Skip to content

Heavy Plate and Sheet Metal Rolling Techniques

Plate Rolling Process

Steel and Aluminum Plate Rolling Process, Basics of Sheet Metal Rolling, Plate Rolling Formula

Metal sheet and plate rolling play an essential part in metal fabrication, it comes down to understanding the properties of the material and how pressure from the plate rolls can affect those properties.

The prefabrication of metal vessels and vertical tanks is the mainstay of the production tasks in metal fabrication workshops.
Metal containers are mostly cylindrical, and the cylinder body is mostly made of tailor-welded cylinder sections. The cylinder section is one or several steel plates/sheet metal, which are welded after rolling and bending. The main tank wall of the vertical tank is also welded after roll bending. Some other arc-shaped workpieces are generally formed by roll bending, so the rolling plate is one of the most widely used bending processing methods.
The equipment used in the roll bending process is a steel plate rolling machine, so the working principle and operation skills of the sheet metal rolling machine must be understood and mastered by relevant employees. The quality of plate rolling directly affects the quality of products, so we must pay attention to the rolling plate process.

What Is The Plate Rolling Or Sheet Metal Rolling Process?

Plate rolling/sheet metal rolling is a metalworking process that involves the deformation of a metal plate or sheet to form a curved or cylindrical shape. The process is often used in the fabrication of pipes, tanks, pressure vessels, and other cylindrical or curved components used in various industries.

The plate rolling process involves three rollers, arranged in a triangle formation, which rotate in the same direction to deform the metal plate or sheet. The two outer rollers, known as the backup or supporting rolls, provide the necessary support to the metal plate during the rolling process. The middle roller, also known as the driving roll, rotates and applies pressure to the metal plate, causing it to deform and take the desired shape.

The plate rolling process can produce a wide range of cylindrical and curved shapes, including cylinders, cones, spheres, ellipsoids, and more. The process is widely used in various industries, including construction, oil and gas, transportation, and manufacturing. The process requires skilled operators and specialized equipment to ensure that the metal plate or sheet is rolled to the desired specifications and meets the required quality standards.

Sheet Metal/Plate Rolling: Principle, Process

Sheet Metal and Plate Rolling: Roll bending the metal sheet(thickness <6mm ¼”) or metal plate, (thickness >= 6mm ¼”), is pressed into great accuracy cylinders and cones, to make bulk storage containers, ductwork, piers for oil rigs, panels for the hulls of ships, etc.

Metal sheet or metal plate rolling(sheet rolling) is typically the 2nd step in the tank or ductwork fabrication process after the flat sheet or plate is typically cut to size on a CNC laser or plasma cutting table, the metal plate rolling process is used for steel and aluminum plate into full cylinders, cylinder segments, full cones, and cone segments for future fabrication at your facility. Plate rolling can help form tanks, metal ductwork, pipes, cones, and more.

Working principle

The plate rolling process of the plate is actually a process of plastic deformation of the steel plate/sheet metal under the action of an external force. During the deformation process, the fibers of the outer layer of the steel plate are elongated, the fibers of the inner layer are shortened, and the fibers of the middle layer remain unchanged. The more the fibers of the outer and inner layers of the steel plate are elongated and shortened, the greater the deformation.

The degree of deformation depends on the plate rolling radius and plate thickness.

  • For the same bending radius, the thicker the steel plate, the greater the degree of deformation.
  • For a steel plate of the same thickness, the smaller the bending radius, the greater the degree of deformation.

Especially the cold plate rolling process of the cylindrical body, if the process is improper, it will cause strain aging and lead to grain growth, so the general permanent deformation should not exceed 5% (that is, the difference between the outer circumference of the cylinder and the inner circumference is the same as the inner circumference. The ratio is not more than 5%) due to the limitation of the mechanical properties of the material, the degree of deformation must be controlled within a certain range, that is, the minimum plate roll-bending radius of the workpiece is specified.

