An alternative or rotary tablet press is used for the compression and high production of tablets in the pharmaceutical, nutraceutical and cosmetic industries. This mechanical equipment compresses powders into tablets of constant size, shape and weight.
The powder is fed via a feed hopper. The powder is then fed to the machine’s filling block via a feeding system. The filling and compression unit consists of several elements.
A tablet is formed by the combined pressing action of two punches and a die. The die is the immobile mould that will contain the powder. Upper and lower punches compress the powder in the die. The different dies and punches form a tooling. All the tools are positioned on a turret to obtain a continuous movement.
The filling block ensures the precise filling of the die cavities. The tablet making process involves precise filling and compression of the powder into the cavity of each die. Excess is scraped off the top of the die, the bottom punch is lowered and temporarily covered to prevent overflow.
The production capacity depends on the size of the turret of the rotary tablet press. The larger the turret is, the more format tooling it has.
The pressing force is provided by high-pressure compression rollers that fuse the granulated material into a hard tablet. The turret has a first pre-compression roller. The pre-compression process removes any air that may be present in the powder particles. The second roller, the main compressor, exerts a strong force that compacts the powder to the desired thickness and hardness. After compression, the lower punch is raised to eject the tablet by using an ejector. The tablet finally exits the machine via the discharge spout. Equipped with selection flaps and sensors, this module can be used to sort good and bad tablets. It also allows for sampling.
A tablet press is often associated with a dust removal module.
Punches and dies are usually custom made for each application, and can be manufactured in a wide variety of sizes, shapes, and can be customised with manufacturer codes and marking lines to make tablets easier to break.
Generally speaking, TSM standards are mainly used in the United States and have been established by the American Pharmacist Association (APhA).
It is possible to classify existing tablet press tooling systems as follows: