We offer buying advice for plate rolling machines here because despite significant advances in plate rolling machine technology the multiple forces and directions of inertia that occur as the forming takes place in plate rolling still require a high level of skill as well as a comprehensive knowledge of materials and rolling practices. Aside from a skilled machine operator, your choice of plate rolling machine is equally imperative for effective and precision production. With a wide range of plate rolling machines now available on the market which one should you choose, and what are the factors that could, or should influence your choice?
With a well-established management and technical team we have more than 30 years of expertise in the metal fabrication machine and forming machine tool industries. To help you choose which plate rolling machine is best suited to your specific requirements read our buying advice for plate rolling machines below.
Alternatively, take a look at the SweBend range of plate roll bending machines here. We choose to work with plate roll bending machine specialists, SweBend and highly recommend their range of three roll and four roll plate bending machines.
WHAT TYPE AND SIZE OF MATERIAL ARE YOU ROLLING?
To determine the proper plate roll 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.
Minimum and maximum width is also important because even something as straightforward as material thickness can vary, yet still fall into accepted plate and sheet mill tolerances.
Are there overhead supports to prevent light materials from collapsing when rolled to large diameters? A side support can also assist in preventing light materials from recurving toward the floor if the radius is very large.
On the application side, you will need to know the minimum and maximum diameter of the cylinders to be formed.
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.
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 wear. A hardness rating exceeding 60 will have a shallow penetration and will likely result in cracking or crazing of the roll surface.
WHAT TYPE OF MACHINE BEST FITS YOUR PRODUCTION NEEDS?
Certain types of plate rolling machines are easier to operate than others. In addition, certain types of machine achieved greater accuracy for cone rolling or rolling of special shapes. We offer buying advice for each of the different types of plate rolling machines here.
FOUR-ROLL MACHINES
These plate rolling machines produce the fastest and most accurate bends. Our buying advice for four-roll plate rolling machines is as follows:
Plate held securely in place between the top and bottom rolls, while the side rolls move vertically to create the bend. Bottom roll moves up to hold the plate surface securely against the top roll while the side roll is raised to form an accurate pre-bend, minimising the flat zone on the plate edge.
Pre-bending on a three-roll plate rolling machine requires that plates be tilted down as they are being fed whereas on a four-roll machine plates are loaded horizontally at the feed level which allows the use of horizontal motorised roller tables to help feed the plate.
Plate feeding can take place on either side of a four-roll machine. If fed from only one side, they can be placed up against a wall to save floor space.
Side rolls positioned to the right and left of the bottom roll and on their own axes. The independent axis of each roll helps make a perfect bend. The back side roll (at the far side of the feeding point) also functions as a back-gauge to square the plate for proper alignment which eliminates the need for someone to assist the operator.
Plate is kept square without slipping during both pre-bending and rolling because of the constant secure clamping of top and bottom rolls.
Four-roll machines do not require the operator to remove, flip, and then try to square the plate a second time after pre-bending, machine (this is not possible in three-roll, initial-pinch machines.)
A cylinder can be rolled to the required diameter immediately following pre-bending because the material can be kept in the machine.
Bending the back edge takes place after the cylinder is rolled allowing for a one-direction, single-pass operation.
For cone-rolling on a four-roll machine, the side rolls can be tilted to establish the cone angle, and the bottom roll also can be tilted to clamp and drive the major end of the cone.
THREE-ROLL, VARIABLE-GEOMETRY MACHINES
The widest range of material types and thickness in relation to the size of the top roll can be rolled on three-roll, variable-geometry machines. They are suitable for medium and thick plate bending. Our buying advice for three-roll plate rolling machines is as follows:
Unlike traditional three-roll cylinder machines, the lower rolls on three-roll, variable geometry machines move horizontally right to left, and the upper roll moves up and down. As on four-roll machines, material loads parallel to the floor, so the machine pit can be constructed to working level.
Side rolls positioned to the right and left of the bottom roll and on their own axes. The independent axis of each roll helps make a perfect bend. The back side roll (at the far side of the feeding point) also functions as a back-gauge to square the plate for proper alignment which eliminates the need for someone to assist the operator.
THREE-ROLL, INITIAL OR DOUBLE-PINCH MACHINES
Single initial-pinch plate rolls are generally only suitable for light-capacity applications. They can be electromechanical or hydraulic and work by pinching the flat sheet between two vertically opposed rolls while the third bending roll moves upward to contact then bend the sheet. These tend to be older machines which in most applications require removal and reinsertion of the sheet to prebend both ends so although cost-effective they are more labour-intensive in a production setting than their modern counterparts.
