Introduction
In the metal fabrication industry, bending and curving metal sheets are done using 3-roll plate rolling machines. A 3-roll bending machines are known for providing precise and efficient sheet metal bends. These machines can be utilized in various industries, including shipbuilding, aerospace, construction, and petrochemicals, where cylindrical, conical, and arc-shaped components are required.
In this article, you will learn about the complete details regarding 3-roll plate rolling machines, including their working, applications, and types. Moreover, you will have the idea of using these machines for metal fabrication.
Definition of a Three-Roll Plate Rolling Machine
In the past, manufacturers used single or double rollers to bend metal sheets; this process has evolved to provide greater convenience. The three-roll bending machine simplifies the process of converting flat metal sheets into precise curved shapes. With thick pressure vessel plates and the fineness of stainless-steel sheets, this machine offers repeatable results and outstanding productivity.
In this machine, three rollers are arranged in a triangular configuration. These rollers work in coordination to convert straight metal sheets into curved or bent surfaces.
Working Principle of a Three-Roll Plate Rolling Machine
The process of shaping the metal sheets into curved surfaces is rooted in the plate rolling process. This process has basic steps as follows:
- A metal sheet is positioned between the single upper roller and the lower double rollers.
- An adjustment is made to the diameter of the metal curve as needed. The operator adjusts the distance between the lower rollers to adjust the diameter.
- The system uses mechanical or hydraulic pressure for rolling actions; the rollers act in the opposite direction.
- The incremental bending of the sheet determines the diameter of the roll. The diameter increases as the sheet passes between the rollers. The average thickness of the metal sheet is almost 2 mm to 100 mm.
- The rollers apply pressure in a uniform direction to avoid deformation. The rollers are adjusted to maintain the diameter ≥ 200 mm.
Types of Three-Roll Plate Rolling Machine
The configuration of the rollers determines the types of the three-roll plate rolling machine as:
· Symmetrical 3-Roll Machines
A three-roll bending machine has two roller sets; the upper one travels vertically in the center of the two lower rollers. A screw, nut and worm gear system controls this movement.
The two bottom rollers are motorized. A reducer provides the transfer of the power of the motor, the output gear of which is joined to the lower roller gears to deliver the force required to bend the sheet.
· Asymmetrical 3-Roll Machines
In this arrangement, the top roller drives one bottom roll, which moves vertically both upward and downward. You can pre-bend the metal sheet without any extra equipment. The asymmetrical 3-roll machines have rolls with a smaller diameter and require less space. The operator must be highly trained and equipped to use asymmetrical 3-roll machines.
· Mechanical vs. Hydraulic Drives
Mechanical drives use a motor and gears to bend the metal sheet, while hydraulic drives use a hydraulic piston to work. Here is the comparison between the two:
| Features | Mechanical | Hydraulic |
| Cost | lower | Higher |
| Noise | Louder | Quieter |
| Stability | Moderate | High stability |
| Plates handled | Light medium | Heavy-duty |
Advantages and Disadvantages of a Three-Roll Plate Rolling Machine
There are advantages and disadvantages of using a 3-roll plate machine that are as follows:
Advantages:
- The machine can provide a high level of precision in bending, ensuring accurate production.
- It offers consistent results over many uses for bending a metal sheet.
- The machine has reduced labour costs by providing efficient bending in metal fabrication.
- A wide range of metal materials with different thicknesses can be bent by using 3-roll plate machines.
- The design is compact, so there is no need for a large installation space.
Disadvantages:
- The machine requires pre-bending before the rolling process can begin.
- The machine requires proper maintenance, which increases its operating costs.
- The design is quite complex and requires skilled labour for operation.
- A faulty mechanical 3-roll plate machine is a cause of noise pollution due to vibration and misalignment.
Applications of a Three-Roll Plate Rolling Machine
Today, 3-roll plate rolling machines are widely used in modern manufacturing processes across almost every industry where metal sheets are utilized. But there are some major fields of application:
| Industry | Applications |
| Aerospace | The conical fuselage parts and exhaust ducts are made by bending the metal sheets via these machines. |
| Automotive | Cars have exhaust pipes, cylindrical brackets that use a 3-roll plate rolling machine. |
| Petrochemical | For transporting fuel in high-pressure vessels, reactor shells are manufactured using this method. |
| Construction | Curved beams and steel arches are made. |
| Manufacturing | Cylinders for machinery and tanks. |
Comparison of a 3-Roll Plate Rolling Machine with a 4-Roll Plate Rolling Machine
The main difference between the 3-roll plate rolling machine and the 4-roll plate machine is as follows:
| Features | 3-roll machine | 4-roll machine |
| Design | Simple | Complex |
| Accuracy | high | Very high |
| Straight edge exclusion | Partial | Complete |
| Number of rollers | 3 | 4 |
| Suitable plate thickness | 2 – 100 mm | 5 – 150 mm |
Conclusion
The 3-roll plate bending is a reliable choice for bending and curving metal sheets in the aerospace, construction, shipbuilding, petrochemical, and automotive industries. It is a vital part of contemporary metal fabrication due to its capability to minimize and manage a broad variety of plate thicknesses, providing dependable and repeatable outcomes. The cost of operation and maintenance needed is significant, but the benefits of its efficacy, precision, and flexibility are greater than the disadvantages.
MIHARMLE CNC has high-quality plate rolling machines. Here, you can find superior equipment designed for accuracy and performance.