Plate rolling process

PRV Heavy Plate Rolling Machine – Learn More

In the plate rolling process, a flat plate of metal is formed into a specific curve or radius. The plate is placed between rollers, which turn in opposite directions, and which have a gap smaller than the thickness of the metal plate. As the plate moves between the rollers it is compressed or made thinner. As the work is performed, the plate is eventually molded into a full cylinder, cylinder segment, full cone, and cone segment that can then be used as part of a fabrication project.
During the rolling plate process, the metal sheet/plate is deformed in such a way that matter is ‘squished’ along the length from the inner surface of the metal sheet/plate to the outer surface. The inner half of the metal sheet/plate is compressed as it is forced around the plate roll while the outer half is stretched. The section of the metal sheet/plate that is exactly in the middle, (with regard to the thickness), is not affected. The length of the middle section of the steel plate is called the ‘mean running’.

Read More: 11 Key Points For The Plate Rolling Process

How to measure the length of a metal sheet to make a cylinder of a certain diameter? To develop the blank flat length for a cylinder rolled from a metal sheet or plate, should calculate the centerline arc :

  • (Outside Diameter – Thickness) x 3.1416 = Length of Plate Required
  • (Inside Diameter + Thickness) x 3.1416 = Length of Plate Required

Read More: Top 4 Formulas For Plate Rolling Process Calculation

Steel Plate Rolling Machine

Plate rolling machines typically use a series of hardened precision rolls utilizing either hydraulic or mechanical power.

Steel plate rolling machines work with a wide range of materials in sheet metal and heavy plate rolling services. Plate rolling machines can roll plates in most metal materials and grades. For sheet metal, a plate roller can roll aluminum, stainless steel, galvanized steel, mild steel, painted, and polished materials. While there are countless applications for rolled plate and rolled sheet metal, encounter certain applications more than others. The heavy plate rolling services are most often used to create components for metal duct work, circular tank walls, machine housings, piping, stacks, molds, and bridges.

Read More: Plate Rolling Machine, Sheet Metal, Steel Plate Bending Roll

Types of Sheet Metal/Plate Rolling Machine

According to the arrangement of the upper and lower rolls, the types of plate rolls are generally divided into four types: 2-roll plate rolling machines, symmetrical 3-roll plate rolling machines, asymmetrical 3-roll plate rolling machines(initial pinch plate rolling machines), and 4-roll plate rolling machines.
Among them, the symmetric 3-roll plate roll has an double pinch plate rolling machine, variable geometry plate rolling machine, and top roll variable geometry plate rolling machine, the special structure allows them to perform both symmetrical or asymmetrical rolling plate.

What are the two types of rollers used in plate work?

The two most common types of rollers used in plate work are as follows:

  • Top and Bottom Rollers: This type of roller consists of two parallel rollers arranged one above the other. The bottom roller stays in a fixed position, while the top roller moves up and down to bend the sheet. The sheet is fed between the two rollers and is gripped and bent as the top roller is driven downwards. This type of roller is commonly used for rolling simple cylindrical shapes.
  • Pyramid Rollers: This type of roller consists of three rollers–two on the sides and one at the top. The two side rollers are angled and are positioned at a fixed distance from each other. The central roller is positioned higher up, and is adjustable to control the degree of curvature in the sheet metal. This type of roller is used for rolling cones and complex shapes.

Both top and bottom rollers and pyramid rollers work using the principle of bending the sheet metal between two or more rollers to form a curve or a cylinder. They find application in metal fabrication and manufacturing processes and are versatile for handling various thicknesses and sizes of sheet metal. The rollers can be machined with different geometries and coatings to better handle specific material properties.

What size are plate rolling machines?

The size of plate rolling machines can vary widely, as they are available in a range of sizes to suit different applications. Generally, plate rolling machines are classified by their maximum roll bending capacity, which refers to the thickest and widest piece of material that they are designed to roll.

