Definition of Press Brake Machine

А Press Brake Machine (also known as a bending machine or brake press) is a piece of equipment used for processing metal sheets by applying external force to bend the sheet into a specific angle or shape. Press brakes are widely used across various industries, especially in automobile manufacturing, construction, machinery, and home appliance production, to process materials such as metal, aluminum alloys, and stainless steel. The working principle of a press brake typically involves the interaction between the upper die (ram) and the lower die, which applies pressure to plastically deform the metal sheet.

Key Technical Parameters

The performance of a press brake machine is influenced by several key technical parameters. When selecting a press brake, attention should be paid to the following parameters:

Rated Pressure (Max Bending Force):

The rated pressure of a press brake is typically measured in tons (T), indicating the maximum force the machine can exert on the metal sheet. The rated pressure is closely related to the thickness and strength of the material being processed.
For example, a 100-ton press brake is suitable for processing thin metal sheets, while a 200-ton or higher press brake can handle thicker materials.

Max Bending Width:

This parameter refers to the maximum width of the metal sheet that the press brake can process. The maximum bending width can range from a few hundred millimeters to several meters, depending on the machine’s size and design.

Table Length:

The table length determines the maximum length of the metal sheet that the press brake can handle. Longer tables are suitable for processing longer metal sheets.

Stroke Length:

The stroke length refers to the maximum distance the upper die (ram) moves up and down during one cycle. This distance determines the depth of bending and the maximum thickness of the material that can be processed.

Max Sheet Thickness:

This indicates the maximum thickness of the sheet that the press brake can handle. When selecting a press brake, it is important to ensure that the rated pressure and die design can meet the requirements for the sheet thickness to be processed.

Bending Accuracy:

Bending accuracy is typically measured by the deviation in the bending angle. For example, an accuracy of ±0.5° is common. Листогибочные прессы с ЧПУ offer higher precision and are suitable for applications requiring high bending accuracy.

Speed of Bending:

The speed of bending refers to the time required for the press brake to complete a single bending operation. It is usually measured as the time required to bend each meter of sheet. The bending speed depends on the machine’s power system, CNC control system accuracy, and operating mode.

Spring back:

Spring back refers to the phenomenon where the metal sheet partially returns to its original shape after bending. Different materials exhibit varying degrees of springback, which needs to be compensated by adjusting the bending angle and the die design.

Drive Type:

Press brakes are available with different drive types, including mechanical, hydraulic, and electric. Each drive type is suited to different production needs.

Types of Press Brake Machines

Press brake machines can be categorized based on their operating principles and structure:

Mechanical Press Brake

• Principle: A mechanical press brake is driven by an electric motor, crankshaft, and connecting rods. Mechanical transmission components (such as gears and linkages) transmit power to the ram to perform bending operations.
• Advantages: Simple structure, low cost, suitable for small-scale or low-precision production.
• Disadvantages: Slow production speed, lower precision and repeatability, suitable for thin sheets and simple bending tasks.

Гидравлический листогибочный пресс

• Principle: A hydraulic press brake uses a hydraulic cylinder to drive the ram’s vertical movement. The hydraulic system controls pressure and stroke length to precisely adjust the bending process. Hydraulic press brakes generally offer higher rated pressure and are suitable for bending thicker sheets.
• Advantages: Even pressure, easy adjustment, wide application range, capable of bending materials of varying thickness and hardness.
• Disadvantages: More complex structure, higher cost, requires regular maintenance of the hydraulic system.

Electric Press Brake

• Principle: An electric press brake uses an electric motor to drive an electric ball screw or gear transmission system to control the ram’s vertical movement.
• Advantages: Higher precision, easy to operate, suitable for small and medium-sized parts production.
• Disadvantages: Generally suited for thinner materials, limited ability to process thick plates.

CNC Press Brake

• Principle: A CNC (Computer Numerical Control) press brake uses a computer control system to manage all machine operations, including the ram’s downward stroke, applied pressure, and die selection. Once the bending program is input, the machine automatically completes complex bending tasks.
• Advantages: High precision, high efficiency, suitable for complex and precise parts production, capable of mass production.
• Disadvantages: Requires higher technical support and programming skills, higher equipment cost.

Key Components and Functions of a Press Brake

The core components of a press brake machine and their functions include:

Upper Die (Ram)

The upper die (or ram) is the part of the press brake responsible for applying pressure. It moves vertically (up and down) via hydraulic or mechanical transmission systems, bending the metal sheet to the desired angle. The upper die is usually replaceable, and different shapes of upper dies can be selected depending on the bending requirements.

