Tablet compression machines compress granules into tablets using dies and punches. There are single punch and multi-station rotary presses. Compression problems include capping, lamination, chipping, cracking, sticking, picking, and double impressions. Capping is caused by air entrapment during compression. Lamination occurs from air entrapment and high turret speeds. Machine settings and worn tools can cause chipping. Rapid tablet expansion from deep concave punches causes cracking. Improperly dried granules can cause sticking and picking. Punches rotating during ejection can cause double impressions. Solutions involve adjusting machine settings, tooling design, and processing parameters.

1. TABLET COMPRESSION
OPERATION/TOOLING
AND PROCESSING
PROBLEMS
PRESENTED BY: MS. GURAV PRAJAKTA P.
M. PHARM(PHARMACEUTICS)

2. Tablet compression machines
 Tablet compression machines or tablet presses are designed with the
following basic components:
1. Hopper: for holding and feeding granulation to be compressed.
2. Dies: that define the shape and size of the tablet.
3. Punches: for compressing the granulation within the dies.
4. Cam tracks: for guiding the movement of the panches.
5. A feeding mechanism: for moving granulation from the hopper into
the dies.

3. B and D tooling
 Tablet compression machines are made in keeping in view the type
of dies and punches will be used on them ,
 The dies and punches and their setup on compression machine is
called tooling.
 It is classified as B and D mainly. The B tooling dies and punch can
be further have specifications as BB and D tooling can also be dies
and punches can be utilised on B tooling machine which is called as
DB.
 Mainly there are two standards, a D and B.

4. Difference between B and D tooling

5. Different Shapes of Dies and Punches
 Round shape punch die set
 Oval shape punch die set
 Capsule shape punch die set
 Geometric shape punch die set
 Irregular shape punch die set
 Core rod tooling punch die set

6.  Tablet presses are classified as either single punch or multi station rotary
presses
 Single punch tablet press:

7. Single Punch Tablet Press
 Single punch tablet press is also called as a eccentric press or single
station press.
 It is most simplest machine for tablet manufacturing.
 Single station tablet press employs a single tooling station that is a
die and a pair of upper and lower punches.
 This tablet press is available as both manually operated and power
driven.
 In this single punch tablet press, the compaction force on the fill
material is exerted by only the upper punch while the lower punch is
immovable such as action equivalent to hammering motion.

9. Multi stage rotary tablet press:

10. Multi stage rotary tablet press:
 It is also called multi station tablet press.
 Multi station presses are termed
rotary because the head of the machine
that holds the upper punches,
dies and lower punches in place rotates.

12. Working Principle of Compression
Machine:
1. Filling and Dosing of the Dies
2. Compression of the Tablets
3. Ejection and Exit of the Tablets

13. Auxiliary Equipments
 1.Granulation Feeding Device:
In many cases, speed of die table is such that the time of die under feed
frame is too short to allow adequate or consistent gravity filling of die with
granules, resulting in weight variation and content uniformity. These also
seen with poorly flowing granules. To avoid these problems, mechanized
feeder can employ to force granules into die cavity.
 2..Tablet weight monitoring devices:-
High rate of tablet output with modern press requires continuous tablet
weight monitoring with electronic monitoring devices

14.  3. Tablet Deduster : -
In almost all cases, tablets coming out of a tablet machine bear excess
powder on its surface and are run through the tablet deduster to remove
that excess powder.
 4. Fette machine : -
Fette machine is device that chills the compression components to
allow the compression of low melting point substance such as waxes and
thereby making it possible to compress product with low meting points.

15. Tablet compression and processing
problems and remedies
Capping
 The upper or lower segment of the tablet separates
horizontally, either partially or completely from the
main body and comes off as a cap, during ejection
from the tablet press, or during subsequent handling.
 Reason:
 Due to the air–entrapment in a compact during
compression, and subsequent expansion of tablet on
ejection of a tablet from a die.

16. The Causes and Remedies of Capping related to ‘Machine’
SR.
N0.
CAUSES REMEDIES
1. Poorly finished dies Polish dies properly. Investigate other
steels or other materials.
2. Deep concave punches or beveled-edge faces of
punches.
Use flat punches.
3. Lower punch remains below the face of die during
ejection.
Make proper setting of lower punch
during ejection.
4. Incorrect adjustment of sweep-off blade. Adjust sweep-off blade correctly to
facilitate proper ejection.
5. High turret speed. Reduce speed of turret (Increase dwell
time).

