ANNA UNIVERSITY : CHENNAI 600025

BONAFIDE CERTIFICATE

Certified that project report report titled “DESIGN AND FABRICATION OF

SELF BOARD ERASER” is the bonafide work of

V.MURUGESAN 31508114033

B.VETRISELVAN 31508114059

R.VIGNESH 31508114059

who carried out the project under my supervision.

SIGNATURE SIGNATURE

DR.VE.ANNAMALAI Mr.KL.HARI KRISHNAHEAD OF DEPARTMENT SUPERVISOR

ASST. PROFESSOR

Department of Mechanical Engineering Department of Mechanical EngineeringSSNCE, Kalavakkam 603110. SSNCE, Kalavakkam 603110.

Submitted For The Viva-Voce Examination Held On_________________________

INTERNAL EXAMINER EXTERNAL EXAMINER

DESIGN AND FABRICATION

OF

SELF BOARD ERASER

A PROJECT REPORT

Submitted by

V.MURUGESAN 31508114033

B.VETRISELVAN 31508114059

R.VIGNESH 31508114060

In partial fulfillment for the award of the degree

Of

BACHELOR OF ENGINEERING

IN

MECHANICAL ENGINEERING

SRI SIVASUBRAMANIYA NADAR COLLEGE OF ENGINEERING

KALAVAKKAM

ANNA UNIVERSITY : CHENNAI 600025

APRIL 2011

ACKNOWLEDGMENT

We are grateful to Dr.VE.ANNAMALAI, Professor and Head of Department of Mechanical Engineering, SSNCE for his encouragement to do project work.

We express our profound sense of gratitude to Mr.KL.HARIKRISHNA, Asst.Professor Department of Mechanical engineering, SSNCE, for his excellent guidance, help and encouragement throughout the project work. His consistent effort to motivate us held the key. We take this opportunity to assertively state that, without his presence this wouldn’t have been a success.

We would like to thank our parents for their financial and never ending support, for the help in our study and for its success.

Lastly, we offer regards to all of those who supported us in any respect during the completion the project.

TABLE OF CONTENTS

1 .INTRODUCTION

2. OBJECTIVE

3. DETAILS OF PROJECT

4. WORKING OF PROJECT

5. MERITS AND DE-MERITS

6. DESIGN AND DRAWING

7. BELT DRIVE CALCULATIONS

8. MATERIAL REQUIREMENT OF PROJECT

9. DEVELOPMENT OF PROJECT

10. PROBLEMS FACED AND SOLVED

11. CONCLUSIONS

12. REFERENCES

ABSTRACT

The process of getting work from the human being at a faster rate is

very difficult. The faculties in the educational institutions face a lot of

difficulties in cleaning the board because of the dust formed and the effort

required to clean the board is little bit higher. Therefore automatic duster

will be much helpful in such situations and to reduce all these difficulties we

introduce a automatic duster to work effectively in place of human beings.

It is capable of cleaning the board round the clock than humans. The

automatic duster does their work without any needs, and it is time saving.

INTRODUCTION

SELF BOARD ERASER is to do the work with very efficient manner. It

will do their work by itself without any guidance. It requires only electrical

power to work.

The self board eraser which is a mechanical come electrically operated , and

it has micro controller relay switch.

The electrically driven belt which rests on pulley is the transmission system

employed.The vertical plate slides over the belt and it has a reciprocating

motion. At the end of the stroke, the micro switch senses and it reverse the

direction of motion.

OBJECTIVE

The Objective of the self board eraser is as follows.

1. To work for long hours

2. To reduce the fatigue of human being

3. To make the work easy for humans

4. To make the working process to go in a good manner.

DETAILS OF PROJECT

Belt drive:

A flat belt drive is used for the transmission. Pulleys are mounted on the

shaft and continuous belt drive is passes over them. In belt drives the

power is transmitted due to friction between the belt and pulley.

Electical motor:

An electric motor is used to convert electric energy into mechanical energy.

