Physics of tablet compression, mechanism of tablet formation, bonding in tablets, the effect of compressional force on tablet properties, effect of lubricants on tablet compression, binding, instrumented tablet machines and tooling, problems associated with large scale manufacturing of tablets.

1. COMPACTION
AND
COMPRESSION

2. Compression
Compression means a reduction in the bulk volume of a material as a result of the
removal of the gaseous phase (air) by applied pressure.
Consolidation
Consolidation is an increase in the mechanical strength of a material resulting from
particle-particle interactions.
Compaction
Compaction of powders is the general term used to describe the situation in which
these materials are subjected to some level of mechanical force.
The physics of compaction may be simply stated as "the compression and
consolidation of a two-phase (particulate solid-gas) system due to the applied force."
Definitions

3. Some derived properties which help in quantification of important variables are
1.Volume
2. Density
3. Porosity
4. Flow properties.
Volume: Measurement of volume of powder is not easy as the measurement
of mass of powders, because in powders there will be inter and intra- particular
voids. Hence three types of volume can be considered for a powdered mass,
they are,
1. True volume
2. Granular volume
3. Bulk volume
Derived Properties of Powders or Granules

4. 1. Open intraparticulate voids-those within a single particle but
open to the external environment.
2. Closed interparticulate voids-those within a single particle but
closed to the external environment.
3. Interparticulate voids-the air spaces between the individual
particles.
Mass-Volume relationships

5. True Volume of the powder (Vt): True volume is the total volume of the solid particles. It is a
volume of the particles excluding the inter and intra particulate spaces in a powder. Or it is volume of
powder itself .
Granular Volume of the powder (Vg): It is the cumulative volume occupied by the particles,
including all intraparticulate (but not interparticulate) voids. Or it is the volume of powder itself and
volume of intraparticulate spaces.
Bulk Volume of the powder (Vb): It is the total volume occupied by the entire powder mass under
the particular packing achieved during the measurement.
It comprises the true volume and inter and intra particulate voids.
Relative volume (VR): It is the ratio of the the volume, V of the sample under specific experimental
conditions, to the true volume Vt.
VR = V / Vt
VR tends to become unity as all air is eliminated from the mass during the compression process.
Therefore, at least three interpretations of
"powder volume" may be proposed

6. The ratio of mass to volume is known as the density (ρ) of the material
By considering the three types of volume of powders, we can define the respective
densities as,
• True density (ρt ): Mass of the powder/ True volume of the powder .
True density, ρt = M / Vt
• Granular density (ρg): Mass of the powder/ granule volume of the powder.
Granular density, ρg = M / Vg
• Bulk density (ρb): It is the ratio of total mass of the powder to the bulk Volume of
the powder. It is measured by pouring the weighed powder into a measuring cylinder
and the volume is noted.
It is expressed in gm/ml and is given by: ρb = M / Vb
Where , M is the total mass of the powder
Vb is the Bulk Volume of the powder
Density

7. The spaces between the particles in a powder are known to be voids. The volume
occupied by such voids is known to be void volume.
Void volume (Vv) = Bulk volume –True volume
The porosity of the powders is defined as ratio of the void volume to the bulk volume
of the packing. Or, the ratios of the total volume of void spaces (Vv) to the bulk
volume of the material.
Porosity (E) = void volume /bulk volume.
=Vv/Vb
= [Vb - Vt / Vb] (As, Vv= Vb - Vt)
= 1-(Vt/bt)
Porosity is frequently expressed in percent
E = [1- Vt / Vb] x 100
The relation between porosity and compression is important because porosity
determines the rate of disintegration, dissolution and drug absorption.
Porosity

8. Question: A cylindrical tablet of 10
mm diameter and 4 mm height
weighed 480 mg and was made from
material of true density 1.6 g Cm-3 .
Calculate the bulk volume Vb .
Try this at home

