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ca/all-publications/5266:development-of-blade-type-coconut
-dehusking-machine-for-copra-production-in-the-philippines
5th International Conference of the International
Commission of Agricultural and Biosystems Engineering
(CIGR)

Hosted by the Canadian Society for Bioengineering (CSBE/SCGAB)

Québec City, Canada - May 10-14, 2021

DEVELOPMENT OF BLADE-TYPE COCONUT DEHUSKING MACHINE FOR COPRA

PRODUCTION IN THE PHILIPPINES

RONALD E. GARCIA1, ROMEO B. GAVINO2, RUEL G. PENEYRA2, EMMANUEL V. SICAT2

1
Department of Agricultural and Biosystems Engineering, College of Engineering and Architecture, Bataan
Peninsula State University, Abucay Campus, Abucay, Bataan, Philippines
2
Department of Agricultural and Biosystems Engineering, College of Engineering, Central Luzon State
University, Science City of Muñoz, Nueva Ecija, Philippines
Corresponding author’s e-mail: aengr.ronaldgarcia@gmail.com

ABSTRACT Philippines is the second-largest coconut producer in the world. More than
half of the country’s annual coconut production is processed into copra. Coconut
dehusking in the country is commonly done at the farm level using a simple tool such as
the share of a moldboard plow and relies mainly on manual labor which can be quite
tedious and hazardous. This study was conducted to develop a blade-type coconut
dehusking machine for local copra production. The machine had a total dimension of
1275mm x 1370mm x 1665mm and powered by a 5.97kW diesel engine. The machine was
tested and evaluated using newly harvested brown coconut that is small, medium, and
large-sized with equatorial diameter means of 152mm, 182mm, and 211 mm,
respectively. The performance parameters of the machine such as dehusking capacity,
dehusking efficiency, and percent coconut damaged as affected by the coconut sizes
(Factor A: small, medium, large) and the operating speed of the dehusking roller (Factor
B: 50rpm, 75rpm, 100rpm) were analyzed using a factorial experiment in Completely
Randomized Design (CRD). Comparison among means was done using Duncan’s Multiple
Range Test (DMRT) at a 5% level of significance. Results show that the highest dehusking
capacities of 588 pcs/hr and 559 pcs/hr, and dehusking efficiencies of 99.57% and 99.51%,
were obtained at 100 rpm and 75 rpm. On the other hand, the lowest dehusking capacity
of 287pcs/hr and dehusking efficiency of 99.10% was obtained at 50rpm. Increasing the
operating speed of dehusking roller from 50rpm to 75 or 100rpm resulted in a higher
dehusking capacity and efficiency of the machine. However, results also show that
operating the machine at dehusking roller speed of 100rpm and higher would generate
higher percent coconut damaged during machine operation. Thus, operating the machine
at 75rpm will give an average dehusking capacity of 559 pcs/hr and efficiency of 99.52%
with an acceptable amount of percent coconut damaged, giving an increase of 311% in
comparison to the manual coconut dehusking capacity of 180 pcs/hr.

Keywords: Coconut, coconut dehusker, dehusking, copra, copra processing, Philippines.

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 1
INTRODUCTION Coconut is abundantly grown in Indonesia, the Philippines, and India
(FAO, 2013). In the Philippines, the production of a massive supply of coconut is year-
round. Being the second-largest producer of coconut in the world, statistics show that
the country has an average of 3.517 million hectares of coconut area or 26% of its total
agricultural land area (PCA, 2016). In fact, 68 out of 81 provinces comprising of 1,195
municipalities are coconut areas with 329.9 million bearing trees producing an average of
14.902 billion nuts per year or an average yield of 45 nuts per tree per year (PCA, 2016).

More than half of the country’s annual coconut production is processed locally into copra.
Copra, the dried coconut meat, is the main source of coconut oil products. Coconut oil
accounts for 85-95% of the country’s total coconut exports by volume, and 80% by value.
In 2017 alone, a total of 0.911 million metric tons of coconut oil from copra with a total
value of US$1.436 Billion was exported by the country (PCA, 2016).

