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The Ultimate Guide to Understanding the Press Brake Forming Process

press brake forming process

Knowledge of press brake forming is useful in many fields. It’s applicable to everything, from high-precision manufacturing to creative work. Whether you are an expert or just starting out, mastering the press brake forming process will unleash your metal-shaping potential!

The forming starts with preparing a flat sheet, usually made of steel or aluminum. Next, the sheet is clamped between a punch and die on the machine. The press brake’s applied force bends the metal into the desired shapes. Once bent to specifications, it’s released for removal.

However, there is more to that. So, in this article, we will discuss every nook and cranny of the press brake formation. We will also look into its different types and common mistakes to avoid. Keep reading to make your metal shaping top-class.

What Is Press Brake Forming?

Press brake forming is one of the oldest ways to shape metal mechanically. Through this process, a metal piece is “formed” in a straight line.

A punch and die set performs this “forming.” The set could be in the shape of a “V,” a “U,” or a track. Although press brake metal forming appears to be a simple concept, achieving accuracy can be difficult.

Precision bending requires a press, tooling, and workpiece material. Metal properties such as yield strength, ductility, hardness, and material condition all influence the material’s springback. Springback is a phenomenon in which metals, particularly common ones like carbon steel utilized in fabrication processes, revert slightly after being bent.

Press brake metal forming has the following characteristics:

  • The ability to shape ductile materials.
  • The press is used for both low- and medium-production runs.
  • There is a need for a little tooling.
  • It is ideal for producing smaller parts.
  • Long workpieces are output using a “V,” “U,” channel, or other impressive punch and die.

Press Brake Forming Process

The forming with the press brake exemplifies precision and flexibility. In manufacturing, it is a must-have method for shaping sheet metal. Here’s how the forming process takes place:

  • Preparation

The first step is to get a flat metal sheet ready. Stainless steel, aluminum, or steel are common materials for the sheet.

  • Setup

After that, the metal sheet is put into the press brake machine’s die-punch assembly. The punch is the top component, while the die is at the bottom.

  • Clamping

The machine secures the metal sheet between the punch and the die to prevent movement during the forming process.

  • Bending

The press brake machine applies force to the metal sheet via the punch. This force causes it to bend or deform according to the die’s shape. The bending can be a simple angle or a more complex shape. It depends on the final product’s specifications.

  • Release

After achieving the desired bend, the machine releases the clamping force. This allows the operator to remove the formed metal sheet.

press brake metal forming

Common Types of Press Brake Forming

The type of forming used depends on the material being formed, the shape that is wanted, and the final product’s use. Some common types of press brake forming are listed below:

  • Air Bending

Air bending is the most familiar industrial press braking method. It relies on three-point bending. How deeply the punch tip penetrates the “V” cavity determines the bend’s angle. The rise is greater the deeper the punch tip penetrates.

The depth of the stroke, not the tooling itself, determines the bend angle. This means that a single set of tooling can be used for a lot of different bend angles. The main advantage of air bending is that it requires far less force than other methods to achieve a 90° bend. The leverage effect makes this possible.

Air bending causes even less contact with the metal than bottom bending. The tooling only makes contact with the material at three points: the punch, tip, and die shoulders.

Because force does not produce the bend in air bending, less power is required than in coining. Air bending, like bottom bending, will involve some springback. However, to achieve the desired final bend, you will most likely need to bend at a slightly more acute angle.

  • Bottom Bending

Bottom bending is also known as “bottoming.” It involves bringing the punch and die together so that the metal contacts both the punch tip and the sidewalls. Bottom bending differs from coining in that the punch and die do not fully contact the metal. Furthermore, the tonnage used to imprint or thin the metal is insufficient.

Bottom bending uses less force than coining. Hence, the material does not completely conform to the tooling’s bend angle. In fact, bottoming causes the metal to “springback.” This occurs when it relaxes to a wider angle after being bent.

To achieve a specific angle when bottom bending, you must use tooling with a slightly sharper angle. This is to account for the springback that occurs naturally when the sheet metal is released. Different thicknesses and materials produce varying amounts of springback.

  • Coining

The term “coining” is derived from coin-making. Machines use too much force to compress a disc enough to conform to the image inscribed on the die set to put Lincoln’s face on a penny.