9. To get uniformity of the weight of the tablet, the powder should possess a good flow
property. Flow properties of the powders depend on the-
1. Particle size,
2. Shape,
3. Porosity and density,
4. Moisture of the powder.
Particle size
The rate of flow of powder is directly proportional to the diameter to the particles.
Beyond particular point, flow properties decreases as the particle size in increases.
Because in small particle (10µ) the vanderwaal’s, electrostatic and surface tension
forces causes cohesion of the particles resulting poor flow.
As the particle size increases, influence of gravitational force on the diameter
increases the flow property. But appropriate blends of fines & coarse improves flow
characteristic, as the fines get absorbed and coarse particle reduce friction.
Flow Properties

10. Particle shape
Spherical, smooth particles improves flow properties, surface
roughness leads to poor flow due to friction and cohesiveness , flat
and elongated particles tend to pack loosely, obstructing the flow
Density & porosity
Particles having high density and low internal porosity tend to
posses good flow properties.
Moisture
The higher moisture content, the flow property will be poor owing to
cohesion and adhesion.

11. Angle of repose
The flow characteristic are measured by angle of repose . Angle of repose is
defined as the maximum angle possible between the surface of a pile of
powder and the horizontal plane.
tanØ= h/r
Ø = tan-1(h/r)
Where, h = height of pile
r =Radius of the base of pile.
Ø = Angle of repose .
The angle of repose is calculated by measuring the height and radius of heap
of powder formed.
The frictional forces in a loose powder can be measured by Angle of repose.
The lower the angle of repose, better will be flow property.

12. The values of angle of repose are
given below
Angle of repose (in degrees) Type of Flow
<25
25-30
30-40
>40
Excellent
Good
Passable
Very poor
12

13. It indicates powder flow properties. It is expressed in percentage.
It is defined as:
Consolidation Index = I = Tapped density-Poured density /Tapped density
Therefore = (Dt- Db/Dt) × 100
Where, Dt is the tapped density of the powder
Db is the Poured density of the powder
Determination of Tapped density & Poured density.
It is determined by passing a fixed quantity of powder into a measuring
cylinder and the volume is noted .CI can be calculated by founding out by
tapped density and Poured density of powder.
Carr's Consolidation
( Compressibility) Index (CI)

14. Grading of the powder for their flow properties according to
Carr’s index:
Carr’s index(%) Type of flow
5-15 Excellent
12-18 Good
18-21 Fair to passable
23-35 Poor
33-38 Very poor
>40 Very very poor
14

15. Compression properties
This involves compressibility and compatibility .
Compressibility can be defined as the ability of a powder to decease in volume
under pressure.
Powders are normally compressed into tablets using a pressure of about 5.0kg/cm2.
The process is called compaction & compression.
Compatibility can be defined as ability of powder to be compressed in to a tablet
of a certain strength or hardness.
These two relate directly to the tabletting performance.
For proper compression to occur the tablet should be plastic i.e., capable of
permanent deformation and it should also exhibit certain degree of brittleness.
If the drug is plastic , then the excipients chosen should be brittle (lactose, calcium
phosphate) and if the drug is brittle, then the excipients should be plastic
(Microcrystalline cellulose). 15

16. An increase in the mechanical strength of the material resulting from particle or
particle interaction. (Increasing in mechanical strength of the mass)
Consolidation Process
Cold welding: When the surface of two particles approach each other closely
enough, (e.g. at separation of less than 50nm) their free surface energies result in
strong attractive force, this process known as cold welding.
Fusion bonding: Contacts of particles at multiple points upon application of load,
produces heat which causes fusion or melting. If this heat is not dissipated, the local
rise in temperature could be sufficient to cause melting of the contact area of the
particles.
Upon removal of load it gets solidified giving rise to fusion bonding & increase the
mechanical strength of massIn.
Consolidation

17. Both “cold" and "fusion" welding, the process is influenced
by several factors, including:
1. The chemical nature of the materials
2. The extent of the available surface
3. The presence of surface contaminants
4. The inter-surface distances
Factors affecting consolidation

