Study on sink-mark and residual stress generation in a press-formed glassware from a thermal engineering viewpoint

摘要

This paper deals with an experimental study on the generation of sink-mark and residual stress in a press formed glassware. Since both phenomena appear in the cooling process after pressing, it is considered that they were related with the growth of solidification layer on the press-formed surface. In this paper, the generation of sink-mark and residual stress were examined qualitatively by estimating the deformation and stress of the solidification layer; the solidification layer was determined from the temperature distribution within the press-formed glass, and was assumed to be an elastic body. The obtained results can be summarized as follows: (1) With elongating the pressing duration, both the sink-mark depth and the compressive residual stress at the pressed surface decreases. (2) The compressive residual stress at the pressed surface consists of the thermal tempering stress and the bending stress of the solidification layer. (3) Contribution of the bending stress of the solidification layer to the residual stress becomes evident when the thickness of the solidification layer is about 0.5mm.