The size of a plate rolling machine is typically characterized by the following parameters:

  • Maximum sheet thickness – Typically ranging from 2mm to over 150mm depending on the machine.
  • Maximum sheet width – This ranges from as low as 500mm to well over 6000mm based on the plate rolling machine.
  • The number of rolls – Machines available with different numbers of rolls, the most common being 3-roll and 4-roll.
  • Roll diameter – Usually associated with plate thickness, larger rolls are needed for thick plates.

The exact size of a plate rolling machine will depend on the specific application it is designed for, and the size of material it will be handling. A smaller plate rolling machine may be suitable for rolling thinner, narrower materials, while a larger machine would be needed for thicker or wider materials. Additionally, some plate rolling machines can be customized or modified to suit the needs and specifications of a particular job or project.

Read More: Bending Capacity Of Steel Plate: Understanding Its Limitations And Applications

2-roll plate rolling machine

2-roller plate bending machine
2-roll plate rolling machine

In a conventional 2-roll plate rolling machine, the sheet feeds between a steel upper roll and a much larger urethane bottom roll. The urethane allows the sheet to conform around the upper tool. The diameter of the top roll dictates the cylinder radius that can be achieved, and to form a different diameter requires a different mandrel—a tube that slips over the top roll. The urethane roll’s strength limits the machine’s thickness capability.

So 2-roll plate rolling machine meets the thin and small material. Fabricators can precisely bend materials that are less than 24 inches wide and 3/16 of an inch thick. A reliable 2-roll bending machine will boost your shop’s productivity, quickly and accurately bending large batches of small cylinders into a uniform diameter without leading and trailing flats. This makes them ideal for batch production of thin cylindrical items used in household appliances such as filter canisters. Other steel plate rolling machines don’t accommodate these sizes.

Read More: 2 Roll Plate Bending Machine’s Principle and Feature

Symmetrical 3-roll plate rolling machine/pyramid roller

Symmetrical 3-roll bending machine(Pyramid Roller, Pyramid Rolling Machine, Pyramid Plate Roll Machine) has a simple structure, convenient operation, more accurate forming, lightweight, easy manufacture and maintenance, and cheap price. It is the most common plate rolling machine. The plate rolling machines in some factories are all plate rolling machines of this type, but it has a disadvantage in that there is a large remaining straight edge. The 3-roll plate rolling machine is mainly composed of a machine base, transmission device, shaft rolls, and other parts. The lower rolls is driven by the transmission device to rotate synchronously in opposite directions, the top roll is fixed in the sliding bearing, moves up and down through the lifting screw, opens the movable support, and can take out the bent workpiece from this end.

Rolling plate process

The metal sheet/steel plate is placed on the lower rolls, the lower surface of the steel plate is in contact with the highest point of the lower rolls, and the top surface is just in contact with the lowest point of the top roll. If the top roll is lowered, that is, when the lowest point of the top roll is lower than the highest point of the lower rolls, the steel plate will immediately bend, and then through the continuous rotation and rolling of the top and lower rolls, the steel plate will exert force and friction on the shaft rolls under the action of force, it automatically advances and bends. The lower rolls are an synchronous driving rolls, and the top roll is a driven roll. When the plate forms a certain bending arc in the range that should be rolled, then lower the upper roll to roll until the steel plate forms the required bending radius.
The symmetrical 3-roll plate rolling machine is suitable for rolling and bending of various plates, but it needs to pre-bend the straight edge end.

Asymmetrical plate rolling machines/initial pinch plate rolling machine

The structure of the asymmetric 3-roll plate rolling machine/initial pinch plate rolls is relatively simple, the remaining straight edge is small, and no pre-bending operation is required, but the plate needs to be turned around and bent, which is troublesome to operate. The horizontal center distance of the top roll is reduced to a very small position, and the other lower roll is placed on the side, so that only one end of the bent sheet has a straight edge, as long as the sheet is turned upside down after the first bending roll over the head again, and the straight edges on both sides can be eliminated. Due to the asymmetrical arrangement of the rolls, the force on the two lower rolls is uneven, and the force on the lower roll close to the top roll is very large, which is prone to bending and causes the steel plate rolled out to bulge.

