1.What impact does it have on the production process?
Support and tension control: In the continuous high-speed color coating production line, the steel strip (substrate) is wound around the core for unwinding and rewinding. The core must have extremely high strength, stiffness and roundness. If the core rigidity is insufficient or eccentric, the steel strip will vibrate or have uneven tension during operation.
Consequences: The coating may be uneven when rolled, affecting the baking and curing process. In severe cases, it may even cause the coating to be scratched on the production line.
2.What impact does it have on winding quality?
Producing indentations: Inferior cores (such as those made from recycled materials, uneven wall thickness, and dents) will imprint their own defects on the coating surface of the inner steel plate during rewinding, forming periodic indentations or bumps.
Causes "bonding": The pressure between the steel strip layers is huge during winding. If the core is out of round or has poor strength, resulting in excessive local pressure and high storage ambient temperature, interlayer bonding may occur. When uncoiled again, the coating will be adhered and torn off, causing irreparable damage. This is one of the most serious quality incidents.
3.What are the implications for transportation and storage?
Collapsed cores and flat rolls: Cores with insufficient strength (such as some inferior paper or thin-walled steel pipe cores) cannot bear the weight of the entire roll of steel plates (up to dozens of tons) during hoisting, transportation or stacking, and will deform and collapse.
Consequences: The entire color-coated roll turns into an oval or irregular shape, making it impossible to unwind on the machine. The edges will be severely bumped and deformed due to uneven stress (commonly known as "daisy edges"), and the coating and substrate will be damaged. A large number of edges must be trimmed before use, resulting in huge waste.
4.What impact does it have on open-book use?
A sturdy, standard winding core is the basis for the smooth operation of modern high-speed unwinding equipment. Inferior cores will cause unwinding to be unsmooth, causing downtime for adjustments, increasing construction time and costs.
5.What are the main materials and characteristics of the core?
High-strength steel core (high industry standard):
Material: special steel pipe, wall thickness usually ≥16mm, or even thicker.
Advantages: Excellent strength, stiffness, and roundness, and can perfectly withstand various forces in production and transportation. It is the standard configuration of high-quality color coating production lines, which can ensure that the coated products are delivered to customers intact to the greatest extent.
Disadvantages: Highest cost.
Ordinary steel/iron core:
The wall thickness is thin or the material is average, and the strength and deformation resistance are weak. The risk is higher when carrying heavy rolls or lifting improperly. A common choice for many standard products.
Paper/Fibreboard Cores (Low End or Special Purpose):
Mainly used for very light aluminum coils or extremely thin steel coils, definitely not suitable for heavy-duty color-coated steel coils. Its strength cannot bear the weight of several tons to tens of tons, and it is easily prone to catastrophic collapse.