October 26, 2023
1. The material separation process during blanking can be divided into three stages:
<1>Elastic deformation stage: In the initial stage when the punch just contacts the sheet material, elastic deformation occurs.
<2>Plastic deformation stage: The downward pressure of the punch increases and plastic deformation occurs until micro cracks appear.
<3>Fracture and separation stage: The punch continues to move downward, the pressure increases, and micro-cracks expand. The overlapping, breaking, and punching forces gradually decrease.
Elastic deformation stage: The punching force gradually increases.
Plastic deformation stage: the punching force reaches its peak value.
2. Cross-sectional characteristics of ordinary blanking parts:
<1>Collapse zone The initial collapse angle is generated by the main unisexual deformation stage, which drives the edge plastic deformation stage.
<2>The bright band is produced in the plastic deformation stage, and the cross section is smooth and smooth, which is the section with the best quality.
<3>Fault zone is caused by tearing, the surface is rough and dull, and has a taper.
<4>Burr area: Burrs are generated when micro cracks occur.
3. The relationship between characteristics and material (sheet material) plasticity:
The cross-section quality is affected by different blanking conditions, such as: edge clearance, edge shape, sharpness, punching force, lubrication conditions, sheet material quality (surface quality), sheet material type (performance).
Stamping production requires that the punched parts have a larger bright zone and the width of the fracture zone area is reduced.
The better the plasticity of the material, the larger the bright zone, the smaller the fracture zone, and at the same time, the fillet burrs also increase.