Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn Equation
In binder jetting (BJ), an ink is inserted layerwise into a powder bed to selectively bond the particles in the cross-section of a part. By predicting the penetration depth of the ink, the ideal layer thickness for BJ can be set. Each layer should be penetrated with ink. Insufficient penetration wil...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-09-01
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| Series: | Journal of Manufacturing and Materials Processing |
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| Online Access: | https://www.mdpi.com/2504-4494/6/5/101 |
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| author | Maja Lehmann Hannes Panzer Cara G. Kolb Michael F. Zaeh |
| author_facet | Maja Lehmann Hannes Panzer Cara G. Kolb Michael F. Zaeh |
| author_sort | Maja Lehmann |
| collection | DOAJ |
| description | In binder jetting (BJ), an ink is inserted layerwise into a powder bed to selectively bond the particles in the cross-section of a part. By predicting the penetration depth of the ink, the ideal layer thickness for BJ can be set. Each layer should be penetrated with ink. Insufficient penetration will result in a poor layer bond and a low strength of the part; over-penetration will impede a dimensionally accurate production, as the ink will leak from the sides of the part and unintentionally solidify the powder in these areas. The Washburn equation has been used for the calculation of the penetration depth in various fields, such as hydrology or with loose powders. However, a transfer to the BJ process is difficult due to the preferably compact powder bed and the fine particles. In more compact powder beds, the small radii with their greater capillary pressure and their distribution in the layer have a high influence on the penetration depth. This work shows an adaptation of the Washburn equation for powder beds in BJ and a new approach to determine the effective pore radius for calculating the penetration depth. A weighted pore radius was introduced, which accounts for the spatial distribution of the pores in the powder bed and the acting capillary pressure. The validation was performed with two different powders by experimentally simulating the BJ process through the infiltration of a drop into a powder bed. The weighted radius was used in the Washburn equation to calculate the penetration depth. The results were compared with those models from the literature and experimental data, and a good agreement between the calculation and the experiment was found. |
| first_indexed | 2024-03-09T20:02:09Z |
| format | Article |
| id | doaj.art-a6451c218bc34bceafcd615ad7d15635 |
| institution | Directory Open Access Journal |
| issn | 2504-4494 |
| language | English |
| last_indexed | 2024-03-09T20:02:09Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Manufacturing and Materials Processing |
| spelling | doaj.art-a6451c218bc34bceafcd615ad7d156352023-11-24T00:42:14ZengMDPI AGJournal of Manufacturing and Materials Processing2504-44942022-09-016510110.3390/jmmp6050101Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn EquationMaja Lehmann0Hannes Panzer1Cara G. Kolb2Michael F. Zaeh3Institute for Machine Tools and Industrial Management, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, GermanyInstitute for Machine Tools and Industrial Management, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, GermanyInstitute for Machine Tools and Industrial Management, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, GermanyInstitute for Machine Tools and Industrial Management, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, GermanyIn binder jetting (BJ), an ink is inserted layerwise into a powder bed to selectively bond the particles in the cross-section of a part. By predicting the penetration depth of the ink, the ideal layer thickness for BJ can be set. Each layer should be penetrated with ink. Insufficient penetration will result in a poor layer bond and a low strength of the part; over-penetration will impede a dimensionally accurate production, as the ink will leak from the sides of the part and unintentionally solidify the powder in these areas. The Washburn equation has been used for the calculation of the penetration depth in various fields, such as hydrology or with loose powders. However, a transfer to the BJ process is difficult due to the preferably compact powder bed and the fine particles. In more compact powder beds, the small radii with their greater capillary pressure and their distribution in the layer have a high influence on the penetration depth. This work shows an adaptation of the Washburn equation for powder beds in BJ and a new approach to determine the effective pore radius for calculating the penetration depth. A weighted pore radius was introduced, which accounts for the spatial distribution of the pores in the powder bed and the acting capillary pressure. The validation was performed with two different powders by experimentally simulating the BJ process through the infiltration of a drop into a powder bed. The weighted radius was used in the Washburn equation to calculate the penetration depth. The results were compared with those models from the literature and experimental data, and a good agreement between the calculation and the experiment was found.https://www.mdpi.com/2504-4494/6/5/101binder jettingpenetration depthWashburn equationpore radiusconceptual modeling |
| spellingShingle | Maja Lehmann Hannes Panzer Cara G. Kolb Michael F. Zaeh Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn Equation Journal of Manufacturing and Materials Processing binder jetting penetration depth Washburn equation pore radius conceptual modeling |
| title | Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn Equation |
| title_full | Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn Equation |
| title_fullStr | Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn Equation |
| title_full_unstemmed | Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn Equation |
| title_short | Influence of the Pore Radius on the Penetration Depth of Inks in Binder Jetting—A Modification of the Washburn Equation |
| title_sort | influence of the pore radius on the penetration depth of inks in binder jetting a modification of the washburn equation |
| topic | binder jetting penetration depth Washburn equation pore radius conceptual modeling |
| url | https://www.mdpi.com/2504-4494/6/5/101 |
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