poor mobility of polymer chains and a low degree of entanglement across a cold deposition interface. This is particularly a challenge when printing large-scale parts, such as with the Big Area Additive Manufacturing (BAAM) system, because layer times can exceed several minutes. The current work presents a method for controlling the temperature of the substrate material on the BAAM just prior to deposition using infrared heating lamps. Long layer times were also simulated by actively cooling the material following deposition of each layer. The effect of substrate temperature on the z-direction mechanical properties of 20 % carbon fiber reinforced acrylonitrile butadiene styrene (ABS) was measured for an initial temperature ranging from 50 °C to 150 °C and a preheated temperature ranging from 150 °C to 220 °C. Infrared preheating proved to be very effective when applied to substrates that had cooled considerably, almost doubling the tensile strength and increasing the fracture toughness by a factor of 7x.
Original language | English |
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Article number | 101068 |
Journal | Additive Manufacturing |
Volume | 33 |
DOIs | |
State | Published - May 2020 |
Funding
The authors acknowledge Dr. Donald Erdman at Oak Ridge National Laboratory for the use of mechanical testing facilities, Techmer ES for providing materials for this work, and Dakota Cauthen for assisting with statistical analysis. 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. Notice of Copyright 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, world-wide 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-public-access-plan ). The authors acknowledge Dr. Donald Erdman at Oak Ridge National Laboratory for the use of mechanical testing facilities, Techmer ES for providing materials for this work, and Dakota Cauthen for assisting with statistical analysis. 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.
Keywords
- Additive Manufacturing
- Fracture toughness
- Infrared heating
- Large-scale printing
- Mechanical properties
- Tensile strength