Three- or four-roller hydraulic bending machines are often used to manufacture tanks. Developments in the market have led to rolling lengths of 6 metres or more.

This has increased production capacity. The machines do not limit manufacture because they are low-maintenance, with a failure rate close to zero.

With the latest CNC numerical control systems, even the trickiest shapes are easy to create: ellipse, rounded square, oblique ferrules, cones.

This shortens the set-up time.