Proper maintenance is essential for keeping a high-efficiency non-perforated coating machine operating reliably and maintaining consistent coating quality. Regular inspection, cleaning, lubrication, and correct operating procedures can help reduce equipment wear and prevent unnecessary downtime.
Preparation Before Operation
Before starting the machine, place the main unit on a stable and level surface. Open the oil-filling port and add lubricating oil to the specified level in the gearbox.
Move the spray support assembly to the right side of the main unit, place the spray gun inside the coating pan, and adjust it to the appropriate position. Fill the liquid cup with the required coating solution.
Connect the power supply and turn on the speed-control switch. Adjust the drum speed and rotation direction according to the process requirements.
Connect the air and liquid lines, then open the corresponding air and liquid valves. Adjust the spray gun position, spray pattern, and spraying direction to achieve a suitable coating effect.
Position the blower outlet toward the coating pan and adjust the airflow direction and heating temperature according to the coating process.
After completing these preparations, start the main motor and allow the machine to run without material for approximately two minutes. Check for abnormal noise, vibration, or other faults. After confirming normal operation, start the air compressor and adjust the air pressure to approximately 4–6 kg/cm² according to the equipment requirements.
Operating Procedure
Loading
Load the tablet cores or other materials to be coated into the rotating coating drum. Move the spray support and spray gun into the drum and secure them in the correct position.
Coating
Turn on the main power switch. When required by the process, activate the air-supply and internal heating systems. The material then moves continuously inside the drum while the coating solution is sprayed and dried under controlled conditions.
Unloading
After coating is complete, move the spray gun and blower assembly out of the drum. Remove the coating pan and discharge the finished material.
Practical Operating Tips
When spraying needs to be temporarily stopped during coating, close the valve below the liquid cup rather than shutting down the entire system. Reopen the valve when spraying needs to resume.
During operation, regularly inspect the coating quality of the tablets and adjust process parameters when necessary. Factors such as spray rate, spray pattern, airflow, temperature, and drum speed may need to be adjusted according to the actual coating condition.
When the machine is used for polishing, drying, or sugar coating, the spray support and spray gun can be removed according to the process configuration. For powder granulation or pelletizing applications, the blower assembly should also be removed after taking out the spray support and spray gun.
Maintenance and Service Requirements
The lubricating oil in the gearbox and the grease inside the rolling bearings should be replaced or replenished at regular intervals according to operating conditions and the equipment manufacturer's maintenance schedule.
When the coating pan is not used for an extended period, clean and dry it thoroughly. Where appropriate, apply a suitable protective coating to exposed copper surfaces to reduce oxidation and moisture-related corrosion.
During operation, monitor the gearbox temperature. For the worm-gear transmission, the temperature rise of the gearbox housing should generally remain below approximately 50°C, provided that this is consistent with the manufacturer's specifications.
The oil seal at the worm-shaft end should be inspected regularly and replaced when necessary. As a general maintenance reference, the seal should not normally remain in service for more than approximately six months without inspection.
The machine must be reliably grounded before operation. Electrical components and belt guards should not be removed or modified without authorization, as these protective devices are essential for safe operation.
Whenever liquid or powder is added during the coating process, it should be distributed as evenly as possible. After adding coating liquid, allow sufficient drying before applying another layer. Excessively viscous coating solutions may spread unevenly and can negatively affect coating uniformity.
After unloading, clean the machine and internal pipelines whenever no further coating operation is planned. Residual coating materials can accumulate inside pipes, valves, spray guns, and other components and may affect subsequent operation.
During operation, never block the blower outlet or spray gun with hands or other objects. Doing so may restrict airflow and potentially damage the blower or spray system.
Finished coated products should generally be dried at a controlled low temperature, preferably with circulating air when appropriate. Avoid direct sunlight and excessive heating, as high temperatures may adversely affect certain coated products or cause surface defects.
Spray Gun Cleaning and Storage
When the spray gun system is not in use, remove the relevant components and store them properly. The spray gun should be stored separately from other components to reduce the risk of contamination or damage.
Before storage, clean the spray gun and liquid cup thoroughly. One practical method is to add clean hot water to the liquid cup, open the relevant valve, and allow water to pass through the spray gun and internal passages. This helps remove residual coating material and reduces the risk of blockage during the next operation.
For pharmaceutical equipment manufacturers, maintenance performance also depends on the quality of the mechanical components used in the coating machine. Hansheng Automation provides made-to-drawing precision machining services for coating-machine components, including shafts, bushings, support parts, connectors, and other non-standard components. We can manufacture parts according to customer drawings and technical specifications, with machining processes selected according to the required dimensions, tolerances, materials, surface finish, and operating conditions.
