Maintenance method of twin screw fish feed production line

The daily maintenance of the twin-screw fish feed extruder needs to start from the four cores of "cleaning, lubrication, firmness, and observation", and formulate standardized processes for several core key components to extend the service life of fish feed production and ensure production efficiency. The following are the maintenance skills and operating points of the transmission system and electrical control system of the fish feed extruder:

1. Gearbox lubrication management
Oil level and oil quality detection: Check the gear oil level through the oil mirror before starting the machine every day (need to be between the upper and lower scale lines). If the oil color becomes darker, emulsification or impurities appear (particle size > 50μm), it needs to be replaced immediately (L-CKC 220# industrial closed gear oil is recommended, and the replacement cycle is 2000 hours).
• Gear meshing abnormal sound treatment: If you hear a "click" periodic abnormal sound during operation, it may be gear wear or foreign matter stuck. It is necessary to stop the machine to check the gear meshing surface (allowable contact area ≥ 70%). If pitting is found (pit depth > 0.5mm), it is necessary to grind and repair or replace the gear.
2. Bearing and coupling maintenance
• Bearing temperature rise monitoring: Use an infrared thermometer to measure the bearing seat temperature (≤75℃). If it exceeds 80℃ and is accompanied by abnormal vibration (amplitude＞0.1mm), check the grease (recommended to use lithium-based grease ZL-3, the replenishment amount is 1/3 of the bearing cavity). If the lubrication is normal, the bearing clearance may be too large (standard clearance 0.02-0.04mm), and the bearing needs to be replaced.
• Coupling alignment: Use a dial indicator to check the coaxiality of the coupling every week (radial deviation ≤0.1mm, end face deviation ≤0.05mm). Excessive deviation will cause motor overload. The motor base height can be adjusted by adding or removing shims. After calibration, tighten the bolts (torque value according to the requirements of the manual, such as M12 bolt torque 40-50N・m).

1. Control cabinet dust cleaning: Regularly use a vacuum cleaner (power ≥1500W) to clean the dust in the control cabinet, focusing on removing dust accumulation on the contactor contacts and relay base (thickness >1mm may cause short circuit), and use an insulation resistance meter to detect line insulation (≥2MΩ) after cleaning.
2. Fish production line Sensor calibration
• Temperature sensor calibration: Use a standard thermometer (accuracy ±0.5℃) to compare the displayed values ​​of the temperature control meter of each section of the barrel every month. If the deviation is >3℃, check whether the thermocouple (model K type) is in poor contact or aging. After replacement, reset the temperature control parameters (such as 60-70℃ for feeding section, 80-90℃ for compression section, and 100-120℃ for melting section).
• Zero calibration of weighing sensor: In the shutdown state, press the "zero calibration" button of the control cabinet. If the displayed value deviates from ±0.5% FS (full scale), check whether the feeder scale bucket is accumulated and whether the sensor cable is broken and grounded. If necessary, use weights (50kg level) for linear calibration (error ≤ 0.2%).

1. Establish a three-level maintenance ledger
o Daily records: temperature of each section, current value, bearing temperature, cleaning content; o Weekly records: gear oil status, cutter wear, screw clearance data; o Monthly summary: number of failures, component replacement records, energy consumption analysis (standard energy consumption ≤ 0.35kW・h/kg feed).
2. Setting of abnormal warning threshold
o When the following situations occur, the machine must be stopped immediately for maintenance:
o The screw speed fluctuation is greater than 5% (standard fluctuation is ≤2%);
o The main motor current exceeds the rated value by 110%;
o The die head pressure suddenly drops by more than 20% (it may be a broken screw tooth or a broken die).

• Before maintenance, the main power supply must be cut off, a "under maintenance" warning sign must be hung, and the control cabinet must be locked (the key is kept by a dedicated person).
• When disassembling high-temperature parts (such as the die head), it is necessary to wear heat-insulating gloves (temperature resistance ≥300℃) and use a torque wrench to loosen the bolts in diagonal order (to prevent deformation).
• When cleaning the barrel, it is strictly forbidden to put your hand into the feed port. A special long-handled tool must be used, and there must be a supervisor nearby.

The above daily maintenance techniques can effectively reduce the failure rate of fish feed equipment (target ≤0.5 times/month), extend the service life of the screw to more than 8,000 hours, and ensure that the qualified rate of feed particles is greater than 98%. The core of maintenance lies in "maintenance instead of repair". A personalized maintenance plan for the fish feed production line is formulated based on the characteristics of production materials to maximize equipment efficiency and life.