A hydraulische Schermaschine is a machine that uses a hydraulic system as its power source to drive a pair of blades (typically a moving upper blade and a fixed lower blade) in relative motion, applying immense shear stress to metal sheets to separate them along a predetermined cutting line.
Main Structural Components
A typical hydraulic shearing machine consists of the following key components:
Frame: Typically a monolithic structure welded from steel plates, it offers extremely high rigidity and stability. Serving as the machine’s skeleton, it supports all components and withstands the immense reaction forces generated during the shearing process.
Blade Beam/Ram: A component used to mount the upper blade, which performs vertical reciprocating motion driven by hydraulic cylinders. Its design directly affects the stability and precision of the shearing process.
Worktable: Used to position and support the sheet metal to be cut; the lower blade is mounted on top of it. The worktable is typically equipped with rollers or material support frames to facilitate the movement of the sheet metal.
Hydraulic System: This includes the oil tank, motor, hydraulic pump, hydraulic cylinders (main cylinder and clamping cylinder), various control valves, piping, coolers, and oil filters, and serves as the machine’s power core.
Electrical Control System: This includes the control cabinet, operator panel, PLC (Programmable Logic Controller) or CNC (Computer Numerical Control) system, limit switches, and other components. It serves as the machine’s “brain,” responsible for receiving commands, controlling the operation of hydraulic valves, and enabling automated operations.
Backgauge System: Used to precisely position the cutting width of the sheet metal, it is a key component for ensuring dimensional accuracy. Modern equipment typically features electric or CNC-controlled backgauges.
Blades: Divided into upper and lower blades, these are the tools that directly perform the cutting task. Their material, hardness, cutting edge angle, and gap adjustment are critical to cutting quality and service life.
Safety Devices: These include physical guardrails, light curtain sensors, and emergency stop buttons, serving as a vital line of defense for operator safety.
Types of Hydraulic Shearing Machines
Hydraulic shearing machines can be classified into Swing Beam Shearing Machines and Guillotine Shearing Machines based on their structural design and transmission methods. The fundamental difference lies in the motion path of the upper blade holder.
Schwingbalken-Schermaschine
Motion Characteristics: The upper blade holder swings in an arc around a fixed pivot point. The blade holder itself is inclined, and the shearing angle is adjusted by changing the angle of inclination.
Advantages: The structure is relatively simple, and manufacturing costs are lower. Because of the arc-shaped motion, the blade holder is subjected to uniform stress, resulting in less wear on the guide rails and a longer service life.
Disadvantages: The cross-section of the sheared sheet may not be a perfect rectangle but may have a slight curvature, making it unsuitable for applications requiring extremely high precision. The range of shear angle adjustment is relatively limited.
Guillotine-Schermaschine
Motion Characteristics: The upper blade carriage moves purely up and down along vertical guide rails on both sides, similar to an ancient guillotine.
Advantages: Cutting precision is very high, ensuring the perpendicularity of the cut surface. The cutting angle can be conveniently and automatically adjusted hydraulically over a wide range to accommodate different sheet thicknesses.
Disadvantages: The structure is relatively complex, requiring high manufacturing and assembly precision for the guide rails; consequently, manufacturing and maintenance costs are relatively higher.
Recommendations: For routine sheet metal processing where the requirements for cut surface perpendicularity are not particularly stringent, the cost-effective swing-type shears are an ideal choice. However, for industries requiring high-precision, high-quality cuts, guillotine shears should be the preferred option.
Uses of Hydraulic Shearing Machines
Its primary functions can be summarized as follows:
- Precisely cutting large sheets of metal (such as steel, aluminum, and stainless steel) into the required dimensions and shapes.
- Enabling efficient, repeatable cutting of sheet metal to provide standardized blanks for subsequent processes such as bending, stamping, and welding, serving as the foundation for large-scale industrial production.
- To perform preliminary processing of raw materials in the initial stage of metal manufacturing, preparing them for the production of complex components.
