{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T12:59:59Z","timestamp":1770814799615,"version":"3.50.1"},"reference-count":22,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T00:00:00Z","timestamp":1770768000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>This study explores the feasibility of using polyurethane (PU) elastomer as a flexible punch-filling medium in cold forming. Microforming processes encounter challenges such as size effects and friction effects, which can lead to defects including fractures, distortions, and central depressions. The proposed method incorporates a high-hardness PU plate (95A) with excellent elasticity and near-incompressibility to address these issues. By compensating for axial compression through lateral expansion, the PU plate distributes pressure uniformly, reduces central stress, mitigates central acceleration effects, and minimizes defects caused by velocity gradients. Experiments and simulations using aluminum alloy Al 1050-O demonstrate that the PU-assisted extrusion\u2013cutting process improves material flow, redistributes forming pressure, and enhances forming stability compared to conventional methods. This approach shows significant potential for advancing microforming technologies, particularly in industries requiring high-precision components.<\/jats:p>","DOI":"10.3390\/mi17020230","type":"journal-article","created":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T09:15:12Z","timestamp":1770801312000},"page":"230","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Exploring Polyurethane Elastomers as Flexible Punch Media for Microforming Applications: A Case Study of Extrusion\u2013Cutting Process"],"prefix":"10.3390","volume":"17","author":[{"given":"Chia-Ling","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Maritime Police, Central Police University, Taoyuan City 333322, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chuan-Hsiang","family":"Chang","sequence":"additional","affiliation":[{"name":"Department of Marine Engineering, National Taiwan Ocean University, No.2 Beining Road, Zhongzheng District, Keelung City 20224, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kuo-Ming","family":"Huang","sequence":"additional","affiliation":[{"name":"Research Center of Material Processing and Measurement, Department of Marine Engineering, National Taiwan Ocean University, No.2 Beining Road, Zhongzheng District, Keelung City 20224, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"289","DOI":"10.1115\/1.4009977","article-title":"Press-Forging Thin Sections: Effect of Friction, Area, and Thickness on Pressures Required","volume":"16","author":"Schroeder","year":"1949","journal-title":"J. Appl. Mech."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4799","DOI":"10.1016\/j.msea.2011.03.005","article-title":"Size Effect on Material Surface Deformation Behavior in Micro-Forming Process","volume":"528","author":"Deng","year":"2011","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1795","DOI":"10.1007\/s11663-020-01858-0","article-title":"Fluidity of Alloys Under High-Pressure Die Casting Conditions: Flow-Choking Mechanisms","volume":"51","author":"Han","year":"2020","journal-title":"Metall. Mater. Trans. B"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1016\/S0924-0136(03)00515-6","article-title":"New Processes to Prevent a Flow Defect in the Combined Forward\u2013Backward Cold Extrusion of a Piston-Pin","volume":"139","author":"Kim","year":"2003","journal-title":"J. Mater. Process. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Kumar, S. (2021). Plastic Deformation Behavior in Steels during Metal Forming Processes: A Review. Material Flow Analysis, IntechOpen.","DOI":"10.5772\/intechopen.97607"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1015","DOI":"10.1007\/s00170-014-6701-y","article-title":"A Novel Fine-Blanking Approach","volume":"78","author":"Wang","year":"2015","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1733","DOI":"10.1007\/s00170-015-8277-6","article-title":"Fine Extrusion Device Approach","volume":"86","author":"Wang","year":"2016","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1016\/S0921-5093(99)00248-8","article-title":"Equal Channel Angular Extrusion: From Macromechanics to Structure Formation","volume":"271","author":"Segal","year":"1999","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1501","DOI":"10.2320\/matertrans.MT-L2025009","article-title":"Strengthening of Aluminum Alloys Using Severe Plastic Deformation","volume":"66","author":"Horita","year":"2025","journal-title":"Mater. Trans."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Dwiyati, S.T., Kiswanto, G., and Supriadi, S. (2023). Grain Refinement of Pure Magnesium for Microforming Application. J. Manuf. Mater. Process., 7.","DOI":"10.3390\/jmmp7040140"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1233","DOI":"10.1007\/s00170-024-14016-6","article-title":"Novel Method of Extrusion Cutting for Refining Grain Size with a Movable Material Container","volume":"134","author":"Huang","year":"2024","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1007\/s00170-022-10383-0","article-title":"Improvement of Product Quality Using Negative Clearance Grooved Punch","volume":"125","author":"Huang","year":"2023","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Hsu, M.-H., Huang, K.-M., Chang, C.-H., and Liu, C.-P. (2024). The Stamping Method Utilizing a Double-Trough Die in Microforming to Enhance Formability. Micromachines, 15.","DOI":"10.3390\/mi15070922"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1016\/j.cirp.2015.04.130","article-title":"Evaluation of Lubricants Without Zinc Phosphate Precoat in Multi-Stage Cold Forging","volume":"64","author":"Wang","year":"2015","journal-title":"CIRP Ann. Manuf. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"475","DOI":"10.1016\/0257-8972(95)02498-0","article-title":"Wear and Friction Properties of Hard PVD Coatings","volume":"76\u201377","author":"Bienk","year":"1995","journal-title":"Surf. Coat. Technol."},{"key":"ref_16","first-page":"1420","article-title":"Investigation on the Forming Mechanism and Process Optimization of Micro-Extrusion","volume":"27","author":"Zhang","year":"2020","journal-title":"Mech. Adv. Mater. Struct."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1016\/S0261-3069(00)00088-1","article-title":"A Numerical and Experimental Approach to Optimise Plate Stamping Technologies: Part II\u2014Aluminium Alloys Rubber-Forming","volume":"22","author":"Sala","year":"2001","journal-title":"Mater. Des."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1097","DOI":"10.1007\/s00170-021-06658-7","article-title":"Numerical Simulation Analysis of Rubber Flexible Die Properties on Forming Quality of the Double-Curved Part for 6K21-T4 Aluminum Alloy","volume":"113","author":"Zhang","year":"2021","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1839","DOI":"10.1007\/s00170-017-0278-1","article-title":"Numerical Investigation of the Forming Capability of Bulge Process by Using Rubber as a Forming Medium","volume":"92","author":"Koubaa","year":"2017","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Prisacariu, C. (2011). Polyurethane Elastomers: From Morphology to Mechanical Aspects, Springer.","DOI":"10.1007\/978-3-7091-0514-6"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"817","DOI":"10.1016\/j.mechmat.2004.08.001","article-title":"Stress\u2013Strain Behavior of Thermoplastic Polyurethanes","volume":"37","author":"Qi","year":"2005","journal-title":"Mech. Mater."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Drobny, J.G. (2014). Handbook of Thermoplastic Elastomers, William Andrew Publishing. [2nd ed.].","DOI":"10.1016\/B978-0-323-22136-8.00012-0"}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/2\/230\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T09:33:40Z","timestamp":1770802420000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/2\/230"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,11]]},"references-count":22,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["mi17020230"],"URL":"https:\/\/doi.org\/10.3390\/mi17020230","relation":{},"ISSN":["2072-666X"],"issn-type":[{"value":"2072-666X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,11]]}}}