Powder modified granulation equipment (such as high-speed mixers, extrusion granulators, fluidized bed granulators, etc.) is used to modify powder materials into particles through physical or chemical methods, and is widely used in fields such as chemical engineering, pharmaceuticals, food, and new materials. Its daily maintenance needs to be combined with the structural characteristics of the equipment (such as mixing blades, screws, heating systems, dust removal devices, etc.) and process requirements (such as temperature, pressure, speed, material characteristics), through cleaning, lubrication, inspection, calibration and other operations, to ensure stable operation of the equipment and extend its service life. The following are specific maintenance steps and precautions:

1、 Daily inspection and recording

1. Running status monitoring
   • Pre startup inspection：
     • Confirm that the power and air sources (such as compressed air) of the equipment are connected normally, and the voltage fluctuation range is within ± 5% of the rated value.
     • Check whether the fastening bolts of each component (such as the mixing blade, screw, and cutter) are loose, and manually rotate the disc (such as through a coupling) to confirm that it rotates flexibly without any jamming.
   • Observation during operation：
     • If there is abnormal noise during equipment operation (such as metal friction sound, vibration sound), it is necessary to immediately stop the machine for inspection (such as bearing damage, screw wear).
     • Observe whether the parameters such as temperature, pressure, and speed are within the set range (such as controlling the screw temperature of the extruder granulator within ± 10 ℃ of the material melting temperature). If the fluctuation exceeds ± 5%, investigate the cause (such as heating element failure or cooling system blockage).
2. Verification of safety devices
   • Test the sensitivity and reliability of emergency stop buttons and safety interlock devices (such as equipment that cannot be started when the door cover is not closed), and conduct functional tests at least once a month.
   • Check if the protective cover and grounding wire are intact to avoid accidents caused by personnel coming into contact with rotating parts or static electricity.
3. data recording
   • Record equipment operating time, output, fault codes (if any), maintenance content, and other data to provide a basis for developing maintenance cycles. For example, equipment operating at high frequencies (>16 hours/day) needs to shorten the lubrication cycle.

2、 Daily maintenance (after each shift or daily operation)

1. Cleaning and dust removal

• Internal cleaning of equipment：
  • High speed mixer：
    • After emptying the material, use a soft bristled brush or compressed air to clean the powder (such as titanium dioxide, calcium carbonate) attached to the inner wall of the mixing chamber and the surface of the stirring blade, to avoid residual material clumping and affecting the next mixing effect.
    • If the material is prone to moisture absorption (such as starch), it is necessary to wipe the sealing ring with a dry cloth to prevent moisture from entering the bearing and causing corrosion.
  • Extrusion granulator：
    • Clean the residual melt (such as plastic or rubber) on the surface of the screw, and use a copper scraper or specialized cleaning agent (such as xylene) to wipe it to avoid scratching the surface of the screw with hard objects.
    • Clean the blockages in the mold orifice plate (such as circular and irregular holes), and use a needle (with a diameter 0.1-0.2mm smaller than the aperture) to clear them to prevent uneven particle size.
  • Fluidized bed granulator：
    • Clean the powder blocked in the pores of the air distribution plate (such as porous plates and sieves), rinse with a high-pressure water gun, and dry to ensure even distribution of air flow.
    • Clean the dust on the surface of the dust collector filter bag, gently tap or use a blowback system to remove the accumulated dust, and maintain breathability (pressure difference ≤ 1.5kPa).
• External cleaning of equipment：
  • Wipe the dust off the control cabinet and motor casing with a damp cloth to prevent dust from entering electrical components and causing short circuits; If there is severe oil pollution in the environment, neutral cleaning agents can be used to wipe and air dry.

2. Lubrication and maintenance

• bearing lubrication：
  • Apply an appropriate amount of high-temperature grease (such as lithium based grease, working temperature range -20 ℃~120 ℃) to the stirring blade bearings and screw support bearings to reduce friction and wear.
  • Lubrication cycle: low-speed bearings (speed<100rpm) are lubricated once per shift; Lubricate high-speed bearings (speed>500rpm) every 2 hours.
• Chain/gear lubrication：
  • If the equipment adopts chain drive (such as conveyor belt), use an oil pot to drip mechanical oil (such as 32 #) to lubricate the chain joints; If gear transmission is used, check the oil level of the gearbox (observed through the oil level mirror). If the oil level is below the lower limit, add lubricating oil of the same model.

3. Seal inspection

• Dynamic sealing：
  • Check whether the shaft seal and screw end face seal (such as mechanical seal and packing seal) of the mixing blade are leaking. If the leakage exceeds the standard (such as dripping>5 drops/minute), adjust the clamping bolts or replace the seals.
• Static sealing：
  • Check whether the flange connection and manhole cover sealing gasket are aged and cracked. If leakage is found, replace the gasket (such as silicone gasket, PTFE gasket).