Hydraulic Shearing Machine Applications
Due to their stable cutting force, excellent cutting quality, and strong adaptability to materials of varying thicknesses, hydraulic shearing machines are widely used in sheet metal fabrication and metal manufacturing. Their primary applications include:
Automotive Manufacturing: Used for the precise cutting of large metal sheets used in automotive body panels, such as doors, hoods, roofs, and fenders. It is also used to cut sheets for high-strength steel structural components like chassis and frames.
Shipbuilding: Used to shear medium- and thick-gauge steel plates required for structural components such as hulls, decks, compartment bulkheads, and bottom plates.
Construction and Steel Structures: In the manufacturing of steel-structured industrial buildings, bridges, and high-rise buildings, it is used for the precise cutting of steel plates that form components such as steel beams, columns, supports, and connecting plates.
Power Industry: Used for processing and manufacturing the outer casings and internal structural components of power equipment such as transformers, switchgear, and distribution boxes.
Electronics and Electrical Industry: Used for cutting and manufacturing precision sheet metal parts such as casings, enclosures, and internal brackets for various electrical products.
Hydraulic Shearing Machine Advantages
Hydraulic shearing machines mainly offer better precision, smoother cutting, greater adaptability, and stronger overload protection than mechanical shears. They are also generally better for thicker plates and variable materials, because the hydraulic drive provides steady force rather than a flywheel-based impact stroke.
Main advantages
Higher cut quality and accuracy: The hydraulic system delivers steady force and smoother motion, which helps reduce vibration, edge distortion, and burrs.
Better thickness capacity: Hydraulic shears are typically more suitable for medium-to-thick plates and tougher materials, while mechanical shears are usually stronger in high-speed light-to-medium gauge cutting.
Adjustability: Operators can more easily adjust cutting force, stroke, blade gap, and rake angle to match different jobs.
Overload protection: Hydraulic systems can include relief-valve protection, so the machine is less likely to suffer damage if the load becomes excessive.
Smoother and quieter operation: Hydraulic shears generally produce less shock, vibration, and noise than mechanical shears.
Better fit for mixed production: They are useful when a shop frequently switches between different materials, thicknesses, or cut requirements.
How Does a Hydraulic Shearing Machine Work?
At the heart of a hydraulic shearing machine lies its precise and powerful hydraulic system. The entire shearing process is a closed-loop operation involving energy conversion and precise control.
1. Power Generation and Transmission
Power is generated by a hydraulic pump driven by an electric motor. The pump draws oil from the reservoir, pressurizes it, and converts mechanical energy into the energy of high-pressure hydraulic fluid. Through precise regulation by a valve assembly—including solenoid directional control valves and relief valves—the high-pressure fluid is accurately directed to the actuators, enabling perfect control over the speed, force, and start/stop of the shearing action.
2. Execution of the Shearing Action
The process primarily relies on the main hydraulic cylinder to drive the upper blade holder. High-pressure oil enters the upper chamber, pushing the piston rod downward. This drives the upper blade mounted on the upper blade holder to form a shearing angle with the lower blade fixed to the worktable, applying immense shearing force to the sheet metal. Simultaneously, the clamping hydraulic cylinder activates first to secure the sheet metal, preventing it from slipping or warping during the shearing process, thereby ensuring shearing precision and cut quality.
3. Return Stroke and Cycle
After shearing is complete, the solenoid directional control valve changes the oil flow direction. High-pressure oil enters the lower chamber or return cylinder, pushing the blade holder to quickly return to its original position, and the clamping foot releases, preparing for the next shearing operation. Some high-performance models are also equipped with a nitrogen accumulator, which stores excess energy during the return stroke and rapidly releases it at the start of the next cycle, thereby significantly shortening cycle time and improving work efficiency.
4. Precision Control and Auxiliary Functions
Precision control relies on system-level hydraulic controllability and auxiliary devices, such as the backgauge positioning device controlled by the CNC system. Modern models also integrate safety features such as guardrails, photoelectric safety devices, and emergency stop buttons to ensure operator safety during high-speed operation.