In the country, the majority of around 3.5 million coconut farmers who are directly
dependent on the coconut industry, process their coconut produce into copra products.
Traditionally, copra production involves a series of processes that begin with coconut
harvesting to dehusking, splitting, drying, scooping, re-drying of the half-dried meat,
bagging, and transport of copra products to the nearest buyer.

Coconut dehusking is one of the key operations relevant to copra production. After
harvesting, the coconut must be dehusked first before it is subjected to splitting and other
processes. Due to the unavailability of a mechanical device for this operation at the farm
level, coconut farmers are forced to rely mainly on the manual method using an idle share
of moldboard plow as a dehusking tool. Using this tool, the person doing the process has
to hold the coconut in his hand and impale it onto the spike to penetrate deep into the
shell. Then, pushes the coconut downward with a slight twist to loosen the husks. The
procedure is repeated along the circumference of the coconut about 4 to 5 times before
all the coconut husks are finally removed from the coconut shell. On average, an
experienced and skilled laborer can dehusk 2 - 3 coconuts per min or around 960 to 1,440
nuts per 8hr per day (Pascua et al., 2018).

In the past decades, many attempts were made to develop a mechanical device for
coconut dehusking. Different concepts and designs were proposed and fabricated.
However, until now, coconut dehusking is still accomplished by a manual process at the
farm level in most coconut growing areas in the country.

The general objective of the study was to develop a blade-type coconut dehusking
machine for copra production in the Philippines. Specifically, the study aimed to (1)
design and fabricate a mechanical device for farm-level coconut dehusking operation; and
(2) evaluate the performance of the machine in terms of dehusking capacity, dehusking
efficiency, and percent of coconut damaged.

This machine would be essential for the mechanization of the local coconut industry
particularly to copra production in the countryside.

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 2
MATERIALS AND METHODS The flow process, as shown in Figure 1, was followed in the
development of the blade-type coconut dehusking machine.

START

Design Conceptualization

Design Calculations and CAD Drawing

Fabrication/Modification

Pre-Testing
No
Machine Functional?
Yes
Target Met? No
Capacity > 240pcs
Efficiency ≥ 90%
Yes
Final Testing

Data Analysis

Painting of Prototype Machine

END

Figure 1. Flow process of developing the coconut dehusking machine

DESIGN CONCEPTUALIZATION AND CALCULATIONS The conceptualized design of the

machine was compact that it could easily be moved from one location to another. In this
design, coconut dehusking was performed in two stages: the first stage was removing the
outer husk by the dehusking unit and the second stage was removing the remaining husks
that were not removed by the dehusking unit. The basic design calculations, governed by
the basic principles of machine design and approaches, were used to compute the
necessary dimension requirements of each component of the machine.

Length of Dehusking Roller (LDR) The length of dehusking roller was designed such that
large coconut sizes were accommodated. The length of dehusking roller used in this study
was 340mm. Equation 1 was used to determine the length of the dehusking roller.

𝐿𝐷𝑅 = 1.10𝐿𝐶 (1)

Where LDR is the length of rollers (mm), and LC is the maximum length of coconut (mm).

Number of Roller Blades (n) The number of the needed blades was determined using
Equation 2.

𝜋(𝐷 + 2ℎ)
n= (2)
w

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 3
Where n is the number of blades, D is the diameter of the cylinder (mm), h is the height
of blade (mm), and w is the width of coconut husk cut by one blade (mm).

Torque Required (T) The torque required to dehusk a large mature (brown) coconut was
480 N.m. It was determined using Equation 3.

T = Fr (3)

Where T is the torque required (N.m), F is the maximum force (N), and r is the distance
from the center of the shaft to the tip of the rollerblade (mm).

Power Required by Dehusking Roller (PDR) The power required by the roller for dehusking
was approximately 3.77 kW. It was computed using Equation 4.

2πTN
PDR = (4)
60,000

Where: PDR is the power available in the dehusking roller (kW), T is the torque required,
(N.m), and N is the operating speed of the dehusking roller (rpm).

Power Required by Dehusking Unit (PD) The power required to operate the dehusking
unit was 4.15 kW. This was determined by adding 10% to the power available in the
dehusking roller to run the belt conveyor as shown in Equation 5.

