Hydraulic vs Servo-Electric Press Brakes
Hydraulic and servo-electric press brakes use different systems to generate and control the bending movement, but the choice between them should be based on more than the drive system alone.
Required tonnage, working length, material thickness, component size, tooling and production requirements all need to be considered. Hydraulic press brakes are available across a particularly broad range of capacities, while servo-electric machines provide an alternative for applications that fall within their available tonnage and working length.
Understanding the differences between the two configurations helps establish which is better suited to the work being produced.
How Does a Hydraulic Press Brake Work?
A hydraulic press brake uses hydraulic cylinders to generate the force required to move the ram and form the material between the punch and die.
On a CNC synchronised hydraulic press brake, the movement of the ram is controlled through the Y1 and Y2 axes. This allows the position of each side of the ram to be controlled during the bending cycle.
Hydraulic machines are available across a wide range of tonnages and working lengths. This allows the same basic machine technology to be used for general sheet metal fabrication, longer components and considerably heavier plate work.
For applications requiring particularly long working lengths, hydraulic machines can also be configured as tandem press brakes.
How Does a Servo-Electric Press Brake Work?
A servo-electric press brake uses an electrically driven system to generate the ram movement rather than the hydraulic cylinders used on a conventional hydraulic machine.
There are different ways of transferring the servo motor movement to the ram, so servo-electric press brakes should not all be treated as mechanically identical.
For example, the MVD iBend E Series uses a belt-drive Y1+Y2 arrangement, while the MVD iBend S Series uses a ball-screw drive Y1+Y2 configuration.
The drive arrangement, available tonnage and working length therefore need to be considered when comparing individual servo-electric machines.
Hydraulic vs Servo-Electric Press Brake Capacity
One of the main differences when specifying the two machine types is the range of bending capacities available.
Hydraulic press brakes are available in considerably higher tonnages and longer working lengths, making hydraulic systems an important option where heavy plate, long components or high bending forces are involved.
Servo-electric machines generally occupy a more defined range of capacities. Where the required bending force and component dimensions fall within that range, they can be considered alongside hydraulic machines.
This is why the required bending force should be established before deciding on the drive system. Material type, material thickness, bend length, tooling and die opening all affect the tonnage required.
Our guide to choosing a press brake looks at the wider factors involved in specifying a machine.
Working Length & Component Size
Working length needs to be considered alongside tonnage.
A machine needs sufficient working length for the longest components being produced, but component dimensions can also affect throat depth, daylight, stroke and how the material is handled at the machine.
Hydraulic machines provide more options where very long working lengths are required. Tandem configurations can extend this further by operating two synchronised machines together for long components.
For smaller and medium-sized components, servo-electric machines may fall comfortably within the required working length and capacity. The decision therefore needs to be made against the actual component range rather than machine type alone.
Speed & Production Requirements
Production requirements should also form part of the comparison.
The time taken to produce a component is influenced by more than the drive system. Ram movement, bend sequence, component handling, back gauge movement, tooling setup and the number of bends all contribute to the complete cycle.
For repeat production, it is therefore more useful to consider the complete bending process than compare hydraulic and servo-electric machines using a single speed figure.
Batch sizes and the frequency of job changes should also be considered, particularly where a press brake is being specified for a mixed production environment.
Energy Use & Hydraulic Oil
The two systems have different power and maintenance requirements because of the way the bending movement is generated.
A servo-electric machine does not use the hydraulic bending system found on a conventional hydraulic press brake. This removes the hydraulic oil associated with that part of the machine and the related hydraulic components.
Energy consumption should be compared using the specifications of the actual machines being considered rather than assuming a fixed saving simply because one machine is servo-electric. Machine capacity, drive arrangement, operating cycle and production use can all affect consumption.
Maintenance Differences
Hydraulic press brakes have hydraulic components that need to be maintained as part of the machine’s service requirements. This includes the hydraulic system, oil and associated components.
Servo-electric machines replace the hydraulic bending system with mechanical and electrical drive components. Their maintenance requirements therefore differ, but they are not maintenance-free.
The drive arrangement used by the particular servo-electric machine should be taken into account when establishing its maintenance requirements.
CNC Control & Back Gauge
CNC control and back gauge configuration are important with either drive system.
The number and complexity of the components being produced, bend sequences, positioning requirements and frequency of job changes all influence the control and back gauge specification required.
A more sophisticated control or back gauge may provide greater benefit to a particular production process than choosing one drive technology over another, so these elements should be considered as part of the complete machine specification.
Press Brake Tooling
Tooling requirements are not determined simply by choosing hydraulic or servo-electric.
Punch and die selection depends on the material, thickness, bend angle and component profile. The die opening also affects the bending force required, making tooling an important part of calculating machine tonnage.
If an existing machine is being replaced and the tooling is to be retained, the tooling system and compatibility with the replacement machine should be checked before the specification is finalised.
More information is available on our press brake tooling page.
Hydraulic or Servo-Electric: Which Should You Choose?
Neither configuration should be selected purely because it is hydraulic or servo-electric.
A hydraulic press brake may be required where the component size, working length or bending force exceeds the available servo-electric range. For work that falls within the capacity and dimensions of a servo-electric machine, both configurations can be compared against the production requirement.
The specification should start with the material, thickness, component dimensions, bend length, required tonnage and tooling. CNC control, back gauge configuration, production volume and maintenance requirements can then be considered alongside the drive system.
This gives a much more useful comparison than treating hydraulic and servo-electric press brakes as two directly interchangeable machine types.
Compare CNC Press Brakes
Our CNC press brake range includes hydraulic and servo-electric machines from RICO, MVD and TECHNA-FAB, allowing the two configurations to be compared against the work the machine needs to produce.
Frequently Asked Questions
What is the main difference between hydraulic and servo-electric press brakes?
A hydraulic press brake uses a hydraulic system to generate the bending movement, while a servo-electric press brake uses an electrically driven system. Servo-electric machines can use different mechanical drive arrangements, including belt-drive and ball-screw systems.
Are servo-electric press brakes available in the same tonnages as hydraulic press brakes?
Hydraulic press brakes are generally available across a broader range of tonnages and working lengths, particularly for high-capacity and long-bed applications. Servo-electric machines cover a more defined capacity range, so the required bending force and component dimensions need to be checked against the individual machine.
Which type of press brake is suitable for heavy plate bending?
Heavy plate work can require high bending forces and longer working lengths, areas where hydraulic press brakes are available in considerably larger capacities. The required tonnage still needs to be calculated from the material, thickness, bend length and tooling.
Does a servo-electric press brake use hydraulic oil?
A servo-electric press brake does not use a hydraulic system to generate the bending movement. Other machine systems can vary by manufacturer and model, so the complete machine specification should still be checked.
Are servo-electric press brakes maintenance-free?
No. They remove the hydraulic bending system and its associated maintenance, but the electrical and mechanical drive components still require appropriate inspection and maintenance. Requirements depend on the design of the individual machine.
Can existing press brake tooling be used on either type of machine?
Potentially. Tooling compatibility depends on the tooling system and machine configuration rather than simply whether the press brake is hydraulic or servo-electric. Existing tooling should be checked before specifying a replacement machine.
