Otimização de posicionamento de dobra para peças estreitas e longas

The narrow and long workpiece is a kind of workpiece with a large aspect ratio and is positioned with the short side during bending. Often, the workpiece is out of tolerance because the contact size between the workpiece positioning side and the back gauge positioning of the bending machine is too short. This article introduces A tooling structure for optimizing the bending and positioning of a narrow and long workpiece is provided, which basically solves the problems of difficult positioning and low precision of the narrow and long workpiece.

With the rapid update of sheet metal deformation technology, CNC bending machine has become one of the important production equipment for sheet metal cold deformation processing. It is widely used in the field of sheet metal parts processing. Considering that, the back gauge is generally used as the positioning device. After simple programming, the functions of back gauge linkage and single action can be realized, which is enough to meet the processing needs of various shapes of bending parts. However, the back gauge positioning used by the CNC bending machine also has its limitations. If the width of the positioning edge of the workpiece to be processed is too narrow, when the back gauge is used for positioning, the contact size between the workpiece and the back gauge is too short, which may easily lead to inaccurate positioning dimensions. , The misalignment of the bending position and the design bending line, etc., make the quality of the formed products poor, and often need to be reworked and repaired, resulting in a huge waste of materials, energy and labor.

Bending Deformation Mechanism

In production, it is often necessary to fold the workpiece into a certain angle, and the bending radius at the bend is small. This process is called bending. Bending is the process of using a die to apply an external force to a sheet to bend it into a certain angle or shape. The bending deformation of the workpiece is divided into several stages. In the initial stage, the material is free to bend. With the pressing of the upper bending die, the material and the surface of the lower bending die are gradually close, and then when the upper bending die continues to be pressed down, the The bending area keeps getting smaller until it contacts with the upper bending die at three points. When the upper bending die is pressed down to the lowest point of the stroke, the material is completely close to the upper bending die. When the material is free to bend, its inner layer fibers are shortened due to longitudinal compression. Since the volume remains unchanged during plastic deformation, it elongates laterally, and the outer layer fibers elongate due to longitudinal tension, causing it to shorten laterally. Therefore, for the width For narrow workpieces, after bending, the cross-section will be slightly fan-shaped; for wide-plate workpieces, the bending cross-section has no obvious deformation.

Bend Positioning

1. Basic Positioning of The Bending Machine

The CNC bending machine generally uses the back gauge to position the workpiece. The basic principle is that during the bending process, the bending program is first compiled, the shape of the workpiece is input into the machine tool, and the machine tool automatically calculates the position of the workpiece bending line. The CNC system controls the servo motor and moves the two back gauges to the bending positioning position through the high-precision screw nut pair. The operator only needs to align the positioning edge of the workpiece with the backgauge of the bending machine to complete the positioning process. , at this time, the position of the center line of the lower die of the bending machine is the workpiece bending line, and the state of the workpiece positioning is shown in the figure.

2. Limitations of Bending Machine Positioning Devices

In production, it is found that when using the back gauge positioning that is commonly used in the current CNC bending machine, if the size of the positioning edge of the workpiece in contact with the back gauge is too short, it is difficult to align the workpiece with the back gauge during positioning, such as As shown in the figure, the slight left and right deviation of the workpiece will lead to inaccurate positioning, resulting in problems such as workpiece out-of-tolerance scrap or uneven bending edge size. The operator needs to align repeatedly in order to ensure the one-time forming effect, but the effect is often not good. Ideal, seriously affect production efficiency and product quality.

Positioning Optimization For The Machining of Narrow And Long Workpieces

1.The structure of the positioning optimization device

Based on the limitation of the positioning device of the CNC bending machine, a positioning optimization device that can be used in the CNC bending machine is designed. The locking block is used to lock the whole device on the lower die of the bending machine, the front plate is used to install the screw, the locking screw is used to fix the movable locking block to the lower die of the bending machine, and the positioning top plate is used for workpiece positioning.

2.Use of Positioning Optimizer

When using the above positioning optimization device, first align it and clamp it on the lower die of the bending machine, and use a square ruler to detect its state. The end of the workpiece is close to the back gauge of the bending machine, and the side of the workpiece is positioned with a positioning optimization device to achieve accurate and stable positioning of the workpiece, as shown in the figure.

Implementation Effect of Auxiliary Positioning Device

1.Improve production efficiency.

Before this device is used, narrow and long workpieces often need to be repeatedly measured to ensure accurate positioning, and the error is often large. After using this device, the operator can quickly locate the workpiece to be processed, which greatly improves the production efficiency of the product, and saves more than half of the production and processing time for a single workpiece.

2.Improve product quality.

Before this tooling is used, the defective product rate of narrow and long workpieces remains high, and there are often problems that the size of the workpieces processed is out of tolerance and scrapped, and the size of the bent edges is uneven. After using this optimization device, the quality problem caused by the inaccurate positioning of the bending line did not occur again, and the product quality was greatly improved.