The asymmetrical 3-roll plate rolling machine/initial pinch plate rolls is suitable for rolling thin and short tube joints without straight edge pre-bending.

Read More: 3 Roll Bending Machine: Profile/Plate, 5 Types, 4 Benefits

4-roll plate rolling machine/double pinch plate rolling machine

The 4-roll plate rolling machine is convenient for centering the plate, and the process is versatile. It can correct defects such as skew and misalignment, and bend both of the plate ends at one rolling plate process to improve work efficiency. However, the structure is complex, heavy, bulky, and expensive.

The working principle of the 4-roll plate bending machine is that the top roll is the driving roll and is fixed, the lower roll can be lifted vertically, and the two side rolls are the auxiliary roll, whose position can be adjusted, and they are all driven rolls. When rolling the plate, first put the steel plate/metal sheet between the upper and lower rolls, then raise the lower roll to press the steel plate tightly, raise the one side roll, and bend the steel plate to a certain degree, that is, the front end of the plate reaches a certain roll bending. Since there is still a straight section at the end that has not been rolled, another side roll, the upper roll, and the lower roll should be raised to form another set of an asymmetrical 3-roll plate rolling machine during the second bending, and the motor should be started again to let the main shaft The rolls are reversed, bending the front and rear ends of the sheet.

A double-pinch plate roll is similar to a four-roll plate roller but without the bottom roll.

Read More: 4 Roll Plate Bending Machine – The Best Buyers Guide

Unbent flat end and pre-bending

When the plate rolling machine performs rolling plate/sheet rolling, the steel plate rolling consists of three steps: pre-bending, centering, and roll bending. Since the metal sheet is bent through the lowermost point of the top roll under the support of two rolls, a section at the beginning and end of the metal sheet cannot be bent through the lowermost point of the top roll. In a symmetrical plate rolling machine In machine, its length is approximately equal to half of the center distance between the two lower rolls, which is what is often called an unbent flat end. The theoretical remaining unbent flat end when the steel plate/metal sheet is rolled and bent is shown in the table below:

Method of rolling plateSymmetrical/3 rollAsymmetrical/3 roll4 roll
Unbend flat endL/2(1.5-2)δ(1-2)δ
Note: L—center distance of side rolls of plate rolling machine, δ—thickness of steel plate


For the problem of the unbent flat end, the following methods are commonly used:

  • Die bending method: First, the straight parts at both ends of the sheet are bent on a press according to the required bending radius.
  • Pad pressing method on plate rolling machine: First, bend a thicker plate on the plate rolling machine, and its bending radius is slightly smaller than that of the steel plate so that straight sides of various diameters can be pre-bent. The thick steel plate is used as a template (backing plate), and then the end of the sheet is placed on the template and rolled together on the rolling machine to bend the end of the steel plate into an arc. At the same time, during the bending process, it should be noted that the shaft roller only bears the pressure of the sheet to be bent, but not the pressure of the bending template, so as to prevent the shaft roller from being deformed due to excessive force. This method is suitable for steel plate thickness of less than 1/2 of the template thickness. Read More: Pre-bending and roll bending process


  1. Eliminates Waste: The pre-bending process helps minimize waste by creating an optimum geometrical formation so that both ends of the material can get in touch after rolling as perfectly as possible. Practicing the pre-bending process while having experience and being a skilled plate rolling machine operator plays a very critical role in eliminating waste.
  2. Eliminates the Need for Extra Trimming: The resources used on extra material trimming in plate rolling are nothing to be ignored for any efficiently and effectively functioning fabrication shops or operations. The need for extra trimming can easily be avoided through pre-bending by forming an optimum alignment of both ends of plate metal after rolling the material.
  3. Saves Time: Especially for high-volume production shops, wasting a minute out of the production time means wasting money and it can add up really fast over time. Since pre-bending helps an operator to form the desired shapes faster, the operating time per plate metal on a plate bending machine diminishes, which means rolling more parts with less time.
  4. Smooth Bending Surface and Uniform Curvature / Thickness: The pre-bending process is one of the most important practices in plate rolling when it comes to being able to get the results that were initially intended to get, which is simply rolling the material correctly. Properly rolled material will inevitably result in a smooth material surface and uniformity in material curvature and thickness.