3、 Weekly maintenance

1. Transmission system inspection

• Belt/Coupling：
  • Check the tension of the belt (press the middle of the belt with your fingers, and the sag should be 10-15mm). If it is too loose, adjust the motor base bolts; Check the surface of the belt for wear and cracking, and replace it if necessary.
  • Check whether the elastic sleeve of the coupling (such as the plum blossom pad) is aging and deformed. If the elasticity weakens, it needs to be replaced to avoid damage to the bearings caused by transmission impact.
• Motor/reducer：
  • Use an infrared thermometer to measure the temperature of the motor casing (should be ≤ 70 ℃). If the temperature is too high, check if the cooling fan is running properly or if the load is too high.
  • Check if the output shaft of the reducer is shifting (axial clearance should be ≤ 0.1mm). If the clearance is too large, replace the bearing or adjust the gear mesh clearance.

2. Maintenance of heating/cooling system

• heating element：
  • Use a multimeter to measure the resistance value of the heating coil (such as 14.4 Ω for a heating coil with a rated power of 10kW and a voltage of 380V). If the resistance value deviates by more than 10%, the heating coil needs to be replaced.
  • Check if the connecting wire of the heating coil is loose or burnt. If a burnt smell is found, stop the machine immediately for treatment.
• cooling system：
  • Clean the dust on the surface of the cooling water jacket or air-cooled radiator to ensure heat dissipation efficiency; Check whether the cooling water flow rate (such as observing through a flow meter) is stable. If the flow rate is insufficient, troubleshoot the water pump or pipeline blockage.

4、 Monthly maintenance

1. Electrical system inspection

• control cabinet：
  • Clean the dust inside the control cabinet, use a vacuum cleaner or compressed air to blow the surface dust of electrical components (such as PLC, frequency converter, contactor) to avoid overheating and component damage.
  • Check if the wiring terminals are loose, and tighten all wiring bolts with a screwdriver (pay attention to moderate force and avoid twisting the wire ends).
• sensor calibration：
  • Calibrate temperature sensors (such as thermocouples, thermistors) and pressure sensors (such as pressure transmitters) to ensure that the displayed values deviate from the actual values. If the deviation is greater than 1%, adjust or replace the sensors.

2. Inspection of structural components

• equipment body：
  • Check whether the mixing chamber, screw cylinder, fluidized bed and other structural components are deformed or cracked. If cracks are found, immediately stop the machine for repair (such as welding or replacing parts).
  • Check if the supporting foot bolts are loose. If the equipment vibrates too much, adjust the levelness (using a level to detect, the deviation should be ≤ 0.1mm/m).

5、 Quarterly maintenance (every 3 months)

1. Replacement of vulnerable parts

• Cutting blade/sieve：
  • Check if the cutting edge of the particle cutter is worn (such as blunt cutting edge causing more burrs on the particles). If the wear is greater than 0.5mm, replace the cutter; Clean or replace the screen mesh (such as vibrating screen, rotating screen) to ensure that the aperture meets the particle size requirements.
• Filter bag/filter element：
  • Replace the filter bag (such as a bag filter) or filter element (such as a cyclone separator) of the dust collector. If the filter bag is damaged, it will cause excessive dust emissions (which need to be checked by a differential pressure gauge or visual inspection).

2. Maintenance of hydraulic/pneumatic systems

• hydraulic power unit：
  • Check the hydraulic oil level (observed through the oil level mirror), and if the oil level is below the lower limit, replenish the same type of hydraulic oil (such as 46 # anti-wear hydraulic oil); Replace the hydraulic oil every 6 months and clean the iron filings on the magnetic plug of the oil tank (reflecting the wear of the hydraulic pump or valve).
• pneumatic components：
  • Clean the moisture and impurities in the three components of the air source (filter, pressure reducing valve, oil mist device), and drain them regularly (such as once a week); Check whether the cylinder piston sealing ring is aging and leaking, and replace it if necessary.

6、 Annual maintenance (every 12 months)

1. Overhaul and refurbishment

• Screw/cylinder repair：
  • Disassemble the screw and cylinder of the extruder granulator, and check the wear amount (if the screw diameter decreases by more than 2%, it needs to be repaired or replaced); If there are scratches or corrosion on the surface, it can be repaired by spraying wear-resistant alloys (such as tungsten carbide) or welding.
• Motor/reducer overhaul：
  • Disassemble the motor and check the insulation resistance of the stator winding (should be ≥ 0.5M Ω). If the insulation is aging, it needs to be dipped in paint and dried; Disassemble the gearbox and inspect the gear meshing, replace worn gears or bearings.