The following is a detailed description of the Standard Operating Procedure (SOP) for a coating machine, covering equipment preparation, operating procedures, safety precautions, and maintenance requirements. It is applicable to coating processes in the pharmaceutical, food, and other industries:
I. Pre-operation Preparation
1. Equipment Inspection
- Cleanliness: Confirm that the pot body, spray gun, and pipelines are free of residue, and that cleaning records are complete (compliant with GMP requirements).
- Sealing: Check that the pot body sealing strip is undamaged; perform a vacuum pressure test (pressure drop ≤ 0.1 MPa after 5 minutes of pressure holding).
- Spray Gun System: Confirm that the atomizing nozzles are not clogged, and that the compressed air pressure (0.3-0.6 MPa) is normal.
- Electrical System: Ensure the emergency stop button functions properly, and that the grounding wire connection is reliable.
- Lubrication System: The reducer lubricating oil level is at 1/2-2/3 of the sight glass; the bearing grease is not dried out.
2. Material and Coating Solution Preparation
- Coating Solution Preparation: Weigh the coating material (e.g., hydroxypropyl methylcellulose, acrylic resin) according to the prescription, sieve (≥80 mesh), and dissolve to the target solid content (usually 8-15%). Stir for ≥30 minutes.
- Flake/Granule Inspection: Meets the standards of the Chinese Pharmacopoeia for friability (≤1%) and moisture (≤3%).
II. Operating Procedures
1. Start-up and Parameter Setting
- Power On: Turn on the main control switch and preheat the coating pan to the set temperature (usually 35-45℃).
- Process Parameters: Inlet air temperature (40-60℃), exhaust air temperature (30-50℃), pan rotation speed (3-15 rpm).
- Spray Parameters: Atomization pressure (0.2-0.5 MPa), spray rate (50-200 mL/min), spray gun distance (15-25 cm).
- No-load test run: Start the reactor rotation and spray gun (using pure water instead of coating solution) to confirm atomization uniformity.
2. Material loading
- Loading quantity control: The loading amount of uncoated flakes/granules should be ≤ 70% of the reactor volume (to prevent accumulation that could affect coating uniformity).
- Balance test: Run at low speed (3-5 rpm) for 1 minute to confirm that there is no uneven material flow.
3. Coating Process Operation
- Preheating Stage: Turn on the hot air system to raise the temperature of the uncoated flakes to 35-40℃ (monitored by an infrared thermometer).
- Initial Coating: Spray at a low rate (50 mL/min) for 5 minutes to form a basic film layer.
- Main Coating Stage: Gradually increase the spray rate to the target value, maintaining a 10-20℃ temperature difference between the inlet and outlet air (to prevent over-drying).
- Endpoint Judgment: Use the weight gain method (target weight gain 2-5%) or online NIR (near-infrared) monitoring to check the coating thickness.
4. Shutdown and Discharge
- Spray Gun Flushing: Turn off the coating solution supply and flush the spray gun pipeline with pure water or ethanol (to prevent blockage).
- Cooling Stage: Turn off the heating and keep the reactor rotating at a low speed until the material temperature is <30℃.
- Discharge Operation: Open the discharge port, collect the coated product into a clean container, and label it (product name, batch number, operator).
III. Safety and Abnormal Handling
1. Safety Precautions
- Explosion-proof Requirements: When using organic solvents (such as ethanol), the equipment must comply with ATEX explosion-proof certification. The operating room must have an air exchange rate of ≥15 times/hour.
- Static Electricity Protection: The grounding resistance of the coating pan must be ≤4Ω. Operators must wear anti-static clothing/shoes.
Emergency Situations:
- Spray gun blockage: Immediately switch to the backup spray gun and stop the machine for cleaning.
- Abnormal Temperature: In case of overheating (>set value +5℃), heating will be automatically cut off; manually initiate an emergency stop.
2. Common Problem Handling
Analysis and Solutions for Abnormal Phenomena
- Uneven Coating: Insufficient atomization pressure/spray gun misalignment. Adjust the spray gun angle and increase the atomization pressure (in 0.1 MPa steps).
- Core Adhesion: Excessive spray rate/insufficient temperature. Reduce spray rate by 10% and increase inlet air temperature by 5℃.
- Film Cracks: Excessive drying rate. Reduce exhaust volume and increase the plasticizer ratio in the coating solution.
- Color Difference: Uneven mixing of coating solution. Extend stirring time and add defoamer (e.g., polydimethylsiloxane).
IV. Cleaning and Maintenance
1. Daily Cleaning
- CIP Online Cleaning: Pure water → 1% NaOH solution (circulate at 60℃ for 20 minutes) → rinse with pure water until neutral (conductivity ≤ 5 μS/cm).
- Spray Gun Disassembly and Cleaning: Ultrasonic cleaning of the nozzle (frequency 40 kHz, time 15 minutes), followed by compressed air drying.
2. Regular Maintenance: Maintenance Item Cycle and Operation Standards
- Sealing Ring Replacement: Every 6 months. Silicone material, no deformation/cracks.
- Gearbox Oil Change: Every 2000 hours. Use ISO VG 68 gear oil, fill to the center line of the sight glass.
- Bearing Lubrication: Monthly. High-temperature lithium-based grease (NLGI 2 grade), grease volume ≤ 70% of the cavity.
- Electrical System Inspection: Quarterly. Insulation resistance ≥ 10 MΩ (tested with a 500V megohmmeter).
V. Records and Compliance
- Batch Production Records: Complete records of coating parameters (temperature, speed, spray volume), and deviation handling (if any).
- Cleaning Records: Completed after each cleaning, including cleaning agent type, time, and operator's signature.
- Calibration Certificates: Temperature sensors and pressure gauges calibrated annually by a third party, with an expiration label affixed.
#PharmaceuticalEquipment #FilmCoatingMachine #CoatingMachine #TabletCoating #TabletCoatingMachine #CoatingMachineOperating #MachineMaintenance #CelinePharma