Grain Size Effects and Multi‐Stage Optimization in Sustainable Micro‐Deep Drawing of Copper Cups: An FEA and Experimental Study

ABSTRACT The demand for miniaturized metallic components in electronics, biomedical devices, and aerospace necessitates sustainable micro‐forming solutions. Conventional deep‐drawing often suffers from stage complexity, excessive die use, and size‐effect limitations. This study aims to optimize stage number, limiting drawing ratio (LDR), and diametrical reduction for sustainable fabrication of copper micro cups. Directionally rolled pure copper strips with 250% deformation (strain −3.5) and an initial thickness of 0.1895 mm were used. Finite element analysis (FEA) was performed to design multi‐stage deep‐drawing die sequences, with validation through experimental trials. Three strategies were investigated: a 4‐stage process (30% reduction per stage), a 6‐stage process (15% reduction), and an 8‐stage process (15%–10% reductions). Experimental punch load, strain distribution, and thickness profiles were compared against simulation. Results showed that while the 4‐ and 6‐stage processes failed due to thinning and fracture from reduced formability, the 8‐stage design achieved defect‐free cups with uniform wall thickness. Bidirectional rolling (BDR) yielded higher dimensional accuracy and reduced thinning compared to unidirectional rolling (UDR), as confirmed by ISO 24213 criteria. Optimizing stage number and LDR proved critical in controlling flow stress, minimizing die wear, and improving sustainability. The study focused on copper microparts of specified dimensions. Broader validation across alloys, geometries, and rolling conditions is required. The findings provide industries with a framework to reduce energy, material waste, and die consumption while ensuring micropart quality. This is the first integrated study combining grain‐size‐controlled copper blanks, FEA‐driven multistage die design, and experimental validation for sustainable micro‐deep drawing.