Working and Principle of Tablet Coating Machine

Working and Principle of Tablet Coating Machine Learn the working and principle of tablet coating machine used for different types...

Working and Principle of Tablet Coating Machine

Learn the working and principle of tablet coating machine used for different types of coatings on tablets.

A tablet coating machine is an equipment that coats the external surface of a tablet using a thin film of coating material. Working principle of tablet coating machine is relatively simple where the application of coating material is done on a moving bed of tablets and removing rapidly the solvent using a current of hot air.

For the tablets to be coated they are placed in a closed drum which is made to rotate continuously in an orbital manner under the influence of a streamlined plate. During the orbital motion of the tablets, the coating medium sprays automatically in a rational manner in order to avoid excess coating on the tablets.

Working of Tablet Coating Machine

Angled baffles are also fitted into the drum and also air flow is provided which acts as a means to mix the tablets. The baffles cause the tablets to be lifted and turned from the sides of the drum and onto the center exposing all the sides of the tablets to the sprayed coating. Whilst the spraying is going on, hot air is introduced from the 50% perforated tablet bed which causes rapid drying of the coating medium. The hot air comes from inlet fan and is regulated in terms of temperature and volume.

The regulation of the air allows for maintenance of the drum pressure relative to that of the outside room for the purpose of providing a completely isolated process atmosphere. The regulation of the air also provides controlled drying and tablet extraction rates. It also allows for an evenly spread medium on the tablets giving the tablets a smooth solid surface. Tablet coating machine may include coating pans, spraying guns, exhaust and heating pipes. The process may include film coating or sugar coating.

The process is also done in batches which include several phases such as batch identification and selection of the recipe to be used. Loading of the required raw materials, warming, spraying of the coating which is coupled with rotation of the tablets, drying, cooling and lastly unloading of the coated tablets.

One would wonder what the importance of coating tablets is. Coating machine allows the drug release to be regulated. This ensures that the drug is supplied to the body in safe amounts that the body can handle and also optimizes their effect on the body.

The coating also increases the stability of the tablets which prevents oxidative degeneration caused by factors that may react with the drug such as light and air.

Another advantageous factor of tablet coating is that the tablets can easily be swallowed as they overcome the poor taste the tablets may have. The coating may be flavored or tasteless. This is because some tablets taste bitter or may not have a very pleasant taste.

The coating also gives the tablets its signature color which allows for easy identification and also compatibility with other drugs. The coating also protects the drug from a gastric environment allowing it to reach the area in which it is intended for absorption.

There are parameters which are considered in coating machines. These parameters include air capacity, coating composition, the surface area of the tablet and lastly the efficiency of the equipment.

The tablet coating machine is mainly used in pharmaceutical and food industries. Featuring mechatronics and conforming to the requirement of GMP, it is a high efficiency, energy saving, safe and clean equipment for coating tablets, pills and candies with organic film, water soluble film, slow and controlled release film, sugar film and etc.

Working Principle of Tablet coating Machine:

The tablet cores to be film coated make continuous complicated orbital motion within the closed rotating drum under the action of a streamline guide plate. During the motion, coating medium automatically sprays according to the technological process and rational technological parameters, at the same time hot air is supplied under a negative pressure.

The hot air penetrates through the tablet core layers and is discharged form the bottom of the layers, so that the coating medium sprayed on the surface of tablet cores will dry rapidly and evenly, thus forming a solid and smooth surface film.


All the operations, including expansion of PLC module, setting and control of hot air temperature and adjustment of drum SERIES HIGH-EFFICIENT speed, are carried out on the touch keys of control panel of computer, and the operating panel is a fully closed light touch film interface which does not influence the cleaning of main machine, thus featuring reliable work, stable performance and conforming to the requirement of GMP.

The peristaltic pump with constant pressure variable eliminates the need for a return pipe. The turning radius of the drum varies along with the pressure change. The output slurry and the quantity of slurry sprayed are balanced automatically, thereby stabilizing the effect of atomization, simplifying the spray system, preventing the spray gun from plugging-up, and saving the coating material, moreover the cleaning is simple, and there is no dead corner.

The spray gun specially designed for the film coating machine features even atomization and large coverage of spraying. The universal adjustable spray head makes the cleaning mechanism of spray gun unaffected by charge quantity, so that film coating can proceed continuously, thus reducing the film coating time and saving film coating material.

Accessory and equipment for the coater

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