PD= 1.10PDR (5)

Power Required by Cleaning Unit (PC) The power required to operate the cleaning unit
was approximately 1.5kW. This was approximately 35% of the power requirement of
dehusking unit (Equation 6).
PC= 0.35PD (6)

Total Power Required by the Machine (PT) The total power required to operate the
coconut dehusking machine was 5.95 kW. This was determined by adding the calculated
power requirements of dehusking and cleaning unit as shown in Equation 7.

PD + PC
PT = (7)
e
Where PT is the total power required by the coconut dehusking machine (kW), PD is the
power required by the dehusking unit (kW), PC is the power required by the cleaning unit
(kW), and e is the overall transmission efficiency (95%).

Shaft Design The coconut dehusking machine involved various sizes of shafting. The
standard shaft for agricultural machines with steel designation 1020 (cold rolled steel)
and allowable shear stress of approximately 41.369 MPa (PAES 305:2000) was selected.
The sizes of shafts subjected to the combination of torsion and bending were determined
using Equation 8.

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 4
 1
3 3
16 x 10
d =[ √T2 + M2 ] (8)
πτ

Where d is the diameter of the shaft (mm), T is the maximum twisting moment (N-m),
M is the maximum bending moment (N-m), and τ is the allowable shear stress (MPa).

Power Transmission System Design analysis on the power transmission system was
carried out to allow proper sizing of the pulleys and sprockets to acquire desired speeds.
The sizes of the pulley, belt, sprocket, chain, and gear were determined based on
Philippine Agricultural Engineering Standards (2000).

Final Design of the Machine Based on the above concepts and calculations, the final
design and detailed drawings of the coconut dehusking machine were generated using
SOLIDWORKS 2016.

FABRICATION OF THE MACHINE The detailed drawings of the machine were used and
followed during the fabrication. Locally available processes, equipment, and materials
were used in the fabrication.

Technical Means for Ensuring Safety For safety reasons, guarding was provided for all
belts and pulleys, chains, and sprockets following applicable standards set by the
Philippine Agricultural Engineering Standard (2000). Moving components of the machine
were generally treated as dangerous particularly the rollers and transmission systems.
Thus, protective machine-like shields or covers were provided to guarantee the safety of
operators.

Principles of Operation While the machine was running, each coconut was fed manually
into the coconut dehusking unit in a horizontal position. During the dehusking process,
each coconut was held between the rotating dehusking roller and running belt conveyor
and pushed against the stationary counter bar. The two springs helped to adjust the
clearance between the belt conveyor and dehusking roller according to the size of the
coconut. As the dehusking roller rotated, the rollerblades penetrated the coconut husk
and tore it away while the coconut was pushed by the roller to the counter bar, while one
side of the belt conveyor was running in an upward direction which helped the coconut
to twist during the process until all husks were removed from the shell of the coconut.
The husk and partially dehusked coconut were then separated by the counter bar. When
the coconut was already dehusked, the ejector lever located at the top cover of the
dehusking unit was pulled at a certain angle to eject the coconut and to feed to the
cleaning unit. Husks were discharged into the husk discharge chute. In the cleaning unit,
as the rollers rotate, the rollerblades remove the remaining husk, particularly the crown
portion of the coconut. The remaining husks were discharged in the husk discharge chute,
while the dehusked coconut was conveyed by the screw conveyor to the coconut
discharge chute to complete the process. Once the dehusking process was completed and
the coconut is ejected, another coconut should be fed into the dehusking unit, and so on.

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 5
TESTING AND EVALUATION After fabrication and some necessary adjustments, the
machine was subjected to final testing and evaluation. The machine was tested to assess
its overall performance in terms of dehusking capacity, dehusking efficiency, and percent
coconut damaged. All coconut samples were brown to ensure homogeneity in terms of
maturity. The coconut samples with an equatorial diameter ranging from 126 – 165 mm,
166 – 205 mm, and 206 – 245 mm were classified into small, medium, and large,
respectively. This range of measurement was decided based on the data provided by
Philippine Coconut Authority (PCA). Two factors were considered: Factor A (coconut size)
with three levels (A1, A2, A3), and Factor B (operating speed of dehusking roller) with
three levels (B1, B2, B3). Three (3) replications were assigned to each of the nine
treatment combinations. Randomization of the replicated treatment combinations was
done to assign the sequence for each trial. Before the start of test trials, 5 pieces of
coconut samples were randomly selected from every size-grouped to assign the number
of samples per trial.

