Electric Coconut Husk Remover Design and Development

Abstract

When coconuts are required in large numbers say 150 to 180 nuts per hour, manual dehusking becomes tedious and labour cost increases steeply. So the process needs to be mechanized. So this paper describes about process of operation and working principle. The shearing blades on roller are attached over cylindrical rollers throught its length. When blades rotate, at a high torque, coconut is pricked by blades and due to inertia of both blades rotating in opposite direction coconut cannot rotate along with both the blades simultaneously, Hence coconut is sheared apart at blade and husk intersection. This process carries on till entire coconut is completely dehusked. This machine is economically far better than manual method interms of per unit basis. Also overall costs will become lesser in long run for mass dehusking for which this machine is intended to do. Each key part of the model was individually analysed in ansys for forces acting on that individual part. In our model key parts were Frame, Roller and Gear. A standard procedure was followed for analysis of all parts. The detailed step is described in Analysis chapter. This model was analysed in ANSYS Version 16. Modeled machine is exact in dimensions with actual machine. Modeling was done in Solid works 2015.

Full text

18
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
Electric Coconut Husk Remover Design and Development
Andanappa S.D1, Suprit B.N1, Sridhar G1, Virupaxagouda F.K1, Prathiba B.G1, S.C.Sajjan2*
1Students, 2Professor,
Department of Mechanical Engineering, KLE Institute of Technology, Hubli, Karnataka, India
*Corresponding Author: sajjansc@gmail.com
ABSTRACT
When coconuts are required in large numbers
say 150 to 180 nuts per hour, manual dehusking
becomes tedious and labour cost increases
steeply. So the process needs to be mechanized.
So this paper describes about process of
operation and working principle. The shearing
blades on roller are attached over cylindrical
rollers through its length. When blades rotate, at
a high torque, coconut is pricked by blades and
due to inertia of both blades rotating in opposite
direction coconut cannot rotate along with both
the blades simultaneously, Hence coconut is
sheared apart at blade and husk intersection.
This process carries on till entire coconut is
completely dehusked. This machine is
economically far better than manual method in
terms of per unit basis. Also overall costs will
become lesser in long run for mass dehusking for
which this machine is intended to do. Each key
part of the model was individually analyzed in
Ansys for forces acting on that individual part. In
our model key parts were Frame, Roller and
Gear. A standard procedure was followed for
analysis of all parts. The detailed step is
described in Analysis chapter. This model was
analyzed in ANSYS Version 16. Modeled
machine is exact in dimensions with actual
machine. Modeling was done in Solid works 2015.
Keywords-- Dehusk, Shearing Blade, Inertia, Power
Transmission, Speed Reduction, Drive Mechanism,
Stress
INTRODUCTION
Coconut is a crucial crop popular in south
India. Whole coconut has multiple uses, Coconut
husk can make fiber for ropes. Grated coconut is
mainly used in cooking as it has medical
applications. Coconut liquid has medical
applications for body development and mental
growth. For all these applications dehusking is
necessary. In the coconut production India falls on
top three countries. Kerala, Tamilnadu, Karnatka,
Goa, etc., are the states which produces maximum
coconut in India [1].
Karnataka [2] contributes 24 percent of
area (513100 hectares) under coconut cultivation
and 26.7 percent of total production (6517.55
million nuts) of coconut in the country with 12702
nuts per hectares. Coconut is the second largest and
important horticultural crop of the Karnataka state,
occupying 31 percent of the total area under
horticultural crop. The crop is grown in all the
districts of the state. Nearly three hectares of area
growing coconut in the state. The varieties which are
grown are Chowghat orange dwarf, Chowghat green
dwarf, Malayan green dwarf, Malayan orange
dwarf, Malayan yellow dwarf and Ganga bondam.
The dwarf variety is grown mainly for tender
coconut purpose.
In the processing of coconut, removal of
raw coconut husk is comparatively difficult task.
Usually the cutters used in the dehusking machine
are sharp and probability of injury to operator is
more.
MATERIAL AND METHODOLOGY
Project model consists of a frame on which
the entire components are mounted. The dehusker is
present at the centre and it consists of two rollers [4].
The rollers are placed parallel to each other (Fig 1).
They are supported by means of a bearing. A motor
is coupled with the shaft and power from one shaft
to the other shaft is transmitted by means of a gear
arrangement. The blades are fixed at the surface of
the rollers so that the blades can peel the husk from
the coconut. Also at the top of the dehusker, a plate
is mounted which helps to prevent the slipping of the
coconut fibers while the dehusking operation.
The coconut is fed from the top which falls
on the rollers, the roller rotates in opposite direction.
The blades on one roller holds the husks while
blades on other tears the husk from the shell. Such a
machine is bigger in size due to its long rollers.
Large force is required due to small mechanical
advantage.

