Additive Manufacturing Benchmarks 2022 (AM-Bench 2022): Melt-Pool Scale III
Program Organizers: Brandon Lane, National Institute of Standards and Technology; Lyle Levine, National Institute of Standards and Technology
Thursday 10:30 AM
August 18, 2022
Room: Old Georgetown Room
Location: Hyatt Regency Bethesda
Session Chair: Brodan Richter, National Aeronautics and Space Administration
10:30 AM Invited
Cross-sectional Melt Pool Geometry of Laser-Scanned Tracks and Pads for the 2022 Additive Manufacturing Benchmark Challenges: Jordan Weaver1; D Deisenroth2; S Mekhontsev2; B Lane2; L Levine2; 1National Institute of Standard and Technology; 2National Institute of Standards and Technology
Single track and pad laser scans on bare plates continue to be a valuable experiment for AM model validation. To this end, the AMB2022-03 benchmark explores a range of individual and overlapping melt pool behaviors using individual laser tracks and 2D arrays (pads) of laser tracks on solid metal IN718 plate. Single track laser scans were created with several combinations of laser power, scan speed, and spot diameter. Two 2.5 mm × 5 mm pad scans were created by scanning the laser in the ±X-direction and ±Y-direction. Single tracks and pads were cross-sectioned perpendicular to the laser track direction and metallographically prepared for optical microscopy. The cross-sectional melt pool dimensions (depth and width) were measured in the center of single-tracks and at multiple locations in pad scans. The measurement results will be presented and compared with anonymized challenge submission results from modelers to show the relative accuracy or trends in the models.
11:00 AM Invited
AM-CFD: a Well-validated Thermal-fluid Simulator for Additive Manufacturing Part Qualification: Wing Liu1; 1Northwestern University
Critical additively manufactured (AM) parts must be formally qualified prior to use. We have developed an in-house software,AM-CFD, for AM process simulation and rapid part qualification. AM-CFD focuses on melt pool scale and thus can accurately capture melt pool geometries and thermal-fluid dynamics, which are critical features for predicting lack-of-fusion porosity, microstructure, and resulting mechanical properties. AM-CFD can simulate numerous cases in parallel and search for the optimal process condition enabling additively manufactured parts with fine-grained microstructures and favorable mechanical properties. To validate the AM-CFD, blind benchmark tests have been independently conducted by National Institute of Standards and Technology (NIST) and Air Force Research Laboratory (AFRL). Our AM-CFD won three 1st place prizes in the NIST AM-Bench (2018) and identified as Top Performer in AFRL AM Modeling Challenge Series (2020). The AM-CFD is very flexible and can be linked with other optimizers for materials design and engineering optimization.
11:30 AM
On-line Melt Pool and Microstructure Sensing of Powder Bed Fusion Grade 91 Stainless Steel: Nathan Kizer1; Christopher Kube1; Abdalla Nassar1; Edward Reutzel1; Corey Dickman1; 1Penn State University
Research into on-line techniques for monitoring metallic additive manufacturing (AM) processes and parts continues to grow. The demand for on-line monitoring stems partially from the need to better understand the thermophysical processes leading to high quality parts. Additionally, moving quality control procedures on-line potentially shortens the amount of time required to adopt the part into a functional system.<br><br>This presentation reports on recent progress of integrating ultrasonic sensors into a powder bed fusion system. The integration was accomplished through redesigning the build substrate to incorporate an array of sensors. The sensor array allows for several AM parts to be monitored during builds. The ultrasonic system was used for on-line monitoring of powder bed fusion Gr91 stainless steel parts. The presentation will highlight measurement results of (1) melt pool dynamics during the first several build layers and (2) sensing microstructure differences amongst multiple parts being built with different processing parameters.
11:50 AM
(On-Demand) A High Fidelity Melt Pool Dynamics Model with Experimental Validation Results Against NIST Benchmark AMB2018-2: Kyung-min Hong1; Corbin Grohol1; Yung Shin1; 1Purdue University
This presentation covers the high fidelity welding model developed to study the melt-pool dynamics with the consideration of relevant physics and laser beam absorption via multiple reflections in the keyhole using ray tracing. The high-fidelity welding model accounts for the effects of phase change, recoil pressure, and energy loss in the form of latent heat. The transport phenomena in both the condensed (solid and liquid) and non-condensed regions (metallic vapor and ambient gas) are calculated by the governing equations of mass, momentum, and energy, coupled with the conservation equation of chemical species. The simulated results of molten pool shapes and cooling rates are compared with various other predictive modeling results for the NIST benchmark AMB2018-02 with and without keyhole formation. Based on the predicted cooling rate distribution around the molten pool, microstructure morphologies are predicted and compared against corresponding experimental results.