1.What is electrostatic oiling? What are its main differences from traditional oiling methods?
Electrostatic oiling is a precision oiling technology that utilizes a high-voltage electrostatic field to atomize and deposit oil, fundamentally different from traditional methods.
Traditional oiling methods mainly include:
Roller oiling: Oil is transferred to the strip surface through contact between an oiling roller and the strip.
Spray oiling: Oil is directly sprayed onto the strip surface through a nozzle.
The core principle of electrostatic oiling: Oil is atomized into negatively charged microparticles by a high-voltage electric field (typically 40~80 kV). Under the influence of electrostatic force, these particles are uniformly adsorbed onto the grounded strip surface, forming an extremely thin and uniform oil film.
2.What are the key advantages of electrostatic oiling in terms of oil film uniformity?
Extremely Uniform Width Aspect:
Electrostatic force ensures oil mist particles are uniformly adsorbed onto the strip surface, unaffected by strip shape or edge effects.
Traditional roller coating often results in "roller marks" or uneven thickness (thicker at the edges, thinner in the middle); electrostatic coating achieves width deviation control within ±0.1 ~ 0.2 g/m², making it particularly suitable for high-end products such as automotive steel and silicon steel.
Stable and Controllable Length Aspect:
The electrostatic coating machine is PLC-linked with the production line speed-automatically adjusting oil pump flow and voltage to maintain a constant oil application rate per unit area when speed changes.
This avoids the uneven oil film thickness caused by speed fluctuations in traditional methods.
Dual-Sided Independent Control Capability:
Modern electrostatic coating machines allow for independent oil volume adjustment on both the upper and lower surfaces, meeting the varying oiling needs of different products (e.g., one side for rust prevention, the other for stamping lubrication).
True dual-sided independent control is difficult to achieve with roller coating.
3.What are the advantages of electrostatic oiling in terms of oil saving and environmental protection?
High oil utilization rate (≥95%):
Electrically charged oil mist particles actively fly towards the strip under the influence of the electric field, with almost no drift loss.
Traditional spray oiling results in a large amount of oil mist escaping into the air, with a utilization rate of only 60%~75%; roller oiling leaves some oil residue on the oiling roller, causing waste.
Extremely thin coating is achievable:
Electrostatic coating can be stably controlled to a minimum of approximately 0.3 g/m², meeting the requirement for "thin coating".
Traditional methods, due to equipment limitations, typically require a minimum coating amount of 0.8~1.0 g/m²; otherwise, uniformity cannot be guaranteed.
Reduce oil consumption and emissions:
Based on an annual production of 1 million tons of cold-rolled coils, reducing the average oil coating from 1.5 g/m² to 1.0 g/m² would save approximately 50 tons of oil annually.
This also reduces oil mist emissions, lowers air pollution in the workshop, improves the working environment, and reduces the load on the exhaust gas treatment system.
4.What are the advantages of electrostatic oiling in terms of equipment maintenance and production stability?
Non-contact, no mechanical wear:
The oiling machine has no physical contact with the strip steel, eliminating mechanical failures such as oiling roller wear and bearing damage.
Traditional roller oiling requires regular roller replacement (usually every 1-3 months), while electrostatic oiling machines significantly extend maintenance cycles and reduce spare parts costs.
High tolerance for strip shape:
Even with slight waviness or edge warping in the strip, electrostatic oiling remains unaffected, and the oil mist can still provide uniform coverage.
Roller-type oiling is prone to "localized missed coating" or "overcoating" when the strip shape is poor, and in severe cases, it can even damage the oiling roller.
5.How does the adaptability advantage of electrostatic oiling manifest itself for different product types?
Automotive outer panel (O5): The oil film uniformity is extremely high (±0.1 g/m²), with no oiling defects, meeting the "zero defect" surface requirements; it can achieve differentiated oiling of the upper and lower surfaces - low oil content for rust prevention on the upper surface and high oil content for stamping lubrication on the lower surface.
Silicon steel (electrical steel): It can achieve extremely thin oil coating (0.3~0.5 g/m²) to ensure the adhesion of the insulating coating; the uniformity of the oil film directly affects the iron loss value and the lamination factor. Electrostatic oiling is the standard configuration of silicon steel production lines.
Galvanized substrate: Non-contact oiling avoids damage to the coating surface; precise oil volume control prevents oil contamination of the galvanizing pot; can be used with a finishing machine to achieve an integrated "finishing + oiling" process.