1. Uneven Coating

Issue: Coating thickness varies across tablets, resulting in an inconsistent appearance. Solution:

• Adjust Spray Gun Settings: Ensure the spray gun settings, including pressure and nozzle position, are calibrated for uniform coating distribution.
• Optimize Pan Rotation Speed: Adjust the pan’s rotation speed to achieve better tablet coverage.
• Use Proper Atomization: Ensure the coating solution is properly atomized to create a fine mist for even distribution.

2. Orange Peel Effect

Issue: The tablet surface exhibits a rough, orange peel-like texture. Solution:

• Optimize Inlet Air Temperature: Adjust the inlet air temperature to ensure the coating solution dries uniformly.
• Improve Atomization: Enhance atomization of the coating solution to create finer droplets for a smoother finish.
• Check Pan Perforation: Ensure the pan’s perforation is clear and unclogged to maintain proper airflow and prevent uneven drying.

3. Tablet Sticking

Issue: Tablets stick together or to the coating pan. Solution:

• Apply Anti-Sticking Agents: Use appropriate anti-sticking agents, such as talc or magnesium stearate, to prevent tablet adhesion.
• Optimize Pan Speed: Adjust the pan’s rotation speed to prevent tablets from clumping together.
• Check Tablet Surface: Ensure the tablets have a smooth and dry surface before coating.

4. Chipping and Edge Defects

Issue: Tablets exhibit chipping, peeling, or edge defects after coating. Solution:

• Optimize Spray Angle: Adjust the spray gun angle to coat the tablet edges properly.
• Use Round Core Tablets: Consider using round core tablets, as they are less prone to edge defects.
• Maintain Proper Tablet Hardness: Ensure tablets have the appropriate hardness to withstand the coating process.

5. Color Variation

Issue: Tablets show color variations within the same batch. Solution:

• Consistent Mixing: Ensure thorough and consistent mixing of the coating solution to avoid color variations.
• Use High-Quality Pigments: Use high-quality pigments and colorants to maintain color consistency.
• Monitor Coating Solution Temperature: Keep the coating solution at a consistent temperature to prevent color changes.

6. Blistering

Issue: Tablets develop blister-like defects on the coating surface. Solution:

• Control Inlet Air Temperature: Adjust the inlet air temperature to prevent rapid drying and blister formation.
• Use Proper Drying Times: Ensure tablets remain in the coating pan for an appropriate duration to prevent blistering.
• Monitor Tablet Core Temperature: Maintain a uniform tablet core temperature throughout the coating process.

7. Film Cracking

Issue: The coating exhibits cracks or splits. Solution:

• Optimize Coating Solution Viscosity: Ensure the coating solution viscosity is appropriate for the coating process.
• Use Plasticizers: Add plasticizers to the coating solution to improve flexibility and reduce the likelihood of cracking.
• Monitor Drying Conditions: Maintain consistent drying conditions to prevent rapid moisture loss and cracking.

8. Inadequate Film Adhesion

Issue: The coating does not adhere well to the tablet surface. Solution:

• Proper Subcoating: Apply a subcoating layer to enhance adhesion before the main coating.
• Clean Tablet Surface: Ensure tablets are free from contaminants or residual powder before coating.
• Optimize Coating Solution Composition: Adjust the composition of the coating solution for better adhesion.

9. Overcoating

Issue: The coating layer is excessively thick, affecting tablet appearance and functionality. Solution:

• Reduce Spray Rate: Decrease the spray rate to apply a thinner coating layer.
• Optimize Inlet Airflow: Adjust the airflow to facilitate drying without excessive solution buildup.
• Monitor Coating Time: Control the coating time to prevent overcoating.

10. Undercoating

Issue: The coating layer is too thin, compromising tablet protection and appearance. Solution:

• Increase Spray Rate: Increase the spray rate to apply a thicker coating layer.
• Maintain Proper Drying Time: Ensure sufficient drying time to allow the coating layer to build up.
• Monitor Coating Solution Concentration: Adjust the concentration of the coating solution for adequate coating thickness.

These troubleshooting tips and solutions can help address common issues in tablet coating machines, ensuring the production of high-quality pharmaceutical products. Regular maintenance and process monitoring are essential to prevent and resolve coating problems efficiently.