18. 1. Density and porosity:
The apparent density of a tablet is exponentially related to applied pressure
(or compressional force) until the limiting density of the material is achieved.
As compressional force increases the density of tablet also increases as a
result of decrease in bulk volume.
As the porosity and apparent density are inversely proportional, the plot of
porosity against log of compression force gives linear plot with a negative
slope (Fig.2.).
Therefore the relation between density and porosity is
E=1-(1/Vr) [Where, E=Porosity and Vr= Relative volume)
Properties of tablet influenced by compression
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35
Porosity
Log of Compressional Force (C.F)

19. There is a linear relationship between tablet hardness & the logarithm of applied
pressure except at high pressure.
The strength of tablet may be expressed as tensile strength. As shown in the
following figure (Fig.2.2). The tensile strength of crystalline lactose is directly
proportional to the compressional force .i.e. Increase in the compressional force
increases the strength of the tablet.
3. Specific surface area:
Specific surface area is the surface area of 1 gm material. Specific surface area
initially increases to a maximal value as the compressional force increases,
indicating the formation of new surface due to fragmentation of granules.
Further increase in force produce a progressive decrease in surface area due to
bonding of particles.
2. Hardness and tensile strength
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35
Hardness
log of C.F.
0
5
10
15
20
25
30
35
40
45
0 2 4 6 8 10 12 14 16 18
Tensilestrength
Compressional force

20. Usually as the applied pressure used to prepare a tablet is increased, the
disintegration time increases (lactose/aspirin alone).
Frequently, there is exponential relationship between disintegration time and pressure
(aspirin-lactose).
In some formulation there is minimum value when applied pressure is plotted against
log of disintegration time (with 10% and 15% starch in sulfadiazine tablets)
For tablets compressed at low pressure, there is a large void, and the contact of starch
grains in the inter-particular space is discontinuous. Thus there is a lag time before the
starch grains, which are swelling due to imbibition's of water, contact and exert a force
on surrounding tablet structure.
For tablets compressed at certain applied pressure, the contact of starch grains is
continuous with the tablet structure, and the swelling of starch immediately exerts
pressure, causing the most rapid disintegration.
For tablets compressed at pressures greater than that producing minimum
disintegration time, the porosity is such that more time is required for the penetration
of water into the tablet, hence increase in disintegration time.
4. Disintegration
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35
DisintegrationTime
log of C.F.

21. Pressure
(MN/cm2)
t50% (min)
Starch paste Methylcellulose solution Gelatin solution
200
400
600
800
1000
2000
54.0
42.0
35.0
10.0
7.0
3.3
0.5
0.8
1.1
1.2
1.4
1.8
10.0
4.5
3.0
4.6
4.9
6.5
5. Dissolution
The effect of applied pressure on dissolution rate may be considered from viewpoint of
disintegrating and non-disintegrating tablets.
For a conventional tablet (non coated) dissolution depends on
•The pressure range of the dissolution medium
•The properties of the API
•The properties of the excipients etc.
The effect of applied pressure on dissolution of disintegrating tablet is difficult to predict.
If fragmentation of granules occurs during compression, the dissolution is faster as the applied
pressure is increased, because of increase in specific surface area.
If bonding of particle predominantly occurs during the compression, then it decreases the
dissolution.