DETERMINATION OF PERFORMANCE PARAMETERS The performance of the machine was

evaluated in terms of dehusking capacity, dehusking efficiency, and percent coconut
damaged. Procedures and equations below were followed for the determination of these
parameters.

Dehusking Capacity (DC) The dehusking capacity of the coconut dehusking machine was
calculated by dividing the number of coconut samples dehusked by the total dehusking
time multiplied by 3600, as shown in Equation 9.

NS
DC = x 3600 (9)
DT
Where DC is the dehusking capacity of the machine (pcs/hr), NS is the number of the
sample (pcs), and DT is the total dehusking time (s).

Dehusking Efficiency (DE) The dehusking efficiency of the machine was calculated by
dividing the weight of the husk removed by the machine by the weight of the total husk
multiplied by 100 percent, as shown in Equation 10.

W1
DE = x 100 (10)
W1 + W2

Where DE is the dehusking efficiency (%), W1 is the weight of husk removed by the
machine (g), and W2 is the weight of un-removed husk (g).

%Coconut Damaged The percent coconut damaged was calculated by dividing the
number of samples that incurred shell crack or breakage by the total number of samples
multiplied by 100%, as shown in Equation 11.

ND
%Coconut Damaged = x 100 (11)
NT

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 6
Where ND is the number of samples that incur crack or shell breakage (pcs), and NT is the
total number of samples (pcs).

Data Analysis Factorial in Completely Randomized Design (CRD) was used to analyze the
effect of coconut sizes and the different levels of speeds of dehusking roller on the
dehusking capacity, dehusking efficiency, and percent coconut damaged. The sources of
variation are presented in standard ANOVA tables. Further, comparison among means
was tested using Duncan’s Multiple Range Test (DMRT) at a 5% level of significance.

RESULTS AND DISCUSSION The coconut dehusking machine was designed and developed
to remove the husks from the coconut shell regardless of the size and husk thickness of
the coconut.

DESCRIPTION OF THE MACHINE The blade-type coconut dehusking machine (Figure 2)

was equipped with three integral parts, namely: dehusking unit, the cleaning unit, and the
prime mover. The machine had a total dimension of 1275 mm x 1370 mm x 1665mm and
a total weight with no engine of 240 kg. The entire assembly was painted to resist
corrosion.

Figure 2. The Blade-type coconut dehusking machine.

Dehusking Unit The dehusking unit was considered the most important component of the
machine because if it failed to do its intended function, other components would be
useless. In this unit, the first stage of the dehusking process was carried out. The
dehusking unit consisted of four main parts, namely; dehusking roller, counter bar, belt
conveyor assembly, and ejector assembly. The dehusking roller was equipped with 21
pieces of blades welded equally around the circumferential area of the steel cylinder. The
counter bar was placed stationary below the dehusking roller at a certain distance from
the tip of the blades and a certain distance from the bottom part of the belt conveyor. It
was employed to hold the coconut and allow it to twist while the dehusking roller and
belt conveyor were running during the coconut dehusking operation. The belt conveyor
assembly was placed in a vertical position at a certain distance from the dehusking roller.
It was equipped with two springs attached at the bottom part of the support bars. The
other ends of the springs were also attached to the frame of the machine. The ejector
assembly was also employed in the dehusking unit to facilitate easy discharge of coconut
to the cleaning unit after the first stage of the dehusking process.

