What should be paid attention to in the daily maintenance of photovoltaic welding strip rolling mill

      The photovoltaic welding strip rolling mill is the core equipment for producing photovoltaic welding strips. The core of its daily maintenance is to ensure the accuracy of the rolling mill, control the cleanliness of the equipment, maintain the stability of the transmission and hydraulic system, and avoid production defects such as scratches/uneven thickness of the strip. At the same time, photovoltaic welding strips have extremely high requirements for dimensional accuracy (thickness tolerance within ± 0.005mm) and surface smoothness. Daily maintenance needs to be carried out around "precision, cleanliness, and stability", covering the entire process of pre shift inspection, in shift inspection, and post shift maintenance. At the same time, it focuses on core components such as rolling mill, transmission, hydraulic, electrical, and feeding/receiving. The following are modular and practical daily maintenance points that are suitable for standardized operations in mass production workshops:

1、 Core component: Roll system maintenance (most critical, directly determining welding strip accuracy)

      The rolling mill is the core of welding strip rolling. Photovoltaic welding strips are mostly rolled from 0.08-0.3mm ultra-thin copper strips. The roundness, coaxiality, and surface smoothness of the rolling mill directly affect the thickness and surface quality of the strip. Daily maintenance requires "light wiping, precise calibration, anti-collision, and timed grinding":

      Pre shift inspection: Use a dust-free cloth dipped in anhydrous ethanol to gently wipe the surface of the upper and lower rolling rolls, check for copper shavings, oil stains, scratches, sticking rolls, and pitting. If there are small sticking roll impurities, do not use hard objects to scrape them, and use fine grinding paste combined with wool felt to gently throw them away; At the same time, check whether the gap between the rollers is zero and whether the roller surface fit is uniform, to avoid the deviation of the gap causing unilateral thickness of the strip.

      In class inspection: Check the operation status of the rolling mill every 2-4 hours, observe whether there are rolling marks or scratches on the surface of the rolled strip. If continuous rolling marks appear, immediately stop the machine and inspect the surface of the rolling mill to check for foreign objects embedded or fatigue damage to the rolling mill surface; It is prohibited to touch the roller surface with hands or tools during the operation of the rolling mill to prevent deformation and scratching of the rollers.

      After shift maintenance: After the rolling is completed, thoroughly clean the copper shavings and oil stains on the surface of the rolling mill, wipe it clean with a dust-free cloth, and evenly apply a layer of anti rust oil (using low volatility, residue free special anti rust oil to avoid contaminating the subsequent strip); If the machine is shut down for a long time (more than 8 hours), a special protective film should be used to wrap the rollers to prevent oxidation and rust.

      Regular calibration and grinding: Grinding is carried out at a fixed frequency according to production capacity. In mass production, for every 5-8 tons of copper strip rolled, the rolling mill is finely ground once to restore the smoothness of the rolling surface; Calibrate the roundness, coaxiality, and levelness of the rolling mill with a dial gauge every week, with a deviation controlled within 0.002mm, to avoid rolling mill deflection causing wavy edges in the strip.

      Anti collision protection: Use specialized lifting equipment and rubber pads when replacing the rolling mill, and prohibit direct contact between the rolling mill surface and metal tools; The idle rolling mill is vertically placed on a dedicated support, with the rolling mill facing upwards to avoid deformation caused by compression.

2、 Maintenance of transmission and speed control system (ensuring stable rolling speed and avoiding strip stretching)

      Photovoltaic welding strip rolling mill requires constant linear speed and low tension operation. The slip, abnormal noise, and speed fluctuation of the transmission system (motor, reducer, coupling, synchronous belt) can cause strip stretching and uneven thickness. Daily maintenance points:

      Pre shift inspection: Check whether the connecting bolts between the motor and the reducer are tightened, whether the elastic pad of the coupling is worn or cracked, whether the synchronous belt is loose or jumping teeth. If the tension of the synchronous belt is insufficient, use a tensioning wheel to fine tune it to avoid slipping during operation; Check if the speed controller parameters match the current rolling process and prohibit arbitrary modifications.

       Lubrication and maintenance: The gearbox should be regularly filled with gear oil according to the instructions (usually check the oil level every 3 months and replace it every 6 months), and the oil level should be kept at the center line of the oil mark. It is forbidden to operate without oil; Couplings, bearing seats and other rotating parts should be filled with high-temperature lithium grease once a week to avoid dry grinding noise.

       In class inspection: Monitor the running sound of motors and reducers. If there is abnormal noise or overheating (temperature exceeding 60 ℃), immediately stop the machine for troubleshooting to avoid motor burnout or damage to transmission components; Observe whether there is sudden acceleration/deceleration during the rolling process of the strip, and check whether there is signal interference in the speed control system.

       Cleaning and protection: Timely clean the copper shavings and dust on the transmission components to prevent impurities from entering the interior of the gearbox and causing gear wear; Keep the motor cooling fan grille clean to avoid dust accumulation affecting heat dissipation.

3、 Hydraulic and Pressing System Maintenance (Control Rolling Pressure to Ensure Uniform Thickness)

      The pressing device of the rolling mill is mostly driven by hydraulic pressure. The pressure fluctuation, oil leakage, and jamming of the hydraulic system will directly affect the stability of the rolling pressure, resulting in the thickness of the welded strip exceeding the tolerance. Daily maintenance focuses on "leak prevention, pressure stabilization, and cleaning":

      Pre shift inspection: Check the oil level of the hydraulic oil tank, maintain the oil level between the upper and lower limits of the oil gauge, and ensure that the oil is clear and free of turbidity; Check whether there is oil leakage in the hydraulic pipelines, joints, and hydraulic cylinders. If there is oil leakage, replace the sealing ring immediately and prohibit operation with leakage; Start the hydraulic system and run it without load for 2-3 minutes. Check if the pressure is stable at the process set value (usually 0.5-2MPa for photovoltaic welding strip rolling), and there is no sudden increase or decrease in pressure.

