9 Useful Press Brake Tips and Tricks

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Publish Date: June 11, 2024

I. Introduction

Press brake is widely used in sheet metal manufacturing, and there are several tips and safety guidelines to keep in mind. For instance, reducing the physical setup time of the press machine, organizing the tool components efficiently, and quickly placing the sheet metal on the workbench.

Additionally, programming the bending procedures, adjusting the workpiece parameters, and accurately positioning the workpiece can improve the efficiency of the press brake operations.

II. Press Brake Tips and Tricks

1. Select Appropriate Materials

The properties, tensile strength, and ductility of materials can vary, and these variations will impact the entire bending process. Plates can be formed into thick or thin plates through hot rolling or cold rolling, which can result in differences in composition and rolling conditions.

The material characteristics can change during press brake bending, causing changes in the bending angle. The harder the material, the greater the rebound on both sides of the bend.

2. Marking and Storage of Tools

Marking and Storage of Tools

When bending a workpiece with a hydraulic press brake machine, having the necessary tools and information readily available can greatly improve work efficiency. To achieve this, it's important to clearly mark all required information on the machine or tools, such as the number, length, bending angle, radius, height, and maximum load.

Having organized tool storage is also important. A customized tool cabinet can be provided to store different sizes and quantities of tool sets, and should be located as close to the press brake as possible for easy access during operation.

This not only helps prevent damage to the tools but also facilitates their replacement and portability to other processing sites using a fork truck.

3. Large Tonnage Bending

Before selecting the tooling, it is important to make sure that the bending tonnage falls within the load range of the punch and die. For example, if the rated range of the die is 20 tons per foot and the workpiece to be bent is 3 feet long, the maximum force exerted by the press brake on the workpiece should not exceed 60 tons.

Exceeding this force could result in damage to the press brake, tooling, and workpiece, and even pose a safety risk to the press brake operator. Additionally, the clamp system of the press brake also has a limited range of force.

Overloading the clamp system can cause damage to the clamping tools. When bending thick plates, you can reduce the required tonnage by selecting a V die with a wider opening.

Tonnage Bending

A V die with a hardened positioning rod and shoulder can roll during the entire bending process, reducing the friction between the workpiece and the die and ultimately requiring less bending force compared to a solid die.

However, this method cannot change the bending radius and flange length of the workpiece. Applying a large amount of lubricating oil to the shoulder of the V die can also reduce the friction generated during bending, effectively reducing the tonnage required. While this method can be used occasionally, it's important to clean the press brake after use.

4. Adjustment of Back Gauge

The accuracy of the back gauge can be improved by adjusting the position of its stop finger. You can measure any error by using a depth gauge, ensuring that the distance between the stop finger and the center of the lower die is consistent.

Next, check the error on the X-axis. If there is any discrepancy, correct the X-axis reference point value, and then perform the bending process after making the correction. To align the X-axis with the mold, adjust the timing belt and move the screw on the X-axis forward or backward.

Check for errors at both ends of the X-axis beam, and if none are found, tighten the screws on the timing belt, then perform a bending measurement. If there is an error on the Y-axis, adjust the Y-axis reference point to correct the error.

Fix the slider below the bending transition point, and after adjusting the parameters of the Y1 and Y2 axes, perform a bending measurement to confirm that there are no errors.

5. Die and Workpiece Wear

The wear of the die or workpiece after bending is related to the bending radius of the bottom die, which can damage the surface of the V die and result in scratches on the surface of the workpiece.

When selecting a V-shaped die, consider the opening size and bending radius of the V die. Surface-hardened dies can also be selected to minimize the potential for wear.

6. Remove Die Marks

During bending, dies may leave marks on the workpiece. This can be remedied by using a press brake dies film, such as a polyurethane non-destructive film, which is commonly used for bending aluminum and stainless steel.

To use the film, simply tape and clamp it to the top of the die before bending. This will prevent the die from leaving marks on the workpiece. The film is made of polyurethane and can be reused.

7. Correct Abnormal Bending Angle

Correct Abnormal Bending Angle

If the bending angle of the workpiece deviates from the programmed angle, it could be due to insufficient tonnage. Additionally, the bending stroke needs to be maintained for a specific duration in order to form the correct angle.

Another possible cause could be a slow bending speed, which doesn't generate enough pressure on the plate. The ductility and tensile strength of different materials affect the rebound degree after bending. The size of the opening in the V-shaped die also influences the final bending result.

To correct an abnormal bending angle, try increasing the tonnage, improving the bending speed, and extending the duration of the bending process. Additionally, consider using a metal sheet with less rebound and a V-shaped die with a wider opening.

8. Calculating Bending Force

(1) Use Standard Formula for Initial Calculation

  • Use the standard bending force calculation formula to quickly estimate the required bending force. The formula is:
F=1.42×σt×T2×L V

where:

  • F is the bending force (tons)
  • σt​ is the tensile strength of the material (N/mm²)
  • T is the thickness of the sheet (mm)
  • L is the bending length (m)
  • V is the width of the V-die opening (mm)

(2) Consider Material Properties

  • Different materials have different tensile strengths and ductility, which affect the bending force. For example, low-carbon steel typically has a tensile strength of 420 N/mm², while stainless steel can have a tensile strength of 650-700 N/mm². Always use the correct material parameters when calculating bending force.

