The stability of a used slitting machine's tension control system has a crucial impact on the quality and efficiency of the slitting operation and is a key indicator for evaluating equipment performance. During the slitting process, stable tension is required throughout the entire coil process, from unwinding, feeding, slitting, and rewinding. Unstable tension control can lead to wrinkles and stretching in the coil, or even breakage. This not only wastes raw materials but also frequently interrupts production and increases rework costs. For used equipment, due to its age, core components of the tension control system may be subject to wear and aging, making its stability even more critical. Therefore, determining the stability of the system and whether the coil tension fluctuates excessively during slitting are key considerations before purchasing a used slitting machine.
From a structural perspective, the stability of a used slitting machine's tension control system depends primarily on the coordinated operation of the tension sensor, controller, and actuators (such as magnetic powder brakes and servo motors). If the tension sensor experiences accuracy degradation and is unable to accurately capture changes in web tension, the controller will issue erroneous commands due to signal deviations. Furthermore, if the actuator is worn, such as aging of the magnetic powder in a magnetic powder brake or delayed response of a servo motor, even if the controller issues the correct commands, it will struggle to precisely adjust tension, leading to fluctuations. For example, in the common practice of film slitting, if the sensor accuracy drops by 0.5%, tension fluctuations can reach ±5N when slitting films as thin as 0.01mm, far exceeding the industry-accepted ±2N range. This can directly lead to wrinkling at the film edges after slitting and make subsequent processing impossible.
The stability of the tension control system also varies when slitting webs of different materials, further highlighting the need to assess fluctuations. Flexible webs (such as plastic film and paper) have weaker tensile strength, and even slight tension fluctuations can cause deformation. Rigid webs (such as metal foil and cardboard) are more tolerant of small fluctuations, but excessive fluctuations can still lead to dimensional deviations in the slits. If a used slitting machine has been slitting a single material for a long time, the tension system may have adapted to the characteristics of that material. When switching to a different material, if the system's adjustment capabilities are insufficient, the fluctuations can increase significantly. For example, if a used machine used to slitting paper is switched to slitting PET film, if the tension controller parameters are not adjusted in a timely manner, the tension fluctuations during the slitting process could increase from ±3N for paper to ±8N, seriously affecting film slitting quality.
To test the stability of a used slitting machine's tension control system, test the web during a cut to determine the fluctuations. During a trial cut, first select a coil material and width that matches actual production, set a standard tension value, and during the slitting process, observe the coil surface for smoothness and signs of local stretching or relaxation. Simultaneously, monitor the real-time tension changes on the device display. If the value remains stable within ±2N of the standard value and the coil's appearance appears normal, the system is stable. However, if the value frequently exceeds ±5N, or if the coil exhibits noticeable wrinkles or ragged edges, it indicates excessive tension fluctuations, possibly due to component failure or parameter inaccuracy.
The maintenance records of a used slitting machine's tension control system can also indirectly reflect its stability and fluctuations. If the previous owner regularly calibrates the tension sensor, promptly replaces aging actuator components (e.g., replacing magnetic powder brake powder every six months), and maintains complete maintenance records, this indicates that the system's core components are in good condition and stability is more assured. Conversely, if maintenance records are missing or key components have not been replaced for an extended period, the system may have accumulated significant wear and tear, significantly increasing the likelihood of tension fluctuations during slitting. For example, a used machine that has been used for five years and has never had its tension sensor calibrated may have a sensor error exceeding [amount missing]. 1%, the tension fluctuation during slitting can be 2-3 times greater than that of regularly maintained equipment.
Furthermore, the linkage between the equipment's electrical control system and the tension system can also affect tension stability and fluctuations. Program errors or poor interface connections in the used slitting machine's PLC (Programmable Logic Controller) can cause delays or interruptions in the transmission of tension control commands, leading to sudden tension fluctuations. For example, during the winding phase, if the PLC fails to adjust the winding tension in response to the increase in coil diameter, this can result in excessive tension, causing the coil to stretch and deform, or insufficient tension, causing the coil to loosen. Therefore, when assessing the stability of the tension system, it's also important to simultaneously check the PLC's operating status and any error logs to ensure the coordination between the electrical control and tension control.
Used slitting The stability of a machine's tension control system isn't fixed; it's influenced by multiple factors, including component condition, coil material, maintenance, and electrical linkages. Tension fluctuations during slitting also require comprehensive assessment through actual testing and historical records. For buyers, not only should they observe real-time fluctuations through test cuts, but they should also review maintenance records and check the condition of key components to fully assess system stability and avoid tension issues impacting subsequent production. If system stability is good and fluctuations are minimal, the equipment can quickly adapt to production needs. If fluctuations are excessive, consider replacing components or abandoning the purchase, thus mitigating production risks at the source.
