Hydraulic Crowning And Mechanical Crowning Features

Hydraulic Crowning or Mechanical Crowning Which Is Better

During the bending process of the CNC bending machine, due to the large force at both ends of the slider, the reaction force during the bending of the plate causes the lower surface of the slider to produce concave deformation, and the middle part of the slider has a large deformation.In order to eliminate the adverse effects caused by the deformation of the slider, it is necessary to compensate the deflection deformation of the slider. Hydraulic compensation and mechanical compensation are to make the middle of the worktable produce upward elastic deformation to offset the deformation of the machine tool slider and ensure the machining joint surface. To improve the accuracy of the workpiece, focus on analyzing hydraulic crowning and mechanical crowning.

Hydraulic crowning: It belongs to the local crowning function. It relies on the crowning cylinder of the lower table of the bending machine to carry out local angle crowning. It cannot achieve the effect of overall crowning like mechanical crowning.

Mechanical crowning: It is the core technology of the current bending machine, and it is also the current advanced crowning technology of the bending machine. It belongs to the overall crowning method, which solves the influence of unpredictable factors such as the difference of materials and the deflection of the equipment during the bending process. The method of overall crowning for the angle of the bending workpiece caused a certain error.

In the case of using hydraulic crowning mechanism, the numerical control system outputs the corresponding analog voltage to the crowning amplifying card according to the thickness and length of the bending material and the crowning amount automatically calculated by the selected mold, and the amplifying card amplifies the signal and controls the hydraulic crowning ratio depending on the opening size of the valve, the crowning proportional valve is always energized when the slider enters the slow down state until the slider starts to return to the top dead center. If the pressure holding time of the slider at the bottom dead center of the machine tool is changed at this time, the actual deformation of the lower worktable under the machine tool may be affected by the machining accuracy of the bending workpiece when the holding pressure time is short or when the holding pressure time is slightly longer. some errors. If there is debris in the hydraulic oil, it will cause the hydraulic proportional valve spool to be stuck, and the machining accuracy error will be larger. Since the crowning pressure is separated from the pressure of the whole system, when the compensation valve is working, the pressure of the whole system will be partially lost. Because of the hydraulic oil control, if the oil pipe is broken, the sealing ring of the crowning cylinder is aged or the joint is loose, there will be oil Leaks can create contamination.

The mechanical crowning technology is a convex wedge block, which is composed of a group of convex wedge blocks with a slope. Each convex wedge block is designed according to the deflection curve of the slider and the worktable finite element analysis. The numerical control system calculates the required compensation amount according to the load force when the workpiece is bent (the force will cause deflection and deformation of the sliding block and the vertical plate of the worktable), and automatically controls the relative movement of the convex wedge, so as to effectively compensate the deflection deformation produced by the sliding block and the vertical plate of the worktable, and can obtain the ideal mechanical deflection crowning of the bending workpiece. The "pre-bulge" is realized by controlling the position, and a set of wedges is formed in the length direction of the table. The curve that matches the actual deflection makes the gap between the upper and lower molds consistent during bending, and ensures that the angle of the bending workpiece in the length direction is consistent. Mechanical crowning the deflection crowning that can be obtained over the full length of the table. The mechanical deflection crowning has long-lasting stability, reduces the maintenance frequency of hydraulic crowning (such as oil leakage), and is maintenance-free during the life of the machine tool. Because there are more compensation points in mechanical deflection crowning, the bending machine can bend the workpiece more in a linear compensation mode and improve the bending effect of the workpiece. The mechanical crowning is driven by the motor, as a numerical control axis, realizes digital control, and makes the crowning value more.

The mechanical crowning method has the advantages of good flexibility, low cost, and continuous crowning of deflection, which is more conducive to enterprise cost control. Please pay more attention to HARSEL.

CNC Press Brake Bending Crowning in Actual Operation

Die bending is usually completed on a bending machine, and workers or robots are required to assist in the bending process. The bending accuracy depends on the proficiency of the technician or the quality of the robot. This bending method is widely used in the production of small parts with a single product type and a simple process.

Due to the uneven material of the plate, it is difficult to perform accurate bending according to the calculated theoretical value during bending, and the bending angle needs to be compensated. Supporting the bending angle compensation operation is the angle sensor. The use of the angle sensor can reduce the influence of the processing material on the bending angle, thereby improving the stability of the accuracy of the bending workpiece. This device is now used as a standard accessory of the bending machine widely used.

The intelligent application of bending is sensing technology. It obtains the information required for workpiece bending through sensing actions before, during and after bending, and automatically compensates and automatically confirms feedback. For example, the deflection compensation device is born for the bending machine, and the same is true for the bending angle compensation, but in fact, the equipment without deflection compensation function is the most ideal equipment.

HARSLE believes that the inhomogeneity of the material determines the inhomogeneity of the bent product, and it is ideal to collect information on these inhomogeneities before bending. Due to the tension in the material, it is ideal to control the warpage of the sheet during the bending process.