1. Die surface waste
The mold has an inverted cone. When the mold wears, the punching gap becomes larger, and the drawing effect of the punching material (such as blanking parts or stamping waste) is enhanced. After the punching, the elasticity of the material needs to be diffused. As a result, the size of the punching part is smaller than the mold. The size of the die, or the blanking waste is smaller than the size of the die edge. As the size of the waste material becomes smaller, the waste material tends to fall off the working surface of the mold due to the vibration of the mold or punch. If production continues at this time, the discharge plate will break or the punch will break, resulting in damage to the mold. There will be a continuous die for punching small holes, this kind of waste is not easy to feel, so special attention should be paid. The cutting edge height of the concave die of the continuous die is small, and the discharge angle is large, so that small punching waste is easy to leak from the lower die, or the punching die forms a taper angle. The waste is not easy to stick to the punch; the conical punch will also bend the steel plate, and the waste will become larger and jammed.
2. Steel plate stacking
A certain die gap is suitable for stamping materials with a certain thickness. If two steel plates are stacked together for stamping, the thickness of the steel plates will be doubled, and the die gap needs to be doubled accordingly. At this time, two superimposed punching is equivalent to changing the die gap, the punching force is doubled, and the mold is easily damaged. Therefore, such punching is not allowed in production. In actual production, because the oil adheres to the steel plate, if you operate it carelessly, it is easy to cause overlapping stamping, which is not allowed.
3. Scrap accumulation inside the die
In the stamping process, the blanking waste cannot accumulate in the mold, but should be discharged from the mold in time, because the deformation of the material causes the cavity wall to bear the vertical expansion force, which is about 30% of the punching force, which will cause the cavity to rupture , The strength of the mold should be analyzed based on the theory of thick-walled cylinders.
4. Incomplete blanking
This situation sometimes occurs in the first few steps of manual blanking and continuous die stamping, or when the automatically stamped coil is about to be stamped out and there is no material to be fed, sometimes in the single-step blanking die. Manual feed position or strip where the error occurred. When the width is not enough, once this “half-drop” phenomenon occurs, the punch will break in the worst case, because the blanking of half of the workpiece will cause the punch to generate lateral force and destroy the punch, so half of the workpiece is not allowed to fall. material.
