Bending machines are essential tools in the metalworking industry, used to bend metal sheets into desired shapes. Based on their working principles and control systems, bending machines can be classified into several types. This article explores these types, their unique features, and the differences between hydraulic and CNC bending machines.
Types of Bending Machines
1. Electro-Hydraulic Bending Machines
Electro-hydraulic bending machines use an electro-hydraulic system to generate pressure, which the punch uses to apply force on the workpiece. The hydraulic oil in the system is pressurized by a motor-driven vane pump.
Key Features:
- Utilizes a motor-driven vane pump.
- Provides robust pressure for bending operations.
- Suitable for heavy-duty tasks.
2. CNC Bending Machines
CNC (Computer Numerical Control) bending machines use CNC technology to control all operations of the machine, including bending angles, stroke, and back gauge positions. They are known for their precision and efficiency.
Key Features:
- High precision and accuracy.
- Automated control of bending processes.
- Reduced downtime and increased productivity.
3. Electro-Hydraulic Proportional CNC Bending Machines
These machines combine electro-hydraulic and CNC technologies, using electro-hydraulic servo valves for more precise control of the hydraulic system, enhancing accuracy and repeatability.
Key Features:
- Combines CNC and electro-hydraulic systems.
- High precision due to servo valve control.
- Improved repeatability and efficiency.
4. Torsion Bar Synchronized CNC Bending Machines
Torsion bar synchronized CNC bending machines use a torsion bar to synchronize the movement of the punch and die on both sides of the machine, ensuring the material remains aligned during the bending process.
Key Features:
- Uses torsion bars for synchronization.
- Ensures material alignment throughout the bend.
- Suitable for symmetrical bending tasks.
5. Fully Servo-Driven CNC Bending Machines
These machines use servo motors to directly drive the movement of the punch and die, providing higher precision, speed, and control compared to other types of bending machines.
Key Features:
- Fully driven by servo motors.
- Exceptional precision and control.
- High-speed operation.
6. Pneumatic Bending Machines
Pneumatic bending machines use compressed air as their power source and are typically used for bending small batches or lightweight materials.
Key Features:
- Powered by compressed air.
- Ideal for small batches and lightweight materials.
- Simple and cost-effective.
7. Pure Electric Bending Machines
Pure electric bending machines use electric motors to drive the punch and die movement directly. These machines are known for their high energy efficiency and low maintenance requirements.
Key Features:
- Directly driven by electric motors.
- High energy efficiency.
- Low maintenance.
Key Differences Between Electro-Hydraulic and CNC Bending Machines
1. Control System:
- Electro-Hydraulic Bending Machines: Use an electro-hydraulic system to control the bending process.
- CNC Bending Machines: Employ CNC technology for precise control over all machine operations.
2. Precision:
- Electro-Hydraulic Bending Machines: Generally less precise compared to CNC machines.
- CNC Bending Machines: Offer higher accuracy due to the fine control of CNC systems.
3. Efficiency:
- Electro-Hydraulic Bending Machines: Can be efficient but may require more manual adjustments.
- CNC Bending Machines: Highly efficient with automated processes, reducing downtime and increasing productivity.
4. Programming:
- Electro-Hydraulic Bending Machines: Typically require manual programming.
- CNC Bending Machines: Use CNC programs that can be stored and reused, simplifying the bending of complex shapes.
Troubleshooting Common Issues in Electro-Hydraulic Bending Machines
Problem: Machine Continues to Return Oil Without Pressurizing
Possible Causes and Solutions:
1. Overflow Valve Open Too Wide:
- Solution: Disassemble the overflow valve, clean it, and adjust its opening.
2. Motor or Oil Pump Malfunction:
- Solution: Check the motor and oil pump for proper operation and look for any signs of oil leakage.
Conclusion
Understanding the different types of bending machines and their unique features is essential for selecting the right machine for your metalworking needs. Electro-hydraulic bending machines and CNC bending machines each have their advantages, with CNC machines offering higher precision and efficiency through advanced control systems. Proper maintenance and troubleshooting are key to ensuring the longevity and optimal performance of these machines. By following these guidelines, you can enhance your bending operations and achieve consistent, high-quality results.