(3) Select the Appropriate V-Die Opening

  • The width of the V-die opening V should be selected based on the sheet thickness T. Generally, the width of the V-die opening is 6 to 12 times the sheet thickness. For example, for a sheet thickness of 3mm, the V-die opening should be 18mm (3mm × 6).

(4) Use Lubricants to Reduce Friction

  • Using appropriate lubricants during the sheet metal bending process can reduce friction, thereby lowering the required bending force. Choose the right type of lubricant and application method based on the calculated results to ensure optimal bending performance.

(5) Monitor and Adjust in Real-Time

  • During actual bending and optimizing press brake operations, monitor the bending force and sheet deformation in real-time and adjust process parameters as needed. This helps to accommodate different materials and bending requirements, ensuring a more efficient and stable production process.

(6) Consider Springback Effect

  • Materials will have a certain springback effect after bending, which affects the final bending angle. By increasing the bending force or adjusting the bending angle, you can compensate for the springback effect and ensure the accuracy of the bending angle.

(7) Use Finite Element Analysis (FEA)

  • For complex sheet geometries and loading conditions, use Finite Element Analysis (FEA) for numerical simulation calculations. This helps to more accurately predict the bending force and sheet deformation.

(8) Refer to Tonnage Charts

  • When selecting tools and setting bending parameters, refer to the tonnage charts provided by the press brake manufacturer. These charts play pivtal role in press brake bending force for different materials and thicknesses, serving as a reference for actual operations.

9. Safety Tips for Press Brake Operation

  • Personal Protective Equipment (PPE). Always wear safety glasses, gloves, steel-toed boots, and ear protection against various potential hazards associated with press brake work.
  • Regular Equipment Inspections. Inspect the press brake before each use, focusing on safety devices and emergency stop buttons.
  • Adherence to Operating Procedures. Only trained and authorized personnel should operate the machine, following the manual's guidelines.
  • Maintaining a Clean Work Area. Keep the area around the press brake free of obstacles and ensure the floor is dry and clean.
  • Proper Die and Tool Selection. Use the correct tooling and dies for the material and thickness being processed. Different metals and material thicknesses require varying tooling considerations.
  • Keeping Hands Clear of the Die Area. Use tools or clamps to position and adjust the workpiece, keeping hands away from the die area.
  • Focus and Attention. Stay focused and avoid distractions during operation.
  • Regular Training and Drills. Conduct regular safety training and emergency drills to keep skills and knowledge up-to-date. Operators should be familiar with different types of press brakes and their capabilities.
  • Utilizing Safety Guards and Devices. Ensure all safety guards and devices are in place and functioning correctly.
  • Reporting and Addressing Safety Hazards. Report any safety hazards or equipment malfunctions immediately and do not operate the common press brake until resolved.

III. Common Bending Processes and Examples in Sheet Metal Fabrication

1. V-Bending: Precision and Versatility

V-bending

V-bending is one of the most widely used methods in bending sheet metal. It involves using a V-shaped punch and die to create precise bends at various angles. This method is highly versatile and can produce acute, obtuse, or 90° bends depending on the punch and die configuration.

Consider the production of a control panel housing for an industrial machine. The housing requires multiple bends to form its complex shape. Using V-bending, the fabricator can achieve the necessary angles with high precision, ensuring that each bend aligns perfectly with the design specifications. This method's flexibility allows for quick adjustments, making it ideal for both prototyping and full-scale production.

2. Air Bending Tasks: Flexibility and Control

Air bending is similar to V-bending but offers greater control over the bend angle. Air bending is a versatile and commonly used press brake bending technique, which is a favorite among many operators, has the metal resting on the die while the punch descends, achieving the desired bend. In this process, the punch does not force the sheet metal into the bottom of the die cavity, leaving a gap (or air) underneath. This allows for more precise control of the bend angle and reduces the risk of springback. 

With this bending basics method, the die opening, not the punch tip radius, determines the inside bend radius. Specifically, the bend radius forms as a percentage of the die opening. In air bending, the wider your die opening, the larger radius you’ll achieve. Air bending, a favorite among many operators, has the metal resting on the die while the punch descends, achieving the desired bend.

A manufacturer producing custom brackets for automotive applications needs to achieve various bend angles with minimal tooling changes. Air bending provides the flexibility to adjust the bend angles on the fly, accommodating different design requirements without the need for multiple sets of dies. This method ensures consistent quality and reduces setup time, enhancing overall productivity for the metal forming and fabricating industry.

3. Bottoming Bending Technique: High Precision and Consistency

press brake bottom bending

Bottoming, also known as bottom pressing, involves pressing the sheet metal into the bottom of a V-die to form the angle. Unlike air bending, bottoming requires higher pressure, and each bend angle requires a different set of dies.

In the production of high-precision electronic device enclosures, bottoming ensures the accuracy and consistency of each bend angle. Because bottoming reduces the springback effect, it is ideal for producing parts that require high precision and consistency.

IV. Conclusion

In this article, we have discussed some important considerations and tips for using a modern press brake. The use of every press brake requires a broad understanding of the machine and a wealth of experience in the intricate world of metal fabrication.

Embracing the latest software and technology can significantly optimize your press brake operations. At ADH, we have extensive experience in the field of bending machine manufacturing. If you need further information, feel free to reach out to us for a discussion.

We are a professional sheet metal machine manufacturer and service provider, offering a range of machines, including CNC press brake, fiber laser cutting machine, shearing machine, and slotting machine. If you have any ideas or requirements for a bending machine, our team members are here to help.

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