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3D sand printing (3DSP) is a comparatively new additive manufacturing (AM) technology which has opened new opportunities for the sand-casting industry. Complex parts with intricate features that were inaccessible through the traditional mold and core making process and would take significant lead time to production can be now easily manufactured using 3DSP technology. Previous studies through numerical modeling have revealed that novel 3D riser geometries offer significant advantages during solidification of the casting by providing higher solidification time, less macro-porosity, and less piping inside the riser. This current study focuses on the experimental validation of the numerical study. Nine different riser geometries were printed as cores using 3DSP which were later installed in a larger sand mold accommodating the rigging (sprue, runners, ingates). Three novel riser shapes (ellipsoid, spherical and fusion) and one traditional cylindrical riser were explored in this study. The spherical risers were studied to understand the effect of the novel riser shape on the neck region. With three repetitions of each design (total of nine designs), a total of 27 castings were manufactured and characterized for statistical analysis. ASTM A216 WCB (wrought carbon steel, grade B) alloy was used to pour all the molds. Results from the ultrasonic tests, flexural test, and X-ray CT inspection show strong agreement with the previous FEA analysis along with 45 % yield improvement, 32 % reduction in riser neck diameter and increased mechanical strength.
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Toward Reducing Casting Defects via 3D Risers via 3D Sand-Printing: A Simulation Study
Abstract The 3D sand printing (3DSP) process is a binder jetting class of additive manufacturing process that can incorporate complex 3D mold designs and consolidate cores with intricate features that were previously inaccessible. Prior studies in 3DSP mold design have been shown to improve pouring and filling conditions for sand casting. However, the opportunity to improve casting quality by exploring 3D riser designs during the solidification stage has not yet been explored. In this research, three novel 3D riser geometries—ellipsoid, spherical, and a fusion riser (combination of cylindrical and ellipsoid riser) were investigated. The results were compared to the benchmark cylindrical risers to assess casting performance (e.g., reduction in shrinkage porosity, increase in solidification time). Computational solidification simulations have been presented to evaluate the characteristics of the novel risers for three different metal alloys- nickel aluminum bronze (NAB), low-carbon steel A216 (WCB), and aluminum alloy (A319) alloy. From the results of this research, spherical risers were found to provide 45% yield improvement of for the three alloys studied. In addition, the riser neck diameter using a spherical riser experienced up to 77% reduction when compared to the recommended dimensions from previous literature. Finally, one of the spherical riser designs provided 18% improvement in terms of riser-pipe safety height over the benchmark design. Findings from this research will help metalcasting industries to optimize their riser designs for complex casting geometries by implementing 3D riser geometries (via 3DSP) into traditional mold making for yield improvement and defect-free castings.
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- Award ID(s):
- 1944120
- PAR ID:
- 10507339
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- International Journal of Metalcasting
- Volume:
- 19
- Issue:
- 2
- ISSN:
- 1939-5981
- Format(s):
- Medium: X Size: p. 876-889
- Size(s):
- p. 876-889
- Sponsoring Org:
- National Science Foundation
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