CNC Bending Machine bending accuracy

CNC Bending Machine bending accuracy

In view of the structural characteristics and working conditions of the CNC bending machine, the following simplification principles have been determined:

1. Simplify the parts that obviously do not affect the overall rigidity and strength of the fuselage, such as screw holes, pin holes, rounded corners, etc., and ignore some small parts on the outer and inner panels that are used for convenient lifting and installation of other devices hole.

2. Regarding the guide rail as a free interface, there is no force transfer between the slider and the guide rail.

3. The anchor bolts of the bottom plate are regarded as infinite rigidity, and the anchor bolts and the ground are regarded as fixed constraints.

4. Ignore the accessories that have little effect on the overall force condition.

5. Assume that the joint strength of welding is equal to the strength of the forging.

6. Keep the detailed structure of the dangerous part.

The purpose of these simplifications and modifications is to prevent small features and small structural parts from generating a large number of finite element elements when performing finite element meshing, and increase the calculation time of the computer. And small features will also cause the quality of the mesh to decrease, which will affect the analysis accuracy of the structure. For this area of the hydraulic cylinder bottom plate model, considering that the force transmission is more complicated, in the modeling process, in order to accurately obtain the stress value of the welding part of the hydraulic cylinder bottom plate and the side plate, the hydraulic cylinder is regarded as a part of the model. , This can be more convenient for loading processing.

The manufacturability of the bent part refers to the adaptability of the bent part to the stamping process. Usually when formulating the stamping process plan, the four-roller bending machine manufacturer must consider the manufacturability of the bent part. Because roll bending is a form of stamping process, it is necessary for this article to briefly analyze several process indicators related to sheet bending.

1. Bending accuracy

The accuracy of the bent part mainly refers to the accuracy and stability of its shape and size, its mechanical properties and thickness, the structure of the forming tool and the accuracy of the tool, the number of processes and the sequence of processes, and the shape and size of the workpiece itself. And other factors. For coils, it is generally necessary to consider whether the roundness, cylindricity, misalignment, misalignment and other indicators after the tube section is formed are within the design requirements.

2. Minimum bending radius

When the relative bending radius r/t of the bending part is small to a certain extent, the tensile strain of the fibers on the outer surface of the bending part will exceed the allowable limit and cracks or breaks will occur. Therefore, there is a minimum bending radius limit for the bending part. Under the premise of ensuring that the fibers on the outer surface of the sheet do not damage, the smallest fillet radius of the inner surface of the workpiece that can be bent is called the minimum bending radius rmin, and correspondingly, rmin/t is called the minimum relative bending radius. The factors that affect the minimum bending radius usually include the mechanical properties of the material, the relationship between the fiber direction of the material and the direction of the bending line, the surface quality and cross-sectional quality of the sheet, the width of the bent sheet, and the thickness of the sheet.