【正文】 s 1–3, 26 May 2020, Pages 247–251 10th International Conference on Advances in Materials and Processing Technologies — AMPT 2020 Die design for stamping a notebook case with magnesium alloy sheets ? HengKuang Tsai, ? ChienChin Liao, ? FuhKuo Chen , ? Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan, ROC ? Available online 8 December 2020. ? How to Cite or Link Using DOI ? Permissions amp。 Reprints Abstract In the present study, the stamping process for manufacturing a notebook top cover case with LZ91 magnesium–lithium alloy sheet at room temperature was examined using both the experimental approach and the finite element analysis. A fouroperation stamping process was developed to eliminate both the fracture and wrinkle defects occurred in the stamping process of the top cover case. In order to validate the finite element analysis, an actual fouroperation stamping process was 7 conducted with the use of mm thick LZ91 sheet as the blank. A good agreement in the thickness distribution at various locations between the experimental data and the finite element results confirmed the accuracy and efficiency of the finite element analysis. The superior formability of LZ91 sheet at room temperature was also demonstrated in the present study by successful manufacturing of the notebook top cover case. The proposed fouroperation process lends itself to an efficient approach to form the hinge in the notebook with less number of operational procedures than that required in the current practice. It also confirms that the notebook cover cases can be produced with LZ91 magnesium alloy sheet by the stamping process. It provides an alternative to the electronics industry in the application of magnesium alloys. Keywords ? Notebook case。 ? LZ91 magnesium–lithium alloy sheet。 ? Multioperation stamping。 ? Formability 1. Introduction Due to its lightweight and good performance in EMI resistance, magnesium alloy has been widely used for structural ponents in the electronics industry, such as cellular phones and notebook cases. Although the prevailing manufacturing process of magnesium alloy products has been die casting, the stamping of magnesium alloy sheet has drawn interests from industry because of its petitive productivity and performance in the effective production of thinwalled structural ponents. As for stamping process, AZ31 magnesium alloy (aluminum 3%, zinc 1%) sheet has been monly used for the forming process at the present time, even though it needs to be formed at elevated temperature due to its hexagonal closedpacked (HCP) crystal structure ( [Chen et al., 2020] and [Chen and Huang, 2020]). Recently, the magnesium–lithium (LZ) alloy has also been successfully developed to improve the formability of magnesium alloy at room temperature. The ductility of magnesium alloy can be improved with the addition of lithium that develops the formation of body centeredcubic (BCC) crystal structure ( [Takuda et al., 1999a], [Takuda et al., 1999b] and [Drozd et al., 2020]). In the present study, the stamping process of a notebook top cover case with the use of LZ sheet was examined. The forming of the two hinges in the top cover of a notebook, as shown in Fig. 1(a and b), is the most difficult operation in the stamping process due to the small distance between the flanges and the small corner radii at the flanges, as displayed in Fig. 1(c). This geometric plexity was caused by a dramatic change in the corner radius when the flange of hinge gets too close to the edge of the 8 notebook, which would easily cause fracture defect around the flange of hinge and require a multioperation stamping process to overe this problem. In the present study, the formability of LZ magnesium alloy sheets was investigated and an optimum multioperation stamping process was developed to reduce the number