When we discuss the process of a product, it is inevitable to consider the minimum bending radius of the product material. The concept is the limit bending radius to prevent the outer fibers from tearing, known as the minimum bending radius. It refers to the minimum radius when the strip material is bent around a round bar without surface cracks, expressed in English as the minimum bending radius, typically represented as a multiple of the material thickness. When forming cold-formed sections, the minimum bending radius also considers factors such as the bending angle, bending length, material properties, the condition of the shearing edge perpendicular to the bending line, and the bending orientation related to the rolling direction of the strip. Generally, the minimum bending radius of low-carbon steel and low-alloy high-strength steel strip is 1 to 4 times its thickness.
Minimum Bending Radius of Common Stamping Materials
When the bending radius of the stamping material is small, the bending force must be increased, and the surface of the bent part may be damaged. The most serious consequence is the fracture of the outer fibers of the bending strip. Therefore, determining the minimum allowable value of the bending radius of the bent part is crucial. If the minimum bending radius of the product in your hand is relatively large, you need to increase the forming process to achieve the desired effect. Additionally, it should be noted that for some common low-carbon steels, not all of their minimum bending radii are listed in the table. You can refer to values between 15# and 50# in the table.
Factors Affecting the Minimum Bending Radius
1. Material Rolling Direction
Here, let's also mention the fiber direction of the sheet metal. As we all know, sheet metal has directionality, and the plastic index along the fiber direction (also known as the rolling direction) is greater than the index perpendicular to the fiber direction. Therefore, when the bending line of the bent part is perpendicular to the fiber direction of the sheet metal, the numerical value of the minimum relative bending radius is the smallest.
2. Bending Angle of the Part
When the sheet metal is bent, deformation is concentrated at the rounded corners, and the straight edges are not significantly involved in the deformation. The larger the bending angle of the part, the more it alleviates the tensile state of the outer layer in the bending area, thus helping to reduce the minimum bending radius. The smaller the bending angle, the more significant the dispersal effect of the straight edge involved in the deformation, and the smaller the minimum bending radius. The bending angle of the part has a significant impact when it is less than 90 degrees, but after exceeding 90 degrees, the influence of the bending angle becomes minimal.
Other influencing factors include the surface quality and edge quality of the material, the thickness of the sheet metal, and most importantly, the mechanical properties of the stamping material.
Minimum Bending Radius of Common Stamping Materials
When the bending radius of the stamping material is small, the bending force must be increased, and the surface of the bent part may be damaged. The most serious consequence is the fracture of the outer fibers of the bending strip. Therefore, determining the minimum allowable value of the bending radius of the bent part is crucial. If the minimum bending radius of the product in your hand is relatively large, you need to increase the forming process to achieve the desired effect. Additionally, it should be noted that for some common low-carbon steels, not all of their minimum bending radii are listed in the table. You can refer to values between 15# and 50# in the table.
Factors Affecting the Minimum Bending Radius
1. Material Rolling Direction
Here, let's also mention the fiber direction of the sheet metal. As we all know, sheet metal has directionality, and the plastic index along the fiber direction (also known as the rolling direction) is greater than the index perpendicular to the fiber direction. Therefore, when the bending line of the bent part is perpendicular to the fiber direction of the sheet metal, the numerical value of the minimum relative bending radius is the smallest.
2. Bending Angle of the Part
When the sheet metal is bent, deformation is concentrated at the rounded corners, and the straight edges are not significantly involved in the deformation. The larger the bending angle of the part, the more it alleviates the tensile state of the outer layer in the bending area, thus helping to reduce the minimum bending radius. The smaller the bending angle, the more significant the dispersal effect of the straight edge involved in the deformation, and the smaller the minimum bending radius. The bending angle of the part has a significant impact when it is less than 90 degrees, but after exceeding 90 degrees, the influence of the bending angle becomes minimal.
Other influencing factors include the surface quality and edge quality of the material, the thickness of the sheet metal, and most importantly, the mechanical properties of the stamping material.