22. The changes in the volume with the applied pressure ids defined by various equations among them the “The
Heckel Theory” is the most important. Heckel considered that the reduction in the voids obey the first order
kinetics relationship with the applied pressure.
For the compressional process Heckel has proposed the following equation known as the “Heckel Equation”
ln
V
V−Vα
= KP +
Vₒ
Vₒ−Vα
-----------------------(1)
Where, V= Volume at the applied pressure “P”
Vₒ=Original volume of the powder including the voids
Vα=Volume of the Solid Powder excluding the voids
K=A constant related to the “yield pressure” of the powder
P=Applied pressure
We know that, porosity “E” is the ratio of the total volume of the void space to the bulk volume of the
powdered material.
i.e. E =
V−Vα
V
Or,
1
E
=
V
V−Vα
--------------------------(2)
From the equation 1 and 2 we get
ln
1
E
= KP +
Vₒ
Vₒ−Vα
--------------------------(3)
This is the rearranged or moderate form of Heckel Equation.
Heckel Equation

23. When ln
1
E
or ln
Vₒ
Vₒ−Vα
is plotted against the applied pressure P, we get a plot known
as Heckel Plot. The nature of the plot depends on the characteristics of the material to
be compressed. The Heckel plot explains the mechanism of bonding.
Materials that are comparatively soft and that readily undergo plastic deformation
retain different degrees of porosity, depending upon the initial packing in the die. This
in tum is influenced by the size distribution, shape, etc. of the original particles. Heckel
plots for such materials are shown by type a in Figure 4-17; sodium chloride is a
typical example.
Conversely, harder materials with higher yield pressure values usually undergo
compression by fragmentation first, to provide a denser packing. Label b in
Figure 4-17 shows Heckel plots for different size fractions of the same material that
are typical of this behaviour. Lactose is one such material.
Heckel Plot

24. Application of Heckel Plot: The plot is used
i. To check lubricant efficacy.
ii. For interpretation of consolidation mechanisms.
iii. To distinguish between plastic and elastic deformation characteristics of a
material.
Limitations
• The plot is linear only at high pressure.
• The plot can be influenced by time of compression and degree of lubrication.
Fig. 4-17: Examples of Heckel plots. Curves i, ii, and iii represent decreasing particle size
fractions of the same material. Type a curves are typical of plastically deforming materials,
while those in which fragmentation occurs initially tend to show type b behaviour.

25. In pharmaceutical tableting an appropriate volume of granules in a die cavity
is compressed between an upper & lower punch to consolidate the material in
to a single solid matrix, which is subsequently ejected from the die cavity as
an intact tablet.
The subsequent events that occur in the process are:
1. Transitional repacking or Particle rearrangement.
2. Deformation at the point of contact.
3. Fragmentation.
4. Bonding.
5. Deformation of the solid body.
6. Decompression.
7. Ejection.
Processes of Compression
Transitional repacking/particle rearrangement.
Deformation at points of contact.
Fragmentation and deformation.
Bonding
Deformation of solid bonding
Decompression
Ejection

26. • The particle size distribution and shape of granule determines initial
packing. In the initial stages of compression, the punch and particle
movement occur at low pressure.
• During this, particle move with respect to each other & smaller particles
enter the voids between the larger particles. As a result the volume
decreases and bulk density of granulation increases.
• Spherical particles undergo less rearrangement than irregular particles as
spherical particle tend to assume a close packing arrangement initially.
• To achieve a fast flow rate required for high speed presses the granulation
is generally processed to produce spherical or oval particles; thus, particle
rearrangement and energy expended in rearrangement are minor
consideration in the total process of compression.
Transitional repacking or Particle rearrangement

27. • When a stress is applied to a material, deformation (change of form)
occurs. If the deformation disappears completely (returns to original
state) upon the release of stress, then it is called an elastic
deformation. If the deformation that does not completely recover after
release of stress is known as plastic deformation.
• The force required to initiate plastic deformation is known as yield stress.
When the particles of the granulation are so closely packed so that no
further filling of the void can occur, a further increase of compressional
force causes deformation at the point of contact.
• Both plastic and elastic deformation may occur although one type
predominates for a given material.
Deformation at the point of contact

28. Deformation
• The force required to initiate a plastic deformation is called as
yield stress or elastic limit.
Stress
applied
deformation
removal of
stress
Original
state regain
Elastic
deformation
Original
state lost
Plastic
deformation

