Tablet compression
After the preparation of
granules (in case of wet granulation) or sized slugs (in case of dry
granulation) or mixing of ingredients (in case of direct compression), they are
compressed to get final product.
The compression is done
either by single punch machine (stamping press) or by multi station machine
(rotary press). The tablet press is a high-speed mechanical device. It
'squeezes' the ingredients into the required tablet shape with extreme
precision. It can make the tablet in many shapes, although they are usually
round or oval. Also, it can press the name of the manufacturer or the product
into the top of the tablet. Each tablet is made by pressing the granules inside
a die, made up of hardened steel. The die is a disc shape with a hole cut
through its center. The powder is compressed in the center of the die by two
hardened steel punches that fit into the top and bottom of the die.
The punches and dies are
fixed to a turret that spins round. As it spins, the punches are driven
together by two fixed cams - an upper cam and lower cam. The top of the upper
punch (the punch head) sits on the upper cam edge .The bottom of the lower
punch sits on the lower cam edge. The shapes of the two cams determine the sequence
of movements of the two punches. This sequence is repeated over and over
because the turret is spinning round. The force exerted on the ingredients in
the dies is very carefully controlled. This ensures that each tablet is
perfectly formed. Because of the high speeds, they need very sophisticated
lubrication systems. The lubricating oil is recycled and filtered to ensure a
continuous supply.
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