Tablet Compression, Single Punch Tablet Machine, Multi Punch Tablet Machine, Rotary Tablet Machine

A. Compression

Dried granules are compressed into tablets by using a tablet machine. The following types of tablet machines are available.

• i. Single punch tablet machine,

• ii. Multi punch tablet machine,

• iii. Rotary tablet machine,

Single punch tablet machine:

Construction: Major parts of single punch tablet machine are

• 1. Hopper

• 2. Hopper shoe

• 3. Die

• 4. Driving wheel

• 5. Lower punch

• 6. Upper punch

• 7. Capacity regulator

• 8. Ejection regulator

Single punch machine has only one die and one set of upper and lower punch. It may be hand-operated or power-operated. It is made of a steel frame with a heavy base. It has a horizantal plate that has space to hold the die. A Lower punch is present just below the stage that moves freely inside the die. The movement of the lower punch is regulated by an ejection regulator. The ejection regulator ejects the tablet from the die after compression. The ejection regulator and capacity regulator are used to fix the capacity of the die. The tablet machine has an upper punch. The diameter upper punch and lower punch always remain the same. The upper punch enters into the die by downward movements. The lower punch enters into the die by upward movement.

Hopper holds granules. Shoes collect granules from the hopper to fill them into the die. The driving wheel operated manually or by an electric motor moves the lower punch in an upward direction, the upper punch in a lower direction, and a hopper shoe on the stage to fill the granules into the die, compress granules into a tablet, eject tablet from the die and move the tablets from the stage.

Working:

Place granules into the hopper. Operate the machine manually or by electric motor. Adjust the lower punch to fix die cavity space and easy ejection of the tablet from the die. Adjust the upper level of the upper punch. Adjust pressure to compress granules inside the die by upper punch and lower punch. Following are the steps in tablet machine during tablet manufacturing

• 1. Rise of upper punch to its uppermost level.

• 2. Movement of lower punch to its lowest level.

• 3. Movement of hopper shoe on stage over die and shaking in hopper shoe

• 4. Filling of granules into the die from the hopper shoe.

• 5. Movement of hopper shoe on stage away from die.

• 6. Movement of lower punch into the die and movement of upper punch into the die.

• 7. Compression of granules.

• 8. Rise of lower punch and upper punch in an upward direction to bring the compressed tablet on stage.

• 9. Further rise of upper punch and movement of hopper shoe towards die to push tablet away from the die.

• 10. Drop of lower punch to make space inside the die.

• 11. Filling of granules into the die from the hopper shoe. And the cycle is repeated.

Multi-punch tablet machine: Same as single-punch tablet machine. The number of punches and dies in one machine is more than one. It manufactures many tablets in one cycle. A Number of tablets depends upon the number of punches and dies used.

Rotary tablet machines:

Rotary tablet machine is used to manufacture tablets at large scale. It can manufacture 1200 tablets in one minute. It has up to 70 sets of dies and punches to compress granules into tablets.

Construction: It consists of a circular rotating head with three parts: the upper part to carry the upper punch, the middle part to carry dies, and the lower part to carry the lower punch. A feed frame fitted over the middle part of a circular rotating head to carry granules from a hopper. Upper roller fitted over upper punch to press upper punch into dies during compression of the tablet. A lower roller is fitted below the lower punch to press the lower punch into the die during the compression of the tablet. The lower punch also ejects the tablet from the die after compression.

Rotation of the rotating head of the machine brings the die under the feed frame one by one. Granules enter into the die. The upper roller and lower roller push the upper punch and lower punch into the die to compress granules and eject the compressed tablet from the die.

Working: Fix rotating heads with upper punches, lower punches, and dies. Attach the hopper with the feed frame. Adjust die capacity, tablet weight, and tablet hardness to compress granules into tablets. Fill granules into the hopper. Switch on the rotary tablet machine. Granules will enter into the feed frame and then into dies one by one during the rotation of the rotating head of the machine. During rotary head rotation, the upper roller and lower roller push the upper punch and lower punch into each die one by one. It will compress granules and eject compressed tablets from dies.

Alok Bains