29. As the compressional load increases the deformed particle starts undergoing
fragmentation. Because of the high load, the particle breaks into smaller fragments
leading to the formation of new bonding areas. The fragments undergo densification
with infiltration of small fragments into voids.
In some materials where the shear stress is greater than the tensile strength, the
particles undergo structural break down. This is called brittle fracture.
Example: sucrose – shear strength is greater than the tensile strength.
With some materials fragmentation does not occur because the stresses are relieved
by plastic deformation.
Such deformation produces new, clean surface that are potential bonding areas.
Fragmentation do not occur when applied stress-
• Is balanced by a plastic deformation.
• Change in shape.
• Sliding of groups of particle (viscoelastic flow).
Fragmentation

30. After fragmentation of the particles, as the pressure increases, formation of new bonds
between the particles at the contact area occurs. The hypothesis favouring for the increasing
mechanical strength of a bed of powder when subjected to rising compressive forces can be
explained by the following theory.
Bonding/Consolidation Mechanism
There are three theories about the bonding of p[articles in the tablet by compression
I. Mechanical theory
II. Intermolecular force theory
III. Liquid-Film surface theory
The mechanical theory
It occurs between irregularly shaped particles.
The mechanical theory proposes that, under pressure the individual particles undergo Elastic /
Plastic deformation and the particle boundaries that the edges of the particle intermesh
forming a mechanical Bond.
Mechanical interlocking is not a major mechanism of bonding in pharmaceutical tableting.
Bonding and Consolidation

31. • The Molecules at the surface of solids have unsatisfied forces which interact
with the other particle in true contact.
• According to this theory, under compressional pressure the molecules at the
points of true contact between new clean surfaces of the granules are close
enough so that vanderwaals forces interact to consolidate the particles.
• Material containing plenty OH group may also create hydrogen bond
between molecules. E.g. microcrystalline cellulose is believed to undergo
significant hydrogen bonding during tablet compression
• The intermolecular forces theory and the liquid-surface film theory are
believed to be the major bonding mechanisms in tablet compression
Intermolecular force theory

32. • Due to the applied pressure, the particles may melt (due to lowering of M.pt.)
or dissolve (due to increased solubility).
• Many pharmaceutical formulations require a certain level of residual moisture
to produce high quality tablets. The role of moisture in the tableting process
is supported by the liquid-surface film theory. Thin liquid films form, which
bond the particles together at the particle surface.
• The energy of compression produces melting or liquefaction of the particles
at the contact areas. As the pressure is withdrawn the melted ingredients
solidifies causing fusing of the particles.
• In addition the solubility of the solution at the particle interface under
pressure is increased and as the pressure is released it gets super saturated
and followed by subsequent solidification or crystallization thus resulting in
the formation of bonded surfaces.
Liquid-surface film theory

33. • Deformation of the Solid Body
On further increases of the pressure, the non- bonded solid is consolidated towards a
limiting density by plastic or elastic deformation.
• Decompression
As the applied force is removed, a set of stresses within the tablet gets generated as a
result of elastic recovery. The tablet must be mechanically strong enough to
accommodate these stress, otherwise the tablet structure failure may occur.
If the degree and rate of elastic recovery are high, the tablet may cap or laminate. If
the tablet undergoes brittle fracture during decompression, the compact may form
failure planes as a result of fracturing of surfaces. Tablets that do not cap or laminate
are able to relieve the stresses by plastic deformation.
*The tablet failure is affected by rate of decompression (machine speed).
• Ejection
Finally as the lower punch rises and pushes the tablet upward, there is continued
residual wall pressure and considerable energy May be expanded due to the die wall
Friction.

