What Is Press Brake Crowning and 2 Types of It

The difference between mechanical crowning system and hydraulic press brake crowning system. How to choose the correct bend crowning system?

Mechanical or Hydraulic Press Brake Crowning System

1.The difference between mechanical crowning system and hydraulic press brake crowning system

Mechanical crowning system technology

Hydraulic crowning system technology

2. How to choose the correct bending crowning system?

During the bending process, when the CNC bending machine bends the sheet, the sheet will also have a reaction force on the machine tool. This reaction force can deform the machine, which affects the bending accuracy. Therefore, in order to improve the bending accuracy, mechanical crowning system and hydraulic compensation, the secondary bending machine camber crowning system is widely used in the sheet bending process.

The Difference Between Mechanical Crowning System and Hydraulic Crowning System

1.Mechanical crowning system technology:

A convex wedge consists of a set of convex wedges with bevels. Each protruding wedge is designed through finite element analysis based on the deflection curves of the slider and table.

The CNC controller system calculates the required crowning system amount according to the load force. This force causes deflection and deformation of the slide and the vertical plate of the table. And automatically control the relative movement of the convex wedge, so as to effectively compensate the deflection and deformation of the sliding block and the vertical plate of the worktable, and obtain an ideal bending workpiece.

The actual deflection curves overlap, so that the upper and lower tool gaps are the same when bending, and the angle in the length direction of the bending workpiece is the same.

Mechanical convexity allows accurate deflection crowning system over the full length of the table. Mechanical deflection compensation has long-lasting stability, reduces the maintenance frequency of hydraulic compensation (such as oil leakage), and is maintenance-free during the life of the machine tool.

Mechanical deflection crowning system Because there are many crowning system points, the bending machine can achieve linear crowning system when bending the workpiece during work, which can improve the bending effect of the workpiece. The mechanical compensation is driven by the motor as the CNC control axis, which realizes the CNC control and makes the crowning system more accurate.

Hydraulic Crowning System Technology:

The automatic hydraulic deflection crowning system of the worktable consists of a set of oil cylinders installed on the lower worktable. The position and size of each crowning system cylinder are designed according to the deflection crowning system curve of the slider and the finite element analysis of the worktable.

Hydraulic is to realize the convex compensation of the neutral version through the relative displacement between the front, middle and rear vertical plates. The principle is to realize the bulge through the elastic crowning system of the steel plate itself, so the crowning system amount can be adjusted within the elastic range of the workbench.

2. How to choose the correct bending compensation?

Since the compensation methods of the two bending machines have different requirements on the operator and product accuracy, it is very important to choose the correct bending compensation.

Hydraulic compensation uses a small oil cylinder to compensate the worktable, and mechanical compensation uses a wedge block to compensate the worktable. The wedge block can be divided into single wedge block and multiple groups of wedge block. The mechanical compensation composed of multiple sets of wedge blocks has more compensation points, more than 3 compensation points of ordinary hydraulic compensation, there is no compensation blind area, the precision of the folded workpiece is high, and the difference between each processing plate is small, which is suitable for mass production.

CNC control hydraulic compensation: We set the bending parameters in the CNC controller, such as plate thickness, plate length, material. The CNC controller automatically calculates the required compensation value, and then transmits the command to the compensation amplifier. The compensation amplifier sends the signal to the hydraulic compensation proportional valve to control the small oil cylinder under the worktable to bulge to reduce the deflection and deformation of the plate.

However, the hydraulic compensation value is affected by various factors, such as whether the hydraulic oil leaks, whether the joint is loose, etc., which will affect the hydraulic compensation amount each time, resulting in inconsistencies and differences in the processing of each plate.

The hydraulic system is more complex, and there may be problems such as oil leakage and loose sealing rings. The advantage of hydraulics is that the machine does not suffer from wear problems over time, whereas mechanical compensation does.

Compared with mechanical compensation, hydraulic compensation machines are easy to operate and therefore can help with higher bending accuracy. In addition, the machine has higher durability.

Hydraulic compensation adopts small cylinder compensation table, and mechanical compensation adopts wedge compensation table. Wedges can be further divided into single wedges and multi-group wedges.

Multi-group wedge mechanical compensation has more compensation points than hydraulic compensation. Ordinary hydraulic compensation has only 3 compensation points, no compensation blind area, higher precision of folding workpiece, and small processing board each time, which is suitable for mass production.

Compared with the hydraulic compensation system, the mechanical compensation system is simpler, will not cause oil leakage, etc., has a low failure rate, and is environmentally friendly.

However, after long-term use, the mechanical convex wedge will wear and affect the compensation effect. Mechanical compensation places higher demands on operation. If the workpiece needs to be bent in multiple steps, workers need to make real-time adjustments.

If the workpiece only needs to be bent in one step, our workers are highly skilled. We can choose mechanical compensation from the perspective of workpiece accuracy. In actual production, we have to consider the ability of workers, the cost of high-skilled workers, etc.

To sum up, both hydraulic compensation and mechanical camber compensation have their own advantages. We can consider configuring the table compensation of our Shenchong CNC bending machine according to the above aspects.