The Advantages of 2-roll Bending Rolls
- Peter Dawber
For rolling thin sheet metal, a 2-roll bending rolls offer a serious alternative to more common 3 or 4-roll machines. These high production models lend themselves to automation and can produce finished parts from blank material very quickly, in some cases without operator interaction.
Various applications are particularly suited to 2-roll bending rolls and for others they have some significant advantages over other methods of rolling. With single pass bending and minimal flat parts they can produce a ready-to-weld rolled shell in just a few seconds. How do they work and which jobs are most suitable for 2-roll bending?
The 2-roll Bending Method
A hardened steel top roll is positioned above a high density urethane lower roll with the sheet metal pinched between the two prior to rolling. The traction provided by the urethane roll results in extremely precise positioning and the pressure of the steel top roll against the urethane lower roll, which is able to compress slightly, allows the bending of the material.
Advantages of 2-Roll Bending
One Pass Bending
Due to the design of the machine, finished shells are rolled in one pass. This lends itself to production environments as bending times are extremely quick, without the typical multi-pass operation associated with 3 or 4-roll designs.
Very Small Flat Areas
With the pre-bending process on a 2-roll bending rolls there is very little flat area at either the start or finished of the bend. A typical flat area is 1.5 to 2 times the thickness of the material can be achieved, e.g. 0.8mm material could result in a flat area of only 1.2mm.
The 2-roll technology lends itself to more complex applications such as rolling perforated material without deformation, bending very small diameters and, with a special conical top roll, production rolling of sheet metal cones.
When a 2-roll bending roll is incorporated into an automated cell, this really takes rolling production to new levels. Rolled shells can be produced from flat blanks in seconds without any operator interaction. Automated systems include loading and feeding of the blank into the machine, and rolling and ejection of the completed part which is unloaded to a holding area.
As you can see the applications for 2-roll bending are broad and cover many situations where 3 or 4-roll machines are commonly utilised. While at like for like capacity a 2-roll machine is more expensive than a traditional solution, if throughput is sufficient then the productivity gains are often able to justify the additional investment. It is also important to understand that 2-roll technology is aimed at light gauge sheet metal and not at heavier plate bending.
If you are producing large quantities of sheet metal shells in thin gauge material, it is well worth understanding whether investing in a 2-roll bending rolls could work for you. To obtain an opinion you can get in touch here.