Lower Die (Table)

The lower die is located on the work table and provides support for the sheet during bending. The shape of the lower die is designed to complement the upper die to achieve the required bending angle. The shape and material of the lower die directly affect the bending quality.

Hydraulic System

The hydraulic system is the key component of a гидравлический листогибочный пресс. It converts hydraulic pressure into mechanical force via a hydraulic cylinder, which drives the ram to complete the bending operation. The hydraulic system typically includes a tank, hydraulic pump, oil pipes, and valves.

Система управления ЧПУ

The CNC system is the core of the CNC press brake. It controls all machine movements based on the input program, such as the ram’s vertical stroke, pressure application, and die selection. The CNC system can automatically calculate and execute the bending program based on part drawings, greatly improving processing efficiency and precision.

Pressure Device

This important component controls the pressure applied to the sheet during bending. Accurate pressure control is critical for achieving high-quality bends.

Support Rods and Clamping Device

Support rods help support the metal sheet to prevent deformation during bending, while the clamping device secures the sheet on the work table, ensuring it remains stationary during processing to maintain precision.

Limit Switches

Limit switches control the ram’s stroke, ensuring it stops at the correct position during each bending operation. This prevents over-bending and protects the dies from damage.

Working Principle of the Press Brake Machine
The working principle of the press brake machine is based on the plastic deformation principle in mechanics. The process is as follows:

1. Placing the Workpiece: Place the metal sheet on the lower die and secure it using clamping devices. Ensure the position of the sheet is accurate for precise bending.

2. Selecting the Appropriate Dies: Choose the correct upper and lower die combination based on the sheet thickness, bending angle, and the required shape.

3. Applying Pressure: Start the press brake machine, and the hydraulic system (or mechanical system) drives the upper die (ram) downward. As the upper die moves down, it applies pressure to cause the sheet metal to undergo plastic deformation.

4. Completing the Bending: As the sheet metal yields and begins to bend, the ram continues to move downward until the desired bending angle is achieved.

5. Unloading the Workpiece: After bending, the ram (upper die) will stop moving downward and begin to rise, allowing the bent workpiece to be removed from the lower die. At this point, the bent metal sheet can be taken out, ready for the next process or for secondary processing.

In high-efficiency production environments, automatic unloading devices are often used to quickly and accurately transfer the finished workpieces to the next station, improving production efficiency.

Applications of the Press Brake Machine
The press brake machine is widely used in multiple industries, particularly in metalworking. Common applications include:

• Automotive Manufacturing
  The press brake is used to produce automotive chassis, body structure parts, door frames, metal protection plates, and other components. The machine can bend metal sheets into various shapes to meet the structural requirements of automobile parts.

• Construction Industry
  In construction, the press brake is used to process steel bars, metal plates, and other materials for making pipe elbows, support frames, and other structural components.

• Machinery Manufacturing
  The press brake is used to make machine shells, frames, reinforcing plates, guides, and other components. Bending the sheets helps achieve various mechanical structure requirements.

• Home Appliance Manufacturing
  In the home appliance industry, the press brake is used to manufacture metal enclosures, internal supports, panels, and other components.

• Sheet Metal Fabrication
  In sheet metal fabrication, the press brake can process various metal sheets according to customer specifications. It is commonly used in the production of equipment enclosures, cabinets, control panels, frames, etc.

Maintenance and Care of the Press Brake Machine
To ensure the long-term stable operation and processing accuracy of the press brake machine, regular maintenance and care are crucial. The following are some basic maintenance and care recommendations:

1. Regularly Check the Hydraulic System
   The hydraulic system is one of the key components of a гидравлический листогибочный пресс. The hydraulic oil quality and oil level should be regularly checked, and the sealing of cylinders should be monitored to prevent leakage. If contamination or aging of the oil is detected, it should be replaced. Inspect the hydraulic pump, pipes, and valves for any damage or abnormalities to ensure stable system pressure.

2. Clean the Press Brake
   The working environment of the press brake machine should be kept clean to prevent metal chips, dust, and other debris from entering the equipment. Regularly clean the worktable, dies, ram, and other components to ensure smooth operation. During cleaning, avoid using highly corrosive cleaners such as strong acids or alkalis.

