The working principle of a three-roll bending machine.
Release time：2026-03-06
1. Feed Positioning: Gently feed the metal sheet to be processed (which can accommodate steel plates of varying thicknesses and widths according to equipment specifications) into the space between the upper roll and the two lower rolls. Adjust the position of the sheet so that its edges are parallel to the roll axes, thereby preventing deviation or distortion during the coiling process and laying a solid foundation for subsequent uniform deformation.
2. Pressure Application and Positioning: The hydraulic system controls the vertical downward movement of the upper roll until the upper roll is in tight contact with the top surface of the sheet material, while the two lower rolls are in contact with the bottom surface of the sheet material, thus forming a three-point contact structure characterized by “pressure applied by the upper roll and support provided by the two lower rolls.” At this stage, the initial pressure applied by the upper roll must just overcome the elastic resistance of the sheet material, enabling the sheet to initially conform to the roll surfaces and preventing slippage during subsequent feeding.
3. Continuous Feed and Deformation: When the drive system is started, the two lower rollers rotate synchronously and in the same direction under motor drive (the rotational speed can be adjusted via the control system). Relying on the friction between the roller surfaces and the sheet metal, the rollers steadily advance the sheet metal forward in a continuous feed. At the same time, the upper roller continuously maintains a constant downward pressure, applying a continuous bending moment to the sheet metal as it feeds forward.
4. Stepwise Plastic Deformation: As the sheet metal advances, each segment, upon passing through the contact point of the three rollers, is subjected to pressure from the upper roller and support forces from the two lower rollers, resulting in localized three-point bending that induces slight plastic deformation in that segment. As the sheet metal continues to advance, these small deformations accumulate segment by segment, gradually causing the sheet to bend from a flat plane into an arc-shaped curve. The radius of curvature is determined by the depth of the lower roller’s downward pressure— the deeper the pressure, the smaller the radius of curvature; the shallower the pressure, the larger the radius of curvature.
5. Forming Correction and Springback Control: Once the sheet metal has been coiled to the preset radius, stop feeding the material and maintain constant pressure on the upper roll. Then, rotate the two lower rolls in opposite directions for 1–2 revolutions to round out the formed component, thereby reducing some of the elastic springback in the sheet metal and ensuring uniform roundness of the component, as well as a smooth surface free of wrinkles and scratches. For thick plates or high-strength materials, further improve forming accuracy by repeatedly adjusting the downward pressure depth of the upper roll and re-coiling the material multiple times, thus effectively preventing defects such as ovalization or distortion.
6. Material Discharge Completed: After the rolled piece has been properly rounded, the upper roll is raised to release the pressure on the workpiece. The rolled cylinder or arc-shaped component is then carefully removed from between the rolls, thus completing the entire rolling process. If a conical cylinder is required, the inclination angle of the upper roll can be adjusted to apply different pressures to the two ends of the sheet metal, resulting in a variable-radius bend and ultimately forming a conical cylinder.
Related Blog
Working Principle of Electric Welding Machines
The core function of an electric welding machine is to achieve a strong, durable bond between metals, with its operating principle fundamentally based on the conversion of electrical energy into thermal energy. By leveraging the coordinated operation of its internal core components, the machine converts mains electricity into the energy required for welding and ultimately fuses the metal through the heat generated by the electric arc, thereby completing the joint. The key components include step-down transformers in conventional models, inverters in high-frequency models, welding electrodes, and control circuits for stable process regulation. These components work in a division of labor to ensure that the welding process proceeds in an orderly and controlled manner.
2026-03-30
What is nondestructive testing? What are the various NDT methods?
Nondestructive testing (NDT) refers to a quality-control technique that, without compromising the structural integrity, service performance, or internal microstructure of the test object, employs physical or chemical methods to perform qualitative, locational, and quantitative inspections for surface and subsurface defects—such as cracks, porosity, slag inclusions, lack of penetration, and looseness—in materials, components, and welded structures.
2026-03-27
Core Principles and Procedures of Fire-Resistance Testing
This is a standardized, controlled test procedure conducted in a laboratory furnace, following nationally or internationally harmonized time–temperature exposure curves (such as GB/T 9978 and ISO 834), to subject building components, fire-protection materials, structural elements, fire-stopping assemblies, equipment enclosures, and similar items to simulated real-fire exposure conditions. Under specified loading, the test continuously monitors three critical performance indicators—load-carrying capacity, structural integrity, and thermal insulation—and defines the fire-resistance rating as the duration from the onset of fire exposure until the first failure of any one of these indicators, thereby providing a standardized, repeatable, and quantifiable method for scientifically assessing the fire-safety performance of materials and components.
2026-03-26
Believe in your trust,
And our strength will bring us common success!
Sales Hotline:
Address: Ximagou Science and Technology Industrial Park, Jianxi District, Luoyang City
©2024 Luoyang Hongde Heavy Industry Equipment Co., Ltd. www.300.cn SEO Privacy Policy