(1) Basic process classification
The stamping process can be divided into two categories: material separation and forming, based on the deformation properties.
The separation process refers to the process of obtaining the required shape and size of the workpiece by causing the material to fracture and separate under the action of stamping force when the stress of the deformed part of the blank reaches the tensile strength.
The forming process refers to the process of obtaining the required shape and size of the workpiece by causing plastic deformation of the blank under the action of stamping and pressing force when the stress of the deformed part of the blank reaches the yield point without reaching the tensile strength.
(2) Categories of separation process
The separation process can be divided into two categories according to different deformation mechanisms: blanking and trimming.
Blanking is a process in which the sheet metal is cut along a certain curve or line by a die. Trimming is a separation method for reworking the cut section of blanking parts. Trimming deformation is a cutting mechanism with better dimensional accuracy and sectional quality than blanking parts.
(3) Categories of forming process
The forming process includes bending, stretching, flanging, bulging, extrusion technology, and so on.
Introduction to the shape and forming process of stamped products
The cross section of the stamped product can be divided into four types during the blanking process: collapsed angle, bright band, fracture band, burr. These four shapes are generated at different stages, positions, and stress levels during the product blanking process.
(1) Elastic deformation stage
Analysis of force: The material of the blade part is subjected to shear force, and the force is less than the elastic limit. If the force disappears, the material will return to its original state.
Description of state: The convex die applies pressure on the material, and the material is slightly pressed into the concave die blade.
(2) Plastic deformation stage
Analysis of force: The material is gradually subjected to force from the edge to the center, which gradually exceeds the elastic limit.
Description of state: The convex mold further enters the material, and the collapsed angle and bright band of the blanking component are generated in this stage.
(3) Shearing stage
Analysis of force: The stress near the concave die blade part of the material first reaches the material's shear strength, which makes the crack near the concave die blade part of the material grow larger. At this time, the material near the convex die blade is still in the plastic deformation stage. As the punch progresses deeper into the material, the material near the punch also reaches its shear strength, and cracks begin to appear. When the two cracks converge, the material separates.
Description of state: The material separates, and burrs are produced when the upper and lower cracks intersect and tear each other.