5th International & 26th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12th–14th, 2014, IIT Guwahati, Assam, India

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DESIGN AND DEVELOPMENT OF AUTOMATED VEGETABLE CUTTING

MACHINE

Tony Thomas.A1*, MuthuKrishnan.A 2, Sre Nandha Guhan.K.S 3

1*Mechatronics Engineering, Kongu Engineering College, Perundurai, Tamilnadu,638 052,dec84tony@gmail.com

2 Mechatronics Engineering, Kongu Engineering College, Perundurai, Tamilnadu,638 052,muthukrishnanas@gmail.com

3 Mechatronics Engineering, Kongu Engineering College, Perundurai, Tamilnadu,638 052, guhansadhasivam@gmail.com

Abstract

Automation was the rage of the engineering world. The investigation on the existing vegetable cutting machine reviews the following drawbacks such as high investment cost, the contamination, additional manpower and time consumption caused by manual processing. The setup involves a hopper arrangement and the pressure block is actuated by a pneumatic cylinder, and has a reciprocatory motion along the vertical length of casing, while the cutting grid remains fixed. The air supply to the cylinder is controlled by a solenoid actuated DCV, which is controlled by a microcontroller. The entry of vegetable into the grid apparatus is controlled using a pneumatic cylinder along with a single bar mechanism. The vegetables are feeded via inclined tube. A tray is placed at the bottom of the apparatus to collect the vegetable pieces after processing. Variable pressure setting for cutting different vegetables is carried out by the microcontroller. The intricacy involved with such a system is the type of vegetables it can process. The system is advantageous in the fact that existing automation is high in cost, and the power consumption is high. The proposed work is benefitted by pneumatic power, which is abundant.

Keywords: Automation, Relays, Microcontroller, DCV

1. Introduction

In the late 90’s, automation was the rage of the engineering world. The best of the minds, rallied day and night to bring forth improvements of significant magnitude, something which could make an impact in the day-to-day life. Today, its’ an plethora of fields which have embraced with automation, from manufacturing to food processing, biomedical and pharmaceutical industries. In such a scenario, domestic applications have also been developed with the common man in mind. Of late, processes which were manual before are slowly being converted to semi-automated and automated nature. Manual cutting of vegetables is still prevalent, in hostels of educational institutions, marriage catering services and even in restaurants, which can cater to a whole set of varying customer tastes and preferences. The amount of vegetables to be cut for the dishes always remains higher than actually what’s consumed. The associated difficulties like time

constraint, contamination, etc. make it pretty difficult for any person handling the job. Therein, arose a need to automate the process of vegetable cutting, and here we are with a proposal which can aid in easing the load off the people associated with it.

1.1. Existing automated vegetable cutter

and its demerits

The automatic vegetable cutter is a Chinese manufactured one, currently available in the market. The cutter operates on the concept of ‘rotating grid’, wherein, the cutting grid is rotating inside a casing, powered by an ac motor. The vegetables are fed via the hopper arrangement, at the top. The cutting grid rotates at a high speed which cuts the vegetables as they pass through them. The cutting grids are varied according to the need of the customer. The shapes of the cut vegetable vary with the change in cutting grids.

DESIGN AND DEVELOPMENT OF AUTOMATED VEGETABLE CUTTING MACHINE

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The above mentioned cutter has some demerits with regards to its operation. First of all, the vegetable feeding is not automatic, and a person has to devote his time to feed the vegetable one by one, till the required quantity is cut. Then, the grids are powered by a motor, which has high power consumption. Considering the fluctuating power supply that, the process has to be electrically powered continuously for operation, is a disadvantage in itself. Most important of all, is the initial investment on the cutter. The cutter is approximately priced at a range of $ 3500, inclusive of shipping cost and taxes. It is a high investment, for those who run a mid-level catering business. Therefore, considering all these demerits, the idea for a pneumatics powered cutter is conceived.

Some of the key problems, which were identified for the initiation of this work, are high cost of the existing automated system, Power fluctuations, additional labour, time consumption in manual cutting and chances of contamination in manual cutting.

