Tube bending machines

Rapidity, precision and safety for the tube bending machines

Duplomatic has been supplying hydraulic systems for tube bending machines for several years.

Since the ‘70s when the machine bending cycles were realized with hydraulic sequence valves, the system has been undergoing a constant evolution with the introduction of the first open loop proportional valves (mainly used to control the bending speed) up to the current circuits assembled using servovalves equipped with integrated electronics and operated by numerical control systems with an interactive three-dimensional graphics programming. Every need for a technical development aimed at improving the machine performances has been met by Duplomatic with a series of top ranking components suitable to satisfy the requirements of the tube processing market.

The tube deforming machines equipped with hydraulic circuits are mainly used to bend and end form big diameter thick tubes.

Thanks to their advanced performances the bending machines of the “8” series can bend tubes with diameters from 4 up to 80 mm.; the bending speed can reach 220°/sec with a bending tolerance of ± 0.1 °.

Particular attention is paid to the bending function which, as shown by the above stated values, requires precision and speed combined with high acceleration. The natural consequence is the need for modern proportional valves operated by custom-made electronic controls.

The hydraulic movements, which are common to all kinds of tube bending machines, are tube traction, bending with speed and position control, core extraction, blocking, lifting, die change and pliers.
Each function has a dedicated circuit developed directly through the cooperation with the technicians of the customer company after a series of lab tests performed on prototypes.

As far as the circuit is concerned, the tube end forming machines are less demanding because they are exclusively equipped with open loop proportional valves and on-off components. Anyway, they must be fast and precise in order to increase the per hour production (the main factor in the choice of the machine type).

A basic element common to all kinds of machines is the search for the operator highest safety. For this reason the circuits have been recently equipped with monitored electrovalves performing a “cut-off” function during the most dangerous sequences carried out by the operator, i.e. machine manual adjustment or maintenance.