34. The tablet should be sufficiently strong to withstand the mechanical shocks
during the subsequent handling and transport. The mechanical strength of
tablet is described by the following parameters.
• Crushing Strength
• Friability
• Hardness
• Bonding Strength
• Fracture resistance.
Strength of the Tablets

35. Crushing Strength
The most popular estimate of tablet strength has been crushing strength, Sc, which may
be defined as "that compressional force (Fc) which, when applied diametrically to a tablet,
just fractures it.”
It may then be described by the equation=
Where ST is the tensile strength, Fc is the compressional force and D & H are the
diameter and thickness of the tablet, respectively.
Friability
The crushing strength test may not be the best measure of potential tablet behaviour
during handling and packaging. The resistance to surface abrasion may be a more
relevant parameter. For example by the friability test.
These test measure the weight loss on subjecting the tablets to a standardized
agitation procedure. The most popular (commercially available) version is the Roche
Friabilator, in which approximately 6 g (Wₒ) of de-dusted tablets are subjected to
100 free falls of 6 inches in a rotating drum and are then reweighed (w).
The friability, f, is given by:

36. The following factors affect the strength of tablet
1. Particle size
2. Particle shape & surface roughness
3. Compaction pressure
4. Binders
5. Lubricants
6. Entrapped air
7. Moisture content
8. Porosity
Particle size
Smaller particles have larger surface area & when these are exposed to atmosphere may be prone to
oxidation and moisture absorption takes place which affects the strength of tablet.
Extensive fragmentation during compaction of a brittle material may result in a large number of
interparticulate contact points, which in turn provide a large number of possible bonding zones. The
tablets made of these materials can have a high mechanical strength.
The increase in mechanical strength is attributed to an increase in the surface area available for
interparticulate attractions, as the particles become smaller.
Factors Affecting Strength of the Tablets

37. Particle shape & surface roughness
The mechanical strength of tablets of materials with a high fragmentation tendency are less
affected by particle shape and surface texture. Particle shape affects the inter particulate
friction & flow properties of the powder. Spherical particles are considered to be ideal.
General particle shapes and their effect on powder flow are as follows:
Spherical particles - Good
Oblong shaped particles - Poor
Cubical shaped particles - Poor
Irregular shaped particles - Medium
Compaction pressure
The compaction pressure and speed affects the strength of the resulting tablet.
A fragmenting material has been shown to be less affected by variations in compression
speed. The behaviour of granules during compaction, the extent to which they bond together
& the strength of the inter granule bonds relative to the strength of the granules determine
tablet hardness.

38. Binders
A binder is a material that is added to a formulation in order to improve the mechanical
strength of a tablet. In direct compression, it is generally considered that a binder
should have a high compactibility to ensure the mechanical strength of the tablet
mixture. Addition of a binder which increases elasticity can decrease tablet strength
because of the breakage of bonds as the compaction pressure is released.
Lubricants
Lubricants are used to improve granule flow, minimize die wall friction & prevent
adhesion of the granules to the punch faces. Lubricant decreases the strength of the
tablets. When lubricants are added as dry powder to granules, they adhere & form a
coat or a film around the host particles during the mixing process. The Lubricant film
interferes with the bonding properties of host particle by acting as a physical barrier.
When the tablet is blended lightly, the lubricant is present as a free fraction. Prolonged
mixing time will produce a surface film of lubricants over the drug particles due to
which inter particulate bonding is reduced.

39. Entrapped air
When the air does not freely escape from the granules in the die cavity, the force created by
the expansion of the entrapped air may be sufficient to disrupt the bonds.
The presence of entrapped air will produce a tablet which can be broken easily & it lowers
the tablet strength.
Moisture content
A small proportion of moisture content is desirable for the formation of a coherent tablet. At
low moisture content there will be increase in die wall friction due to increased stress, hence
the tablet hardness will be poor. At high moisture level the die wall friction is reduced owing
to lubricating effect of moisture. At further increase in moisture content there will be decrease
in compact strength due to reduction in inter particulate bond.
Optimum moisture content is in the range of 0.5 – 4%.
Porosity
When particles of large size are subjected to light compression the tablet will be highly
porous–low tablet strength. Reduction in porosity is due to granule fragmentation giving
smaller particles which may be more closely packed & plastic deformation which allows the
granules to flow into the void spaces.

