why press brake need a crowing system

When the bending machine bends the workpiece, due to its own structural characteristics, under the action of bending force, the upper and lower beams will produce deflection deformation, which will lead to excessive deviation of the bending angle of the workpiece in the full-length direction. The compensation system can effectively compensate the deflection deformation of the bending machine. Using the compensation system on the upper beam or lower beam can ensure the consistency of the bending angle in the whole length.

The compensation system is divided into:

• Hydraulic compensation system

• Mechanical compensation system

Hydraulic compensation system

The principle of the hydraulic compensation system is that several hydraulic cylinders are embedded in the lower beam of the bending machine, and each hydraulic cylinder can be controlled separately, so that the lower beam can form a certain bulge, as shown in Figure 1. Theoretically, the more hydraulic cylinders are used, the more compensation points are, and the higher the compensation accuracy will be.

Hydraulic compensation belongs to built-in discrete compensation. In order to achieve high-resolution compensation effect and achieve high bending accuracy, higher requirements are put forward for the number of hydraulic cylinders and their hydraulic control system, resulting in more complex overall structure and higher cost of the bending machine. The hydraulic compensation system cannot be applied to the upgrading of the customer's existing bending machine.

Fig. 1 Schematic diagram of hydraulic compensation system

Mechanical compensation system

The mechanical compensation system uses the filling method to compensate the lower beam / lower die. Its main principle is to generate different compensation curves through the mutual movement of a pair of deflection compensation wedges, as shown in Figure 2.

Fig. 2 Schematic diagram of mechanical compensation system

There are many kinds of mechanical compensation systems in the market. Take wila's mechanical compensation workbench as an example. It belongs to external relatively continuous compensation. It is directly installed on the lower beam of the bending machine and can be applied to new and old bending machines. For different applications, different compensation curves can be continuously adjusted, as shown in Figure 3.

Fig. 3 Schematic diagram of mechanical compensation curve

Both hydraulic compensation system and mechanical compensation system can effectively compensate the deflection deformation of the bending machine. The difference between the two lies in the compensation accuracy / resolution, in addition to the difference in the cost of the bending machine caused by the different structure design. For high-precision bending applications, we recommend the use of mechanical compensation system.