Various problems and solutions in sheet metal bending processing
For practitioners in the machinery industry, mastering the core skills of sheet metal bending and machining bending problems is the key to improving competitiveness. There is a video showing the processing of Amada equipment, which intuitively reveals the precise requirements and common challenges of this process in actual production.
Quality pain points of bending process
During the sheet metal bending process, dimensional deviations and surface damage are high-frequency problems. Bending edges that are not straight enough will have a direct impact on assembly, and scratches on the surface of the workpiece need to be dealt with later, which will increase costs. Excessive dimensional fluctuations often result in batches of products that fail to meet relevant standards.
What is related to structural integrity is cracks and hole deformation. The material outside the bending angle is prone to cracks due to excessive stretching, and the internal pre-punched holes may deform under the action of bending force. These problems not only affect the appearance, but are also more likely to weaken the strength of the workpiece, causing potential safety risks.
Root cause of problems and design optimization
There are many bending defects in the process design process. Errors in the calculation of unfolded dimensions are fundamental errors, which directly lead to overall errors in the dimensions of the final product. If the texture direction of the material is parallel to the bending line, it is extremely easy to increase the risk of cracking.
The first line of defense is undoubtedly optimized design. When designing parts, be sure to avoid bending radii that are too small. In the process planning process, the punching process can be placed after bending, or process compensation holes can be added in advance to offset the hole deformation caused by bending.
The key role of materials and molds
Springback is directly affected by material properties. The yield strength of hot-rolled steel of different brands and different batches is different, so the amount of springback is different. The yield strength of aluminum plates of different brands and different batches is different during machining and bending , so the amount of springback is different. Putting into production without sufficient mold testing will inevitably lead to unstable angles.
The core parameters are the fillet radius and gap value of the convex and concave molds. Too small a radius will cause aggravation and even cracking. Various problems and solutions in sheet metal bending processing. Unreasonable gaps will affect dimensional accuracy and cross-section quality. Regular inspection and correction of mold wear parts are crucial.
Precise control of bending force
Due to the lack of bending force, the workpiece cannot be formed. If the force is too strong, it may cause excessive deformation or severe rebound. Modern CNC bending machines can accurately control the pressing depth and holding time with the help of parameter settings.
For high-strength thick plate materials, corrective bending is sometimes used instead of free bending, which means that the punch exerts sufficient pressure on the plate to allow it to achieve plastic deformation in the mold cavity, thereby effectively reducing springback and stabilizing the angle.
The value of plastic surgery
Adding a plastic surgery process is an effective way to solve complex problems. In view of the misalignment of the axes of the holes on both sides caused by springback, the bending angle can be fine-tuned and corrected with the help of a shaping mold to restore the concentricity of the hole position.
After bending, bow-shaped deflection occurs in the width direction. The shaping process can apply uniform pressure to eliminate the internal stress caused by uneven material flow and return the part to a straight state, thereby ensuring that the flatness meets the requirements.
Process response to special structures
When the bending height is lower than a specific multiple of the material thickness, the bending line will easily become distorted. The solution is to modify the design to machine the bending problem , increase the bending height, or use a special mold structure to achieve molding.
For objects made with incisions, there is no constraint on the material at the incision location, and deflection will inevitably occur when bending. The process can reserve connecting bridges so that the incisions can still maintain integrity during bending, and the connected parts can be cut off after forming.
In your actual sheet metal bending operations, what is the most difficult dimensional accuracy problem you encounter, and how to solve it? You are welcome to share your experience in the comment area. If this article has inspired you, please like it and support it.
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