Core functional parts of the rotary tablet press machine are:
The hopper holds and supplies the granules/powder mixture to the feeder system. It is the input point of powder mix or granules to tablet press for compression of tablets. Granules or powder mix may feed manually or using automated systems.
Feeder System or Feed Frame
Feeder System: Feeder System helps to force the feed of the granules into the die cavity, especially during faster rotation. It also mixes the granules and inhibits the separation of granules. Feeder System is also called a force feeder. The force feeder of the tablet compression machine contains two vital parts:
Feed Peddles: It rotates continuously and ensures consistent and accurate granules feed into the die cavity in a high-speed machine.
Feeder Housing: Through the feeder housing, granules for tablets from the hopper will enter the die system.
Some tablet press machines have a feed frame rather than Feeder System (Feeder Housing and Feed Peddles). The feed frame delivers the granules /powder mix into the die cavity under gravity. The Tablet scraper and excess granules stripper must attach to the feeder system or feed frame.
Excess granules stripper
This part of the tablet press machine takes away extra granules from the surface of the die bore or cavity. The granules stripper is liable for controlling the granules’ volume and ultimately the tablets’ weight.
Die defines the size and shape of the tablet. Powder mix or granules are compressed into the desired size, diameter, and shape of tablets in a die bore or die cavity.
Two punches (upper and lower) compress the granules/powder mix in the die bore. The lower punch moves upward and the upper punch moves downward and compresses the tablet within the die cavity. Then the upper punch moves upward and the lowers punch moves upward.
The turret hosts the die as well as upper and lower punches on its holes and ensures the position of the die bore and two punches (lower and upper) for the tablet compression process. The turret is the heart-like part of the tablet press machine.
Cam track guides the movement of both the upper and lower punches in the tablet compression process which play an integral role in ensuring a smooth tableting process. As the turret rotates, the cam track helps to move the punches in and down motion.
Tablet press machines have rollers that exert a predetermined and sufficient amount of force to compress the granules into tablets with desired hardness. Most tablet press machines have two sets of compression rollers.
Pre-compression roller: They give the initial compression force. The aim of pre-compression is to eliminate air that could be in the die or granules/powder mix.
Main compression roller: It exerts sufficient compression force to compress the granules into tablets. The rollers stay stable with no vibration during the entire compression process to ensure consistent thickness and size of the tablets.
Ejection cam guides the lower punch upwards assisting the ejection of tablets from the die bore or cavity after compression. The ejection cams slowly and gradually push the lower punch upwards.
Guides the compressed tablets to a collection drum or bin.
Tablet Weight Controller
This is used to adjust the volume of the granules to be compressed and so determines the weight of the tablet with the help of different movements of the cam systems, material will flow into the die cavity depending on the position of the punches.