This document describes the design and development of an electrically powered reciprocating machine for breaking cocoa pods to extract cocoa beans. The machine uses a reciprocating hammer powered by a 1hp electric motor to break cocoa pods placed in a hopper. As the hammer moves up and down, it breaks the pods against fixed angle bars, releasing the beans. The machine was designed, fabricated using locally available materials like mild steel, wood and tested. It achieved a 93% efficiency and 0% bean damage rate when processing 500 pods in batches of 100. The total production cost was estimated to be 56,000 Naira. The machine provides an improvement over manual pod breaking by reducing labor and potential for bean damage.

1. International Journal of Excellence Innovation and Development
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Development of Electrically Powered
Reciprocating Cocoa Pods Breaking Machine
O.O Caleb 1
, B.O Akinnuli 2
1
Department of Mechanical Engineering, Federal University of Technology, Akure, Nigeria
2
Department of Industrial and Production Engineering, Federal University of Technology, Akure, Nigeria
Abstracts––Cocoa (Theobroma cacao) is one of the main
cash crops exported from Nigeria to other countries. The
removal of the beans from the cocoa pods has been done
manually for a very long time which reduces the
efficiency of the process and sometimes results in loss of
an amount of the beans. This work considers the design,
fabrication and cost of a simple reciprocating electrically
powered cocoa pod breaking machine to facilitate the
removal of cocoa beans from the pods. Electric motor of
1 hp power rate and 1400 rpm was installed. After
evaluation of the machine, the seed damage percentage
was found to be 0 %. This shows 100 % effectiveness
while the efficiency of the machine was 93 %.The belt
speed of 6.6 m/s was used with designed hammer weight
of 150 N and the breaking rate per hour ranges from
3600-7600 pods depending on the size of the pods. The
machine production cost was fifty-six thousand eight
hundred Naira (N56,800) only equivalent of US$ 2,272
at exchange rate of N 250 per Dollar as at the time of
this research.
Keywords––Cocoa pods, design, fabrication, cost
estimation, reciprocating machine
INTRODUCTION
Cocoa is one of the cash crops of great significance
grown in the world. In Nigeria, Cocoa is a prominent
perennial cash crop planted in the south western part of
Nigeria. Cocoa production has been a supporting factor
for the economy of producing countries because of its
high export earnings. The cocoa seed usually referred to
as cocoa beans is exported to the western world for
processing where several products are manufactured and
imported back to Nigeriaand other developing countries
at a relatively high cost (Adewumi, 1997). Cocoa is key
import goods for consuming countries due to its various
uses and its economic value.
The cocoa fruit is made up of the pod, beans, husk,
placenta and mucilaginous pulp which has a sweet juice
called ‘sweating’ (Adzimah and Asiam, 2010). The
cocoa pod is a berry which varies in size, shape and
colour. The fully grown and ripe cocoa pod is about
15.24 cm to 32 cm in length, 7.62 cm to 10.16 cm in
diameter at the centre (Adzimah and Asiam, 2010 and
Ramji et. al., 2018). The pod takes about 5 - 6 months to
ripen and Figure 1 and Plate 1 show the transverse
section while Figure 2 shows longitudinal section of a
whole cocoa fruit. The husk has an appreciable
thickness. A pod contains between 30 and 40 beans
usually with each bean surrounded by mucilaginous pulp
(Adzimahans Asiam, 2010; and Ramji et. al., 2018).
Plate 1: Transverse Section of Cocoa Fruit
(Source: Adzimah and Asiam, 2010)
Fig. 1: Transverse Cross Section of a Matured Cocoa
Pod.
Fig. 2: Longitudinal section of a whole cocoa pod.

2. Development of electrically powered reciprocating cocoa pods breaking machine Caleb and Akinnuli
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The principal use and economic importance of cocoa are
in medicine, production of chocolate, oil, petrol, candles,
lightning oil, ointments, and soaps (Opeke, 1987). Cocoa
butter, made from the fat extracted from the beans, is a
stable fat used in the production of cosmetics and
pharmaceutical products. The beans are milled into
powder for making beverages, chocolates, ice cream,
soft drinks, cakes, biscuits, flavouring agents and other
confectionaries (Ramji, et.al, 2018). Syamsiro et. al.
(2012) revealed that cocoa husk is a promising biomass
for renewable energy production which can replace
fossil fuel and reduce CO2 emissions.
The productivity of the cocoa farm can be increased by
simplifying the bean removing process (Arivu et. al,
2018). Cocoa beans processing for human consumption
is growing into different products from time to time
(Akinnuliet.al,2015).The processing of cocoa for
production of cocoa butter, beverage and cake includes
the breaking of the pods; extraction, fermentation,
drying, dehulling and winnowing of the beans,
(Ademosun, 1993; Adewumi, 1997; Faborode and
Oladosun, 1991). The breaking of pods is a size
reduction process, whose aim is to extract the beans
from the pod. According to Audu et al.,( 2004); Vejesit
and Salohkhe, (2004), and Adewumi et al., (2006)
compressive, impact or shearing forces are the forces
involved in breaking of cocoa pods depending on the
type of machine and process used. When done manually,
a lot of seeds are damaged in the process when
cutlass/machete is used in the splitting of the cocoa pods,
reducing the quantity of beans suitable for fermentation.
