Numerical optimisation of blowing glass parison shapes

Industrial glass blowing is an essential stage of manufacturing glass containers, i.e. bottles or jars. An initial glass preform is brought into a mould and subsequently blown into the mould shape. Over the last few decades, a wide range of numerical models for forward glass blow process simulation have been developed. A considerable challenge is the inverse problem: to determine an optimal preform from the desired container shape. A simulation model for blowing glass containers based on finite element methods has previously been developed [6, 7]. This model uses level set methods to track the glass-air interfaces. In previous work of the authors [8] a numerical method was introduced for optimising the shape of the preform. The optimisation method aims at minimising the error in the level set representing the inner container surface. The objective of this paper is to perform an in-depth study of the optimisation method previously introduced and to improve its performance. In particular an initial guess of the preform for the iterative optimisation algorithm is constructed by means of an analytical approximation of the flow problem. The emphasis in this paper is on the analysis of the inverse problem and the development of the optimisation method in consideration of the application to containers of industrial relevance.