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Calculate Center Distance of 3 Roll Bending Machine

Calculating the bending capacity and parameters for a 3 roll bending machine involves several factors, including the material being bent, the machine specifications, the desired bend radius and angle, and the required bending force. Here, I’ll provide a basic overview of the key calculations involved in using a 3-roller bending machine:

Bending Force (Rolling Force) Calculation

4-roll plate rolling machine
4 Roll Plate Rolling Machine

The bending force required to bend a specific material depends on its thickness, width, and properties (such as yield strength). The bending force can be calculated using the following formula:

Bending Force (F) = 0.5 x Material’s Yield Strength x Thickness x Roller Width


  • Material’s Yield Strength: The material’s yield strength (measured in MPa) indicates how much force it can withstand before permanent deformation.
  • Thickness: The thickness of the material being bent (measured in millimeters).
  • Roller Width: The width of the rollers on the 3-roller bending machine (measured in millimeters).
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Bend Radius Calculation

The bend radius is the radius of the arc formed by the plate rolling process. It depends on the material, the machine’s specifications, and the desired bend angle. The bend radius can be calculated using the following formula:

Bend Radius (R) = Roller Diameter / Bend Angle


  • Roller Diameter: The diameter of the center roller (measured in millimeters).
  • Bend Angle: The desired bend angle (measured in degrees).

Minimum Flange Length Calculation

The minimum flange length is the distance between the bend line (where the angle iron contacts the rollers) and the edge of the material that remains flat after bending. It is essential to ensure that the angle iron can be effectively bent without causing excessive deformation. The minimum flange length depends on the material properties and the machine specifications.

Machine Capacity and Limitations

The 3-roller bending machine has its maximum capacity, which includes factors such as maximum thickness, width, and bending force it can handle. It’s essential to consult the machine’s specifications and guidelines provided by the manufacturer to ensure you’re operating within its safe and effective limits.

Pre-Bending Calculation

For some applications, you might need to perform pre-bending before the final bend to achieve the desired shape accurately. Pre-bending helps compensate for springback and ensures that the angle iron conforms to the intended curvature.

Calculate Center Distance of 3 Roll Bending Machine

plate rolling machine
3 Roll Steel Plate Rolling Machine

The center distance of a 3-roller bending machine refers to the distance between the centers of the top and bottom rollers, which determines the radius of the bend that the machine can achieve. To calculate the center distance, you’ll need to consider the diameter of the rollers and the desired bend radius. Here’s the formula to calculate the center distance:

Center Distance (C) = (2 * R) + Roller Diameter


  • R: The desired bend radius (measured in millimeters).
  • Roller Diameter: The diameter of the center roller (measured in millimeters).

Let’s say you want to calculate the center distance for a 3-roller bending machine with the following parameters:

  • Desired Bend Radius (R): 200 mm
  • Roller Diameter: 120 mm (center roller)

Using the formula:

Center Distance (C) = (2 * 200) + 120 = 520 mm

In this example, the center distance for the given 3-roller bending machine is 520 mm, which means the machine is capable of bending materials with a radius of 200 mm using the specified center roller diameter.

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Remember that these calculations provide a basic understanding of the factors involved in bending angle iron using a 3-roller bending machine. Actual bending operations may involve additional considerations, such as material properties, roller settings, and specific machine features. Always refer to the machine’s user manual, consult with experts, and perform tests to ensure precise and safe bending operations.