1.2 Objectives

The primary objectives, upon which, the present work is based are providing an alternative to the existing automated system mainly, targeting the initial investment factor, and to power a domestic product using pneumatics, thereby eliminating the associated difficulties of manual vegetable cutting.

1.3 Literature review

This work has been inspired by several patents filed on the same patent, in that regard belonging to Romeo et al (pub no: US2009/0193953 A1), has portrayed a basic setup, which has been the base upon which we have built upon. The patent helped in bringing about the idea of using a cutting grid for cutting the vegetable.

The second patent, (intl patent no: W0 2008/011671 A1), once again by Romeo et al, has provided more clarity on the actuation mechanism used for a simple cutter with a box frame, along with a stack structure at the bottom.

The patent belonging to Javier Hidalgo Garcia, Aitor Aguirrezabalaga Zubizarreta, and Aitor Gogorza Segurota (patent no: 20120125172), has laid emphasis on various cutting grids for the cutting operation. This patent has served as the reference for our grid design.

The cylinder specifications are taken from the product manual of Janatics pneumatic Ltd. The force calculations for the double acting cylinder, is given by the equation 2.1, adopted from Fluid power with applications (6th edition) by Antonio Esposito. Stainless

steel material properties were referred for the material selection from Strength of Materials (Mechanics of Solids) by Er.R.K.Rajput, and the micro-controller specifications were taken from The 8051 Micro controller and Embedded Systems (2nd edition) by Muhammad Ali Mazidi.

2. System model and Design Calculation

The double acting cylinders are used to perform the critical roles of regulating vegetable entry and performing the cutting. The requirements of the two processes are different, and so are the specifications of the cylinders. For the cutting process, the following calculations were made. Since the force required for cutting process can’t be determined practically, a simple theoretical, force calculation was done and the cylinder was selected using working pressure as the major consideration. During trial and error experimentation, the minimum pressure required for the cutting process was found to be 5 bar. The vegetable used for the calculation, was a potato. The assumed constants:

• Working pressure P = 5 bar = 5×105 N/m2.

• Cylinder diameter d1 = 100 mm = 0.1 m.

• Piston rod diameter d2 = 20 mm = 0.02 m.

Therefore, the force generated by the double acting cylinder [1],

F = P×A, (2.1)

= P× π (d12 – d2

2) / 4

= 5×105×π (0.12 – 0.022) / 4

= 3769 N.

Table 1 Dimension – Mechanical Setup

Parts Dimensions

Hopper block 150×150 mm2

Hopper tube length 500 mm

Cutting case 100×100 mm2

Cutting grid 100×100 mm2

5th International & 26th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12th–14th, 2014, IIT Guwahati, Assam, India

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Figure 1 Part Drawings of the setup using Pro/E

Hopper is the regulator for the entry of vegetables into the cutting section. It has a square case, which acts as a vegetable holder. A sliding bar mechanism is used along with the hopper to ensure the regulated entry of the vegetable. It is a single bar, with one end attached to the piston rod plate of a pneumatic cylinder and the other end connected to a 45˚ angled plate. It is shown in the figure 1.The cutting grid is a square shaped one, with inter meshed blades. The mesh, which almost resembles a net as shown in the top view presented in Figure 1, is made of stainless steel blades. The material is specified with reference to its’ high young’s modulus and suitability in food processing. The complete assembly view of the project is shown in figure 2.

Figure 2 Assembly View

3. Working of the project

This work consists of two major parts; one is the mechanical setup involving the hopper block, hopper tube, square cutting case and grid along with the supporting frame, while the other part is the electrical circuit involving AC – DC converter, relays, micro controller, LCD display, and keypad. The two parts, work with synergy, to perform the vegetable cutting process automatically. The actuation of the pressure plate is linked to a pneumatic cylinder piston reciprocatory motion. The entry of the vegetables inside

the cutting casing is regulated using another pneumatic cylinder. The vegetables are placed above the cutting grid. The cutting grid consists of stainless steel blades, which are placed in a mesh. The pneumatic cylinder delivers a piston stroke for a set pressure, controlled by the micro-controller. The solenoid DCV varies the supply for extraction and retraction of the pneumatic cylinder. The pressure plate is used to force the vegetables through the cutting grid. There are regular, square shaped spaces between the cutting blades. The vegetables are forced between the spaces, thereby getting cut for the same shape. The whole process, is automated by, regulation of the amount of vegetables cut, timing of the extension, aided by the micro-controller. The number of vegetables entering the apparatus is regulated by a pneumatic cylinder, with a single bar mechanism attached to the piston rod end. The bar mechanism, has an angled plate, which acts like a cup holding the vegetable at the hopper tube. When vegetable is released from the angled plate, it reaches the cutting casing, and the piston stroke performs the cutting operation.

