Gravity bending is a thermal glass bending process that is used in the automotive industry for example. This process is used to produce laminated safety glass. The lamination is done by joining two sheets of glass using a film as an interlayer.
In this process, the glass sheet is conveyed onto the bending tool or mould and subjected to heat treatment in a special facility called a gravity bending furnace. Due to the change in viscosity, i.e. the degree of its viscosity, the effect of gravity and its own weight, the glass sheet literally falls into the bending mould and the desired shape or geometry is achieved
In press bending, which is a horizontal process, the glass sheets are transported on roller tables through the furnace chamber and heated to bending temperature. They are given their desired shape or geometry with the aid of a punch consisting of a male die (positive) and a female die (negative). This process represents the state of the art in glass bending technology and makes it possible to achieve any desired shape of the pane precisely due to the lowest bending tolerances.
In another variant of glass bending, the panes are suspended vertically on an edge by means of several tongs and thus pass through the gravity bending furnace. Following this thermal procedure, the panes are formed into the desired shape, analogous to the press-bending process.
Industrial furnace types used
Gravity bending furnace →