The process is time consuming, dependent on the
strength of the manpower, and prone to accidents
(Bamgboye, 2003). Fonsso et al.,(2016) observed that a
major problem facing cocoa farmers during breaking
process is Cocoa seeds damage. Over the years, efforts
have been put in place to simplify the procedures of
processing cocoa through mechanical means.
Jabagun (1965) reported that the first cocoa pod breaker
in Nigeria was constructed and tested at the Cocoa
Research Institute of Nigeria (CRIN).This machine
required at least two operators in which one will be
feeding the cocoa pods and the other one will collect the
beans. Ademosun (1990) designed a medium-scale
cocoa dehulling and winnowing machine. From the
performance evaluated, the machine is easy to operate
with only the adjustment of roller clearance. The
machine was found to have high dehulling and
winnowing efficiencies at the optimum roller clearance.
Faborode and Oladosun (1991) developed a machine to
break cocoa pods and extract wet beans. The machine
consists of a hopper, meter plate, hammer and a
reciprocating sieve. The pods were broken by the
hammer. The husk was separated by the vibrating sieve.
The beans were then collected through the discharge
chute. In 2010, Adzimah and Asiam designed a cocoa
pod splitting machine which was manufactured from
locally available scrap materials. It was assembled and
maintained at a relatively low cost. The knives were
actuated by simple hydraulic mechanisms devoid any
major stresses, forces or moments acting on them. These
mechanisms were powered by hydrostatic hydraulic
pumps of power rating of 87.5 kW (65.625 hp). The
machine can be assembled and/or disassembled easily
and quickly, and, therefore can be owned by a group of
cocoa farmers who can easily bear the cost.
The problems identified from the existing technology are
to: reduce the human effort, improve the production, and
make working process simple and easily controlled by
farmers. The aim of this work is to design a cocoa pod
breaking machine. The objectives are to design a simple
electrically powered reciprocating cocoa pod breaking
machine and to carry out the cost estimation of the
design of the machine towards its development.
METHODOLOGY
The aim of breaking cocoa pod is to extract cocoa beans
from placenta. The machine was designed and fabricated
using locally available materials. Thorough design
analysis was done. The size of the cocoa pods in terms
of length and diameter were found to range from 160
mm to 234 mm and 88 mm to 118 mm respectively.
The dimension of hopper outlet and the clearance
between the hammer and the breaking surface is
determined by the size of the cocoa pod. Physical
properties of wet cocoa pods are shown in Table 1 and
the properties of wet cocoa beans are shown in Table 2.
Table 1: Physical properties of whole cocoa pods (± standard error).
S/N Physical properties Variety
amelonado criollo trinitario
1 Angle of repose (o
) 15.5 ± 1.0 16.1 ± 1.4 20.1 ± 1.3
2 Bulk density (kg/m3
) 389.9 ± 8.9 464.5± 7.8 470.3 ± 8.0
3 Volume (cm3
) 397.3 ±22.7 710.5 ± 57/2 599.5 ± 44.0
4 Coefficient of friction
On wood 0.38 ±0.01 0.25 ± 0.02 0.25 ± 0.03
On galvanised steel 0.32 ± 0.02 0.25 ± 0.02 0.25 ± 0.03
5 Number of wet beans per pod 38 ±1 38 ±2 36 ± 2
6 Gravimetric composition
Pod husk (%) 68.6 ± 0/84 78.3 ± 1.0 76.5 ± 1.2
Wet beans (%) 28.5 ±0.76 18.7 ± 0.8 20.2 ±1.2

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Table 2: Physical properties of wet beans.
Sr. No. Physical properties Variety
amelonado criollo trinitario
1 Angle of repose (o
) 52.3 ± 1.4 48.6 ± 2.4 51.4 ±2.9
2 Coefficient of friction
On wood 0.39 ± 0.03 0.48 ± 0.06 0.57 ± 0.07
On galvanised steel 0.24 ± 0.01 0.44 ±0.06 0.55 ±0.01
Table 3: Material selection and criteria for selection.
Sr. No. Component Criteria for selection Material selected Reason for selection
1 Pulley Resistance to wear Wood Readily available
2 Frame Rigidity and stability Angle iron Rigidity
3 Shaft Resistance to torsional
stress
Mild steel Great machinability and
Readily available
4 Hopper and outlet collector Durability and rigidity Mild steel Readily available
5 Hammer High density Mild steel Readily available
6 Breaking surface Strength Angle iron durability
7 Belt Tension and strength V- belt
The angle of repose of cocoa pods, husks and beans were
determined. For a solid material to flows down an
inclined surface freely, the angle of inclination of the
surface to the horizontal must at least be equal to the
dynamic angle of repose of the material (Maduako and
Faborode, 1990).
