1.What are the requirements for dimensional accuracy?
Length Tolerance: This is the most critical precision indicator for leveling machines (fixed-length cross-cutting production lines). High-end requirements can reach within ±0.5 mm, while ordinary requirements are between ±1.0 and ±2.0 mm. Precision depends on the servo system, encoder accuracy, and the stability of the shearing mechanism.
Width Tolerance: The width precision after slitting typically requires ±0.1 mm to ±0.5 mm to ensure the sheet material can be used smoothly for subsequent precision assembly or edge curling.
Diagonal Difference: This measures the squareness of rectangular sheet material. A diagonal length difference of ≤ 2.0 mm is typically required (depending on the sheet length), which is crucial for the assembly of doors, windows, cabinets, etc.
2.What are the requirements for shape accuracy?
Flatness: The core purpose of leveling and straightening. The sheet material should be placed on the platform without localized warping, wavy edges (ruffled edges), or central arching. This is typically measured using a feeler gauge to check the gap between the sheet and the platform, or by visually inspecting for any visible deformation.
Sickle Curvature: Refers to the lateral bending of the sheet material along its length, a crucial indicator for longitudinal shearing. The lateral bending amount per meter should be ≤ 1.0 mm (high precision requirements can reach ≤0.5 mm/m). Severe sickle curvature can cause feeding jams in subsequent automated processing.
Burst Height: Burrs on the sheared edges can scratch the coating, affect assembly safety, and accelerate cut corrosion. The burr height should be ≤ 0.05 mm (50μm), with excellent equipment achieving ≤0.02 mm. A deburring device (rolling or scraping type) is required.
3.What are the precision requirements for surface and coating protection?
Zero surface damage: All conveyor rollers and straightening rollers must be highly smooth, clean, and of moderate hardness to ensure that the coating surface is never crushed or scratched during straightening and conveying. This is the essential difference between leveling color-coated coils and ordinary cold-rolled sheets.
No roller marks: The equipment must effectively prevent iron filings and dust from adhering to the roller surface; otherwise, periodic marks will be pressed into the coating.
4.How to achieve high-precision configuration and process control of key equipment?
Straightening System:
Number and Layout of Straightening Rolls: A higher number of rollers (e.g., 17 or 21 rollers) provides a stronger ability to eliminate complex internal stresses and improve flatness. A staggered arrangement of multiple rollers is typically used.
Roll Diameter and Pitch: Smaller roller diameters and pitches provide a more precise straightening effect, especially for thin sheets.
Adjustment Method: The pressure of each roller must be independently and precisely adjustable to accommodate materials of different thicknesses and strengths.
Measurement and Control System:
High-Precision Encoder: Used for real-time measurement of strip length and speed, forming the basis for length accuracy.
Servo Drive System: Used for feeding and positioning, offering fast response and accurate positioning.
Automatic Thickness Detection (AGC Optional): Monitors and fine-tunes straightening pressure in real time to ensure consistency.
Shearing System:
Hydraulic or Mechanical Cross-Cutting: Hydraulic systems offer smoother operation and are suitable for thicker sheets; high-speed mechanical systems are suitable for thinner sheets.
Cutting material and clearance: Use special cutting steel and precisely adjust the clearance between the upper and lower blades (usually 8-12% of the plate thickness) to obtain the best shearing surface and minimal burrs.
5.What are the requirements for operation and maintenance?
Parameter Setting: Straightening pressure, tension, and blade gap must be precisely set according to the thickness, width, coating hardness, and substrate strength of each color-coated roll. Unchanging parameters will lead to quality fluctuations.
Equipment Maintenance: Regularly cleaning the roller surface, checking blade wear, and calibrating the measurement system are fundamental to maintaining accuracy.