The working principle of the rolling machine

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The Working Principle of the Rolling Machine

The upper roller of the symmetrical plate rolling machine is centrally positioned between the two lower rollers. This positioning is achieved through the hydraulic oil acting on the piston in the hydraulic cylinder, enabling vertical lifting movement. The main reducer's final gear drives the gears of the two lower rollers, resulting in rotational movement which provides torque. The flat plastic metal plate of the bending machine passes between the three working rolls (two lower rolls and one upper roll). Using the pressure exerted by the upper roll along with the rotation from the lower rolls, the metal plate undergoes multiple passes of continuous bending. This process results in permanent plastic deformation, forming the required cylinder, cone, or a combination of both from the metal plate. A notable disadvantage of this hydraulic three-roller bending machine is that the ends of the plate require pre-bending conducted by other equipment. This type of rolling machine is particularly suitable for large applications with a thickness exceeding 50mm. A row of fixed idlers placed beneath the two lower rollers reduces the span between them, enhancing the precision of the rolled workpiece and the overall performance of the machine.

The Structural Characteristics of the Rolling Machine

The rolling machine's automatic feeding equipment typically consists of a sheet trolley, an actuator, a sheet transfer mechanism, and supporting mechanisms. The sheet trolley is designed to hold the sheets that need to be rolled. The actuator primarily functions in transporting the plates to the feeding platform from the trolley. Plate handling operations often employ rectangular coordinate manipulators and vacuum suction cup devices. In automated industrial systems, workpiece handling is crucial, and vacuum suction cups are commonly used in suction cup manipulators.

The transmission methods for Cartesian coordinate manipulators can be categorized as: mechanical transmission (such as rack and pinion, synchronous belt transmission, ball screw transmission), linear motor transmission, and pneumatic transmission. The sheet material transfer mechanism serves to move the sheet being rolled and typically employs roller shaft transfers or universal ball transfers. Auxiliary mechanisms aim to enhance the precision of sheet rolling and may include devices for sheet center alignment, pushing, and displacement detection.

Frame:

The frame of a rolling machine supports all components and absorbs the mechanical forces during the rolling process. It is usually constructed from high-strength steel to ensure stability and durability. The robustness of the frame is essential for handling heavy loads while maintaining alignment and accuracy.

Rolls:

Number of Rolls: Rolling machines are categorized based on the number of rolls present, including two, three, or four rolls, each serving distinct purposes:

• Two-roll machines: Used mainly for simple bending and shaping into cylindrical forms.
• Three-roll machines: Offer greater versatility, capable of performing both symmetrical and asymmetrical bending, common in plate bending applications.
• Four-roll machines: Provide superior control for precision bending, facilitating easier material feeding and rolling tighter diameters.

Material and Hardness: Rolls are constructed from hardened steel or may be coated to enhance wear and corrosion resistance.

Drive System:

Rolling machines may be driven by mechanical, hydraulic, or electric means, depending on required precision, speed, and power:

• Mechanical drives: Generally employed for lighter applications.
• Hydraulic drives: Provide increased power and precision, suitable for heavy-duty rolling tasks.
• Electric drives: Ensure efficiency and facilitate automation.

Adjustment Mechanism:

For three and four-roll machines, adjusting the side rolls and pinch roll is vital for controlling the bending process and achieving the desired curvature. Adjustments can be manually, motorized, or hydraulic, affecting both ease of use and final product precision.

Control System:

Modern rolling machines feature advanced control systems, including computer numerical control (CNC), which enhances precision, repeatability, and automation. CNC systems can manage roll movements, control rolling speed, and adjust positions based on input parameters.

3-Roller Video

4-Roller Video

Ever wondered how the metal around you is getting its shape? Be it an automobile part, a ship, or a large metal container. It's not magic, but a machine breathing life into metal and turning it into breathtaking art.

Plate rolling is an incredibly essential part of any metal industry. The task of these rolling machines is simple: shaping metal plates into cones, cylinders, and curved shapes.

