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Analysis of common faults and Countermeasures of film coating machine

Analysis of common faults and Countermeasures of film coating machine

Mar 30,2021

Analysis of common faults and Countermeasures of film coating machine


Film coating machine is a kind of equipment which integrates strong current, weak current, hydraulic and pneumatic. In the pharmaceutical industry, it is often used in sugar coating, film coating and other coating processes of Chinese and Western medicine. The film coating has bright color after polishing, and the complete consolidated coating produced by the crystallization of sugar on the surface can not only prevent the chip from oxidation, deterioration, moisture or volatilization, but also cover up the uncomfortable smell of the chip. In recent years, with the continuous development of China's pharmaceutical industry, the market demand of film coating machine is also considerable.



In terms of structure, the film coating machine is mainly composed of main engine (original sugar coating machine), controllable room temperature hot air system, automatic spray system for supplying liquid and gas. The main motor can be variable-frequency speed regulation, which can spray coating excipients onto the tablet surface with high atomization spray gun. At the same time, the tablet makes continuous and complex trajectory movement in the coating pot, so that the coating liquid is evenly wrapped on the tablet core. There is controlled room temperature hot air in the pot to dry the tablet at the same time, so that the tablet surface can quickly form a solid, fine, complete and smooth surface film.



Nowadays, the film coating machine has been widely used in the pharmaceutical industry, but with the coating powder quality unchanged, many users occasionally encounter some failures in the coating operation, such as sticking, frosting, bridging and so on. In this regard, some factory technicians said that these are common problems, as long as you master the corresponding solutions, you can no longer be troubled by them. The author lists 8 common faults and Countermeasures of film coating machine, which is only for reference in the industry.


Adhesive sheet

The main reason for sticking is that the amount of spray is too fast, which violates the principle of solvent evaporation balance and makes the sheets adhere to each other. In this case, the spraying amount of coating liquid should be reduced, the hot air temperature should be increased, and the speed of the boiler should be increased.


Spray frost

If there is "spray frost" on the surface of clothing film, it is not necessary to make a mess. This phenomenon is caused by high humidity of hot air, long spray distance and poor atomization effect. At this time, we only need to reduce the temperature properly, shorten the spray range and improve the atomization effect.


Orange peel film appeared

If the dried fruit is not properly dried, the spray pressure of the coating solution is low, and the droplets will be heated and concentrated in different degree. In this case, evaporation rate should be controlled immediately and spray pressure increased.



Color spots appear

The color spot is caused by uneven mixing or insufficient fineness of solid when preparing coating solution. This also reminds users to mix the coating solution well.


There are cracks on the surface of the tablet

If the coating liquid-solid content is not properly selected, the film coating machine speed is too fast, and the spray volume is too small, the performance of the tablets will appear cracks, cracking, peeling or tablet edge wear. In order to avoid this situation, the user should choose the appropriate coating liquid-solid content, and adjust the rotation speed and spray amount properly. However, if the hardness of the core is too poor, the formulation and process of the core should be improved.


There are pinholes on the surface of the film

If pinholes are found on the surface of coating film, this situation is caused by too much air involved in the preparation of coating solution. Users should avoid getting involved in too much air when mixing liquid.


There is a color difference between the tablets

The color difference is caused by the uneven fan, the excessive liquid-solid content and the slow speed of the coating machine. At this time, the spray angle of the spray gun should be adjusted, the solid content of the coating liquid should be reduced, and the rotation speed of the film coating machine should be appropriately increased.