Click for the chart of tensile strengths for aluminum and stainless steel to compare with mild steel

Centerline alignment of roll and sheet(workpiece)

The purpose of aligning the center line is to make the plain line of the workpiece parallel to the axis of the roll of the plate bending machine, prevent skewing, and ensure that the geometric shape of the workpiece after bending is accurate. The centering methods of the symmetrical 3-roll plate rolling machine include special baffle centering and lower roll groove centering.

Detailed rolling plate process of 3 roll bending machine

When rolling the plate/metal sheet, adjust the distance between the top and lower rolls. Generally, at the beginning, the top roll is pressed down to a certain value, and after the plate rolling machine is started to roll repeatedly several times, it is pressed down to a certain value again.
It is not possible to adjust the gap between the top and lower rolls at one time to roll and bend to the required curvature. The top roll should be adjusted 2-5 times according to the bending radius of the workpiece, and the value of pressing down each time is about 5-10mm. When the mouth is closed into a cylinder, fine-tune the amount of pressure, and do not use the arc template to check the curvature until it reaches the standard. When bending with a symmetrical 3-roll plate rolling machine, according to the known bending radius, the position of the top roll axis during bending can be calculated, the formula is as follows:

h=[(R+δ+r2) 2 -L2 -(R-r1)]1/2
In the formula, h——vertical center distance between top roll and side rolls (mm)
R – bending radius (mm)
δ——thickness of steel plate (mm)
r1——the radius of the top roll (mm)
r2——the radius of the lower roll(mm)
L——1/2 side roll center distance (mm)

Read More: Minimum Recommended Bend Radius Chart

Four steps of the rolling plate on a 3-roll plate rolling machine

  • Adjust the metal plate position: The purpose of adjusting the position of the metal plate is to make the central axis of the metal plate parallel to the roller axis to prevent skew.
  • Pre-bending: Pre-bending, when the plate is rolled, there is a length at both ends of the plate that does not bend because it cannot contact the upper roller, which is called the unbent end flat. The size of the unbent end flat that cannot be bent is related to the structure and bending form of the bending machine (symmetric bending, asymmetric bending).
  • Roll bending: Roll bending processing is the main process of product form, which is divided into two types: one-time feeding and multiple feeding. Rolling the thick plates is often used for multiple feeding. The number of feeds depends on process constraints (such as the maximum allowable deformation during cold rolling) and equipment constraints (such as non-slip conditions and power conditions).
  • Correct roundness: The final work is to correct the roundness of the roll forming. The purpose of correcting the roundness is to make the curvature of the whole circle as uniform as possible to ensure product quality.

Read More: Plate Rolling Machine Rolls Metal Cylinders

The detailed rolling process of the 4-roll plate rolling machine

  • Pre-bending beginning sheet: The position of the left roller rises to pre-bend the end of the plate.
  • Partially Rolled: After the pre-bending of the front section of the beginning sheet metal is completed, the right roller is lowered to a position 30~50 mm less than the pre-bending distance, and then partial rolling is performed to avoid discontinuity.
  • Continuous rolling: The right roller falls so that the height of its upper axis is slightly higher than the upper axis of the lower roller by 20 mm, and the left roller rises to the continuous rolling position, then the upper and lower rollers are fed forward for continuous rolling.
  • Pre-bending end-sheet: Continue rolling until the end of the plate reaches the vertical center line of the upper and lower rollers, the position of the left roller rises by 10~20 mm to pre-bend the end of the plate.
  • Close the circle: Forward and reverse feeding with rolling, and constantly adjust the feed displacement of the left roller and right roller until the plate can be the circle closed.

