{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T12:58:23Z","timestamp":1776776303541,"version":"3.51.2"},"reference-count":46,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T00:00:00Z","timestamp":1776729600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Dispensing-based in situ casting offers a practical route for introducing dense or mechanically distinct polymer regions into fused deposition modeling (FDM) parts during fabrication. This study investigates the curing-dependent process constraints governing stable integration of in situ casting within an FDM workflow. In the proposed process, FDM is used to fabricate thermoplastic confinement geometries, after which liquid polymer is dispensed into selected cavities and cured before printing resumes. Two representative curing systems were examined: a UV-curable photopolymer and a two-component epoxy resin. The experimental program included UV curing characterization under perpendicular 405 nm exposure, infrared thermal imaging of curing-induced heat generation and dissipation, confined curing of epoxy resin, layer-wise integration within an FDM-printed cavity, and a representative mechanical linkage demonstration. The results show that UV-based in situ casting is constrained by the coupled effects of curing depth, peak temperature, and visible deformation, making staged curing with intermediate thermal relaxation necessary for stable operation. In contrast, the epoxy system enabled bulk cavity filling with lower peak temperature, but required substantially longer curing time, introducing a different process limitation. A layer-wise UV curing strategy enabled successful stacking of four cast layers within an FDM-printed confinement without visible leakage or shell collapse. Mechanical testing of hybrid linkage specimens further showed that localized casting can modify structural stiffness through selective reinforcement. These findings demonstrate that dispensing-based in situ casting can be integrated into FDM when thermal, temporal, and filling constraints are explicitly managed, and they provide practical process guidance for hybrid polymer fabrication involving confined casting during printing.<\/jats:p>","DOI":"10.3390\/polym18081003","type":"journal-article","created":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T11:42:45Z","timestamp":1776771765000},"page":"1003","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["In Situ Casting Integrated with FDM 3D Printing: Curing Behavior, Process Constraints, and Mechanical Demonstration"],"prefix":"10.3390","volume":"18","author":[{"given":"Supatpromrungsee","family":"Saetia","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pimolkan","family":"Piankitrungreang","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0409-3860","authenticated-orcid":false,"given":"Ratchatin","family":"Chancharoen","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand"},{"name":"Human-Robot Collaboration and Systems Integration Research Unit, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zhou, L., Miller, J., Vezza, J., Mayster, M., Raffay, M., Justice, Q., Al Tamimi, Z., Hansotte, G., Sunkara, L.D., and Bernat, J. (2024). Additive Manufacturing: A Comprehensive Review. Sensors, 24.","DOI":"10.3390\/s24092668"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e2522951","DOI":"10.1080\/17452759.2025.2522951","article-title":"Advances in interlayer bonding in fused deposition modelling: A comprehensive review","volume":"20","author":"Omer","year":"2025","journal-title":"Virtual Phys. Prototyp."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"532","DOI":"10.1039\/D5MH01403D","article-title":"Additive manufacturing of polymers and composites for applications in aerospace and aeronautics","volume":"13","author":"Aliberti","year":"2025","journal-title":"Mater. Horiz."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1007\/s40964-017-0032-0","article-title":"Strengthening of plasma treated 3D printed ABS through epoxy infiltration","volume":"2","author":"Zaldivar","year":"2017","journal-title":"Prog. Addit. Manuf."},{"key":"ref_5","first-page":"60","article-title":"Embedding electronics in 3D printed structures by combining fused filament fabrication and supersonic cluster beam deposition","volume":"24","author":"Bellacicca","year":"2018","journal-title":"Addit. Manuf."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Freitas, B., Richhariya, V., Silva, M., Vaz, A., Lopes, S.F., and Carvalho, \u00d3 (2025). A Review of Hybrid Manufacturing: Integrating Subtractive and Additive Manufacturing. Materials, 18.","DOI":"10.3390\/ma18184249"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Raz, K., Chval, Z., Hula, F., and Markopoulos, A. (2025). Surface Treatment and Analysis of 3D-Printed Plastic Molds for Prototype and Small-Series Injection Molding. Polymers, 17.","DOI":"10.3390\/polym17222977"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Carta, M., Loi, G., El Mehtedi, M., Buonadonna, P., and Aymerich, F. (2025). Improving Surface Roughness of FDM-Printed Parts Through CNC Machining: A Brief Review. J. Compos. Sci., 9.","DOI":"10.3390\/jcs9060296"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1007\/s00170-021-07173-5","article-title":"Additive, subtractive, and formative manufacturing of metal components: A life cycle assessment comparison","volume":"115","author":"DeBoer","year":"2021","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_10","first-page":"101658","article-title":"Fused filament fabrication of polymer materials: A review of interlayer bond","volume":"37","author":"Gao","year":"2021","journal-title":"Addit. Manuf."