Optimal Process Design in High-Precision Glass Forming
The focus of the present study is the optimal process design for high precision glass forming and in particular, the question we wish to address is, "How to design the mould and the temperature regime so that at the very end of the forming process we will get at room temperature a prescribed glass geometry with a precision in the order of the Micron?". The aim is to reduce and possibly eliminate completely from the manufacturing process the costly and timeconsuming post-processing stage (grinding, polishing) when the final shape does not precisely conform to the desired one. The adopted method first tackles the optimization of the cooling curve in order to reduce the residual stresses in the glass piece below an admissible threshold while keeping the processing time as low as possible. After this first optimization stage, the deformations are mostly produced by thermal strains and the identification of the required initial geometry before cooling (mould geometry) is eased. An intuitive yet very efficient iterative algorithm is presented to tackle this second problem.
Glass Forming, Viscoelasticity, Finite Element Method, Stress Relaxation, Structural Relaxation, Optimization.