Three-roll, double-pinch machines are available in light to very heavy capacities and do not require the operator to remove, flip, and then try to square the plate a second time after pre-bending, as is the case with three-roll, initial-pinch machines. Cylinders can be rolled to the required diameter immediately following pre-bending because the material can be kept in the machine (this is not possible in three-roll, initial-pinch machines.)
Side rolls positioned to the right and left of the top roll and are on the same axis. The axis of each roll helps make the bend. The back side roll also functions as a back-gauge to square the plate for proper alignment which eliminates the need for someone to assist the operator.
For cone rolling on a three-roll, double-pinch machine, the side rolls can be tilted to establish the cone angle.
DON’T UNDERESTIMATE THE IMPORTANCE OF CROWNING!
Insufficient crowning will create an unsatisfactory roll form with barrel effect (where the part has a greater diameter in the middle than at the ends) and hourglass effect (the material is tighter in the middle than on the ends) both possible deformations that can be caused.
Most metal fabricators need a plate roll to work with numerous materials which will affect the plate rolling machine’s rolls in different ways. As a result rolls are machined with optimal crowning which is typically 75% of nominal capacity if yield, width, diameter, pinch pressure, and speed are equal.
The range of a roll (thickness/width/diameter) depends on the tolerance, with accepted variance of your parts. Options can be installed on the plate rolling machine to adjust for different tolerances and specific crowning can be applied to reach the desired range of material characteristics and part tolerances.
BUYING ADVICE FOR PLATE ROLLING MACHINES – OTHER CONSIDERATIONS
What part handling options do you need for your rolling applications?
Your plate rolling application could require NC or CNC side and overhead supports, motorised loading tables, plate alignment systems, in-feed conveyors, or part ejectors. Don’t forget these important safety and productivity tools when choosing a new plate rolling machine!
Don’t forget about safety considerations!
Most new plate rolling machines are equipped with safety devices such as emergency-stop buttons; safety trip wires; 24-VAC, low-voltage control circuitry; and detached operator control consoles. It is however still your responsibility as the owner to ensure the installation and proper use of these operation safety guards or devices.
Will you be doing any welding in the plate roller?
It’s never normally something that is planned at the outset before you realise it, your welder is on top of the plate roller trying to join up the two ends. It can be convenient, but if it’s not done properly or without proper protection on the machine then controls and electrical systems could be damaged. If this is even a possibility for your machine fabricating operation then you need to have an upgraded, shielded electronic system to protect the plate rollers’ electronics.
PLATE ROLLING MACHINES IN ACTION
SweBend Plate Roll PB4 12
SweBend Spiralling flights and augers
SweBend – SB4B-65 CNC ellipsehis
Swedish Quality Bending & Forming Machines
SweBend VSB3 400-3200 H-profile bend
Swebend Section Bending Machine SB3S 105
SweBend VSB3 400-3200 Angle-shape Bend
SweBend Spiralling flights and augers
Repair, Service & Support
Unrivalled experience in service and repair plus access to original machine data files and support from OEMs means we can deliver fast, cost effective resolutions to ensure that your machines are always up and fully operational. We offer a variety of technical support packages tailored to your individual needs and machine requirements with the provision of daily, weekly, and monthly service checks between annual services plus intervention in the case of unplanned maintenance or breakdown and training for customer engineers enabling more autonomy.
Roundo Spare Parts
In April 2016, following a bankruptcy and ownership transition, Roundo® closed operations in Sweden. WJS Machine Tools is able to offer full technical support and service to Roundo machine owners in the UK with our access to a huge stock of parts and support to keep your Roundo machinery running at full potential for many years to come. In addition, with access to former Roundo engineers as well as electronics and design staff, WJS Machine Tools are without doubt best placed to provide support in the UK for these machines.
“Our business succeeds on the Worldwide market by delivering quality parts, on time and at a competitive cost. Often, our major structural contracts are won on capability to deliver against challenging designs in a world of ever more complicated geometries. Working with WJS Machine Tools and their partners has allowed us to develop machines for this purpose”
CB – Section Bending SpecialistWHY CHOOSE WJS MACHINE TOOLS?
Expertise
More than 30 years experience and expertise in fabrication and forming machine tool industries.
Service
A wealth of experience in technical service and spare parts for our full range of metal fabricating machines.
Support
Factory-trained engineers with a vast experience in hydraulic, mechanical and electronic systems.