17. Lamination
 Separation of a tablet into two or more distinct horizontal layers.
 Reason:
 Air–entrapment during compression and subsequent release on ejection.
 The condition is exist by higher speed of turret.

18. The Causes and Remedies of Lamination related to
‘Machine’
SR.NO. CAUSES REMEDIES
1. Rapid relaxation of the peripheral
regions of a tablet, on ejection from a
die.
Use tapered dies, i.e. upper part of the
die bore has an outward taper of 3° to
5°.
2. Rapid decompression Use pre-compression step. Reduce
turret speed and reduce the final
compression
pressure.

19. Chipping
 Breaking of tablet edges, while the tablet leaves the press or during subsequent
handling and coating operations.
 Reason:
 Incorrect machine settings, specially mis-set ejection take-off.

20. The Causes and Remedies of Chipping related to
‘Machine’
SR. NO. CAUSES REMEDIES
1. Groove of die worn at compression
point.
Polish to open end, reverse or replace
the die.
2. Barreled die (center of the die wider
than ends)
Polish the die to make it cylindrical
3. Edge of punch face turned
inside/inward.
Polish the punch edges
4. Concavity too deep to compress powder
blend.
Reduce concavity of punch faces. Use
flat punches.

21. Cracking
 Small, fine cracks observed on the upper and lower central surface
of tablets, or very rarely on the sidewall are referred to as ‘Cracks’.
 Reason:
It is observed as a result of rapid expansion of tablets, especially
when deep concave punches are used.

22. The Causes and Remedies of Cracking related to ‘Machine’
SR.NO. CAUSES REMEDIES
1. Tablet expands on ejection due to air entrapment. Use tapered die.
2. Deep concavities cause cracking while
removing tablets
Use special take-off.

23. Sticking
 Tablet material adhering to the die wall. Filming is a slow form of sticking and is
largely due to excess moisture in the granulation.
 Reason:
Improperly dried or improperly lubricated granules.

24. The Causes and Remedies of
Sticking related to ‘Machine’
SR.
NO.
CAUSES REMEDIES
1. Concavity too deep for granulation. Reduce concavity to optimum.
2. Too little pressure. Increase pressure.
3. Compressing too fast. Reduce speed.

25. Picking
 Small amount of material from a tablet is sticking to and being removed off from the tablet-
surface by a punch face.
 The problem is more prevalent on the upper punch faces than
on the lower ones.
 Reason:
 Picking is of particular concern when punch tips have engraving or embossing letters.
 Granular material is improperly dried.

26. The Causes and Remedies of Picking related to
‘Machine’
SR.
NO.
CAUSES REMEDIES
1. Rough or scratched punch faces. Polish faces to high luster.
2. Embossing or engraving letters on
punch faces such as B, A, O, R, P, Q,
G.
Design lettering as large as possible.
Plate the punch faces with chromium to
produce a smooth and non-adherent face.
3. Bevels or dividing lines too deep. Reduce depths and sharpness.
4. Pressure applied is not enough; too
soft tablets.
Increase pressure to optimum.

27. Double Impression
 Involves only those punches, which have a monogram or other
engraving on them.
 If the upper punch is uncontrolled, it can rotate during the short travel
to the final compression stage and create a double impression.
 Reason:
 At the moment of compression, the tablet receives the imprint of the
punch.
 The lower punch freely drops and travels uncontrolled for a short
distance before riding up the ejection cam to push the tablet out of the
die
 Now during this free travel, the punch rotates and at this point, the
punch may make a new impression on the bottom of the tablet,
resulting in ‘double impression’.

28. The Causes and Remedies of Double
Impression
SR.NO. CAUSES REMEDIES
1. Free rotation of either upper
punch or lower punch during
ejection of a tablet.
-Use keying in tooling, i.e. inset a key alongside of
the punch, so that it fits the punch and prevents
punch rotation.
-Newer presses have anti-turning devices, which
prevent punch rotation.

29. Other problems
1. Mottling : - is an unequal distribution of color on a tablet.
2. Weight variation
3. Granule size and size distribution before compression
4. Poor flow
5. Poor mixing
6. Punch variation
7. Hardness variation