How Does the Rectifying Function Work in High Speed Rewinding Machines?

In modern industrial production, high-speed winding machine is core equipment in fields of chemical fiber and battery manufacture, and its performance directly determines product quality and efficiency. Among them, the rectifying function is a key technology to ensure the winding accuracy, and the reel deformation and tension fluctuations can be effectively prevented by the real-time monitoring and dynamic adjustment of the material's running path. In this paper, the working mechanism of rectifier is analyzed systematically from four dimensions: rectifier function principle, core components, technology realization and industry application.
I. Physical Foundations foundations and Core Objectives of rectifying functions
The essence of rectifying function is to detect the edge position of the material by sensor and modify the material running trajectory dynamically by control system. Its core objectives can be summarized in three points:
1.Edge Alignment Precision
Ensure that the deviation between the material edge and the centerline of the scroll is within ±0.1 mm to prevent defects such as "tower" or "chrysanthemum" on the end of the scroll. For example, if the edge of the filament deviates by 1 mm during the rewinding of a chemical fibre filament, the ratio of unevenness at the end will exceed 0.6% when the diameter of the reel reaches 300 mm, directly leading to an increase in the rate of breakage of the filament during subsequent stretching.
2.Tension stable
Edge bias can lead to local tension mutations. The rectifier system maintains a straight line and reduces the influence of tension fluctuations on the compactness of the drum. During the rewinding of the battery electrode, the separator has an edge deviation of more than 0.2 mm, which poses a risk of short circuit within the battery.
3.Production Continuity
The automatic rectifying function can compensate material jitter and vibration of equipment in real time, avoid production stoppages caused by manual intervention, and improve the overall Effectiveness (OEE equipment.
ii. Core Components and working principle of rectifier system
The rectifying system is composed of sensor, actuator and control algorithms, and its workflow is divided into three closed-loop stages: detection,calculation andcorrection.
1. Edge Detection Sensors: The "Eyes" for data collection
The sensor is the input end of the rectifier system, and the performance of the sensor directly influences correction accuracy. Current mainstream technologies include:
Photoelectric sensors: These sensors emit infrared beams that measure the strength of reflected signals to determine the edge of the material. They have advantages such as high response time (<1 millisecond) and high resolution (less than 0.01 mm), but are susceptible to dust interference and require regular cleaning.
Ultrasonic Sensors: Positioning with ultrasonic reflection time difference at the edge of the material, suitable for transparent or low-reflectivity materials (such as certain battery separators), but with slightly lower accuracy than photoelectric sensors.
CCD Vision Sensors: This sensor uses image processing algorithms to recognize the contours of the edges and can monitor multiple paths at once, but is relatively expensive and used mainly on high-end devices.
Sensors should be installed in such a way as to avoid material wobble areas, usually between 100 and300 mm in front of the coil head, to balance detection lag and installation space requirements.
2. Executing Agency: Dynamic Calibration of "Muscles"
The operating path of the material is adjusted by the actuator according to sensor signals. Common technical methods include:
Guide Roller Oscillation Type: A servo motor drives guide roller vibration around its axis, changing the material's running direction. The structure is simple and cost-effective, but with a limited correction range (usually + -10mm) and is suitable for low speed equipment.
Expand Shaft Movement Type: The unwinding shaft is mounted on a slide table that can be moved horizontally. It is driven by a linear motor or air cylinder. This method provides a large correction range (up to ±50 mm), but has a large inertial mass and slower response speed.
Clip roller drive: Install a pair of differentially rotating pinch rollers at the inlet of the material to produce lateral force through speed difference, causing the material to deviate from the direction. The technique has a high correction precision (<0.05 mm), but the pressure of pinch roller needs to be precisely controlled to avoid damaging the material.
Take a certain type of chemical fiber rewinding machine for example. Using the compound structure of "guide roller oscillation + clamp roller drive": guide roller is responsible for extensive rough tuning (response time: 50 milliseconds) and pinch rollers achieves micrometer-level fine adjustments (response time: 10 milliseconds). Together, they keep the edge deviation of the filament to ±0.05 mm.
