What are the rolling performance requirements for a four-roll plate bending machine?

Rolling Performance Requirements for a Four-Roll Plate Bending Machine

Compared to a three-roll machine, the advantages of a four-roll plate bending machine are direct pre-bending, no need for turning around, shorter straight sections, and higher forming accuracy. The main rigid requirements for rolling performance are as follows:

I. Pre-bending Performance Requirements

The machine should be able to fully pre-bend the plate ends, minimizing the remaining straight edges at both ends. Generally, the straight edge length should be ≤1.5 to 2 times the plate thickness.

Sufficient pre-bending force is required to prevent slippage, indentation, and scratches on the plate surface. Strict surface quality control is especially necessary for stainless steel and aluminum alloys.

Uniform pre-bending angles ensure uniform butt joint gaps and minimal misalignment after rolling.

II. Rolling Accuracy and Shape Accuracy

High roundness accuracy: Small diameter deviation for the same workpiece, no elliptical, tapered, or bulging shapes.

Good overall straightness: The plate should not exhibit lateral bending, twisting, or conical shapes in the width direction.

Consistent cylindricity after rolling, suitable for welding cylinders, pressure vessels, pipes, and other high-precision workpieces. Capable of stably rolling small-diameter cylinders (close to the minimum rolling diameter of the equipment), without excessive springback or rebound.

III. Operational Stability and Forming Consistency:

 Excellent roller rotation synchronization with no speed difference, preventing sheet material deviation, wrinkling, and tearing.

Uniform and slightly adjustable downward feed prevents abnormal deformation caused by localized overpressure.

High dimensional consistency and good repeatability when continuously rolling multiple products.

Vibration-free and impact-free rolling process ensures stable forming of thick and high-strength plates.

IV. Sheet Material Adaptability:

Adaptable to various materials: carbon steel, stainless steel, aluminum alloy, wear-resistant plate, high-strength steel, etc.

Good adaptability to varying thicknesses: thin plates do not wrinkle, and thick plates can be rolled without slippage.

When rolling wide plates, the roller system has sufficient rigidity, preventing sagging and deformation in the middle, ensuring consistent curvature across the entire width.

V. Surface Quality Protection Requirements

When rolling stainless steel, polished sheets, and mirror-finish aluminum sheets, the roller surface must be smooth, free of hard spots, and free from indentations and scratches.

Polyurethane-coated rollers and anti-slip roller sleeves can be used to prevent surface scratches.

The output material should be free of obvious scratches, pits, and blemishes, meeting the requirements for coating, polishing, and container appearance.

VI. Rigidity and Deformation Resistance (Structural Performance)

The work rollers and frame have sufficient rigidity, resulting in minimal roller deflection when rolling thick plates, preventing the formation of a "waist-shaped" roll.

The side roller and upper roller lifting and tilting mechanisms are rigid and reliable, ensuring no deformation or shifting under long-term heavy loads.

The hydraulic system maintains stable pressure, with no creeping or vibration, ensuring a smooth rolling process.

VII. Control and Process Performance

The CNC/digital display system provides accurate positioning; roller gap and curvature can be preset, enabling one-button rolling.

It features inching, semi-automatic, and fully automatic modes for convenient roundness correction and fine-tuning.

It supports process expansion such as conical rolling and multi-segment variable diameter rolling.