Abstract
A new forming process for fabricating silica glass plates, called Cylinder Spreading Method has been successfully developed. It is found theoretically and experimentally that a glass cylinder, which is cut a slit in parallel with its axial direction and horizontally placed on a flat holder with the slit upwards, can be spread towards a plate under the gravity at an elevated temperature. The forming process shows such fast forming speed and good stability that no active force and no tool is used expect the gravity force and a simple guide tip to prevent upward slit from rolling on the holder at the beginning stage of the spreading deformation. The cylinder spreading method is of industrially practical use for making silica glass plates, especially for making a larger size plate, nevertheless edge areas of the spread plate remain a curvature due to the decreasing driving force of bending moment in the last stage of the spreading deformation. For thin-walled cylinder, a cylinder spreading mechanics can be deried under a coordinate system transformation from the real space and time to cylinder spreading space and time which is expressed by corresponding dimensionless quantity. The characterization of cylinder spreading then can be identically realized with the cylinder spreading coordinate system. The mechanics is verified by finite element analysis.