3. Check the Electrical System
   Regularly check the electrical system components such as cables, switches, and contactors to ensure proper connections and avoid equipment failures due to poor contact. Inspect the CNC system’s communication lines, display screens, control panels, etc., to ensure they are working correctly.

4. Смажьте движущиеся части
   Moving components such as the ram, support shafts, and gears should be regularly lubricated to reduce friction and wear. Follow the manufacturer’s recommendations for the appropriate lubricants or greases.

5. Check the Dies and Workpiece Support System
   The upper and lower dies are vital components of the press brake and should be checked for wear. If there are signs of significant wear, scratches, or deformation, replace the dies. The workpiece support system should also be maintained in good condition to prevent workpiece deformation or loss of processing accuracy due to inadequate support.

6. Inspect Safety Devices
   Press brakes are typically equipped with safety devices such as protective shields, emergency stop buttons, and light curtains. Regularly check these safety devices to ensure they function properly and that operators are fully protected during operation.

7. Maintain and Calibrate the CNC System
   For CNC press brakes, it is important to regularly check and calibrate the CNC system. Adjust system parameters and upgrade software according to the user manual to ensure system stability and accuracy.

8. Maintain Worktable Flatness
   The worktable of the press brake should remain flat to prevent the workpiece from shifting or deforming during processing. Periodically check the horizontal and vertical alignment of the worktable and make necessary adjustments or corrections.

Safety Operating Guidelines for the Press Brake Machine
Safety is the most critical consideration when operating a press brake machine. The following are safety operating guidelines:

1. Operator Training
   All operators of the press brake machine must undergo professional training. They should be familiar with the user manual, working principles, and operating procedures, and should understand basic safety knowledge.

2. Wear Protective Equipment
   Operators should wear appropriate protective gear, such as safety glasses, earplugs, work uniforms, and non-slip gloves, when using the press brake.

3. Regularly Check Safety Devices
   The press brake should be equipped with necessary safety devices such as emergency stop buttons, mechanical shields, and anti-clamping devices. Before use, operators must confirm that these devices are functioning properly.

4. Avoid Overloading the Machine
   Do not exceed the press brake’s rated pressure and processing capacity. Using inappropriate dies or processing materials that are too thick or hard can overload the machine and lead to failure or safety incidents.

5. Observe During Operation
   During bending, operators should constantly observe the machine’s operation, especially the condition of the dies, pressure, and sheet metal. If abnormal sounds, vibrations, or other issues are detected, stop the machine immediately and investigate the cause.

6. Prevent Hand and Body Injuries
   Operators should avoid placing hands or other body parts in the working area of the machine. Strictly follow the operating guidelines and refrain from making adjustments or performing cleaning tasks while the machine is running.

7. Cut Off Power When Machine is Stopped
   After each use, turn off the press brake’s power supply to ensure that the machine is in a stopped state. This is also a good time to clean the work area and perform necessary checks and maintenance on the machine.

Common Faults and Solutions
Despite the press brake machine’s high reliability, common faults may still occur with long-term use. Below are some typical issues and solutions:

1. Hydraulic System Leaks

   • Cause: Loose hydraulic oil pipes or damaged seals.
   • Solution: Check hydraulic pipe connections for tightness and replace worn or damaged seals.

2. Misalignment of Upper or Lower Dies

   • Cause: Die wear or machine misalignment due to extended use.
   • Solution: Inspect dies for damage or deformation and adjust die positioning. Replace the dies if necessary.

3. Poor Bending Accuracy

   • Cause: Worn-out dies, unstable hydraulic pressure, or inaccurate CNC system settings.
   • Solution: Check the dies for flatness, verify hydraulic system pressure, and ensure CNC system settings are correct. Perform calibration if needed.

4. Increased Machine Noise

   • Cause: Low hydraulic oil levels, bearing wear, or insufficient lubrication.
   • Solution: Check and replenish hydraulic oil levels; inspect and lubricate bearings and other components. Replace damaged parts if necessary.

5. Excessive Hydraulic Oil Temperature

   • Cause: Insufficient oil levels, pump failure, or cooling system malfunction.
   • Solution: Check and replenish the hydraulic oil; inspect the pump and cooling system for proper operation. Replace or repair components as needed.

The press brake bending machine is an essential tool in modern manufacturing. Proper selection, usage, and maintenance can significantly enhance production efficiency and processing quality. By understanding the machine’s working principles, key parameters, maintenance procedures, and common fault resolutions, you can improve safety, accuracy, and productivity in the bending process.