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Stainless steel foils are extensively used in the manufacture of micro-metallic products for their excellent corrosion resistance, high mechanical strength and superior ductility. In the present work, stainless steel foils with 50 μm thickness were annealed at temperatures ranging from 750 to 1150 °C for 5 min and then cupped at drawing speeds ranging from 0.1 to 2 mm/min. The formability of metal foils was systematically investigated and the quality of drawn cups via micro deep drawing (MDD) was discussed. The results show that the total elongation of metal foils appears a gradual increase when annealing temperature rises from 750 to 950 °C. With a further increase of annealing temperature from 950 to 1150 °C, both the ultimate tensile strength and the total elongation decline sharply, while the scatter of stress increases. The results of MDD tests show that wrinkling problem becomes increasingly significant on the drawn cups whilst thickness distribution on the drawn cup mouth become quite nonuniform with the increase of drawing speed from 0.1 to 2 mm/min. Overall, optimal annealing temperature and drawing speed are obtained with the purpose of manufacturing high quality micro circular cups.

With the advantages of high utilization of raw materials, high precision and low cost, micro metallic parts produced by micro deep drawing (MDD) have been tremendously used in a variety of fields such as micro-electromechanical systems (MEMS), vehicle engineering and chemical engineering. In order to study the deformation behavior of two-layer stainless steel-copper composite foils during MDD, a series of MDD tests were performed with specimens annealed at temperatures ranging from 600 to 1000 °C. The results show that complete circular cups cannot be formed using the as-received material due to its poor formability. For the specimens annealed at 600 and 700 °C, significant wrinkling is observed on the drawn cups. Differently, few wrinkles are characterized on the drawn cups when the composite foils are annealed at temperatures ranging from 800 to 1000 °C. An optimal annealing temperature of 800 °C is obtained for the MDD of stainless steel-copper composite cups with high surface quality.