JAYALAKSHMI INSTITUTE OF TECHNOLOGY THOPPUR, DHARMAPURI
AUTOMATIC COCONUT DEHUSKING MACHINE USING MECHATRONICS PRINCIPLES
Presented by K.NANDHAKUMAR J.JOVIN JAMES
[email protected]
ABSTRACT The outer shell (husk) of the coconut is removed for various purposes like extraction of oil, coir products, preparation of food items, etc. Until now the shell of the coconut is removed manually. The manual dehusking involves risk due to injury and consumes more time to dehusk (peel) the coconut shell and labor fatigue. This leads to less productivity and more labor cost. To overcome this, there is a need to automate the dehusking process. The invention of the project is that, the removal of the husk of coconuts by low cost automation. This project technique consists of pair of curved shells, multi hooks and two double acting pneumatic cylinders to remove the husk of the coconut, and one single acting pneumatic cylinder to hold and press the coconut. Here 5/2 spring return single solenoid direction control valve is used to actuate the two pistons which are used to remove the husk and 2/2 single solenoid direction valve is used to actuate the holding cylinder which press and hold the coconut in the shell. The range of operating pressure is 12 to 16 bars. The project is an attempt to replace man power required to dehusk (peel) the outer shell of the coconut. All the analysis and conclusions in this paper are strictly based on the project “AUTOMATIC COCONUT DEHUSKING MACHINE”, done at our college.
INTRODUCTION The outer shell (husk) of the coconut is removed for various purposes like extraction of oil, coir products, preparation of food items, etc. The outer shell is now being removed manually. Manual dehusking involves risk and consumes more time. This leads to less productivity and more labor cost. To overcome this, there is a need to automate the dehusking process. Low Cost Automation (LCA), the buzzword in all industrial firms generally involves pneumatic, electrical as well as electronic components. LCA is important in the automation of factories, for example, the electronic component assembly plants. Automation saves a lot of tedious manual work and speeds up the production processes. Agriculture is a potential area for automation. Automation can be applied for activities like irrigation, harvesting, ploughing, weeding, etc. Our project aims at automating the process of removing the outer shell of the coconut by help of pneumatics and mechanical parts. The following are the reason for automating: •
To remove the husk easily
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To increase productivity
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To reduce manual power
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To reduce the risks and accidents
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To reduce labour cost and time consumption.
The following are the objectives of the project 1. To automate the process of Dehusking with low cost •
Holding the coconut
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Pressing the coconut into hook
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Peeling the outer shell of the coconut
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Control of the operation of the System.
2. To design, model and assembly of the components of the system. 3. To compare the various factors of dehusking for both present and the automated system. The following are the advantages of our system: •
Improved safety
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Increases the productivity.
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Reduces the risk and accidents.
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Avoids manual effort.
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Reduces labor cost and time consumption.
METHODS OF ATTAINING AUTOMATION: Automation can be attained by the following ways •
Hydraulics
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Pneumatics
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Electric control
Due to the requirement of higher productivity we would like to go for fixed low cost automation process.
Comparison between manual & Automatic MANUAL
AUTOMATION
20*
30*
NO. OF COCONUTS
* Approximately
/ hour RISK
MORE
LESS
TIME
MORE
LESS
DESCRIPTION OF EQUIPMENT The complete equipment has been described under the categories of mechanical, pneumatics, and Control Circuit.
1. MECHANICAL COMPONENTS The various mechanical components of the system consists of the following
Base Table The base table is an important component of the system. The flange, rotating part and other components of the system are mounted on the base table. The base table is designed so that to withstand the shock load and vibrations generated by the system. The size of the base table is 820 X 620 X 875mm.
HOOK BLADES: Hooks are placed at the bottom of the shell. It is capable of piercing the outer shell of the coconut. It is placed in the bottom inner circumference of the shell, so that all the hooks can pierce into the shell of the coconut. It is made of high carbon steel (HCS) which is sharp at the end. The high carbon steel is cut to required length and it is hardened. The one end of the hook is very sharp and the other end is attached with the bottom of the shell. As the hooks are very sharp, it can easily pierce into the shell of the coconut. The reason for using high carbon steel is that to withstand the stress and deformation developed in it, while peeling the coconut.
CURVED SHELL A Pair of shells is used, which has multi hooks present at its bottom and two cylinders are attached to it. The coconut will be placed inside the shell and it will hold the coconut.
The pair of shells are made up of mild steel and attached to the base with help of hinges present at its tangential curve. Hence the shell can be oscillated when the cylinder moves linearly. Multi hooks are placed at the bottom of the shell. So that when coconut is placed and pressed in the shell, the multi hooks get pierced into the shell. Also at the bottom of the shell (opposite side of the shell where hooks are attached), hinges are present to hold the piston of the cylinder. Hence when the piston is actuated, the shell obtains oscillating movement as it attached with the base table with help of other hinges.