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Wickramasinghe, S., Do, T., and Tran, P. (2020). FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments. Polymers, 12.","DOI":"10.3390\/polym12071529"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"987","DOI":"10.1007\/s00170-023-11566-z","article-title":"Surface roughness of as-printed polymers: A comprehensive review","volume":"127","author":"Golhin","year":"2023","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_13","unstructured":"Pinilla, M., Kao, J.-h., and Prinz, F. (1998, January 10\u201312). Process Planning and Automation for Additive-Subtractive Solid Freeform Fabrication. Proceedings of the Solid Freeform Fabrication Symposium, Austin, TX, USA."},{"key":"ref_14","first-page":"100224","article-title":"Additive manufacturing: Shaping the future of the manufacturing industry\u2014Overview of trends, challenges and opportunities","volume":"22","author":"Klenam","year":"2025","journal-title":"Appl. Eng. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"107718","DOI":"10.1016\/j.polymertesting.2022.107718","article-title":"A review of current advancements in high surface quality injection molding: Measurement, influencing factors, prediction, and control","volume":"115","author":"Gim","year":"2022","journal-title":"Polym. Test."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1038\/s44334-025-00023-2","article-title":"Material and surface roughness effects on adhesion of thermoplastic-elastomeric interfaces for dissimilar material 3D printing","volume":"2","author":"Donoughue","year":"2025","journal-title":"npj Adv. Manuf."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"593","DOI":"10.1021\/acsapm.8b00165","article-title":"Photopolymerization in 3D Printing","volume":"1","author":"Bagheri","year":"2019","journal-title":"ACS Appl. Polym. Mater."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"B\u00e1rtolo, P. (2011). Stereolithography: Materials, Processes and Applications, Springer.","DOI":"10.1007\/978-0-387-92904-0"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Hozdi\u0107, E. (2024). Characterization and Comparative Analysis of Mechanical Parameters of FDM- and SLA-Printed ABS Materials. Appl. Sci., 14.","DOI":"10.3390\/app14020649"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2417609","DOI":"10.1002\/adma.202417609","article-title":"Hybrid Formative-Additive Manufacturing","volume":"37","author":"Brown","year":"2025","journal-title":"Adv. Mater."},{"key":"ref_21","first-page":"390","article-title":"A methodology for near net shape process feasibility assessment","volume":"5","author":"Marini","year":"2017","journal-title":"Prod. Manuf. Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1038\/s43246-021-00211-5","article-title":"Cavity vat photopolymerisation for additive manufacturing of polymer-composite 3D objects","volume":"2","author":"Bachmann","year":"2021","journal-title":"Commun. Mater."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1038\/s44431-025-00006-5","article-title":"Non-planar additive manufacturing with hydrogels: A review of flow control and toolpath strategies","volume":"1","author":"Mirzaali","year":"2025","journal-title":"npj Soft Matter"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"107466","DOI":"10.1016\/j.porgcoat.2023.107466","article-title":"Shrinkage stress of thermal cured epoxy resin reduced by addition of functional hollow microspheres","volume":"178","author":"Sun","year":"2023","journal-title":"Prog. Org. Coat."},{"key":"ref_25","first-page":"102408","article-title":"Water-soluble sacrificial 3D printed molds for fast prototyping in ceramic injection molding","volume":"48","author":"Tschamper","year":"2021","journal-title":"Addit. Manuf."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Prajapati, S., Sharma, J.K., Kumar, S., Pandey, S., and Pandey, M.K. (2024). A review on comparison of physical and mechanical properties of PLA, ABS, TPU, and PETG manufactured engineering components by using fused deposition modelling. Mater. Today Proc.","DOI":"10.1016\/j.matpr.2024.05.018"},{"key":"ref_27","unstructured":"Rajesh, K.D., Ganesh, N., Reddy, S.Y.K., Mishra, H., and Naidu, T.M.T. (2023). Experimental research on the mechanical characteristics of fused deposition modelled ABS, PLA and PETG specimens printed in 3D. Mater. Today Proc."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2000509","DOI":"10.1002\/admt.202000509","article-title":"3D Printing of Core\u2013Shell Capsule Composites for Post-Reactive and Damage Sensing Applications","volume":"5","author":"Rupp","year":"2020","journal-title":"Adv. Mater. Technol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"e2553180","DOI":"10.1080\/17452759.2025.2553180","article-title":"Rapid in-situ thermal curing 3D printing of engineering thermosetting resins","volume":"20","author":"Yang","year":"2025","journal-title":"Virtual Phys. Prototyp."