The traditional bending process is to use the two edges of the lower die opening and the edge of the upper die to bend the metal sheet under the pressure of the upper and lower dies of the bending machine, and the metal sheet undergoes elastic deformation to plastic deformation.In today’s society, people have higher and higher requirements for the shape of workpieces. Some workpieces with complex shapes cannot be bent using traditional free bending, bending machine bending and even three-point bending processes, and traditional bending methods cannot control the bending. The size of the radius of the rounded corners makes it difficult to achieve the technological requirements of seamless bending. Therefore, a new bending process – slotting bending process came into being.
CNC V Grooving machine is a sheet metal processing CNC machine widely used in elevator manufacturing, decorative material manufacturing, stainless steel processing, home appliance manufacturing and other industries. Its working principle is to carry out V-grooving on the metal plate to make the remaining thickness of the plate smaller, and the smaller plate thickness is conducive to subsequent bending processing.
It can be seen from the bending process that the radius of the edge arc of the workpiece after bending is proportional to the thickness of the metal plate. The thicker the metal plate, the larger the arc radius formed by bending. After V-grooving the metal sheet, the remaining thickness of the sheet becomes half of the original, or even smaller, so that the radius of the edge arc can be greatly reduced after the workpiece is bent.
In addition, because the remaining plate thickness at the bending position after grooving is relatively thin, the deformation force during bending will also be reduced accordingly, and will not spread and affect the unbent area, so there is no crease on the surface of the workpiece after bending, and due to the bending The thickness of the plate is thinner, and the reduction of the pressure required during bending can well avoid the risk of indentation on the decorative surface. In this way, in the metal decoration of hotels, banks, commercial centers, airports and other places, the process requirements of the workpiece edge arc radius are small, the surface has no creases, and the decorative surface has no indentation.
In the bending process, the bending force required for the sheet metal is proportional to its thickness. The greater the thickness of the metal sheet, the greater the required bending force, and the required equipment tonnage is also increased accordingly. After the V-shaped groove is performed on the bending part of the metal plate before bending, the remaining thickness of the plate at this place is greatly reduced, so that the bending force required for bending the plate will be correspondingly reduced, so that the thick plate can be used in a small tonnage. Bending on the bending machine. This not only reduces the investment in equipment, but also saves energy consumption and space.
How to avoid deviations in bending angles and dimensions
For the bending process, the quality of the bending mainly depends on the two important parameters of the bending angle and size. When bending, in order to ensure the forming size and angle of the bending, it is necessary to pay attention to the following issues.
(1) The upper and lower dies are not concentric, which will lead to errors in the bending dimensions. Before bending, the upper and lower dies must be adjusted to the center.
(2) After the backgauge moves to the left and right, the relative position of the sheet and the lower die may change, thereby affecting the bending size. The position distance of the rear stopper needs to be re-measured before bending.
⑶ The parallelism between the workpiece and the lower die is not enough, which will cause the bending springback and affect the bending angle. It is necessary to measure and adjust the parallelism before bending.
⑷ When the first bending angle is insufficient, the second bending will also be affected, and the accumulation of bending errors will lead to an increase in the forming size and angle errors of the workpiece, so it is particularly important to ensure the accuracy of unilateral bending.
⑸ When bending, the size of the V-port of the lower die is inversely proportional to the bending pressure. When processing metal sheets of different thicknesses, it is necessary to select the appropriate V-shaped groove of the lower die according to the regulations. Generally, it is appropriate to choose 6 to 8 times the thickness of the plate.
⑹ When the workpiece is bent on the bending machine after the V-shaped groove is planed, it is necessary to ensure that the edge of the upper die, the bottom edge of the V-shaped groove of the workpiece and the bottom edge of the V-shaped groove of the lower die are on the same vertical plane.
⑺When bending the workpiece after grooving, in order to prevent the tool from being clamped, the angle of the upper die is controlled at about 84°.
