The plate bending machine is a kind of special forging machine equipment,which could bend metal sheets into cones, spheres, cylinders or other shapes.
Figure 1 BLMA plate rolling machine
The upper roller of the plate rolling machine is in the symmetrical position of the center of the two lower rollers center through the hydraulic oil in the hydraulic cylinder acting on the piston, to make vertical lifting motion. The upper roller is passive, and is installed in a bearing that can move up and down. The lower roller is active, and is installed in a fixed bearing. The last gear of the main reducer drives the gears of the two lower rollers to mesh and rotate, in order to provide torque for the rolled plate. The flat plastic metal plate of the machine passes between the three work rolls (two lower rolls and one upper roll) of it. With the help of the lower pressure of the upper roll and the rotation of the lower roll, the metal plate passes through multiple passes, continuously bending, to produce permanent plastic deformation. And roll into the required cylinder, cone or part of them. The adjustment of the rollers on the large plate rolling machine is mechanical or hydraulic, and the small plate rolling machine is often manually adjusted.
Figure 2 Rolling process
According to the above-mentioned bending principle, it can be known that only when the part of the sheet material and the upper roller is in contact, the required bending radius would be reached. Therefore, the length of the two sheet ends that might not touch the upper roller and not bend, which is called the remaining straight side. And the remaining straight side length, is about half of the distance between the two lower rollers. Since it is a straight line segment that cannot be spliced into a circle, it will generally be cut off after rolling, which is a waste of material. Therefore, in most cases, pre-bending will be performed first to reduce the length of dead edges as much as possible.
Figure 3 The remaining straight side
The four-roller plate bending machine adds a side roller in the structure. The bending of the edge of the sheet is performed by two side rollers. The added side rollers can also act as a back-gauge similar to a press brake, which can make sure your sheet is not tilted, and overcomes the problem of the sheet and the trouble of turning and bending on a symmetrical three-roller plate bending machine.
Figure 4 Four roller pre-bending function