Read More: 6 Steps Of Plate Rolling Process Of The 4-Roll Plate Rolling Machine

Metal sheet centering: The purpose of plate centering is to prevent the plate from slipping and deviation during the rolling process. 

Sheet metal cone rolling

The operation of rolling the cone with a 3-roll sheet metal rolling machine/plate rolling machine is more complicated because the two ends of the cone have different development lengths and the blank is fan-shaped, so the axial bending degree and curvature radius of each end will be in order from large to small. When rolling, the end with a small diameter requires a slow speed, and the end with a large diameter requires a fast speed. However, it is impossible to require two different speeds on the 3-roll steel plate rolling machine/sheet metal rolling machines, so the following technological measures should be adopted when rolling the cone.

  • The billet is first divided into several equal areas according to the rolling direction, and the rolling and bending are carried out in sections so that the difference in bending length at both ends is reduced, which can be similar to the rolling of a cylinder.
  • Make three samples of the upper and lower calibers and taper of the cone.
  • After the inclination angle of the top roll is determined, start the sheet metal rolling machine to roll the two end areas first, and then stagger one area and one area for rolling in an inward order. Each rolling area should be inspected with a sample plate. When the workpiece is basically formed, make another full revision to bring it up to quality.


tgβ=[(R1+r)2 -(c/2 )2 1/2 – [(R2+r)2 -(c/2 )21/2/ L

  • β—the angle between the axis of the inclined shaft roller and the horizontal direction;
  • R1, R2—the angle between the large mouth and the small mouth of the truncated cone;
  • r — the radius of the lower shaft roller;
  • c—the center distance between the two lower shaft rollers;
  • L—the length of the conical frustum busbar;

Plate rolling machine is applied to the rolling and bending of profiles

When the plate rolling machine is applied to profile bending since the line of gravity and the line of action of the force are not on the same plane, the profile is subjected to the action of torque in addition to the bending moment, which makes the profile section distorted, and the degree of deformation of the profile determines the stress. The size of the stress and the size of the stress is determined by the bending radius, the smaller the bending radius, the greater the degree of distortion.

In fact, for the bending work of profiles, we still recommend using profile bending machines/angle rollers to complete this work.

Quality analysis of plate rolling Workpieces

When the plate/metal sheet is rolled and bent, there will be some defects due to various reasons, mainly including shape defects, surface crushing, and bending cracks.

The causes and preventive measures for appearance defects are shown in the table below

Defect typeCausePrecaution
The workpiece is taperedUnbalanced top roll and side rollThe top roll and the side roller are kept horizontal, and the pressure on both ends of the side roller is even
Hourglass shapeThe rigidity and jacking force of the lower roll is insufficient, and the back pressure of the top roll is too largeCorrectly select the lower jacking force and adjust the distance between the top and lower rolls; Correctly select the back pressure of the top roll
ConcaveThe lower pressure of the top roll is too large or the back pressure is insufficient, The upper force of the lower roll is too largeCorrect selection of top roll down pressure and back pressure Correct selection of lower roll top force
 SkewWhen the sheet material is not rectangular in shape, the centering is not good, and the force on the roller along the axis is uneven.Check the sheet metal and strictly implement the centering operation
Edges and cornersExcessive pre-bending or insufficient pre-bendingStrict pre-bending operation, check with sample in time

Workpiece surface crush

Since scale and other sundries are attached to the roll or fall on the steel plate, the surface will be crushed during plate rolling. Therefore, the scale and sundries on the steel plate and the roll shaft should be removed in time before prefabrication. When the surface quality of rolled parts is high, such as stainless steel, aluminum, composite plates, etc., the surface of the roll should be cleaned and polished before plate rolling to remove the edges, corners, and burrs on the surface of the sheet, so that the surface of the workpiece will not be damaged.