3. Control Algorithms: the 'brain' of intelligent decision-making
Control algorithm is the core of rectifying system, and two difficult problems need to be solved:
Dynamic Response Optimization: During rewinding, material speed can exceed 4000 m/min. Sensor signals need to be processed and actuated within 1 millisecond to avoid correction lag and overshoot.
Anti jamming ability: Interference factors such as vibration of equipment and material elastic deformation of materials introduce noise signals and require filtering algorithm (such as Kalman) to extract effective edge position.
Current mainstream control strategies include:
PID Control: The output of this adjustment drive is through proportional integral derivative component, suitable for linear systems, but requires adjustment of empirical parameters.
Fuzzy Control: Edge bias is divided into multiple linguistic variables (such as "large bias" and "small bias"), and is well adapted to nonlinear nonlinear systems the output correction amounts of fuzzy rule library.
Adaptive control: It combines machine learning algorithms to dynamically adjust control parameters based on historical data to achieve "smarter" rectifications over time.
Fuzzy control-PID compound control strategy was adopted in a battery electrode rewinding machine: Fuzzy control rapid response was initiated when the deviation was large, then switched to PID control fine tuning when the deviation was small, the rectification response time was shortened to 8ms, and the overadjustment rate was less than2%.
III. Technological Evolution and Industry Application of Correction Function
With the advancement of Industry 4.0 and Intelligent Manufacturing, the rectifying function is developing from "single correction" to "intelligent collaboration," with the following technological trends and industry applications:
1. Technology Trends: Digitization and Integration
Digital Twin Technology: by building the virtual model of rewinding machine, simulating the rectification effects under different material parameters, optimizing sensor layout and control algorithm, reducing physical debugging time.
Multi-sensor Fusion: combining data of tension sensors and vibration sensors, a multi-dimensional rectification model of position-tension-vibration is established to enhance the robustness of the system.
Edge computing: AI chips embedded in rectification controllers for localized data processing, reducing reliance on host computers and improving real-time performance.
2. Industry Applications: Cross-cutting Expansion from Chemical Fibers to New Energy
Chemical fiber industry: polyester and nylon filaments rewinding, rectifier system needs to adapt to different filament densities (0.5-5 dtex) and surface friction coefficients, through adaptive control algorithm to achieve "multi-use."
Battery fabrication: the rectification precision of square cells should be ± 0.02 mm when rewinding to avoid lithium plating risk due to gap between electrode and separator. 1 with laser vision sensors and high-speed actuators, a reduced the rectification cycle to 5ms and a 1.2% increase in battery output.
Thin film packaging: In the rewinding of food packaging films and optical films, the rectifier system requires a balance of speed (up to 1,000 m/min) and precision (±0.05 mm) to achieve "ultra-quiet rectification" through pneumatic bearings and linear motor drive technology.
IV. INTRODUCTION Challenges and future Prospectss
While significant progress has been made in the the rectifying function, two major challenges remain:
1. Dynamic Balance in Ultra-high-speed Scenarios
When the rewinding speed exceeds 5,000 m/min, the inertial force and air resistance of the material increase significantly, necessitating the development of new new lightweight actuators and low latency control algorithms.
2. Ultra-thin material correction
battery separators thickness reduced to less than 3 μm. Traditional contact sensors tend to damage materials and commercial applications of non-contact sensors such as terahertz waves are in urgent need of breakthrough.
In the future, the rectifier function will move toward ``full process autonomous optimization '': by data interconnection with other modules of the reel machine,such as tension control and reel replacement systems, a "perception-decision-execution" closed-loop system will be constructed, leading to ``zero intervention"intelligent rewinding. For example, a research team is exploring a correlation analysis between rectification data and battery performance, optimizing rectification parameters with big data to improve battery cycle life by more than 5%.
V. Conclusion
As the ``nerve center"of high-speed winding machine, the evolution of rectifying function directly promotes the development of industrial manufacturing in the direction of ``high accuracy, high efficiency and high reliability ''. From photoelectric sensors to artificial intelligence algorithms, from single calibration to intelligent collaboration, every breakthrough in calibration technology has redefined the boundaries of "regression." With the emergence of new materials and processes, the rectifying function will evolve to inject more impetus into intelligent manufacturing.