Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength
Parts made through additive manufacturing (AM) often exhibit mechanical anisotropy due to the time-based deposition of material and processing parameters. In polymer material extrusion (MEX), printed parts have weak points at layer interfaces, perpendicular to the direction of deposition. Poly(lacti...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-03-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/17/7/1526 |
| _version_ | 1797212327691419648 |
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| author | Lucinda K. Slattery Zackery B. McClelland Samuel T. Hess |
| author_facet | Lucinda K. Slattery Zackery B. McClelland Samuel T. Hess |
| author_sort | Lucinda K. Slattery |
| collection | DOAJ |
| description | Parts made through additive manufacturing (AM) often exhibit mechanical anisotropy due to the time-based deposition of material and processing parameters. In polymer material extrusion (MEX), printed parts have weak points at layer interfaces, perpendicular to the direction of deposition. Poly(lactic acid) with chopped carbon fiber was printed on a large-format pellet printer at various extrusion rates with the same tool pathing to measure the fiber alignment with deposition via two methods and relate it to the ultimate tensile strength (UTS). Within a singular printed bead, an X-ray microscopy (XRM) scan was conducted to produce a reconstruction of the internal microstructure and 3D object data on the length and orientation of fibers. From the scan, discrete images were used in an image analysis technique to determine the fiber alignment to deposition without 3D object data on each fiber’s size. Both the object method and the discrete image method showed a negative relationship between the extrusion rate and fiber alignment, with −34.64% and −53.43% alignment per extrusion multiplier, respectively, as the slopes of the linear regression. Tensile testing was conducted to determine the correlation between the fiber alignment and UTS. For all extrusion rates tested, as the extrusion multiplier increased, the percent difference in the UTS decreased, to a minimum of 8.12 ± 14.40%. The use of image analysis for the determination of the fiber alignment provides a possible method for relating the microstructure to the meso-property of AM parts, and the relationship between the microstructure and the properties establishes process–structure–property relationships for large-format AM. |
| first_indexed | 2024-04-24T10:40:38Z |
| format | Article |
| id | doaj.art-e6eef88822144b778259dbb00eae9050 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-04-24T10:40:38Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-e6eef88822144b778259dbb00eae90502024-04-12T13:21:54ZengMDPI AGMaterials1996-19442024-03-01177152610.3390/ma17071526Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile StrengthLucinda K. Slattery0Zackery B. McClelland1Samuel T. Hess2Engineer Research and Development Center, U.S. Army Corps of Engineers, 3909 Halls Ferry Road, Vicksburg, MS 39180, USAEngineer Research and Development Center, U.S. Army Corps of Engineers, 3909 Halls Ferry Road, Vicksburg, MS 39180, USADepartment of Physics and Astronomy, University of Maine, 5709 Bennett Hall, Orono, ME 04469, USAParts made through additive manufacturing (AM) often exhibit mechanical anisotropy due to the time-based deposition of material and processing parameters. In polymer material extrusion (MEX), printed parts have weak points at layer interfaces, perpendicular to the direction of deposition. Poly(lactic acid) with chopped carbon fiber was printed on a large-format pellet printer at various extrusion rates with the same tool pathing to measure the fiber alignment with deposition via two methods and relate it to the ultimate tensile strength (UTS). Within a singular printed bead, an X-ray microscopy (XRM) scan was conducted to produce a reconstruction of the internal microstructure and 3D object data on the length and orientation of fibers. From the scan, discrete images were used in an image analysis technique to determine the fiber alignment to deposition without 3D object data on each fiber’s size. Both the object method and the discrete image method showed a negative relationship between the extrusion rate and fiber alignment, with −34.64% and −53.43% alignment per extrusion multiplier, respectively, as the slopes of the linear regression. Tensile testing was conducted to determine the correlation between the fiber alignment and UTS. For all extrusion rates tested, as the extrusion multiplier increased, the percent difference in the UTS decreased, to a minimum of 8.12 ± 14.40%. The use of image analysis for the determination of the fiber alignment provides a possible method for relating the microstructure to the meso-property of AM parts, and the relationship between the microstructure and the properties establishes process–structure–property relationships for large-format AM.https://www.mdpi.com/1996-1944/17/7/1526additive manufacturingmaterial extrusionX-ray microscopymicrostructurefiber alignmentthermoplastic |
| spellingShingle | Lucinda K. Slattery Zackery B. McClelland Samuel T. Hess Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength Materials additive manufacturing material extrusion X-ray microscopy microstructure fiber alignment thermoplastic |
| title | Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength |
| title_full | Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength |
| title_fullStr | Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength |
| title_full_unstemmed | Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength |
| title_short | Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength |
| title_sort | process structure property relationship development in large format additive manufacturing fiber alignment and ultimate tensile strength |
| topic | additive manufacturing material extrusion X-ray microscopy microstructure fiber alignment thermoplastic |
| url | https://www.mdpi.com/1996-1944/17/7/1526 |
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