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How to choose the right plate rolling machine?

A plate rolling machine is a device that utilizes working rollers to bend and shape sheet metal, capable of forming parts of various shapes such as cylindrical and conical, making it crucial processing equipment. The working principle of a plate rolling machine involves bending the metal sheet between the upper roller and the two side rollers through the action of external forces such as hydraulic pressure and mechanical force; the third or sometimes the fourth roller is used to push the sheet, forming initial bending (also known as pre-bending). As the plate rollers start to rotate, they drag the material over the push roller and the squeezing roller, thereby forming arcs in the material, thus bending or rolling the sheet into shape. Depending on the rotational motion and position changes of differently shaped working rollers, parts such as ellipses, arcs, and cylinders can be processed.

The working capacity of a rolling machine is determined by four main parameters: the width of the rolled sheet, the thickness of the rolled sheet, the diameter of the rolled cylinder, and the yield limit of the sheet metal.

Applications of Plate Rolling Machine

Plate rolling machines can be categorized into two-roll plate rolling machines, three-roll plate rolling machines, and four-roll plate rolling machines based on their structure. Two-roll plate rolling machines are mostly used for processing smaller-sized plates, while three-roll and four-roll plate rolling machines are typically used for processing large-sized plates. They are commonly used in various industries including the manufacturing of pressure vessels for the oil and gas industry, marine instruments, household appliances, wind power, aerospace, automotive modification, etc.

Due to different requirements from various industries, there are various specialized rolling machines available in the market. Some widely used rolling machines include:

  • Vertical plate rolling machine (ideal for rolling large radii, such as ground fuel and water tanks)
  • 3-roll double-pinch plate rolling machine (suitable for heavy-duty applications)
  • 3-roll initial-pinch plate rolling machine (cost-effective and widely applicable)
  • Variable geometry plate rolling machine
  • 4-roll double-pinch plate rolling machine (suitable for all designs)
  • 2-roll plate rolling machine (mainly used for thin sheet rolling)

Among these bending machines, the most widely used are three-roll and four-roll plate bending machines. You can click here to learn more about them in detail: 3 Roll Bending Machine, 4 Roll Bending Machine.

Clear about needs and requirements: Parameters of plate: material, thickness, and width.
Processing requirements: workpiece drawings, shape, roll diameter, precision, roundness, error, angle, opening size, and some special requirements.

First, you’ll also need to know if you will be making cones or special shapes as this will determine the correct type and size of plate roll.

What is the capacity of the bending rolls?

Each plate rolling machine is made to spec to make a very specific item. The size and pressure (tonnage) available change as machine size increases. Each Plate Roller has its own capacity and that capacity is determined by the size of the rolls and the power to drive the material through them. The larger the capacity the larger the workpieces that can be formed, however as you go up in machine size also lose the ability to form the smallest of work.

Capacity is one of the biggest differences between machines, to determine the proper sizing it is critical that yield, tensile strength, width, thickness, and diameter (or radius) of the part are all considered because, for example, a higher yield or tighter diameter will require more pressure to form.

The Difference in the Number of Rolls in a Plate Rolling Machine

Plate Rolling Machines come in different types. Initial pinch and double pinch. Double-pinch rollers offer more precision and perform pre-bending on both ends in one setup, but they are slightly more expensive.

The number of rolls a plate rolling machine has made a big difference. Typically they are of a 3-Roll configuration. The rolls are the round part that spin to bend and shape the metal inside the machine. Each of these rolls can be configured with a specific shape in order to closely hold the working material without distorting it during the forming process. Each design has at least one pinching roll that’s used to feed the metal plate into the machine.

Pressing rolls are the rolls that provide the force that takes care of the bending process. The number of pinching and pressing rolls is how each machine is classified. The most common include a four-roll double-pinch and three-roll initial pinch plate bending machine.

Read More: 6 types of plate rolling machines

What features of the plate rolling machine will you need?

Look carefully at the features and options of available machines to determine the perfect plate rolling machine for your particular projects. Some things to consider include:

  • Machine construction. How sturdy is the machine housing? Is the frame solid with post-welding stress relief? What material was used to make the roll shafts? Are the rolls ground and hardened?
  • Machine power. Smaller capacity plate rolling machines will be motorized, but most profile bending machines are hydraulically powered. Size won’t matter if your new plate rolling machine doesn’t have the power to perform, so confirm the power source of the machine before purchase.
  • All rolls are driven. Good hydraulic plate rolling machines will have independent power to all rolls instead of a couple of drive rolls and an idle roll. This improves accuracy by reducing the chance of the workpiece slipping. See if the plate rolling machines you look at also offer features such as high torque drive systems and hydraulic brakes for greater strength and accuracy during rolling.
  • Control systems. Will digital readouts work for you, or will you want an NC control system? (Or a more specialized CNC upgrade?) Will you want a portable control unit that can be moved around to view the part from any angle during rolling?
  • Support device: Are there overhead supports to prevent light materials from collapsing when rolled to large diameters? Side support can also assist in preventing light materials from recurving toward the floor if the radius is very large.
  • The hardness rating of outer roll surface: The harder materials and laser/plasma cutting techniques used today require hard outer roll surfaces on rolling equipment. A hardness rating from 50 to 55 Rockwell C scale will have a reasonable penetration depth and provide long-lasting protection against roll surface wearing.

Read More: What is bending machine

Four buying suggestions for plate bending machines

Part-handling Options

Your roll bending application may require NC or CNC side and top supports, motorized loading tables, board alignment systems, infeed conveyors, or part ejectors. When choosing a new plate rolling machine, don’t forget this important safety and productivity tool!

Security considerations

Most new plate rolling machines are equipped with safety devices such as emergency stop buttons; safety trip wires; 24-VAC, low-voltage control circuits; and separate operator consoles. However, it is still your responsibility as the owner to ensure that these operating safety guards or devices are installed and properly used.

Will I Be Doing Any Welding in the Plate Roller?

Welding around expensive controls found on a new plate rolling machine could lead to extensive electrical damage from the welding power source. It could even fry the system.
You need to take special care to make sure the welding ground is on the part, not on the machine.
If you even think that this is a possibility, you need to have an upgraded, shielded electronic system to protect the plate rollers’ electronics. It’s better to be safe than sorry.

Do You Require a Mar-free Finish on the Rolled Parts?

If you require a mar-free finish, you need polished, precision-ground rollers. They are easy to clean and won’t pick up mill scale as much as traditional rollers.

If you need to have rollers made out of specialty alloys, you won’t suffer sticker shock. The cost of the rollers typically isn’t exorbitant, but of course, the application ultimately might justify the cost.