How Does The Crowing System Work  in A Press Brake?

A CNC press brake is an important piece of equipment in sheet metal processing, and its working accuracy directly affects the bending precision of the workpiece. During the bending process, the press brake experiences the greatest force at both ends of the slider. The reaction force from the material bending causes the lower surface of the slider to deform into a concave shape. The deformation is most pronounced in the middle part of the slider, causing the final bending angle of the workpiece to vary across the entire length.
 

To eliminate the adverse effects caused by slider deformation, it is necessary to compensate for the deflection deformation of the slider. Common compensation methods include hydraulic compensation and mechanical compensation. Both methods create an upward elastic deformation in the middle of the worktable to counteract the deformation of the machine’s slider. This ensures the accuracy of the processing joint surfaces and improves the overall precision of the workpiece.

Mold Safety Factor Analysis Chart

Two Compensation Methods

1. Hydraulic Compensation
   The hydraulic automatic deflection compensation mechanism of the worktable consists of a set of cylinders installed on the lower worktable. The positions and sizes of the compensation cylinders are designed based on the deflection compensation curve of the slider and the finite element analysis of the worktable. Hydraulic compensation is achieved through the relative displacement between the front, middle, and rear vertical plates to implement the neutral plate’s bulging compensation. The principle is to achieve the protrusion through the elastic deformation of the steel plate itself, so the compensation amount can be adjusted within the elastic range of the worktable.

2.  Mechanical Compensation
   Mechanical compensation consists of a set of protruding inclined wedges, each designed based on the deflection curve of the slider and worktable using finite element analysis. The CNC system calculates the required compensation amount based on the load force when the workpiece bends (this force causes the skewed deformation of the slider and worktable vertical plates), and automatically controls the relative movement of the wedges to effectively compensate for the deflection deformation of the slider and worktable vertical plates. This ensures the desired bend in the workpiece. Mechanical deflection compensation is achieved by controlling the position to create a “pre-collision” effect. A set of wedges forms a line along the length direction of the worktable. The curve with the same deflection ensures uniform upper and lower mold gaps during bending, guaranteeing the same angle along the length direction of the bent workpiece.

    

   

    

   3. Bidirectional Mechanical Compensation

   Meca Press Brake equipped with bi–directional mechanical crowing system. The compensation wedge consists of upper and lower plates, each with several pairs of wave-shaped inclined surfaces of varying angles, ensuring high matching precision.By moving the upper and lower wave-shaped wedges relative to each other along the length direction, a compensation curve is generated to counteract deflection deformation of the press brake during bending. The lower compensation wedge adopts an integrated wave-shaped inclined surface structure, providing stable compensation with no repeat positioning error.