{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:29:28Z","timestamp":1760059768529,"version":"build-2065373602"},"reference-count":25,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,7,8]],"date-time":"2025-07-08T00:00:00Z","timestamp":1751932800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Fundac\u00e3o para a Ci\u00eancia e a Tecnologia (FCT)"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Eng"],"abstract":"<jats:p>A novel forming process was developed to create rotating elements in collector coins by shaping thin-walled tubes into toroidal shells in a single stage. This process introduces new aesthetic effects and functionalities to the coin market. By controlling the end-forming of a tube, a gap is created between the toroidal shell and the coin blank, allowing free rotation. The technique, a modification of conventional tube end inversion, results in distinct deformation mechanics. Through finite element modeling and experimentation, key process variables were identified, ensuring sound hollow toroidal shells with efficient rotation.<\/jats:p>","DOI":"10.3390\/eng6070155","type":"journal-article","created":{"date-parts":[[2025,7,8]],"date-time":"2025-07-08T07:31:57Z","timestamp":1751959917000},"page":"155","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Manufacturing of Rotational Toroidal Shells in Coin Minting"],"prefix":"10.3390","volume":"6","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7170-0333","authenticated-orcid":false,"given":"Lu\u00eds M.","family":"Alves","sequence":"first","affiliation":[{"name":"IDMEC, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"given":"Paulo","family":"Alexandrino","sequence":"additional","affiliation":[{"name":"INCM, Imprensa Nacional Casa da Moeda, 1000-042 Lisboa, Portugal"}]},{"given":"S\u00f3nia","family":"Pereira","sequence":"additional","affiliation":[{"name":"INCM, Imprensa Nacional Casa da Moeda, 1000-042 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2358","DOI":"10.1177\/0954405419840566","article-title":"A new type of bi-material coin","volume":"233","author":"Afonso","year":"2019","journal-title":"Proc. IMechE Part B J. Eng. Manuf."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1115\/1.3667550","article-title":"The mechanics of the coining process","volume":"84","author":"Bocharov","year":"1962","journal-title":"J. Eng. Ind."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"100265","DOI":"10.1016\/j.jajp.2024.100265","article-title":"Joining by forming of bi-material collector coins with rotating elements","volume":"10","author":"Rosado","year":"2024","journal-title":"J. Adv. Join. Process."},{"key":"ref_4","first-page":"842","article-title":"Numerical and experimental analysis of coin minting","volume":"233","author":"Alexandrino","year":"2017","journal-title":"Proc. IMechE Part L J. Mater. Des. Appl."},{"key":"ref_5","first-page":"3","article-title":"Finite element design procedure for correcting the coining die profiles","volume":"5","author":"Alexandrino","year":"2018","journal-title":"Manuf. Rev."},{"key":"ref_6","first-page":"601","article-title":"Metal forming beyond the limits: Research and applications in incremental and hybrid technologies","volume":"69","author":"Tekkaya","year":"2020","journal-title":"CIRP Ann."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Pragana, J.P.M., Rosenthal, S., Bragan\u00e7a, I.M.F., Silva, C.M.A., Tekkaya, A.E., and Martins, P.A.F. (2020). Hybrid additive manufacturing of collector coins. J. Manuf. Mater. Process., 4.","DOI":"10.3390\/jmmp4040115"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1177\/0954405420971128","article-title":"Coin minting by additive manufacturing and forming","volume":"235","author":"Pragana","year":"2021","journal-title":"Proc. IMechE Part B J. Eng. Manuf."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/j.jmatprotec.2014.04.011","article-title":"Tube joining by asymmetric plastic instability","volume":"214","author":"Alves","year":"2014","journal-title":"J. Mater. Process. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"196","DOI":"10.1016\/j.jmatprotec.2016.11.037","article-title":"Joining tubes by internal mechanical locking","volume":"242","author":"Alves","year":"2017","journal-title":"J. Mater. Process. Technol."},{"key":"ref_11","first-page":"243","article-title":"An analysis of external inversion of round tubes","volume":"133","author":"Sekhon","year":"2003","journal-title":"J. Mech. Work. Technol."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Alves, L.M., Reis, T.J., Afonso, R.M., and Martins, P.A. (2021). Single-stroke attachment of sheets to tube ends made from dissimilar material. Materials, 14.","DOI":"10.3390\/ma14040815"},{"key":"ref_13","first-page":"689","article-title":"Forming of thin-walled tubes into toroidal shells","volume":"210","author":"Alves","year":"2010","journal-title":"J. Mech. Work. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Nielsen, C.V., Zhang, W., Alves, L.M., Bay, N., and Martins, P.A.F. (2013). Coupled Finite Element Flow Formulation. Modelling of Thermo-Electro-Mechanical Manufacturing Processes, Springer.","DOI":"10.1007\/978-1-4471-4643-8_3"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Yin, Y., Xu, J., Dong, J., Li, Y., Wang, Y., Zhong, W., and Zhang, Z. (2025). CUDA-based parallel dual-grid material point method for simulating bimetallic coining process. Comput. Part. Mech.","DOI":"10.1007\/s40571-025-00955-8"},{"key":"ref_16","first-page":"456","article-title":"Numerical simulation of metal flow in coin minting using MPM","volume":"16","author":"Zhang","year":"2023","journal-title":"Materials"},{"key":"ref_17","first-page":"107820","article-title":"A hybrid FEM\u2013MPM approach for high-accuracy modeling of axisymmetric forming processes","volume":"236","author":"Liu","year":"2023","journal-title":"Int. J. Mech. Sci."},{"key":"ref_18","first-page":"117690","article-title":"Experimental and numerical analysis of tubular component deformation using die-based forming","volume":"305","author":"Mohamed","year":"2022","journal-title":"J. Mater. Process. Technol."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Gavril\u0103, C.C., Late\u015f, M.T., and Grebeni\u015fan, G. (2024). Sustainable Approach to Metal Coin Canceling Methods, Using 3D Modeling and Finite Element Method Analysis. Sustainability, 16.","DOI":"10.3390\/su16062322"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Hartl, C. (2019). Review on Advances in Metal Micro-Tube Forming. Metals, 9.","DOI":"10.3390\/met9050542"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Suntaxi, C., Ghassemieh, E., and Roy, A. (2021). Tube expansion by single point incremental forming. Metals, 11.","DOI":"10.3390\/met11091481"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Alexandrov, S., and Lyamina, E. (2022). Analysis of strain-hardening viscoplastic wide sheets subject to bending under tension. Metals, 12.","DOI":"10.3390\/met12010118"},{"key":"ref_23","first-page":"1002","article-title":"Finite element analysis of tube hydroforming process for automotive applications","volume":"11","author":"Kumar","year":"2021","journal-title":"Metals"},{"key":"ref_24","first-page":"361","article-title":"Process simulation of tube hydroforming: Benchmarking study","volume":"125\u2013126","author":"Altan","year":"2002","journal-title":"J. Mater. Process. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Palumbo, G., Sorgente, D., and Tricarico, L. (2022). Design and manufacturing of titanium cranial prostheses via sheet metal forming. Metals, 12.","DOI":"10.3390\/met12020293"}],"container-title":["Eng"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2673-4117\/6\/7\/155\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:06:20Z","timestamp":1760033180000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2673-4117\/6\/7\/155"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,8]]},"references-count":25,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2025,7]]}},"alternative-id":["eng6070155"],"URL":"https:\/\/doi.org\/10.3390\/eng6070155","relation":{},"ISSN":["2673-4117"],"issn-type":[{"type":"electronic","value":"2673-4117"}],"subject":[],"published":{"date-parts":[[2025,7,8]]}}}