Torsion Axis vs Electro-Hydraulic CNC Press Brake: How to Make the Right Choice

Many manufacturers struggle to choose between torsion axis and electro-hydraulic CNC press brakes. While both machines perform metal bending, they differ significantly in features, performance and limitations. This article compares the two types of press brakes from multiple dimensions, helping both new entrants and seasoned industry professionals select the ideal equipment.

A torsion axis CNC press brake relies on torsion bars for synchronous motion. It adopts a torsion-bar synchronisation structure: two torsion bars mounted on the machine frame transfer motion via connecting rods and rocker arms to drive the upper and lower dies in sync, completing workpiece bending. This is defined as mechanical forced synchronisation. Typically, the machine is fitted with a main motor and multiple clutches to transmit power and drive the slide assembly.

Machines adopting electro-hydraulic synchronisation are known as electro-hydraulic CNC press brakes. They combine hydraulic systems and electric servo drives to realise synchronous movement of upper and lower slides. The system consists of hydraulic cylinders, servo valves, sensors and a control unit. Electronic signals deliver precise positioning control of the slide. Synchronisation is realised through servo valves installed on both sides. Servo motors convert rotary motion into hydraulic power, while sensors continuously track die position. Supported by sensors and feedback loops, position deviations are monitored and adjusted in real time for superior bending accuracy.

Synchronisation on torsion axis CNC press brakes largely depends on mechanical transmission. Accuracy is affected by torsion bars, connecting rods and other components. Elastic deformation of torsion bars and clearance on adjusting rods may cause asynchronous slide movement, negatively impacting bending angle and straightness. Standard precision stands at around 0.1 mm. This type fits general bending applications, especially small workpieces requiring medium-to-low precision.

Our torsion axis CNC press brakes achieve positioning accuracy up to 0.01 mm, surpassing industry standards and delivering high performance at a cost-effective price.

Electro-hydraulic CNC press brakes adopt closed-loop control for high-precision synchronous bending. The electro-hydraulic valves regulate cylinder movement to guarantee perfectly synchronised die motion. Electro-hydraulic models deliver higher bending accuracy, normally within 0.01 mm tolerance or better, and maintain stable performance after long continuous operation. They are ideal for high-precision tasks, especially manufacturing complex workpieces.

Restricted by the mechanical torsion system, torsion axis CNC press brakes have relatively low speed and response performance. They usually run fast on downward stroke, yet slow on lifting and return strokes. The torsion mechanism requires extra time to maintain synchronisation between upper and lower dies. Adjusting bending speed or executing complex multi-step bending demands extra setup time, and operating speeds are mostly fixed.

Electro-hydraulic CNC press brakes utilise advanced electro-servo and hydraulic control technology. The electro-hydraulic servo system rapidly adjusts cylinder speed and output force, enabling faster bending cycles and higher productivity. Precise electro-hydraulic control shortens working cycles and boosts overall output.

The torsion axis CNC press brake features a simple mechanical synchronisation system with low maintenance costs. Its straightforward structure eliminates the need for complex control peripherals. Routine inspection and lubrication of key components (such as torsion bars) are sufficient, and spare part replacement costs remain low.

Electro-hydraulic CNC press brakes integrate sophisticated electrical and hydraulic systems, leading to higher maintenance expenditure and more complex servicing. Apart from regular lubrication and component checks, the control system needs ongoing maintenance and calibration. Electrical and hydraulic components require periodic inspection, and replacement parts come at a higher cost.

Torsion axis CNC press brakes normally come with 3 primary axes:

Electro-hydraulic CNC press brakes support more axes for greater flexibility and precision. Standard models are equipped with 4 or more main axes:

Due to different working principles and product positioning, torsion axis CNC press brakes are generally not equipped with crowning compensation systems.

In contrast, electro-hydraulic CNC press brakes occupy a higher product tier with programmable advanced controllers, and can be fitted with crowning compensation for precise bending correction. The compensation system improves workpiece quality and accuracy to meet demands for complex components. The added investment is justified by enhanced functionality and processing flexibility.

Electro-hydraulic CNC press brakes adopt more intricate structures and control systems, so they are generally higher-priced. Torsion axis CNC press brakes feature simpler mechanical structures and basic electro-mechanical controls, resulting in lower purchase costs.

Electro-hydraulic models require high-precision components and advanced controllers, pushing up design and manufacturing expenses. In the short term, torsion axis machines offer better economy. From a long-term perspective, electro-hydraulic press brakes deliver greater return on investment.

Electro-hydraulic CNC press brakes are suitable for processes demanding high precision and efficiency, well-suited to mass production and complex workpiece fabrication. Despite higher upfront cost, they provide superior machining quality and operational flexibility.

Torsion axis CNC press brakes fit general bending applications, recommended for small-to-medium batch production and simple workpieces.

Torsion axis CNC press brakes have limited expandability. Integration with other equipment, multi-machine linkage or robotic automation is difficult to implement.

Electro-hydraulic CNC press brakes feature strong expandability, supporting multi-machine linkage and easy integration with robots and other automation systems. Automated configurations drastically lift production efficiency, cut labour costs and reduce safety risks.

Owing to its mechanical structure and CNC logic, torsion axis CNC press brake operation heavily relies on operator experience, meaning companies may need to hire seasoned workers at higher salaries.

Electro-hydraulic CNC press brakes boast higher automation levels and simpler operation, lowering the experience threshold for operators.

In summary, manufacturers should select equipment based on their actual production demands. In most scenarios, electro-hydraulic CNC press brakes outperform torsion axis models. If budget permits, electro-hydraulic press brakes represent a better long-term investment. When capital is limited, torsion axis press brakes can satisfy regular processing requirements.

We recommend press brakes manufactured by Kafe Press Brake. Kafe consistently focuses on producing high-quality machinery. Our torsion axis and electro-hydraulic CNC press brakes follow unified manufacturing standards. The slide is designed with anti-falling protection to minimise deformation. All workbenches of torsion axis machines are fully machined on machining centres with strict control over details and precision. DURMAPRESS welcomes customers to compare our build quality and craftsmanship with other suppliers.