Plate rolling can trace its history back to the middle ages when early metalworkers found that forging a shape using hammers from a simple cast produced a far stronger object than casting alone.
However, hand-hammering is an incredibly labour intensive process, so it wasn’t long before simple sheet metal rolling machines were developed to make the job easier. The early machines were simple two roller systems but by the mid-eighteenth century complex 4 roller designs appeared which were capable of creating o-type, u-shaped, multi-segment and other complex shapes.
How plate rolling machines work
Today’s plate rolling machines are similar in design to those early machines. They consist of two to four rollers with pinch and manipulate the metal plate as it passes through the machine. The geometry of the rollers can be adjusted to create almost any cylinder or cone shape with great precision.
Types of plate rolling machines
Plate rolling machines fall into three main categories: two-roll, three-roll and four-roll machines. Simple two-roll machines are used in light industry while three-roll machines can be used to create more complex shapes using higher gauge metal. Four-roll machines have an extra roll which pre-bends both ends of the plate during processing.
Two-roll bending machine
Two-roll bending machines use a single pinch roller that moves up against the smaller top roller to create a simple tube shape. Basic two-roll machines work extremely fast, but they are not as versatile as three-roll machines. As a result, they can only be used to create small diameter tubes.
Two-roll machines are the best choice for applications where a simple small diameter tube needs to be manufactured from low gauge metal quickly.
Three-roll bending machine (symmetrical)
Symmetrical three-roll machines consist of a top roller which moves vertically and two lower pinch rollers which move horizontally. The geometry of the rollers can be adjusted to create single-pinch, double-pinch or initial pinch bending.
Symmetrical three-roll machines are low-cost and versatile machines which can be both mechanically and hydraulically operated. This allows them to work with a wide range of metals and plate gauges. The downside of symmetrical rollers is that they leave a straight line segment which must be removed using either pre-bending or removal after processing.
Three-roll bending machine (asymmetrical)
Asymmetrical three-roll machines consist of three rollers with the top roller moving horizontally and the two lower rollers moving vertically. The advantage of these machines is that the two lower rollers can be adjusted on a half-roll to eliminate the straight line left by symmetrical machines.
Asymmetrical machines are more expensive than symmetrical rollers but the elimination of the straight line during processing means they are more productive in high capacity environments.
Four-roll bending machine
Four-roll machines have an additional roller underneath the top roller which pre-bends both ends of the plate during processing. The extra roller also eliminates slippage which allows four-roll machines to be combined with CNC machines to create a more comprehensive manufacturing process.
Much like three-roll machines, four-rollers can be mechanically or hydraulically operated making them suitable for medium and heavy-duty plate rolling applications.
If you would like help choosing a plate rolling machine for your application, give our team a call or complete the contact form here. Our experts will take the time to understand your requirements before recommending the most cost-effective machine for your needs.