Multi roll leveling principle: Mechanism of internal stress elimination under pressure gradient
The basic principle of the multi-roll leveling machine is to realize the internal stress balance in the repeated bending process of the sheet metal by the staggered arrangement of the upper and lower roll groups and the pressure gradient design.
The technical implementation can be divided into three steps:
First stage stress analysis
Before entering the leveling machine, the surface of the board has defects such as wave deformation and edge wave shape, which are essentially caused by the uneven distribution of internal stress due to inconsistent longitudinal fiber length. For instance, the traditional method easily causes deformation of harvester blades during leveling. Multi-roll leveling machines use a 19-roll matrix structure and apply high-pressure rough leveling (the pressure can be twice that of traditional equipment) in the front section to quickly break the internal stress on the surface of the board.
Stage of implementation of pressure gradient
The upper and lower roller groups are staggered and the roller diameter reduces gradually from the inlet to the outlet. So the pressure reduces gradually from the inlet to the outlet.
For example, leveling of high-strength steel:
Front roller group: Apply high pressure (like 500MPa) to make the sheet plastic deformation, stretch the shorter fibers to the length of the longer fibers;
Mid section roller group : Reduce pressure to 300MPa, repair micro deformation, avoid local overload;
Rear roller group: Low-pressure (100MPa) precision correction, eliminating residual stress, so that the flatness of the board is ≤0.03mm.
Verification step of elastic recovery
Once the board leaves the leveling machine, a laser profiler scans the 3D flatness “map” in real time and the data is returned to the control system. If local rebound is detected, the system automatically initiates secondary leveling to constitute a closed-loop control. For example, in leveling of car body panels, this mechanism reduces the flatness error from ±0.5mm to ± 0.01mm .
Intelligent compensation system: dynamically adjusted to prevent overcorrection & undercorrection
The intelligent compensation system achieves adaptive optimization of the leveling process by means of multi-parameter real-time linkage and AI prediction models. Its technical architecture comprises four key modules:
High precision monitor unit
Laser profiler: The surface of the sheet is scanned with a micrometer accuracy to obtain 3D morphology data;
Pressure sensor: real-time monitoring of each roller group pressure value error ≤ 0.5%;Thickness gauge: Contactless measurement of sheet thickness, response time <0.1 seconds.
2. Decision and prediction module of AI
By using material database such as elastic modulus and yield strength parameters of steel, aluminum and composite materials, AI models can predict the distribution of residual stress of flattened plates. For example,Enter parameters such as sheet thickness and initial curvature (0-50mm/m), and the model will output the optimal pressure gradient curve; Dynamically adjust the roller gap inclination angle (± 2 °) and leveling speed (0-15m/min) to avoid cracking caused by overcorrection or rebound caused by undercorrection.
3. Mechanism of execution module
Servo motor: roller group up and down movement, the positioning accuracy ± 0.01mm;Hydraulic system: high pressure power supply, pressure wave is less than 1%. Roller gap adjustment mechanism: worm gear transmission with stepless adjustment, response time is less than 0.5 seconds.
4. Module for collaboration in the cloud
The device’s operating data is uploaded to the cloud, so the manufacturers can remotely diagnose problems and optimize programs. For instance:The wear of the roller group is simulated and the remaining life is predicted by applying the digital twin technology;
Apply trained AI models to historical data to improve prediction accuracy (currently 98.7%).
Typical application case: Blade leveling for agricultural equipment
In the production of harvester blades the synergistic effect of multi roll levelers and intelligent compensation systems significantly improves the quality of the products:
1. Effects of process optimizationReduction of residual stress: to 40MPa from 200MPa in traditional processes, providing the fatigue life of more than 2000 hours;
Reduce cutting resistance: The straightness error of the cutting edge is ≤ 0.03mm, the surface smoothness of the cut is improved by 50%, and the crop loss rate is controlled within 1.5%; Improve production efficiency: The daily production capacity of a single machine can reach 3000 pieces, and the yield rate has increased from 95% to 99.6%.
Economic analysis
Cost saving: the leveling cycle is shortened by 70%, the frequency of blade replacement is reduced by 40%, and the annual maintenance cost is saved by more than 100,000 yuan (based on a scale of 100 harvesters); Environmental benefits: no sparks and low noise during the leveling process, reducing the scrap rate from 5% to 0.4%, and minimizing steel waste and environmental pollution.
Technology development trend
1.Ultra precision leveling: The number of roller groups has increased to more than 20 and the pressure control accuracy has reached ± 0.1MPa;
2. Enlargement of material adaptability: from metal sheets to composite materials such as carbon fiber, ceramics;
3. Complete process intelligence: Connect data with upstream and downstream processes such as stamping and cutting to achieve “zero defect manufacturing”.