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"110671","DOI":"10.1016\/j.compositesb.2023.110671","article-title":"Additive manufacturing of continuously reinforced thermally curable thermoset composites with rapid interlayer curing","volume":"257","author":"Deng","year":"2023","journal-title":"Compos. Part B Eng."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Y\u00fcceer, \u00d6.M., \u00d6zt\u00fcrk, E.K., \u00c7i\u00e7ek, E.S., Akta\u015f, N., and G\u00fcng\u00f6r, M.B. (2025). Three-Dimensional-Printed Photopolymer Resin Materials: A Narrative Review on Their Production Techniques and Applications in Dentistry. Polymers, 17.","DOI":"10.3390\/polym17030316"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Tulcan, A., Vasilescu, M.D., and Tulcan, L. (2021). Comparative Study of the Influence of Bio-Resin Color on the Dimension, Flatness and Straightness of the Part in the 3D Printing Process. Polymers, 13.","DOI":"10.3390\/polym13091412"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Li, S., Shi, Z., Wang, Y., Wang, W., and He, R. (2025). The 3D Printing of Flexible Materials: Technologies, Materials, and Challenges. Materials, 18.","DOI":"10.3390\/ma18235428"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"108761","DOI":"10.1016\/j.polymertesting.2025.108761","article-title":"Epoxy composites reinforced with nanomaterials and fibres: Manufacturing, properties, and applications","volume":"146","author":"Parvizi","year":"2025","journal-title":"Polym. Test."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Hao, J., Yang, K., Wu, J., Wu, M., and Li, Y. (2025). Overview of Recent Developments in Composite Epoxy Resin in Organic Coating on Steel (2020\u20132024). Materials, 18.","DOI":"10.3390\/ma18071531"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Chancharoen, R., Sithiwichankit, C., Chaiprabha, K., Suthithanakom, S., and Phanomchoeng, G. (2025). Observer-Based Volumetric Flow Control in Nonlinear Electro-Pneumatic Extrusion Actuator with Rheological Dynamics. Actuators, 14.","DOI":"10.3390\/act14100496"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Ning, F., Shi, Y., Cai, M., Wang, Y., and Xu, W. (2017). Research Progress of Related Technologies of Electric-Pneumatic Pressure Proportional Valves. Appl. Sci., 7.","DOI":"10.3390\/app7101074"},{"key":"ref_38","first-page":"e214-8","article-title":"The use of ultraviolet LED illumination for composite resin removal: An in vitro study","volume":"58","author":"Bush","year":"2010","journal-title":"Gen. Dent."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Stiles, A., Tison, T.-A., Pruitt, L., and Vaidya, U. (2022). Photoinitiator Selection and Concentration in Photopolymer Formulations towards Large-Format Additive Manufacturing. Polymers, 14.","DOI":"10.3390\/polym14132708"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"567","DOI":"10.37256\/sce.5220245325","article-title":"Insight into the Bouguer-Beer-Lambert Law: A review","volume":"5","author":"Kiteto","year":"2024","journal-title":"Sustain. Chem. Eng."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"16694","DOI":"10.1021\/acsami.2c02076","article-title":"3D Printing of Short-Carbon-Fiber-Reinforced Thermoset Polymer Composites via Frontal Polymerization","volume":"14","author":"Ziaee","year":"2022","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Jiang, F., and Drummer, D. (2022). Analysis of UV Curing Strategy on Reaction Heat Control and Part Accuracy for Additive Manufacturing. Polymers, 14.","DOI":"10.3390\/polym14040759"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"7180","DOI":"10.1021\/acs.analchem.0c04944","article-title":"PDMS Curing Inhibition on 3D-Printed Molds: Why? Also, How to Avoid It?","volume":"93","author":"Venzac","year":"2021","journal-title":"Anal. Chem."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"11343","DOI":"10.1007\/s40964-025-01290-3","article-title":"Toward a hybrid material extrusion technique: Exploring the benefits of integrating fused deposition modeling and material injection","volume":"10","author":"Katbeh","year":"2025","journal-title":"Prog. Addit. Manuf."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"110902","DOI":"10.1016\/j.polymdegradstab.2024.110902","article-title":"The thermal properties of FDM printed polymeric materials: A review","volume":"228","author":"Shanmugam","year":"2024","journal-title":"Polym. Degrad. Stab."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1080\/17452759.2021.1917039","article-title":"Post-processing treatments to enhance additively manufactured polymeric parts: A review","volume":"16","author":"Tamburrino","year":"2021","journal-title":"Virtual Phys. Prototyp."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/8\/1003\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T12:06:25Z","timestamp":1776773185000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/8\/1003"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,21]]},"references-count":46,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["polym18081003"],"URL":"https:\/\/doi.org\/10.3390\/polym18081003","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,21]]}}}