What is a tablet press machine?
A tablet press, also known as a tablet compressing machine or tableting machine, is used to compress pharmaceutical powder formulations into tablet form, creating tablets of uniform size, shape and weight. The tablet press may also be used for the manufacture of products in the form of tablets for other sectors such cosmetics, cleaning products and catalysts for the petrochemical industry.
Tablet making process
The tablet making process starts with the formulation of a powder. This is usually a mixture of several components. For pharmaceutical products, these include the active pharmaceutical ingredient (API) or drug, and various inactive but essential excipents, which include diluents, lubricants and binders. The powder may undergo a process of granulation to achieve the required particle size distribution before it is fed to a tablet press. The powder is fed into a hopper on the tablet press from where it is metered into a cavity formed by a die and two punches (an upper and lower punch). The dies and punches are what define the size and shape of the finished tablet and are usually known as the tablet tools. Force is applied to the punches which press on the powder to fuse together the materials and create the solid tablet form.
Basic Components of Tablet Press
Hopper – this holds the materials that are to be compressed
Die – this is the cavity that defines or moulds the size and shape of the powder
Punches – the punches compresses the materials within the die
Cam track – this helps or guides the movement of the punches
Feeding mechanism – it moves the materials from the hopper to the die.
Types of Tablet Press
Also known as a single punch or eccentric press. This is the simplest of all types of tablet making machine. It uses a single tooling station that has a die and a pair of upper and lower punches. It can be operated by hand or by an electric motor. The compression force is exerted by the upper punch only – during the compression step the lower punch is stationary.
Multiple station tablet presses are also know as rotary tablet presses. The distinguishing features of the rotary press are the die table, the turrets that hold the punches, and the cams and cam tracks that control the punches and the tablet ejection process, In the rotary press many dies are located near the edge of the large circular die table that is able to rotate horizontally. The upper and lower punches that correspond to each of the dies are located on turrets above and below the die table. As the die table rotates, cams above the upper turret and below the lower turret cause the appropriate punches to move up or down in such a way that (a) the lower punch is stationary for the compressive step in which the upper punch forces down on the powder compressing it into a tablet, and (b) once the tablet is formed, the upper punch withdraws upwards, and at the same time the lower punch also rises so as to eject the newly formed tablet from the die. As the head of the machine rotates, the fixed cam tracks controls the filling, compression, and the ejection process.
Tableting Machine Tooling
The size, shape and the identification marks of the tablet are determined by the compression machine tooling, i.e., the punches and dies. The tooling must meet the specific requirements to satisfy the needs of dosage uniformity, production efficiency and aesthetic appearance. Internationally there are two recognized standards for tablet compression tooling: the TSM standard and the EU standard. TSM is acronym for the ‘Tablet Specification Manual’, widely recognized and exclusively used in the United States. The EU or ‘European Standard’ is probably more widely used than the TSM standard.
Based on the TSM and EU standards, tablet tooling is mainly classified as B tooling and D tooling. The B tooling punches and dies can be further classified as BB, and D tooling can also be used on B tooling machine that is call as DB.