40. Tablet presses are designed with following basic components:
1. Hopper for holding and feeding granulation
2. Dies that define the size and shape of the tablet.
3. Punches for compressing the granulation within the dies.
4. Cam tracks for guiding the movement of the punches.
5. A feeding mechanism for moving granulation from hopper into the dies.
Parts of a Tablet Press

41. 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.
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.
Auxiliary Equipment's

43. 43

44. 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. Also, it can
press the name of the manufacturer or the product into the top of the tablet.
Tablet punching machines work on the principle of compression.
A tablet is formed by the combined pressing action of two punches and a die.
Punches & Dies
Tooling Station: - The upper punch, the lower punch and the die which
accommodate one station in a tablet press.
Tooling Set: A complete set of punches and dies to accommodate all stations
in a tablet press.
Instrumented tablet machines and tooling

45. 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 utilized on B tooling machine which is called as
DB
Mainly there are two standards, a D and B
Difference between B and D tooling
45

46. 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
46

47. Used by pharmaceutical
and veterinary industry.
Can manufacture
following type of tablets:
Shallow Concave Ball
Shape
 Deep Concave Flat
Faced
Concave with Edges
Flat with Bevel Edges
Normal Concave
Round shape Punch Die Set
47

48. Applicable to pharmaceutical
and ayurvedic industries.
Can manufacture following
types of tablets:
Flat Faced Flat with
bevel edges
Concave/Deep/Deep
Concave with bevel edges.
Oval Shape Punch Die Set
48

49. Applicable to
pharmaceutical and
ayurvedic industries.
Can manufacture
following types of tablets:
Concave with Edges
Deep Concave Flat
Faced
Normal concave Flat
with Bevel Edges.
Capsule shape punch die set
49

50. Applicable to
pharmaceutical,
confectionery, chemical,
industrial powder
metallurgy industries. Can
manufacture following
types of tablet:
Triangular
 Benzene
 Rhombus
 Rectangular Square
Geometric Shape Punch Die Set
50

51. Are applicable to
confectionery
industries.
Available with
different size,
concavity, and flat in
plain or engraved
break line.
Irregular Shape Punch Die Set
51

52. Problems associated with large scale
manufacturing of tablets.
• In olden days tablets were initially punched on small scale with hand
operated machines, which suffered the problem of varied strength
and integrity.
• But now the tablet punching machines are all mechanized, the
mechanical feeding of feed from the hopper into the die, electronic
monitoring of the press, but tablet process problem still persist.
• The Imperfections known as: ‘VISUAL DEFECTS’ are either related
to Imperfections in any one or more of the following factors[1]:
I. Formulation design
II. Tableting process
III. Machine
52

53. Visual
Defects
Process
Related
Capping
Lamination
Cracking
Chipping
Formulation
Related
Sticking
Picking
Binding
Machine
Related
Double
Impression 53

54. The defects related to Tableting Process..
CAPPING:
Partial or complete separation of the top or bottom of tablet due to air-entrapment in
the granular material.
LAMINATION:
Separation of tablet into two or more layers due to air-entrapment in the granular
material.
CRACKING:
Small, fine cracks observed on the upper and lower central surface of tablets, or very
rarely on the sidewall.
CHIPPING:
Breaking of tablet edges.
54

55. The defects related to Formulation.
STICKING:
The adhesion of granulation material to the die wall.
PICKING:
The removal of material from the surface of tablet and its
adherence to the face of punch.
BINDING:
Sticking of the tablet to the die and does not eject properly out
of the die.
55

56. The defect related to Machine.
DOUBLE IMPRESSION:
Due to free rotation of the punches, having some engraving on their faces.
The defect related to more than one factor.
MOTTLING:
Unequal distribution of color on a tablet with light or dark areas.

57. HT
A N
SK