      Oil and filter maintenance: Use anti-wear hydraulic oil (recommended No. 46) for hydraulic oil, replace it every 6 months, and thoroughly clean the oil tank during replacement; The hydraulic oil suction filter and return filter should be cleaned once a month and replaced every three months to prevent clogging of the filter and contamination of the hydraulic oil, as well as wear and tear on the hydraulic valves and cylinders.

      In class inspection: Observe whether the hydraulic cylinder presses down smoothly, whether there is any jamming or movement. If there is shaking when pressing down, check whether the hydraulic valve is blocked or the hydraulic cylinder is leaking; Check the hydraulic system pressure once every hour, and adjust it promptly if the pressure deviation exceeds ± 0.1MPa.

      Post shift maintenance: After turning off the hydraulic system, reset the gap between the rollers to zero, so that the hydraulic cylinder is in a pressure free state, reducing the aging of the seals; Clean the dust on the surface of the hydraulic station and maintain ventilation and heat dissipation.

4、 Maintenance of feeding/receiving and tension system (to avoid strip deviation, stretching, and breakage)

      The feeding rack (uncoiler) and receiving rack (coiler) are coordinated with the tension control system to ensure low tension and no deviation during the welding strip rolling process. The ultra-thin photovoltaic welding strip is prone to breakage, and the maintenance of this system needs to be fine:

      Pre shift inspection: Check whether the centering devices of the feeding and receiving rolls are tightened, whether the rolls are skewed, and if the rolls are uneven, level them first before feeding; Check whether the surface of the tension roller is smooth, whether there are scratches or debris, whether the tension sensor is clean, and whether there is no dust obstruction (to avoid signal distortion).

      Tension adjustment: Adjust the tension value according to the thickness of the welding strip (thin strip 0.08-0.15mm tension is controlled at 5-10N, thick strip 0.2-0.3mm tension is controlled at 15-30N). It is forbidden to cause the strip to stretch due to excessive tension, or cause the strip to deviate or stack due to insufficient tension.

      In class inspection: Observe whether the strip is running in the center during the rolling process. If there is deviation, adjust the guide rollers of the feeding rack in a timely manner to avoid scratches caused by the strip rubbing against the edges and corners of the equipment; Check the flatness of the receiving roll, without tower shaped or loose rolls. If loose rolls occur, adjust the receiving tension slightly.

      Component maintenance: Lubricate the bearings of the guide roller and tension roller once a week, check whether the polyurethane adhesive layer on the surface of the guide roller is worn or cracked. If the adhesive layer falls off, replace it immediately to prevent the metal roller surface from scratching the strip.

5、 Electrical and control system maintenance (ensuring accurate operation of equipment and avoiding downtime due to faults)

      The electrical system is the "brain" of the rolling mill, including PLC, touch screen, sensors, solenoid valves, etc. Daily maintenance focuses on preventing dust, loosening, and signal interference:

      Pre shift inspection: Open the electrical cabinet and check if the internal wiring terminals are securely fastened without looseness or oxidation; Whether the touch screen display is normal, and whether the process parameters (rolling speed, pressure, gap, tension) are clear and free of garbled characters; Whether the wiring of each sensor (thickness, position, tension) is firm and not loose.

      Cleaning and Protection: The cooling fan of the electrical cabinet should be kept clean, free of dust accumulation, and ensure ventilation inside the cabinet. The temperature should be controlled below 40 ℃; Clean the dust inside the electrical cabinet with compressed air (low pressure, ≤ 0.3MPa) every month, and prohibit wiping electrical components with water or damp cloth; The electrical cabinet should operate with the door closed to prevent copper chips and dust from entering.

      Troubleshooting: If the parameters of the touch screen cannot be modified and the device does not move, first check whether the sensor is faulty and whether the wiring is loose, and then check the PLC module. It is forbidden to plug and unplug the PLC wiring at will; If the solenoid valve is stuck, rinse it with clean hydraulic oil. If it cannot be repaired, replace it immediately.

      Data backup: Backup the process parameters in the touch screen once a week to avoid parameter loss caused by system failures and affecting production efficiency.

6、 Equipment overall cleaning and on-site management (basic support, avoiding secondary pollution)

      It require extremely high surface cleanliness. Equipment dust and copper chips can directly cause contamination and scratches on the surface of the strip. On site management needs to achieve the goal of "clearing the site after the work is completed and materials are used up":

      Class cleaning: Use a specialized brush and vacuum cleaner to clean the copper shavings on the equipment table, both sides of the rolling mill, and the feeding/receiving rack. It is forbidden to directly blow the surface of the rolling mill with compressed air (to prevent copper shavings from being embedded in the rolling mill surface); During the rolling process, there are no scattered copper shavings or oil stains on the transmission path of the strip.

      Post shift comprehensive cleaning: thoroughly clean the entire equipment and the surrounding ground of copper shavings and dust, wipe all parts in contact with the strip with a dust-free cloth; The surface of the equipment should be free of oil and water stains, and idle tools should be returned to their original positions. It is prohibited to place heavy objects such as metal tools and coils on the equipment.

      On site environment: The rolling mill workshop is kept dust-free and dry, with humidity controlled at 40% -60% to avoid copper strip oxidation; Prohibit dust generating operations such as grinding and cutting in the workshop to prevent cross contamination; When entering the workshop, it is necessary to wear dust-free clothing and gloves to prevent oil stains from coming into contact with the strip and rollers.