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 7
Cleaning Unit The second stage of the dehusking process was done at the cleaning unit.
In this unit, the remaining husks still attached to the coconut shell after the first stage of
dehusking, particularly the crown of the coconut husk were removed. The cleaning unit
was composed of three main parts, namely: cleaning rollers, screw conveyor, and side
cover. Both cleaning rollers were placed such that the line joining the center of their shaft
was parallel. Each roller was equipped with 32 pieces of blades. The screw conveyor was
placed at a certain distance above one of the rollers to convey the coconut to the
discharge chute. A side cover was provided to the cleaning unit to keep the coconut on
the rotating rollers while the coconut was conveyed by the screw conveyor to the coconut
discharge chute during the second stage of dehusking.

Prime Mover Fuel price was one of the considerations in the selection of prime mover.
Since diesel fuel was cheaper than gasoline, a diesel engine was selected. Based on the
calculated power requirement of the machine of 5.95 kW, the nearest available rated
power for diesel engines available in the local market was 5.97kW. Thus, a diesel engine
with a maximum power of 5.97kW was selected as a prime mover of the blade-type
coconut dehusking machine.

MACHINE PERFORMANCE The overall performance of the machine was determined by

measuring such parameters as dehusking capacity, dehusking efficiency, and percent of
coconut damaged. Table 3 shows the summary of machine performance.

Dehusking Capacity The average dehusking capacity of the coconut dehusking machine
as affected by coconut size and the operating speed of the dehusking roller is shown in
Table 1. The highest dehusking capacity of 604 pcs/hr was obtained for medium coconut
sizes at 100rpm. On the other hand, the lowest capacity (265 pcs/hr) was observed for
small coconut sizes at 50 rpm operating speed of dehusking roller. Analysis of variance on
the dehusking capacity of the machine as affected by coconut size and the operating
speed of the dehusking roller reveals that the operating speed had a significant effect on
the dehusking capacity of the machine. The coconut sizes and the interaction of the two
factors, on the other hand, had no significant effect on the dehusking capacity of the
machine. Comparison among means of the dehusking capacity as affected by the
operating speed of the dehusking roller reveals that the dehusking capacities of 588pcs/hr
and 559 pcs/hr at 100 rpm and 75 rpm, respectively, had no significant differences. Both,
however, were significantly higher than the mean dehusking capacity of 287 pcs/hr at
dehusking roller speed of 50 rpm.

Table 1. Average dehusking capacity (pcs/hr) as affected by coconut size and operating
speed of dehusking roller
SPEED COCONUT SIZE
MEAN
(rpm) Small Medium Large
50 265 297 298 287b
75 574 557 545 559a
100 589 604 572 588a
MEAN 476 486 472 478
Means not sharing the same letter, in a row and a column, differ significantly by DMRT at a 5% level of significance

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 8
Increasing the operating speed of dehusking roller from 50 rpm to 75 or 100rpm resulted
in a higher capacity of the coconut dehusking machine. Furthermore, the machine in this
study recorded a higher dehusking capacity (559 to 588 pcs/hr) as compared to the 240
pcs/hr dehusking capacity of the mechanical coconut dehusker developed by Pascual et
al. (2018).

Dehusking Efficiency The average dehusking efficiency of the coconut dehusking machine
as affected by the coconut size and operating speed of the dehusking roller is shown in
Table 2. Coconuts dehusked at 100rpm, 75rpm, and 50rpm had a dehusking efficiency
means of 99.57%, 99.51%, and 99.10%, respectively. These results indicate that the higher
the operating speed of the dehusking roller, the higher the dehusking efficiency of the
machine. Analysis of variance on the dehusking efficiency reveals that dehusking
efficiency was affected significantly by the size of the coconut and the operating speed of
the dehusking roller. Comparison among means of the dehusking efficiency as affected
by coconut size shows that the coconut dehusking machine tended to be more efficient
in small and large-sized coconuts than in medium-sized coconuts. The mean dehusking
efficiency for small (99.51%) and large-sized coconuts (99.49%) had no significant
differences, but both were significantly different from that of the medium-sized coconuts
(99.18%). Furthermore, comparison among means on the dehusking efficiency as affected
by the operating speed of dehusking roller indicates that mean dehusking efficiencies of
99.57% and 99.51% for 100- and 75-rpm, respectively, had no significant differences.
Comparing both to dehusking efficiency of 99.10% at 50rpm exhibited significant
differences. This indicates that the machine performed better at either 100 or 75rpm of
the dehusking roller. Moreover, the fabricated coconut dehusking machine also recorded
a dehusking efficiency higher than 99% at the different operating speeds which were all
higher when compared to the 85.23% dehusking efficiency of the mechanical coconut
dehusker developed by Pascual et al. (2018).

