Press brakes are essential machines in metalworking, used for bending and shaping metal sheets. They come in various types, each suited for different applications and precision levels. This article explores the different types of press brakes, their working principles, and provides a guide on how to select the right press brake for your specific needs.
Types of Press Brakes
Manual Press Brakes
Manual press brakes are the simplest form, operated entirely by hand. They are suitable for small-scale operations and require significant manual effort to achieve the desired bends.
Hydraulic Press Brakes
Hydraulic press brakes use hydraulic fluid to power the bending process, offering greater force and precision. They are classified into several types based on synchronization and movement mechanisms:
Synchronization Types:
- Torsion Bar Synchronized Hydraulic Press Brakes: These use a torsion bar to ensure both ends of the machine move simultaneously, providing consistent bending.
- Hydro-Mechanical Synchronized Hydraulic Press Brakes: These combine mechanical and hydraulic systems to achieve synchronization.
- Electro-Hydraulic Synchronized Press Brakes: These use electrical signals to control hydraulic movements, offering the highest precision and flexibility.
Movement Types:
- Top-Moving Hydraulic Press Brakes: The ram moves downwards to perform the bend.
- Bottom-Moving Hydraulic Press Brakes: The ram moves upwards to achieve the bend.
CNC Press Brakes
Computer Numerical Control (CNC) press brakes are highly advanced, offering programmable precision for complex bends. They are ideal for high-volume production and intricate designs.
CNC Systems
CNC systems enhance the functionality of press brakes. Key systems used include:
- Shearing Machines: DELEM E21S, DAC310, DAC360
- Press Brakes: DELEM DA41, DA52, DA56, DA66T
These systems provide precise control over bending processes, improving efficiency and accuracy.
Working Principle
A press brake consists of several key components:
- Frame: Provides structural support.
- Worktable: The surface on which the metal sheet is placed.
- Clamping Plate: Holds the metal sheet in place during bending.
The worktable is mounted on the frame, comprising a base and a press plate. The base and press plate are connected by hinges, and an internal coil generates electromagnetic force to clamp the sheet between the press plate and base. By changing the press brake molds, different bending requirements can be met.
Selection Guide
Considerations
1. Workpiece:
- Size and Shape: Determines the size of the press brake needed.
- Material Grade and Thickness: Influences the required tonnage.
- Bend Radius: Affects the choice of die.
2. Deflection:
- Choose shorter worktables to reduce deflection and increase precision.
3. Tonnage:
- Depends on material and thickness.
- For free bending, use a die angle of 85° or less.
- For bottom bending, use a die angle of 86° to 90°.
- For coining, use a die with a punch tip radius smaller than the material thickness.
Estimating Tonnage
To estimate the tonnage required for free bending, use the formula:
```
Tonnage = (Material Tensile Strength / 1000) × Material Thickness (in inches) × Bend Length (in feet) × K-factor
```
| Material | K-Factor |
|------------|----------|
| Low Carbon Steel | 0.8 |
| Stainless Steel | 1.2 |
| Soft Aluminum | 0.5 |
Recommendations
Purchase a press brake that meets your processing needs with the minimum necessary tonnage. For low carbon steel with a maximum thickness of 16 gauge and a maximum length of 10 feet, a free bending force of less than 50 tons is usually sufficient. For materials up to 1/4 inch thick requiring bottom bending, a machine with at least 600 tons is necessary.
Common Questions
What is the die angle?
The die angle refers to the angle between the punch and die, which controls the bend radius and springback.
What is the bend radius?
The bend radius is the internal radius of the bend in the workpiece.
What is springback?
Springback is the tendency of a material to return to its original shape after bending.
Conclusion
Understanding the different types of press brakes, their components, and their operating principles is crucial for selecting the right machine for your needs. By considering factors like workpiece dimensions, material properties, and required precision, you can ensure optimal performance and accuracy in your bending operations.
Types of Press Brakes
Manual Press Brakes
Manual press brakes are the simplest form, operated entirely by hand. They are suitable for small-scale operations and require significant manual effort to achieve the desired bends.
Hydraulic Press Brakes
Hydraulic press brakes use hydraulic fluid to power the bending process, offering greater force and precision. They are classified into several types based on synchronization and movement mechanisms:
Synchronization Types:
- Torsion Bar Synchronized Hydraulic Press Brakes: These use a torsion bar to ensure both ends of the machine move simultaneously, providing consistent bending.
- Hydro-Mechanical Synchronized Hydraulic Press Brakes: These combine mechanical and hydraulic systems to achieve synchronization.
- Electro-Hydraulic Synchronized Press Brakes: These use electrical signals to control hydraulic movements, offering the highest precision and flexibility.
Movement Types:
- Top-Moving Hydraulic Press Brakes: The ram moves downwards to perform the bend.
- Bottom-Moving Hydraulic Press Brakes: The ram moves upwards to achieve the bend.
CNC Press Brakes
Computer Numerical Control (CNC) press brakes are highly advanced, offering programmable precision for complex bends. They are ideal for high-volume production and intricate designs.
CNC Systems
CNC systems enhance the functionality of press brakes. Key systems used include:
- Shearing Machines: DELEM E21S, DAC310, DAC360
- Press Brakes: DELEM DA41, DA52, DA56, DA66T
These systems provide precise control over bending processes, improving efficiency and accuracy.
Working Principle
A press brake consists of several key components:
- Frame: Provides structural support.
- Worktable: The surface on which the metal sheet is placed.
- Clamping Plate: Holds the metal sheet in place during bending.
The worktable is mounted on the frame, comprising a base and a press plate. The base and press plate are connected by hinges, and an internal coil generates electromagnetic force to clamp the sheet between the press plate and base. By changing the press brake molds, different bending requirements can be met.
Selection Guide
Considerations
1. Workpiece:
- Size and Shape: Determines the size of the press brake needed.
- Material Grade and Thickness: Influences the required tonnage.
- Bend Radius: Affects the choice of die.
2. Deflection:
- Choose shorter worktables to reduce deflection and increase precision.
3. Tonnage:
- Depends on material and thickness.
- For free bending, use a die angle of 85° or less.
- For bottom bending, use a die angle of 86° to 90°.
- For coining, use a die with a punch tip radius smaller than the material thickness.
Estimating Tonnage
To estimate the tonnage required for free bending, use the formula:
```
Tonnage = (Material Tensile Strength / 1000) × Material Thickness (in inches) × Bend Length (in feet) × K-factor
```
| Material | K-Factor |
|------------|----------|
| Low Carbon Steel | 0.8 |
| Stainless Steel | 1.2 |
| Soft Aluminum | 0.5 |
Recommendations
Purchase a press brake that meets your processing needs with the minimum necessary tonnage. For low carbon steel with a maximum thickness of 16 gauge and a maximum length of 10 feet, a free bending force of less than 50 tons is usually sufficient. For materials up to 1/4 inch thick requiring bottom bending, a machine with at least 600 tons is necessary.
Common Questions
What is the die angle?
The die angle refers to the angle between the punch and die, which controls the bend radius and springback.
What is the bend radius?
The bend radius is the internal radius of the bend in the workpiece.
What is springback?
Springback is the tendency of a material to return to its original shape after bending.
Conclusion
Understanding the different types of press brakes, their components, and their operating principles is crucial for selecting the right machine for your needs. By considering factors like workpiece dimensions, material properties, and required precision, you can ensure optimal performance and accuracy in your bending operations.