PNEUMATIC CYLINDERS The pneumatic cylinder is an actuator, which converts air pressure into linear motion. When the pressure on one side of the piston is relatively higher than on the other side, it results in linear displacement. The speed of traversal is proportional to the pressure difference. 1. DOUBLE ACTING CYLINDER A "double-acting" cylinder has two ports through which the supply of air is reversed to cause displacement in either direction. The general specification for a
pneumatic cylinder is in terms of the bore diameter of the cylinder, the stroke length of the piston and the maximum operating pressure range. To return the piston to its resting position, not only apply pressure to the second port, but also open up the first port so that the gas in it can be expelled. In this project double acting cylinders are used for the obtaining movement of the shell.
DOUBLE ACTING CYLINDER Specifications
of
double acting cylinder
PARAMETER Make Stroke Length Bore Diameter Max Pressure
VALUE JANATICS 160mm 40mm 20 bar
2. SINGLE ACTING CYLINDER A "single-acting" cylinder has a single port for compressed air. The forward stroke takes place when the air is fed in the input port; the return stroke takes place when the air supply to the input port is stopped. This is achieved by the spring force inside the cylinder. When air pressure is removed; the cylinder does nothing to retract the piston. Whatever the piston pushed out must push the piston back in. When air pressure is removed, the spring pushes the piston back into the resting position. In some cases the cylinder is sealed and the trapped air performs as an "air spring".
In this project the single acting cylinder is used to press and hold the coconut into the shell.
SINGLE ACTING CYLINDER
Specifications of single acting cylinder PARAMETER Make Stroke Length Bore Diameter Max Pressure
VALUE JANATICS 80mm 30mm 20 bar
DIRECTION CONTROL VALVE: DCV’s are used to control the direction of flow of fluid through a pneumatic system. In this project two direction control valves are used. The 2/2 single solenoid DCV is used to actuate the single acting cylinders and 5/2 single solenoid spring return DCV used to actuate the double acting cylinders. The specifications are given below. Specification: Double acting cylinder with solenoid
Single acting cylinder with solenoid
Actuation
Actuation
PARAMETER Make Actuation Mechanism Return mechanism Actuating Voltage Type
VALUE JANATICS Solenoid Spring 230 V A.C 5/2 valve
PARAMETER Make Actuation Mechanism Return mechanism Actuating Voltage Type
VALUE AIRMAX Solenoid Spring 230 V A.C 2/2 valve
ELECTRO – PNEUMATIC CIRCUIT: To remove the outer shell of the coconut, three cylinders should be actuated in synchronizing manner. Firstly, the press and hold cylinder is actuated and followed by the shell actuating cylinders simultaneously. The press and cylinder is actuated by 2/2 single solenoid DCV and the shell actuating cylinders are actuated by 5/2 single solenoid spring return DCV.
WORKING: The working guidelines of the automatic coconut dehusking machine is explained below •
Switch ON the system
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Specify the mode of operation (manual or Automatic)
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Check the input air supply is 12 bar
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Use Emergency stop incase of any problem
SEQUENCE OF OPERATIONS FOR AUTOMATIC COCONUT DEHUSKING MACHINE: STEP PARAMETER FUNCTION 1 Cylinder 1 ON Press and hold the coconut 2 Cylinder 2 and Performs the movement of shell Cylinder 3 ON to peel the outer shell of the and OFF 3 Cylinder 1 OFF Sequence of operations
coconut. Leaves the coconut freely.
Firstly, the coconut is placed vertically between two shells. Then auto mode or manual mode is selected. Then press button is pressed which activates the solenoid to actuate the single acting cylinder. Hence the coconut is pressed into hooks. Now all the hooks in the pair shells will get pierce into the coconut. Then shell button is pressed in the control box, which actuates both the double acting cylinder simultaneously. This moves the shell in oscillating movement which removes the husk of coconut as the hooks were present inside the coconut. Thus husk of the coconut removed separately by automation.
CONCLUSION The project highlights the following results: •
Use of pneumatics arrangements instead of manual system.
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Reduction of dexterity of human hands and provides safety to labour.
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Reduction in the man power required for the dehusking process, since the process is made automatic.
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Automation of the dehusking process reduces the 2/3 of cycle time which increases productivity.
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Reduces the risk and accidents.
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Extremely high speed operation
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Simple and safe operation
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Efficient use of space
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Avoids manual effort.
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Reduces labor cost and time consumption.
SCOPE FOR FUTURE WORK The implemented Automatic Coconut Dehusking Machine can be made further advanced by the following ways: •
In our dehusking process, a closed loop control system using limit switches feed back to electro – pneumatic circuit is used. In future, the microcontrollers and PLC can be interfaced to making it as a flexible system.
•
Spring arrangements can be made for accommodating coconut of different sizes.Separate conveyors can be used, one for collecting the coconut and the other for collecting the husk.
BIBLIOGRAPHY •
Pneumatic control - Werner Deppert / Kurt Stoll 1986
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Pneumatic application - Werner Deppert / Kurt Stoll 1986
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Automated assembly - jack. D.Lane (Society of Manufacturing Engg.Michigan, 1986)
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Assembly and assembly automation- Dr.V.Radhakrishnan professor, IIT, Madras. (Engg. Staff college of hyderabad.1986)
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Strength of materials – R.K.Rajput
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Fluid power-Anthony Esposito
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Automation and production system - Mikell P Groover
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Pro/e – user’s guide
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Festo manuals
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http://www.hypac.com
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http://www.festo.com
