In sheet-metal fabrication, CNC press brakes and guillotine shears are standard equipment.
Most optimization efforts focus on control systems, linear scales and compensation algorithms.
However, one critical factor is often underestimated: hydraulic stability at low speed.

In practical operation, many machines still exhibit the same issue:

Cylinder creep or vibration during low-speed motion

This directly leads to angle deviation in bending and inconsistent cutting quality in shearing operations.

Root Cause: Pump Performance at Low Speed

In many cases, the instability does not originate from the control system, but from the hydraulic power source.

Traditional pump selection is typically based on performance near rated speed, assuming sufficient flow and pressure under nominal conditions.
However, in modern systems equipped with servo drives or VFD control, pumps frequently operate at low speed, often in the range of 300–500 r/min.

Under these conditions, conventional pump designs tend to show:

Increased internal leakage

Higher flow and pressure pulsation

Reduced volumetric efficiency

These effects directly degrade motion stability and system response.

Solution Trend: FG Internal Gear Pumps

To address these limitations, more machine builders are adopting FG internal gear pumps as the main hydraulic power source.

Their internal gear structure provides inherent advantages for low-speed operation:

Low pulsation output, supporting stable micro-movement and precise gap control

Stable volumetric efficiency, maintaining consistent performance at low speed

Wide speed adaptability, compatible with servo and VFD-driven systems

Typical Technical Configuration

In sheet-metal equipment, commonly used configurations include:

Displacement: 25–40 mL/r

Rated pressure: 31.5 MPa

Maximum pressure: up to 35 MPa

Speed range: 200–3000 r/min

This range covers the requirements of small and medium press brakes and shears, including full-tonnage bending and thick-plate cutting.

Performance Improvements in Practice

Field experience shows clear improvements when using internal gear pumps.

For press brakes:

Smoother pressure curves during slow approach and bending

More stable contact control

Consistent return motion

For shears:

More predictable speed transitions at cutting start and end

Improved cutting quality and repeatability

Reduced vibration during operation

Because the pump maintains stable volumetric efficiency at low speed, the system no longer depends heavily on compensation algorithms or large safety margins.

Engineering Value

Upgrading the hydraulic pump fundamentally changes system behavior.

Instead of relying on control compensation to correct instability, the system gains inherent stability from the power source.

This approach enables:

More stable low-speed motion

Reduced tuning complexity

Improved consistency across production cycles

Summary

In press brakes and shears, precision is not determined solely by the control system.
Hydraulic performance at low speed plays a decisive role.

By adopting internal gear pumps, machine builders can extend precision from the control layer down to the hydraulic source, achieving more stable, predictable and repeatable operation.