Imang Eko Saputro, Intan Mardiono, Chun-Nan Lin, Marlon Ho, Ching-Shiang Tzeng, Yiin-Kuen Fuh
Products with high-dimensional precision are expected in medical devices. This study identified severe defects in AA7075 curve cutter stapler products underscoring the necessity for modifications in the near-net shape forging process. To address this issue, finite element method (FEM)-based numerical simulations were employed to analyze material flow during the forging process. A novel aspect of this analysis involved the integration of hot processing map analysis (PMA) of material into a numerical model to assess material flow performance. Based on the numerical results of instability criterion, controlled deformation zone (CDZ) was implemented in the preform shape design of the workpiece and optimized using a response surface methodology (RSM). The aim was to mitigate the observed massive unstable material flow, particularly in the area around the rectangular hole. Through this methodology, an optimal preform design was proposed and successfully improved material flow in the critical areas, shown by decreasing Garfield values to less than 0.30 and increasing instability values to be in the range of 0.70–1.30 in all whole areas of the final product. Experimental observations employing microstructure examination and 3D scan overlaying method validated this improvement, where previous defects were no longer observed in the final product and the grain microstructure became finer and more uniform. This study demonstrated a novel strategy for generating preform design in the hot forging process and was successfully implemented in an actual case of an industrial product. © King Fahd University of Petroleum & Minerals 2025.
Department of Mechanical Engineering, National Central University, No.300, Zhongda Road, Zhongli District, Taoyuan County, 320317, Taiwan; INTAI Industrial Co., Ltd., Taichung City, Taiwan; Industrial Engineering Study Program, Institut Teknologi Sumatera, Terusan Ryacudu Street, South Lampung, Bandar Lampung, 35365, Indonesia