Workpiece cracked

Large internal stress may be formed due to cold work hardening during rolling and bending, which will reduce the plasticity of the steel plate, and in severe cases, it will be cracked. The precautionary measures are as follows:

  • To limit the degree of deformation, the greater the thickness of the steel plate and the smaller the roll bending diameter, the greater the degree of deformation and the more serious the cold work hardening.
  • Eliminate stress concentration factors that may be caused by the surface of the sheet, and pay attention to the rolling direction of the workpiece that is consistent with the roll bending direction.
  • Heat treatment for some special plates

Seven notes of plate rolling

  • Due to the spring back phenomenon of the sheet metal, the value of h needs to be corrected properly in practical applications.
  • Generally, multiple roll bending is used, and one-time forming should be avoided as much as possible to prevent the transition of roll bending.
  • In general, the minimum diameter of the barrel section capable of roll bending is about 1.2 times the diameter of the top roll.
  • When rolling a tube with a large diameter, a crane must be used to cooperate, so as to avoid flattening and deformation of the rolled tube due to the self-weight of the sheet during the rolling process.
  • An excellent plate rolling machine operator can improve the efficiency and roll bending quality. When the top roll of the plate rolling machine is raised and lowered, the two ends must be kept parallel, otherwise the rolled barrel section will have a taper.
  • During the plate rolling process, pay attention to whether the plate is aligned at any time. When the sheet metal rolling machine stops each stroke, pay attention to leaving a certain distance at the end of the plate to prevent the workpiece from falling off due to the inertia of the bending roll.
  • When the cylindrical workpiece is rolled to the joint on both sides, it can be tack welded on the steel plate rolling machine, and the spot welding should be flat. Then, the plate rolling machine can be started to correct the rounding. The focus of the correction is near the docking position. After repeated inspections with the sample plate, it can be unloaded.

Other 3-types of the metal plate bending process

  • Air Bending – this process works by pressing a punch onto the workpiece and forcing it down into a bottom V-shaped die. This die is mounted onto the press. The punch creates the bend so that the space between the side wall of the V and the punch is larger than the thickness of the workpiece. As this process requires less bend force, it tends to use smaller tools than other techniques. Air bending is extremely flexible, allowing a number of different materials and thicknesses to be bent at variable angles. This process also requires fewer tool changes than other methods, meaning higher productivity.
  • Bottoming – in this technique, sheet metal is forced against the V opening within the bottom tool. A set amount of space is left between the bottom of the V opening and the workpiece. This method offers more precision and less spring back, but a different tool set will be required for every different material, bend angle, and thickness.
  • Coining – in the coining process the top tool forces the material down into the bottom die with 5-30 times the amount of power of air bending. This causes perpetual deformation through the workpiece and there is very little spring back if any at all. This method offers high levels of accuracy.

Read More: Bending basics: 12 types of metal bending processes

Plate Rolling Formula

Metal Plate Rolling Capacity Calculator Table
Metal Plate Rolling Capacity Table

The plate rolling process entails two groups of important variables. The first group hinges on the machine, such as the number of rolls, their diameter, position, and how they move. All these depend on the machine being used. The second variable group deals with the workpiece involved, such as the maximum plate width (W), maximum plate thickness (Th), and minimum workpiece diameter (Ø), as well as the type of metal and its yield strength (YS). These variables can be plugged into an equation: W x Th2 x YS/g = K, where K is the constant and g is a parameter that takes into account the workpiece diameter and the machine geometry.

Applying such equations requires detailed application information, of course, but the important takeaway here is the factor Th2. Note that the sheet thickness value is squared, implying that a small change in thickness can have a dramatic effect on roll parameters.