19
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
Figure 1: Principle of Working [4].
MACHINE DESCRIPTION
The frame is the main supporting
structure upon which the other components of
this machine are mounted on. The frame is a
welded structure, constructed from 25x50x2mm
rectangular iron with dimensions of 500mm in
length, 500mm width and 993mm height. The
drive mechanism comprises of a motor, speed
reduction worm gear box, belt drive, pulley and
a rotating roller. A three phase 1HP induction
motor with speed of 1440rpm is used to drive the
rollers. The machine also uses a gearbox with a
40:1 ratio and connected to a shaft, which is a
long rotating cylinder that transmits power from
one place to another. The roller type mechanism
can be explained as two rollers, each having an
elongated configuration, are parallel to one
another with respect to the base and in a readily
accessible configuration. Each roller consists of
hollow shaft of outer dia 60mm and inner dia
48mm, solid shaft of dia 25mm and end caps of
thickness 5mm, outer dia 48mm and inner dia
25mm. 6 straight and equally spaced metal
blades (5 x 25 x 450mm) are welded on a hollow
shaft. Roller length is 670mm for the main shaft
and 620mm length for the parallel one, supported
at both ends by flange type bearing block. When
the switch is turned on, the rollers with straight
blades rotate in opposite directions towards the
centre. It is possible with the help of two spur
gears having 30 teeth and pressure angle of 200
one on each rollers end, causing both gripping
and tearing of the husk of the coconut fruit
placed in between the rollers. It is shown in Fig
2.
Figure 2: Completely Assembled Coconut Dehusking Machine.

20
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
DESIGN OF COCONUT DEHUSKING
MACHINE
Design of Various Element of Coconut Dehusker
shall be carried out as follows:
Design of Straight Blades
The adhesion [5] between fibers in the husk
is greater than that between the shell and the husk;
hence separation occurs at the husk-shell interface.
The thickness of fiber is in the range of 20 to 30mm.
The dimension of straight blades should be so
selected to get effective penetration with coconut.
The blades can be attached to cylindrical rollers by
welding (Fig 3).
Figure 3: CAD Model of Straight Blade.
Circular Pitch of Blades
Circular pitch (shown in Fig 4 and 5) is the
distance between blades about the periphery of
cylindrical roller [5]. Six blades are placed at equal
interval around cylinder to have effective dehusk.
Figure 4: Circular Pitch of Blade.

21
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
Figure 5: Side View of Blade Arrangement.
Power Transmission and Speed Reduction Unit
The power [5] from electric motor is
transmitted to the rotating cylinders through pulleys
and gears (shown in Fig 6). Power should have less
speed and high torque at the rotating cylinders and
this is obtained by using a speed reduction gearbox.
The gears and pulleys will be arranged in such a way
that desired output is obtained by making use of
readily available sizes of gears and pulleys, so as to
keep the manufacturing cost low.
Figure 6: Drive Mechanism.
Design Calculations
A three phase motor with 1hp, speed of
1440rpm is used. Power will be transferred from the
motor through several power transmission
components designed to rotate the dehusking roller.
Below is the calculation for the mechanisms
showing all the calculation for the theoretical design.
Torque output of motor is 4.95Nm is obtained from
below equation.


Where:
P= Power in Watts (1HP = 746 Watts)
N= Speed of motor in RPM
Tm= Torque of motor in Nm
Gear ratio of speed reduction gear box used in the

22
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
machine is 40:1 shown in below equation.







Therefore, from above equation total Torque at the
roller input or Torque output of gear box with input
of Tm= Tin = 4.95 Nm is 198 Nm, is calculated from
below equation.
     
SELECTION OF GEARS
The machine requires two gears. For
simple design and easy availability and maintenance
steel spur gears with pressure angle 200 were chosen.
These gears are suitable for heavy loads and absence
of end thrust. The driving gear as well as driven gear
has 30 teeth.
SELECTION OF PULLEYS AND
DETERMINATION OF BELT SPEED
Standard pulley and V-belt is selected with
groove angle β=30⁰. It is because of simplicity in
design and availability purpose.
Centre distance ‘C’ between the adjacent pulley [6]
  

 
Where:
VR= Velocity ratio
 

Do = Diameter of driven pulley
Di = Diameter of driver pulley
C = Centre distance between pulleys
Length of the belt drive [6]
The length of the belt, l was computed as 782 mm
by using equation as follows:
      
 
MILD STEEL MATERIAL PROPERTIES
1. Yield strength, σy=378MPa
2. Ultimate strength, σu=585MPa
3. Shear modulus, G = 81Gpa
Working or Allowable normal stress,
  
   


      
 
General expression for Torsion
 



Torque T=198 Nm = 198 103 N mm
For strength:
 


  


 

   
    
  
Choosing standard available diameter of the shaft is
  
ANALYSIS IN ANSYS
METHODOLOGY
In Ansys workbench we have different
kinds of analysis, among those we choose static
structural analysis as shown in Fig.7 in which we can
observe maximum and minimum principle stress,
shear stress, deformation etc.
Figure 7: Steps in Static Structural Analysis. Figure 8: Details of Contact Face of Objects.

