Injection molding of complex hollow products using an eco-friendly salt core technique
-
Chung-Chih Lin
and
Wu-Sheng Xu
Abstract
Molding complex hollow products with intricate contours via plastic injection molding remains a major challenge due to mold design limitations. For example, components such as plastic intake manifolds are typically molded in separate segments and subsequently assembled. Traditional sand or salt cores used in metal casting are unsuitable for injection molding because molten plastics are thousands to millions of times more viscous than molten metals. As a result, these cores are prone to fracture under high injection pressure. This study presents a novel salt core technique to overcome this constraint. The core is fabricated using a sugar-based syrup with an optimized sugar-to-salt ratio, and a balanced mix of coarse and fine salt particles to reduce voids and improve structural compactness. The method’s effectiveness is demonstrated through successful molding of a Tri-Ring connector, a part typically difficult to produce integrally. Core shift behavior was analyzed through CAE simulations and confirmed by experimental validation. The dimensional precision of the molded product was further optimized using the Taguchi method. This work highlights a sustainable and practical solution for producing complex, high-precision molded parts without assembly.
Funding source: Ministry of Science and Technology in Taiwan
Award Identifier / Grant number: 113-2221-E-150-013
-
Research ethics: Not applicable.
-
Informed consent: Not applicable.
-
Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
-
Use of Large Language Models, AI and Machine Learning Tools: None declared.
-
Conflict of interest: The authors state no conflict of interest.
-
Research funding: This research was funded by the Ministry of Science and Technology in Taiwan, grant no. 113-2221-E-150-013.
-
Data availability: The data presented in this study are available on request from the corresponding author.
References
1. Lin, C. C.; Yang, C. L. A Water-Soluble Core for Manufacturing Hollow Injection-Molded Products. Polymers 2022, 14 (11), 2185. https://doi.org/10.3390/polym14112185.Search in Google Scholar PubMed PubMed Central
2. Boos, D.; Zaremba, S.; Drechsler, K. Viability of Flax Fiber-Reinforced Salt Cores for Aluminum High-Pressure Die Casting in Experiment and Simulation. Inter. Metalcast. 2024, 19, 2269–2298; https://doi.org/10.1007/s40962-024-01461-y.Search in Google Scholar
3. Jelínek, P.; Adámková, E.; Mikšovský, F.; Beňo, J. Advances in Technology of Soluble Cores for Die Castings. Arch. Foundry Eng. 2015, 15 (2), 29–32; https://doi.org/10.1515/afe-2015-0032.Search in Google Scholar
4. Gong, X.; Liu, X.; Chen, Z.; Yang, Z.; Jiang, W.; Fan, Z. 3D Printing of High-Strength Water-Soluble Salt Cores Via Material Extrusion. Int. J. Adv. Manuf. Technol. 2022, 118, 2993–3003. https://doi.org/10.1007/s00170-021-08131-x.Search in Google Scholar
5. Tu, S.; Liu, F.; Li, G.; Jiang, W.; Liu, X.; Fan, Z. Fabrication and Characterization of High-Strength Water-soluble Composite Salt Core for Zinc Alloy Die Castings. Int. J. Adv. Manuf. Technol. 2018, 95, 505–512. https://doi.org/10.1007/s00170-017-1208-y.Search in Google Scholar
6. Liu, X.; Liu, W.; Wang, X.; Song, L.; Xin, F. H.; Li, Y. M. Composition Optimization and Strengthening Mechanism of High-Strength Composite Water-soluble Salt Core for Foundry. Int. J. Metalcast. 2022, 16, 1809–1816. https://doi.org/10.1007/s40962-021-00725-1.Search in Google Scholar
7. Zhang, F. K.; Lin, Y.; Huang, Y. X.; Zhang, Z. W.; Wu, J. A.; Du, L. S. Forming Characteristics of Channel-Section CFRP-Aluminum Hybrid Profiles Manufactured by Inflatable Mandrel-assisted Hot-Pressing Process Dissolution. Compos. Struct. 2022, 296, 115895. https://doi.org/10.1016/j.compstruct.2022.115895.Search in Google Scholar
8. Egmond Plastic. Fusible-Core Technology for Complex Hollow Polymer Parts; Aerospace & Defense Technology Magazine: Egmond aan den Hoef, The Netherlands, 2015. https://www.egmondplastic.nl.Search in Google Scholar
9. Martin, C.; Sofia, A.; Zhang, B.; Nunes, S. S.; Radisic, M. Fusible Core Molding for the Fabrication of Branched, Perfusable, Three-Dimensional Microvessels for Vascular Tissue Engineering. Int. J. Artif. Organs. 2013, 36 (3), 159–165. https://doi.org/10.5301/ijao.5000179.Search in Google Scholar PubMed
10. Kim, D. Effect of Adjusting for Particle-Size Distribution of Cement on Strength Development of Concrete. Adv. Mater. Sci. Eng. 2018, 1763524; https://doi.org/10.1155/2018/1763524.Search in Google Scholar
11. Meddah, M. S.; Zitouni, S.; Belâabes, S. Effect of Content and Particle Size Distribution of Coarse Aggregate on the Compressive Strength of Concrete. Constr. Build. Mater. 2010, 24 (4), 505–512. https://doi.org/10.1016/j.conbuildmat.2009.10.009.Search in Google Scholar
12. Pan, L.; Li, X.; Zhang, Y.; Han, F.; Zibibula, A.; Zhu, Z. Study on Salt Dissolution Law of High Salinity Reservoir and Its Influence on Fracturing. Processes 2023, 11 (2), 304. https://doi.org/10.3390/pr11020304.Search in Google Scholar
13. Autodesk. Moldflow Plastic Injection and Compression Mold Simulation; Autodesk, 2024. https://www.autodesk.com.tw/products/moldflow/overview.Search in Google Scholar
14. Tang, S. H.; Tan, Y. J.; Sapuan, S. M.; Samin, R.; Ismail, N. The Use of the Taguchi Method in the Design of Plastic Injection Mould for Reducing Warpage. J. Mater. Process. Technol. 2007, 182 (1–3), 418–426. https://doi.org/10.1016/j.jmatprotec.2006.08.025.Search in Google Scholar
15. Cao, Z.M.; Wu, Y.; Han, J. Roundness Deviation Evaluation Method Based on Statistical Analysis of Local Least Square Circles. Meas. Sci. Technol. 2017, 28, 105017. https://doi.org/10.1088/1361-6501/aa770f.Search in Google Scholar
© 2025 Walter de Gruyter GmbH, Berlin/Boston
