Design of Starting Hole for Cold Rolling
Cold rolling technology is mainly used for processing thin sheet, strip, foil and other thin steel products. To ensure the normal process of cold rolling, it is necessary to punch a starting hole at the edge of the blank before rolling. The punching size and shape of the starting holes directly affect the product quality, so it is extremely important to carefully design the punching size and shape of the starting holes.
The punching size of starting holes mainly refers to the size of starting hole diameter and center distance. The punching shape mainly refers to the conventional round holes and slot holes.
For the diameter of the starting holes, its size mainly depends on the thickness of the material and the size of the blank material. Generally, the diameter is close to the thickness or slightly greater than the thickness. If it is too small, the holes will break during punching and the blank will have cracks when processing, resulting in poor surface quality; if it is too large, the buried drag between the steel plate and the rolling wheel will be large, which will reduce efficiency and increase the difficulty of rolling.
In addition, it is also necessary to consider the relationship between the material and the punched holes. For example, for thin steel plate below 0.6 mm, the die can be inverted to reduce the burrs on the surface; for materials with a plate thickness within the range of 0.6-1.2 mm, the die should choose external convex teeth due to the force effect of the teeth.
In addition, the center distance of the two starting holes also needs to be designed. If the distance is too close, it is not conducive to the last deformation, and it is also not conducive to the maintenance of the foam wheel; if it is too far away, the surface of the material will deform seriously and the product quality will be affected. Therefore, the center distance design of the starting hole should be considered from different points such as the processing technology and product requirements of cold rolling material.
In summary, starting hole punching size design is to ensure the normal process of cold rolling, and it has a great influence on product quality. Therefore, it is very important to think carefully about the punching size and shape of the starting holes. When designing the size and shape of the starting holes, the following aspects should be considered: thickness of steel plate, material characteristics and processing technology requirements. Doing so will ensure the accuracy and rationality of the punching size and shape of the starting holes.