The definition looks simple, but the plate bending/rolling machines deliver sophisticated, cutting-edge, unique products. Different types of plate rolling/bending machines are available in the market. This blog will provide a detailed view of a 3-roll plate rolling/bending machine's working principle and rolling process.

What is a Plate Bending/Rolling Machine?

A Plate Rolling machine, also known as a roller machine, is a type of metal rolling equipment designed to shape metals into conical, cylindrical, or curved forms. Industries require various machines depending on their specific needs.

Plate rolling is a complex but crucial process that expands the bending possibilities available to customers, depending significantly on the precision of operators.

What Are the Types of Roll Plate Bending Machines?

There are three types of plate rolling/bending machines that various industries utilize:

• 2-roll Plate Bending/Rolling machine

• 3-roll Plate Bending/Rolling machine

• 4-roll Plate Bending/Rolling machine

As mentioned above, each machine serves specific uses; however, this article will focus on the 3-roll Plate Bending/Rolling machine.

What is the Working Principle of a 3-Roll Plate Rolling/Bending Machine?

Before delving into the working principle, let's briefly review the 3-Roll Plate Rolling/Bending Machine. Industries of all sizes, from shipping to metal fabrication, require 3-roll plate bending/rolling machines. The primary function of this machine is to bend metal sheets into the desired shapes.

A 3-roll bending machine consists of three rolls: two side rolls that move back and forth while the upper roll remains fixed but rotates. The upper roll can be interchanged to accommodate varying shell sizes.

The manufacturer controls the roller's amount and speed to achieve the desired shape effectively. As illustrated, the plate bends uniformly with the intervention of the three rollers. Engineers can also manipulate specific locations during the pre-bending process to reach the required shapes.

Step 1: Placing the Plate

The initial step involves positioning the plate between the upper (I) and lower rollers (II and III). This operation bends the plate into an arc or a closed circle. As the metal sheet traverses through the three contact points formed by the rollers, it molds into the desired shape.

Step 2: Plastic Bending Deformation

After inserting the metal plate, the top roller presses downwards against the plate, inducing a plastic bending deformation due to compression.

Plastic bending deformation takes place when an object's shape and size alter under applied force. It happens when the force applied exceeds the material's yield limit, resulting in permanent deformation.

Step 3: Rotation & Friction

The friction between the rollers and plates causes the lower rollers to begin rotating, driving the plate longitudinally back and forth.

This movement occurs as the lower roller alternates between forward and reverse rotations while the upper roller consistently exerts downward pressure on the plate.

During this operation, stress can exceed the yield limit, leading to plastic deformation as the plate transforms to meet shape requirements.

Key Factors of a 3-Roll Plate Bending/Rolling Machine

• Adjust the relative positions of the upper and lower rollers to bend the plate to a radius no longer than the upper roller.

• The lower roller’s rotation is powered by a motor and reducer that rotates them in the same or opposite directions.

• To vary the curvature of the plates, adjust the positions of the upper rollers.

• If the desired curvature isn't achieved after the initial rolling, you can reconfigure the upper rollers and repeat the process until the ideal shape is attained.

A limitation of this machine design is that the three rolls create an isosceles triangle configuration. This arrangement leaves a straight segment at both ends, equal to half the distance between the two lower rollers centers where the rollers cannot process.

Despite this limitation, the advantages and features of a 3-roll plate bending machine dominate, with key benefits including its structure, ease of operation, and low cost.

Wrapping Up!

In various industries, including shipping, oil tanks, metal structures, tubes, and pipes, 3-roll plate bending machines continue to play a crucial role. Whether for 2-roll, 3-roll, or 4-roll bending machines, you can count on our plate-bending solutions.

We hope this blog post has enhanced your understanding of the working principle behind our 3-roll bending machine. For all your plate-bending machinery needs, feel free to contact us. The team at Himalaya Machinery is eager to assist.

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