23
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
Engineering Data
For our work we have selected mild steel
for making components because of less cost, easy to
machine and availability of material. In ansys
several material files are predefined in engineering
data but mild steel is not available in it, so we need
to create mild steel material file and need to store its
properties.
Geometry
Here we need to design CAD model, we
have modeled in solid works, and assembly is saved
in IGES format which is compatible for ansys
software, geometry clean is made to eliminate faults,
errors in geometry.
Model
After geometry cleanup connections are
made between each component and what type of
connections (as shown in Fig. 8) are required like
frictional, friction less, bonded. Contact and target
bodies are checked are correct connections.
ANSYS ANALYSIS OF COCONUT
DEHUSKING MACHINE PART BY PART
The main components of coconut
dehusking machine are Frame, Roller and Gear.
CAD model and analysis of above components are
shown in below figures 9 to 11.
Figure 9: Equivalent Stress.
Figure 10: Von Misses Stress Image.

24
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
Figure 11: Maximum and Minimum Von Misses Stress Image.
RESULT AND EVALUATION
The performance of dehusking machine
was tested for ten randomly selected coconut
samples. The observations viz. total time
required to dehusk and recorded. It is evident
that the dehusking time for coconuts is varied
from 11 to 22 seconds and average time was
about 15 seconds. The dehusking capacity of
machine was determined from the dehusking
time required to dehusk the coconut which is
shown in Fig 12. The average dehusking capacity
of machine for coconut is around 320 nuts per
hours and it was varied from 250 to 390 nuts per
hours. The higher size of coconut is responsible
for higher dehusking time.
Figure 12: Result of the Performance Evaluation of Coconut Dehusking Machine.
Thus, the machine gave encouraging
performance. No damage and slippage of coconut
were obtained throughout the testing period. This
indicated that the cutting and gripping mechanism of
developed machine worked well.
CONCLUSION
After performance evaluation of developed
coconut dehuskers following conclusions are drawn,
the developed model is simple, efficient, requires
less time and cost effective when compared to the
existing available model. Average time required to
dehusk one coconut was 13.5 seconds and average
output capacity was 260 coconuts per hours. The
dehusked coconuts were found to be without nut
breakage and without cutting the useful coir fibers.
5
8
11
14
17
20
23
0246810 12
Dehusking Time
Number of Trials

25
Page 18-25 © MAT Journals 2020. All Rights Reserved
Volume-2, Issue-2 (May-August, 2020)
https://doi.org/10.46610/JMMDM.2020.v02i02.004
Journals of Mechatronics Machine Design and
Manufacturing
www.matjournals.com
REFERENCES
1. Production and marketing of coconut in India
(2011), Ministry of Agriculture GOI , Available
at
https://ideas.repec.org/p/ess/wpaper/id4532.ht
ml
2. Kera Bhavan(2011), “Annual Action Plan”,
Coconut Development Board, Kochi, Available
at
https://www.coconutboard.in/docs/anreport201
5-16english.pdf
3. “State wise and Item-wise estimates of value of
output from agriculture and allied sectors with
new base year (2012)” Available at
http://mospi.nic.in/sites/default/files/publicatio
n_reports/Final1Brochure_30july2018.pdf
4. Dany Thomas, Ajmal k, Deepak Devassia.
(2017), “Design and Fabrication of Low-Cost
Coconut Dehusking Machine” International
Journal of Engineering Research and General
Science, Volume 5, Issue 3.
5. Mr. R.M. Sabale & Dr. K. P. Kolhe (2016),
“Design and Development of a coconut
dehusker for small scale coir industry and
marginal farmers” International journal of
Science, Engineering and Technology
Research, Volume 5, Issue 2, pp.591-595,
Available at http://ijsetr.org/wp-
content/uploads/2016/02/IJSETR-VOL-5-
ISSUE-2-591-595.pdf
6. Azmi, H., Sanuddin, A. B., Zakimi, M. Z.,
Jamali, M. S., Radhwan, H., Khalil, A. N. M.,
... & Annuar, A. F. (2015), “Design and
Development of a Coconut De-Husking
Machine (Machine Component
Design)”, Journal of Advanced Research
Design, Volume 4, Issue 1, pp. 9-19, Available
at
https://www.researchgate.net/publication/2803
08727_Design_and_Development_of_a_Coco
nut_De-
Husking_Machine_Machine_Component_Desi
gn