Sheng-Chan Lee, Sukhoiri Khoiruddin, Zih-Siang Hung, Yu-Hao Pan, Cheng-Fu Huang, Chien-Wei Chan, Yiin-Kuen Fuh
The manufacturing of thin-walled 316L stainless steel manifold components via investment casting remains challenging due to their high susceptibility to shrinkage porosity and distortion during solidification. This study presents a systematic optimization of the investment casting process for a 316L stainless steel manifold used in liquid-cooling systems, integrating numerical simulation with experimental validation. Six tree assembly configurations were initially evaluated, from which two representative designs (Cases 4 and 5) were selected for detailed investigation. A combined approach incorporating filling and solidification simulation, Niyama criterion analysis, and experimental verification was employed to identify defect-prone regions and elucidate the mechanisms governing shrinkage formation and distortion. The results show that shrinkage porosity is primarily concentrated in thick–thin transition zones and side-hole regions, where thermal hot spots and insufficient feeding conditions dominate. Distortion is mainly driven by non-uniform thermal gradients and constrained solidification, leading to uneven residual stress distribution and bending deformation. To mitigate these issues, a two-stage optimization strategy was developed, involving the introduction of pre-cast holes and targeted gate redesign. The results demonstrate that shrinkage porosity is reduced from approximately 70–45% after geometric modification, and eliminated after gate optimization through improved feeding and directional solidification. Additionally, distortion is significantly reduced, with maximum deformation decreased by 30–40% and dimensional deviations maintained within machining tolerances. Among all configurations, Case 4 exhibits the most favorable performance among the evaluated configurations, with no shrinkage defects detected in the functional region of the inspected castings, the lowest distortion, and the most consistent dimensional results among the configurations tested. The main contribution of this work is the development of an integrated design–simulation–validation framework that quantitatively links geometry, feeding behavior, and thermal evolution to defect formation. The key innovation lies in the combined geometric–gating optimization strategy, enabling simultaneous control of shrinkage porosity and distortion in thin-walled casting systems. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2026.
Department of Mechanical Engineering, Zhongli District, National Central University, No. 300, Zhongda Road, Taoyuan City, 320317, Taiwan; GlobalTek Fabrication Co., Ltd., Xinwu Factory, Taoyuan City, 327001, Taiwan; Department of Mechanical Engineering, Vocational Studies, State University of Surabaya, Prof. Moch Yamin Street, Ketintang District, Surabaya City, 60231, Indonesia