Summary of Component Design
The resistance force of the cocoa pod was also
determined for the appropriate selection of weight of
hammer that will not cause damage to the cocoa beans.
The weight of the hammer was determined to be 150 N.
Electric motor of 1hp was selected. V-belt “A” type was
selected based on the type of electric motor. Diameter of
the small pulley on the motor was found to be 90 mm
while that of the big pulley was determined to be 270
mm with a centre distance of 270 mm between them.
The V-belt rating is 1.39 kW for belt speed of 6.6 m/s
and equivalent pitch diameter 102.6 mm and one belt is
selected for the operation. The shaft of length 690 mm
with diameter 25 mm carrying hammer is supported on
two bearings. The designed machine is shown in Figure
3. Materials selected for various components of the
machines are shown in Table 3.
Principle of Machine Operations
The hopper is fed manually with the cocoa pods to be
broken. As the hopper is filled, the electric motor of the
machine is energized. The hammer with its sheet plate
moves vertically upward which allows the cocoa pods to
be rolled in between the hammer and the fixed angle
bars horizontally welded to the frame directly under the
flat hammer. As the hammer is coming down, it
compresses the cocoa pods against the horizontal angle
bars this makes the pods broken into smaller pieces both
the seeds and the broken pods falls by gravity into the
collector. The process continues to repeat till all the pods
were crushed and operation stopped.
Maintenance of the Machine
Since usage of this machine is seasonal and only used
when there is ripe cocoa, it should be water washed after
use. The surfaces that made contact with cocoa should
be covered with film of oil. This will prevent corrosion
and increases the life span of the machine.
Sr. No. Description Qty. Material
1 Hopper 2 Metal sheet
2 Bearing 2
3 V- belt – A –SO 1 Rubber
4 Shaft 1 Mild steel
5 Pulley 1 Wood
6 Frame Angle iron
7 Electric motor 1
Fig. 3: Machine Designed.
7

4. Development of electrically powered reciprocating cocoa pods breaking machine Caleb and Akinnuli
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The machine was fabricated component by component
according to the design specifications and materials
selected on Table 3. Arc welding was used in fabrication
of the frame, hopper, crushing surface and housing
support. The components were assembled together and
the machine was tested by an operator. The cost of
production of the machine is presented on Table 4.
Table 4: Bill of engineering measurement and
evaluation.
Sr.
No.
Components
and
materials
Specification Qty Unit
cost
(N)
Total
cost
(N)
1 Hammer 460 mm by
460mm
1 3,200 3,200
2 Angle iron 2 length 2 4,500 9,000
3 Bearing 1
pair
2,200 2,200
4 Pulley 1 1,100 1,100
5 Hacksaw
blade
1 500 500
6 Electrode Guage 12 1
pack
3,500 3,500
7 Iron rod 1 ft 3 1,500 4,500
8 Metal plate 2.5 mm thick 1
sheet
7,500 7,500
9 Paint and
brush
1
litre
2,000 2,000
10 Belt A 80 1 1,300 1,300
11 Cutting disc 1 1,000 1,000
12 Grinding disc 1 1,200 1,200
13 Electric motor 1 hp 1 10,300 10,300
14 Workmanship 5,000
15 Miscellaneous 4,000
Total 56,800
RESULTS AND DISCUSSIONS
The machine developed has a total mass of 45 kg; the
hammer was designed to be 150 N by weight, while the
electric motor was 1 hp of power rating. The small and
big pullies were of 90 mm and 270 mm diameter with
their centre distance of 270 mm. the driving belt of type
“A” was designed to have a power rating of 1.39 kW,
speed of 6.6 m/s and equivalent pitch diameter of 102.6
mm. the driving shaft is of 690 mm in length and 25 mm
diameter.
Concerning the machine performance evaluation, 500
cocoa pods were crushed at 100 pods per batch that gave
an average efficiency of 93 %, 0 % of damage which
proved the machine to be 100 % effective, while the
production cost is N 56,000.
CONCLUSION AND RECOMMENDATIONS
The machine for breaking cocoa pods was designed and
fabricated based on reciprocating motion principle. One
operator is needed for the efficient use of the machine.
The machine was found to be more efficient in breaking
cocoa pods at preliminary processing level before
fermentation for sun drying. This has reduced drudgery,
and injury sustained by farmers when cutlass is used as
means of breaking cocoa pods.
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Biography of Author(s)
O. O. Caleb (B. Eng. Mechanical Engineering, M. Eng.
Building Services Engineering) is a lecturer at the
Department of Mechanical Engineering Federal
University of Technology Akure, Ondo State, Nigeria
B.O Akinnuli (B. Eng. Mechanical Engineering, M.
Eng. and Ph. D in Industrial and Production
Engineering,) is associate Professor at the Department of
Industrial and Production Engineering, Federal
University of Technology, Akure, Ondo State, Nigeria.