Table 2. Average dehusking efficiency (%) as affected by coconut size and operating speed
of dehusking roller.
SPEED COCONUT SIZE
MEAN
(rpm) Small Medium Large
50 99.40 98.72 99.15 99.10b
75 99.60 99.28 99.65 99.51a
100 99.55 99.52 99.62 99.57a
MEAN 99.51a 99.18b 99.49a 99.39
Means not sharing the same letter, in a row and a column, differ significantly by DMRT at a 5% level of significance

Percent coconut damaged The result shows that the percent coconut damaged increased
as the size of the coconut was increased. Similarly, operating the coconut dehusking
machine at dehusking roller speed of 100rpm and higher would generate a higher
percentage coconut damaged during machine operation.

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 9
SUMMARY OF MACHINE PERFORMANCE A total of 27 trials were done in this study. Table
3 below shows the summary of the performance of the blade-type coconut dehusking
machine.

Table 3. Summary of machine performance.

Treatment Combination Dehusking Dehusking Coconut
Trial Capacity Efficiency Damaged
RPM Coconut Size (pcs/hr) (%) (%)
1 50 small 254 99.6 0
2 50 large 279 99.2 0
3 75 medium 594 98.7 20
4 100 large 593 99.4 40
5 100 large 562 99.7 20
6 75 small 573 99.7 0
7 100 large 560 99.8 60
8 50 large 306 99.2 0
9 100 small 542 99.6 20
10 75 small 583 99.5 0
11 75 large 527 99.6 0
12 75 medium 545 99.5 0
13 75 large 514 99.7 20
14 100 small 638 99.6 20
15 75 medium 532 99.6 0
16 50 small 261 99.1 0
17 50 small 279 99.5 0
18 50 medium 283 98.7 0
19 50 large 310 99.1 0
20 50 medium 321 99.1 0
21 75 small 566 99.6 0
22 75 large 595 99.7 0
23 100 medium 584 99.5 20
24 100 small 587 99.4 0
25 100 medium 665 99.6 40
26 50 medium 287 98.4 0
27 100 medium 564 99.5 20

CONCLUSION A blade-type coconut dehusking machine for copra production has been
successfully designed and fabricated. Operating the machine at 75rpm will give an
average dehusking capacity of 559 pcs/hr and efficiency of 99.52% with an acceptable
amount of percent coconut damaged, giving an increase of 311% in comparison to the
manual coconut dehusking capacity of 180 pcs/hr.

Acknowledgments The authors are thankful to the Engineering Research and

Development for Technology - Department of Science and Technology (ERDT-DOST) for
funding the study.

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 10
REFERENCES
FAO, 2013. COCONUT Post-harvest. Operations – Post-harvest Compendium. Food and
Agriculture Organization of the United Nations. http://www.fao.org/3/a-au999e.pdf.
PCA 2016, Coconut Statistics. http://www.pca.da.gov.ph/index.php/2015-10-26-03-15-
57/2015-10-26-03-22-41
PAES, 2000. Engineering Materials – Shafts for Agricultural Machines – Specifications
and Applications. PAES 305:2000
PAES, 2000. Engineering Materials – Spur Gears for Agricultural Machines –
Specifications and Applications. PAES 306:2000.
PAES, 2000. Engineering Materials – V-belts and Pulleys for Agricultural Machines –
Specifications and Applications. PAES 301:2000
PAES, 2000. Engineering Materials –Roller Chains and Sprockets for Agricultural
Machines – Specifications and Applications. PAES 303:2000.
Pascua A. M., Pascua M. L., Peralta E. K, 2018. Performance Characteristics of a Coconut
Dehusking Machine. International Journal of Advances in Agricultural Science and
Technology. Vol.5 Issue.2, February- 2018, pg. 1-14

CIGR 5th International Conference – Québec City, Canada – May 10-14, 2021 11