In the same vein, “coining” with a press brake entails exerting enough force to conform to the punch’s precise angle and die. During the coining process, the metal is more than bent. It thins as a result of the impact between the punch and die and along the bending surfaces.

The idea behind coining is that with enough force, your metal will bend to the exact angle of your tooling. As a result, your tooling should be identical to the desired grade.

  • Wipe Bending

Wipe bending, also known as wiping, is performed by clamping the sheet between two beams. The tool then adjusts its height to contour the sheet’s protruding edge to the bend profile.

Wiping is a faster way to bend. But it makes it more likely that the tool will scratch or damage the sheet in some other way as it moves across it. This risk is particularly high when bending at sharp angles.

This technique is commonly used to create panel-style products with small, profiled edges. It is simple to perform on press brakes with the right tools.

  • Rotary Bending

Rotary bending is a process that shapes metal sheets into cylindrical or conical forms by means of a rotating tool. This technique is commonly used to create pipes, tubes, and other curved components.

large press brake forming

Avoid These Common Mistakes in Press Brake Forming

Malicious forming mistakes are like power losses in a laser beam. Here are some common mistakes:

  • Over-Bending

It is possible to overbend when using the press brake. Being overly powerful or forceful can have negative consequences.

Precision is key when bending sheet metal. The force that is most suitable depends on the metal’s thickness, type, and the angle that is to be bent. A common cause of overbending is:

  • Inaccurate determination of bending force using thickness and bend radius as inputs.
  • Using the wrong bending techniques, like air bending or bottom bending, depending on the metal.
  • Missing the mark when it came to press brake machine settings for the workpiece.

Having sound knowledge of the bending methods and calculations can resolve these issues.

  • Tooling Troubles

Choosing the wrong punch and die can have a negative impact on press brake results. They define the work’s precision and quality.

One mistake in tool selection can lead to:

  • Misalignment of the sheet metal, which causes unnecessary effort and waste.
  • Inconsistencies in results.

One solution to these problems is to integrate CNC controllers. Modern press brake machines frequently include a CNC controller. This facilitates tool selection based on input parameters, such as

  • Material type
  • Thickness
  • Desired bend angle
  • The Springback Surprise

Springback can alter the expected results of press brake work. Here are some necessary considerations:

  • Springback is more common in certain metals due to their ductility, such as alloy steel and stainless steel. Knowing these characteristics allows one to predict the amount of springback.
  • Coining and air bending techniques have different effects on the workpiece when it comes to springback tendencies.

The best way for operators to reduce the impact of springback is to factor in natural reversion. Predictive tools and technologies, blended with operator experience, can confirm that the final bend angle and shape meet the specifications.

  • Improper Handling

Consider sheet metal to be the sensitive surface of a laser lens; any mishandling can cause irreversible damage. Proper material handling is critical to the grade of the sheet metal during the bending process.

Press brake operation is based on using mechanisms such as back gauges to position the sheet precisely under the press brake ram. It is also necessary to keep the work table and tools free of debris, oil, and other substances that can cause surface defects.

  • Overlooking Safety Protocols

There are inherent dangers in using press brakes and any other metal fabrication machinery. Ignoring safety protocols when operating a press brake is not only incorrect but can lead to serious injuries.

Here are some essential safety considerations:

  • Make sure that the Emergency Stop Button button is accessible and working.
  • To keep the press brake from breaking down on you, make sure to keep all of its parts in excellent working order.
  • Guarantee that all operators understand the machine’s safety features and the importance of following protocols.

Conclusion

The press brake forms the metal workpiece in a straight line. After setting up and bending the desired piece, the operator removes the sheet. There can be different types of forming, such as air bending, bottom bending, coining, etc. The material, desired shape, and intended use of the final product dictate the forming technique.

However, like any other metal fabrication, it’s crucial to avoid certain mistakes to get the best outcome. The operator needs to be well-versed in tooling and bending angles. Besides, adhering to the protocols is a must to avoid unintended accidents.

But before anything else, a top-class press brake is the prerequisite of a find forming. And you can get that from Fab-Line Machinery. If you need a multiple-axis press brake, graphical control, or maximum flexibility for your bending application, contact us.

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