Analyzing sustainable performance on high-precision molding process of 3D ultra-thin glass for smart phone

Abstract

Ultra-thin curved (2.5D, 3D) glass is widely used in the most recently developed smartphones, and the market demand for it is steadily increasing. The high-precision ultra-thin glass molding process (UTGMP) is very important in the fabrication of high-quality 2.5D/3D ultra-thin glass for smartphones; however, the UTGMP, with its high energy consumption and low pass rate, is not considered to be environment-friendly. Therefore, in this study, the sustainability of the molding process for 3D ultra-thin glass was comprehensively investigated. First, the ultra-thin 3D glass molding process is described, including a discussion of the glass molding apparatus, and the principle of glass thermos-formation is explained. Secondly, a thermo-mechanical coupling model is proposed to study the effects of loading heat and pressure on the distributions of temperature and internal stress of ultra-thin glass. The results demonstrate that significant amounts of stress were concentrated at the edges, and in holes and slots. A series of experiments were conducted to reveal the respective effect of various UTGMP parameters on the energy consumption, pass rate, and carbon emission level of the process. Consequently, the percentage of the main effect of loading temperature on energy consumption was found to be 23.65%, whereas that of the duration of applied pressure on the pass rate was determined to be 52.48%. The optimal process parameter combinations were determined by analyzing the above-mentioned research results and subsequently implementing them in a hybrid intelligent optimization algorithm that utilizes quantum-behaved particle swarm optimization (QPSO) and a back-propagation neural network (BPNN). The algorithm revealed that energy consumption and carbon emissions can be respectively decreased by 3.39% and 3.45% at a relatively high pass rate (i.e., over 70%). Eventually, the suggested combinations for the UTGMP will be able to achieve at least 60%–76% of the pass rate, as well as consume no more than 0.756 kW⋅h/pcs to meet sustainable manufacturing requirements. Thus, this study contributes to the effective application of a high-precision glass molding process for the sustainable manufacturing of ultra-thin curved glass.