http://www.zjgzr.com/what-is-a-three-roller-rolling-machine.html
When you explore the equipment manufactured by Zhangjiagang Zhongrui Automation Equipment Co., Ltd., one key machine type is the three-roller rolling machine (also called three-wheel or three-roll rolling machine). This article explains what it is, how its unique three-roller structure works, and how it stacks up against other roller configurations such as two-roller, four-roller and seven-roller machines.
1. What is a Three-Roller Rolling Machine?
A three-roller rolling machine is a metal forming device designed to bend or roll sheet, plate or tubular materials into curves, cylinders or conical shapes by means of three rollers (also referred to as “wheels” or “rolls”). The basic configuration uses one upper roller and two lower rollers (in a symmetrical arrangement) so that material fed between them is gradually bent as the upper roller presses and the two lower rollers drive the rotation. (See general descriptions of three-roller machines.)
Manufacturers like Zhangjiagang Zhongrui Automation Equipment produce such machines for pipe forming, plate rolling and other metal-shaping applications.
2. How does the three-roller structure (upper, middle, lower—or left, centre, right) achieve rolling and forming?
In a typical three-roller configuration:
-
You have two lower rollers which are fixed (in terms of vertical position) and rotate, providing the driving torque to the material. For example, two bottom rollers gear-mesh or are driven via gearbox to rotate.
-
You have one upper roller, centrally positioned between the lower pair. This upper roller moves vertically (and sometimes horizontally) to press the material into contact with the lower rollers, thus establishing curvature. For example, the upper roller is lifted by a screw/worm drive mechanism to adjust the gap and create bending.
-
The material (plate or tube) is fed between the rollers; as the upper roller presses and the lower rollers rotate, the piece is gradually bent. The upper roller pressing creates a deformation zone; the lower rollers drive movement and help wrap the material around an imaginary or real bending radius.
In effect: by adjusting the vertical position of the upper roller you change the curvature (bending radius). The symmetrical arrangement ensures consistent bending and helps produce cylindrical or conical shapes. For example, one description says “three-roller plate rolling (one upper / two lower rolls) forms cylinders/curves simply and reliably.”
Thus, the machine achieves bending and forming through:
-
Driving motion (rotation) by the lower rollers
-
Vertical (or slight lateral) adjustment of the upper roller to achieve the proper gap and curvature
-
Feeding material and controlling passes until the desired shape (e.g., a tube or cylinder) is formed.
3. How does it compare with two-roller, four-roller and seven-roller rolling machines?
Two-roller machines:
-
Usually consist of just two rollers (top and bottom), or sometimes one fixed and one movable. These are simpler but have limitations: less control over forming, fewer supports for the material, and limited ability to form certain shapes (especially large diameter cylinders or thicker plates).
-
The three-roller machine offers more support (two lower rollers) and better bending control thanks to the upper roller adjustment.
Four-roller machines:
-
A four-roller machine adds an extra roller (so two upper, two lower, or other variants) which increases control, precision and ability to handle thicker, larger or more complex shapes. The extra roller(s) reduce force required, improve stability and offer more uniform bending.
-
Compared to a three-roller machine, a four-roller one may offer higher precision, less material distortion, better for high‐end applications (e.g., precision cylinders, large diameter vessels).
-
However, a four-roller machine is more complex, more expensive, maybe larger and requires more maintenance.
Seven-roller machines (or multi-roller machines):
-
These are even more advanced machines with multiple rollers (often 7 or more) which offer very fine bending control, excellent surface quality, high precision, minimal residual stress, and are used for very specialized tasks (large pressure vessels, aerospace parts, etc.).
-
The cost, footprint, installation complexity, and maintenance requirements are significantly higher.
-
Compared to that, the three-roller machine represents a more economical, simpler choice for many standard bending tasks.
In summary: a three-roller machine is a good mid-level solution — more capability than the simplest two-roller machines, but less complexity (and cost) than four-roller or multi-roller machines. For many manufacturers needing to form tubes, pipes, or cylindrical shapes with moderate precision and cost-effectiveness, a three-roller machine is often the optimal choice. (Sources describing three-roller cost‐effective solution:
4. Working principle in more detail
-
The workpiece (plate or tube) is placed between the three rollers.
-
The two lower rollers are rotated by a motor/gearbox; they drive the workpiece to move (feed) and rotate.
-
The upper roller is lowered (by screw/worm drive or hydraulic) to press the workpiece towards the lower rollers. This generates bending moment around the contact area and gradually wraps the material around an effective axis. For example, one machine description says: “The upper roller do vertical elevating moving at the center position of two lower rollers… through the reducer output gear meshing with the lower roller gear to obtain the two lower rollers for mutual rotation movement.”
-
As the machine continues to feed the material and the rollers rotate, the piece is rolled into a curved or cylindrical shape. The curvature (or final diameter) is adjusted by how far the upper roller presses and by the gap/center-distance of the lower rollers.
-
For conical shapes, additional attachments or unequal settings may be used so the roll angle or gap changes along the length of the piece. Many three-roller machines allow for pre-bend, main bend and drop off features to ensure good shape and minimal distortion.
By carrying out this process, the machine converts flat or straight material into curved or tubular forms efficiently and with good repeatability.
5. Why choose a three-roller machine (such as those from Zhangjiagang Zhongrui Automation Equipment Co., Ltd.)?
-
It offers a balanced mix of capability and cost: suitable for many industrial applications (pipe manufacturing, structural tubing, boiler shells, metal furniture, etc.).
-
The structural simplicity (three rollers) means easier maintenance, fewer components, and lower cost than more complex multi-roller machines.
-
It is versatile: many models can handle various thicknesses, widths and diameters (depending on the model).
-
For manufacturers who don’t require ultra‐high precision or extremely large diameter bending, a three-roller machine is an efficient choice.
A three-roller rolling machine is a cornerstone in the metal forming industry: one upper roller, two lower rollers, allowing controlled bending and forming of sheet, plate and tube materials. Compared to simpler two-roller machines it offers better control and capability; compared to four- or seven-roller machines it offers a more economical and manageable solution. With manufacturers like Zhangjiagang Zhongrui Automation Equipment Co., Ltd. offering high-quality machines in this category, businesses can benefit from reliable forming equipment without breaking the bank.
http://www.zjgzr.com/what-is-a-three-roller-rolling-machine.html
Zhangjiagang Zhongrui Automation Equipment Co., Ltd.