The mechanical setup and the electrical setup are shown in figure 3 and figure 4. Both the mechanical setup and the electrical setup, combine to work with synergy to exhibit the automated working of the cutter. The mechanical setup consists of a hopper case, a hopper tube, a 45˚ angled plate, a square cutting case, and a square cutting grid. While, the electrical setup consists of an AC-DC converter, two relay circuits, a micro controller circuit and a keypad.

Figure 3 Mechanical Setup

DESIGN AND DEVELOPMENT OF AUTOMATED VEGETABLE CUTTING MACHINE

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Figure 4 Electrical setup

4. Conclusion

Thus, this work provides an alternative to the existing automatic vegetable cutter, in terms of automating the vegetable entry into the cutting apparatus, eliminates power fluctuation and lesser initial investment. Time consumption is less when compared to manual cutting. This work provides the desired output and the variety of the cuts is done by use of different cutting grid.

Appendix A. Micro controller program

#include<AT89x52.h>

#include"smcl_lcd8.h"

sbit set_key=P1^0;

sbit mov_key=P1^1;

sbit inc_key=P1^2;

sbit dec_key=P1^3;

sbit ent_key=P1^4;

sbit Relay1=P1^5;

sbit Relay2=P1^6;

void key_function();

void cut_process();

unsigned int n,z;

void main()

{

Relay1=Relay2=1;

Lcd8_Init();

while(1)

{

Lcd8_Decimal3(0xc0,n);

if(!set_key)

{

while(!set_key);

Lcd8_Command(0x01);

key_function(); n=z;Delay(50000),Delay(50000);

}

while(n--)

{

cut_process();

}

n=0;

Relay1=Relay2=1;

}

}

void cut_process()

{

Lcd8_Decimal3(0xc0,n);

Relay1=0,Relay2=1;

Delay(50000),Delay(50000);Delay(50000),Delay(50000);

Relay1=1,Relay2=0;

Delay(50000),Delay(50000);Delay(50000),Delay(50000);

}

void key_function()

{

Lcd8_Display(0x80,"N?",2);

while(ent_key)

{

if(inc_key==0)

{Delay(5000);z++;}

else if(dec_key==0&&z>0)

{Delay(5000);z--;}

Lcd8_Decimal3(0xc5,z);

}

5th International & 26th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12th–14th, 2014, IIT Guwahati, Assam, India

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Lcd8_Command(0x01);

}

References

Anthony Esposito (2011) ‘Fluid Power with

applications’, 6th

Edition, Pearson Education Inc.

Er.R.K.Rajput (2009)‘Strength of Materials’,2nd

Edition,

S. Chand & Company Limited.

Existing automatic vegetable cutter image and specifications from http://www.alibaba.com/produtcgs/

automatic_vegetable_cutter.html viewed on 27 July

2012.

Javier Hidalgo Garcia, Aitor Aguirrezabalaga Zubizarreta, and Aitor Gogorza Segurota (patent no: 20120125172). “Cutting grid patent”

Muhammad Ali Mazidi, Janice Gillispie Mazidi, and Rolin D. McKinlay (2008) ‘The 8051 Micro Controller

and Embedded Systems’, 2nd

Edition, Pearson

Education Inc.

Pneumatic cylinder and solenoid DCV from product manual of Janatics ltd, Coimbatore, Tamilnadu. Cutting grid types – image from www.jasenterprise.com

viewed on 23 August 2012.

Romeo et al (pub no: US2009/0193953 A1),”Design of

pneumatic powered cutter “

Romeo et al (intl patent no: W0 2008/011671 A1). “Actuation mechanism”