{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,24]],"date-time":"2025-12-24T05:16:54Z","timestamp":1766553414542,"version":"3.48.0"},"reference-count":18,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T00:00:00Z","timestamp":1766361600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100020595","name":"National Science and Technology Council of Taiwan","doi-asserted-by":"crossref","award":["113-2622-E-212-002"],"award-info":[{"award-number":["113-2622-E-212-002"]}],"id":[{"id":"10.13039\/100020595","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Henghau Enterprise Company"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>This study optimized the punch-assisted demolding technique for the separation of contact lenses, incorporating finite-element analysis to evaluate the effects of punch geometry (punch material: 304L stainless steel) on the stress and strain distributions of polypropylene lens molds. The simulation results revealed that the punch surface featured a flat base with a central arc-shaped groove (groove diameter: 7 mm, depth: 0.75 mm), which exhibited optimal stress dispersion characteristics during the demolding process, effectively reducing mold deformation. Experimental validation over 100 demolding cycles confirmed that the use of the aforementioned punch resulted in the manufactured lens having high central stability and reduced van der Waals forces during demolding, allowing smoother lens release and facilitating improved demolding performance. Comprehensive evaluation based on defect inspection and centering stability indicated that a yield of 82% was achieved with the optimized punch, with this yield being 13% higher than that obtained with a flat punch lacking an arc groove (69%). These results indicate that the optimized punch design not only reduces development costs but also enhances manufacturing yield and throughput, demonstrating strong potential for application in contact lens production.<\/jats:p>","DOI":"10.3390\/mi17010010","type":"journal-article","created":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T11:43:31Z","timestamp":1766403811000},"page":"10","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effect of Punch Geometry on Stress and Strain Distribution During Contact Lens Demolding"],"prefix":"10.3390","volume":"17","author":[{"given":"Ching-Mu","family":"Cheng","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, Da-Yeh University, Changhua 515006, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yun-Shao","family":"Cho","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Da-Yeh University, Changhua 515006, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tieh-Fei","family":"Cheng","sequence":"additional","affiliation":[{"name":"Henghau Enterprise Company Limited, Hsinchu 303117, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jui-Yu","family":"Wang","sequence":"additional","affiliation":[{"name":"Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology, Yunlin 640301, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4812-0875","authenticated-orcid":false,"given":"Jung-Jie","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Information Engineering, Asia University, Taichung 413305, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"204","DOI":"10.1097\/OPX.0000000000001873","article-title":"Long-term effect of dual-focus contact lenses on myopia progression in children: A 6-year multicenter clinical trial","volume":"99","author":"Chamberlain","year":"2022","journal-title":"Optom. Vis. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"5475","DOI":"10.1038\/s41598-023-32700-7","article-title":"Long-term myopia control effect and safety in children wearing DIMS spectacle lenses for 6 years","volume":"13","author":"Lam","year":"2023","journal-title":"Sci. Rep."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Whayeb, Y., Wolffsohn, J.S., Logan, N.S., and Rubido, J.S. (2025). IMI-global trends in myopia management attitudes and strategies in clinical practice\u2014A nine-year review. 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Mater."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1557\/S0883769400033868","article-title":"History of vision correction: Contact and intraocular lenses","volume":"22","author":"Selinger","year":"1997","journal-title":"MRS Bull."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"834","DOI":"10.1097\/00006324-198912000-00006","article-title":"Symptomatology of HEMA contact lens wear","volume":"66","author":"Brennan","year":"1989","journal-title":"Optom. Vis. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1111\/j.1747-1567.2012.00819.x","article-title":"On-line force measurement to monitor contact lens polymerization","volume":"38","author":"Tucker","year":"2014","journal-title":"Exp. Tech."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"104","DOI":"10.4028\/www.scientific.net\/KEM.699.104","article-title":"Demolding moment calculation for injected parts with internal trapezoidal thread","volume":"699","author":"Negrean","year":"2016","journal-title":"Key Eng. Mater."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Wang, Y., Weng, C., Sun, H., Deng, Z., and Jiang, B. (2022). Effect of interfacial interaction on the demolding deformation of injection molded microfluidic chips. Nanomaterials, 12.","DOI":"10.3390\/nano12193416"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1002\/jab.770030406","article-title":"The surface treatment of polypropylene molds and its effect on the quality of cast contact lenses","volume":"3","year":"1992","journal-title":"J. Appl. Biomater."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"042001","DOI":"10.1088\/2399-7532\/ac1e7d","article-title":"Multifunctionality as design principle for contact lens materials","volume":"4","author":"Sahabudeen","year":"2021","journal-title":"Multifunct. Mater."},{"key":"ref_13","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_14","doi-asserted-by":"crossref","first-page":"109807","DOI":"10.1016\/j.matdes.2021.109807","article-title":"Effects of punch geometry and grain size in micron scale compression molding of copper","volume":"206","author":"Zhang","year":"2021","journal-title":"Mater. Des."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1007\/s00170-019-03746-7","article-title":"Determination of the effective geometrical features of the piercing punch for polymer composite belts","volume":"104","author":"Wojtkowiak","year":"2019","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Gaikwad, A., and Desai, S. (2021). Molecular dynamics investigation of the deformation mechanism of gold with variations in mold profiles during nanoimprinting. Materials, 14.","DOI":"10.3390\/ma14102548"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/j.finel.2019.07.002","article-title":"Inverse design based on nonlinear thermoelastic material models applied to injection molding","volume":"165","author":"Zwicke","year":"2019","journal-title":"Finite Elem. Anal. Des."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Zhang, Y., You, K., and Fang, F. (2020). 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