Plate Rolling Calculation Formula/PRV 3 Roll Bending Machine

The entries in the table with the subscript “1” are known quantities, while those with the subscript “2” are the quantities to be determined. Dc represents the diameter of the working roll closest to the upper roll. Symbols for conversion when the plate width varies are shown in the figure below. When material, plate width, curvature, etc., change simultaneously, solutions can be obtained by simultaneously solving the equations in the table below.

NoAssuming Conditions.Conversion Formula
1Different Bending CurvaturesPlate Rolling Calculation Formula
2Different Steel Plate/Sheet Dimensions

a1≠c1,a2≠c2 Plate Rolling Calculation Formula

a1=c1,a2=c2, b1≈L Plate Rolling Calculation Formula

b1≈2L-b2 Plate Rolling Calculation Formula

3Different Steel Plate/Sheet Materials

Rx is a Constant. Typically,  Rx=10-20 Plate Rolling Calculation Formula

Ignoring Differences In Material Hardening. Plate Rolling Calculation Formula

4Different Rolling TemperaturesRx is a Constant. Typically, Rx=10-20. During Hot Rolling, σs=σbt. Plate Rolling Calculation Formula
Plate to Pipe Rolling Formula
Plate Rolling Calculation Formula
Plate to Pipe Rolling Formula.
Plate Rolling Calculation Formula PDF file download: PDF;
Plate Rolling Calculation Formula JPG file download: PNG

Seven steps to calculate the load and power required for a 3-roll plate bending machine

To calculate the load and power required for a symmetrical 3-roll plate bending machine, you will need to consider several factors, including the material being bent, the thickness of the material, the length of the material, and the diameter of the rolls.

  • Determine the material being bent: The first step is to identify the type of material that will be bent. This can include steel, aluminum, or other metals. The material type will impact the load and power requirements.
  • Calculate the thickness of the material: The next step is to determine the thickness of the material being bent. This is typically measured in millimeters or inches.
  • Determine the length of the material: You will also need to know the length of the material being bent. This can be measured in meters or feet.
  • Calculate the diameter of the rolls: The diameter of the rolls will impact the load and power requirements. This can be measured in millimeters or inches.
  • Use the following formula to calculate the load required: Load (tons) = 0.0175 x Material tensile strength (psi) x Thickness (inches) x Length (inches)
  • Use the following formula to calculate the power required: Power (hp) = Load (tons) x Rolling speed (ft/min) x Rolling force (lbs/in) / 33,000
  • Determine the rolling speed and rolling force: The rolling speed is the speed at which the material is being fed through the machine, measured in feet per minute. The rolling force is the force exerted by the rolls on the material, measured in pounds per inch.


It is important to note that these calculations are only estimates and may vary based on the specific machine being used and other factors. It is always important to consult the manufacturer’s specifications and guidelines when operating any machinery.

7 steps to calculate the sheet metal cone rolling process

To calculate the sheet metal cone rolling process, you will need to determine several geometrical parameters of the cone, such as the base diameter, the height of the cone, and the thickness of the sheet metal being used. Once this information is known, you can follow these steps to calculate the required length and development of the sheet metal required.

Determine the geometry of the cone, including its base diameter (BD), its height (H), and the thickness of the sheet metal being used (t).

Calculate the slant height (L) of the cone using the equation:

  • L = √(H² + (BD/2)²)
  • Determine the arc length (AL) of the cone required using the formula:
  • AL = Π × (BD/2) × (360° / θ)
  • where θ is the angle you wish to roll the cone to.
  • Calculate the developed length of the sheet metal required using the equation:
  • Developed Length (DL) = (AL × t )/ (2 × Π)
  • Add extra length or overlap as needed to allow for the seam to be welded or riveted together.

By following these steps, you can calculate the required length and development of the sheet metal needed to roll a cone of specific dimensions and thickness. It is important to note that these calculations are theoretical and may differ slightly from actual operating conditions due to factors such as friction, material properties, and the variability of the sheet metal being used.

Works Cited: Plate rolling rolls on CAPACITY CALCULATOR - BARNSHAWS