tablet compression machine, parts of tablet compression machine

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Tablet Compression
Machine
Prepared by:
Sahebrao S. Boraste

2. TABLET COMPRESSION MACHINE
 The tablet press is a high-speed mechanical device.
 It compresses 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.
 After the preparation of granules either by wet granulation,
dry granulation or 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).
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TABLET COMPRESSION MACHINES

4.  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 centre.
 The powder is compressed in the centre 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.
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TABLET COMPRESSION MACHINE

5. STEPS IN TABLET COMPRESSION
Complete cycle of compression occurs in four stages:
Stage 1:
 Top Punch is withdrawn from die by upper cam.
 Lower punch is low in the die, so powder falls through the hole
in the die to fill it.
Stage 2:
 Bottom punch moves up adjust the powder weight.
 It raises & expels the excess powder.
Stage 3:
 Top punch is driven in to die by upper cam& bottom punch is
lowered by lower cam.
 Both punches heads passes between heavy rollers to
compress the powder.
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6. Stage 4:
 Top punch is withdrawn by upper cam.
 Lower punch is pushed up with ejects the tablet out of the die
Stage 5: return to stage 1.
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7. PARTS OF TABLET COMPRESSION MACHINE
1. Hopper
2. Feeder System
3. Punches
4. Die System
5. Turret
6. Cam Tracks
7. Filling Station & Weight Control
8. Compression Rollers
9. Ejection Cam
10. Take –off blade and Discharge Chute
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8. 1. HOPPER
 The tablet compression process
starts from here. It is at this point
from where powder flows in to die
through feed frame
 Tablet press hoppers come in a
wide range of shapes and designs.
Which helps the material to flow
seamlessly into the tablet
compression chamber.
 Depending on the design of a tablet
press machine, the powder can be
filled manually or using other
automated systems.
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 The design of the system should be such that it allows an
accurate and consistent amount of powder to flow to the
punch and die system.
 Tablet press machine feeder system is made up two critical
components:
1. Feeder housing
 Material from the hopper will enter the dye system through
the housing. The feeding process should be consistent and
accurate to produce high quality tablets.
 The feeding housing is made of stainless steel 316L, since it
is in contact with the product.
 Also, the product must not stick on the feeder housing as it
will cause inconsistencies during the feeding process.
2. Feeder System

10. 2. Feed peddles
 Quite a number of high speed rotary tablet press machines
have a feed peddles.
 The feed peddles ensures consistent and accurate material
feeding into the die systems.
 Without a feed peddle, especially if the machine is operating
at a high speed, there could be chances of some dies being
filled half way.
 This may result in tablets with varying thickness or the
degree of compaction.
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11. 3. PUNCHES
 To produce the desired tablets, punches move within the die,
thereby compressing powder into the desired tablets.
 In any tablet press machine there is
Upper punch system
 The tablet press upper punches are on the upper section of the
rotary system. They move vertically, in and out of the die bore.
Lower punch system
 The lower punches are on the lower section of the rotary
system of the tablet press machine. During the tablet
compression process, the lower punches remain within the die
bore throughout the entire cycle.
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12. PUNCHES
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13. 4. DIE SYSTEM
 In the die cavity the powder is compressed into desired
tablets of definite thickness and size.
 It is the die cavity that determines both the thickness and
size of a tablet.
 Like the punches, a die system should have the following
key features:
1. Clean impression on every punch
2. Prevent chipping or damaging of tablets
3. Feature anti-corrosion protection
4. Have non-stick treatment
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14.  Tapering angle is the a critical aspect of die cavity since
it allows excess air to escape, while minimizing the
tablet ejection force and frictional heat.
 Other technical specifications include die height,
chamfer, die bore and die diameter.
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15. 5. TURRET
 The rotating turrets have holes that host the die system of a
tablet making machine.
 Every bore on its surface ensures the die and punch are fully
aligned for optimal tablet making process.
 Turret in tablet press determines the number of stations which
helps to determine the production capacity of the machine for
every complete rotation of the turret.
 with a properly designed tablet tooling system, you can easily
incorporate the multi-tip punches which is common in the high
capacity tablet press machines.
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Turret

17. 6. CAM TRACKS
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 The main work of the cam tracks is to guide the upper and
lower punches in different stages in the tablet compression
process.
 As the turret rotates, it is the cam trucks that move the
punches in an up and down motion which helps to control
filling, compression and ejection of already processed tablets.
 As the upper cam withdraws top punches from the die, powder
flows in filling the cavity.
 On the other hand, the lower cam track pushes the bottom
punches upwards within the die cavity.
 This makes the die to be overfilled by material, allowing for
accurate adjustment of the die content.

18.  To achieve a maximum compression force, the upper cam track
drives the top punch and the lower cam adjusts the bottom
punch.
 With the tablet compressed to the desired specifications, the
upper cam withdraws top punches.
 On the other hand, the lower punches move upwards to expel
the compressed tablets with the help of lower cam.
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19. 7. FILLING STATION & WEIGHT CONTROL
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 With the help of different movements of the cam systems,
material will flow into the die cavity depending on the position of
the punches.
 A critical procedure in this section of tablet compression process
in the:
Weight control
 By controlling the depth fill, tableting machine can easily
regulate the content within its die cavity. Normally, with the help
of lower cam track, the bottom punch moves upwards to a
predetermined height.
 This ensures the die cavity is filled to a required depth before
any compression process begins.

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• At times, as the bottom punch moves up, the excess powder
may overflow. Therefore, to avoid wastages, the excess
powder automatically moves to the next die cavity, which is
just about to be filled.

21. 8. COMPRESSION ROLLERS
 Air may get entrapped with in the particle during
compression of powder to desired shape and size..
 To prevent this, tablet compression machines feature a
series of rollers that exert a sufficient amount of force to
compress the powder. That is, they expel air first before
the compression process begins.
 Most machines have two sets of rollers:
1. Pre-compression rollers
2. Main compression rollers
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22. Pre-compression rollers
 These are the very first rollers in rotary tablet press.
Basically, these rollers apply a small amount of force on the
upper and lower punches.
 This gives the initial compression force.
 The aim of this process is to remove air that could be in the
die or powder particles.
 Any air within the die cavity or powder particles will
obviously result in low quality tables.
 This process is necessary for the reason that, any powder in
the machine’s hopper may have air between its particles.
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23. Main compression rollers
 Main compression rollers exert a predetermined amount of force
(final compression force) for the formation of tablets.
 The compression force at this stage is higher than the pre-
compression force.
 It is important that the rollers remain stable with no vibration
during the entire process to ensure consistency of the tablets’
thickness and size.
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 Ejection cam is located just after the main compression rollers.
 The ejection cams steadily and slowly push the bottom punch
upwards. At the same time, the top cams move up and so are the top
punches.
 As a result, the fully compressed tablets leave the die cavity, i.e. the
compressed tablet remains just at the top of the die.
9. Ejection Cam

25. 10. TAKE –OFF BLADE AND DISCHARGE CHUTE
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 The take –off blades are fitted just above the feeder housing.
Their main role is to deflect the fully compressed tablets into the
discharge chute.
 The discharge chute, then directs the tablets to a collection bin.

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