A method for forming a hollow cylinder, in a single step, into a quartz glass tube with a large outer diameter and high dimensional stability is provided. To produce the tube, the cylinder, while rotating, is softened in portions in a heating zone which is moved at a relative feed rate Va and the softened portion is radially expanded by a centrifugal force and/or internal overpressure applied in the hollow cylinder bore so as to form a deformation zone. The radial expansion of the softened portion is carried out at a location-dependent radial expansion rate Vr, the profile of which along the deformation zone has a maximum value Vr,max which is smaller than 20 cm/min. The temperature in a rear heating portion of the heating zone, assigned to the end of the deformation zone, is lower than in a front heating portion assigned to the beginning of the deformation zone.

An apparatus for the automated production of glass assemblies includes: a turning machine with at least two spindles, which are rotatable about a common axis of rotation and which each have a workpiece holder, wherein the workpiece holders are arranged opposite one another; one or more gas burners or lasers fixed on a first tool carriage which is movable in parallel and/or perpendicularly to the axis of rotation; one or more drives for driving a rotational movement of the spindles and a movement of the first tool carriage; a pressure module including a pump device at least one working cylinder for applying a pressure to an inner tube and/or to a space between the inner tube and an outer tube; and a control unit configured to control the burners or lasers, one or more drives, the first tool carriage and the pressure module.

An apparatus for the automated production of glass assemblies includes: a turning machine with at least two spindles, which are rotatable about a common axis of rotation and which each have a workpiece holder, wherein the workpiece holders are arranged opposite one another; one or more gas burners or lasers fixed on a first tool carriage which is movable in parallel and/or perpendicularly to the axis of rotation; one or more drives for driving a rotational movement of the spindles and a movement of the first tool carriage; a pressure module including a pump device at least one working cylinder for applying a pressure to an inner tube and/or to a space between the inner tube and an outer tube; and a control unit configured to control the burners or lasers, one or more drives, the first tool carriage and the pressure module.