It is fixed onto one end of the pulley so that the transmission is carried out

through the flat belt drive. It is a 90 RPM motor to move a vertical plate a

load of 6KN can be transmitted.

Micro Switch:

Two micro switches are fixed at each end of the rod. A signal is sent from

the micro switch to the relay so that the motion is reversed. A micro switch

is an electric switch that is actuated by very little physical force. They are

very commonly used due to their low cost and durability, greater than 1

million cycles and up to 10 million cycles for heavy duty models.

Vertical Plate:

A vertical plate used is made up of aluminium and it is fixed on the two rods

which is placed horizontally and it acts a support. a wooden plywood with

duster is attached to the vertical plate.

Supporting rod:

Two supporting rods are fixed on the base plate one rod is of dia 10mm and

the other one is of 7mm. a vertical plate is fixed on the bigger diameter rod.

the length of the rods are 450mm. it can safely carry a load on 10N

Base plate and wooden stand:

The base plate is the one in which all the components rest upon. In addition

to withstand the load wooden stand is used which is attached with roller.the

base plate is of 620 X 300 mm.

Roller support:

In order to move the self board eraser four wheels are attached to the

wooden stand which makes the movement comfortable.

Working of Project

1.The Self board eraser is a mechanically operated one and has an electric

motor attached with it to run in a efficient way.

2.When the electrical supply is given through motor, the motor transmits

power to the belt drive.

3.The belt drive is rested upon the pulleys on either side.The belt drive is

attached with a vertical plate through which the motion is carried out.

4.Two supporting rods are basically used on which the vertical plate is

mounted upon.

5.The vertical plate is attached with a duster. The duster used can be of

different material and even different length can be varied which is employed

for cleaning action.

6.The electric motor produces the motion only in one direction. But as per

our application, we need reciprocation motion.

7.In order to achieve a reciprocating motion, a micro switch is employed at

both the ends.

8.The micro switch is the electrically operated switch and it is based on the

tipping point mechanism.

9.When the vertical plate reaches the end of the rod, the plate hits a micro

switch and a click sound is heard.

10.The signal is sent from the micro switch to the relay switch, where the

direction of the current reverses and therefore the reverse motion is obtained.

11.A transformer of 230V and 50Hz AC supply is used to transform the

energy from one circuit to another circuit.

12.A speed regulator circuit is employed to vary the speed of the belt drive.

The self board eraser it totally rested on the wooden table. The roller support

is attached to the wooden table so that the it can be moved anywhere

comfortably.

MATERIALS REQUIREMENT FOR PROJECT

S.NO. DESCRIPTION SIZE MATERIAL1. VERTICAL PLATE 270X45mm

Thickness-1mmaluminium

2. SUPPORT ROD-1 Dia-10mmLength-450mm

Steel

3. SUPPORT ROD-2 Dia-7mmLength-450mm

Steel

4. Electric motor 90 RPM

STD STD

5. Micro Switch STD STD

6. Belt Drive Length-460mm Rubber

7. Base 580X280mm wood

8. Wooden stand Height-590mm Wood

9. Rollers -4 nos. STD Nylon

10. Duster 130X40Variable

Cotton

11. Transformer 0-230V STD

DEVELOPMENT OF PROJECT

1.The same miniature model can be designed for a board of specific

length, by varying the length of the belt drive and the support rods and

the vertical plate.

2.The high speed motor can be used.

3.The regulator which is now built with the circuit can be made

operated by a switch.

4.A dust collector can be attached to collect the dust

particles.

5.The dust material of high quality can be used for effective cleaning.

6.The use of stand can be avoided if this setup is directly mounted on

the black board.

PROBLEMS FACED AND SOLVED

We thought of using gears for transmission , but it was bit complex and even

wobble of vertical plate was there.

With motor only one direction of motion can be achieved. Then we used a

micro switch relay control which helped us to achieve the reverse motion

The speed variation could not achieved at the beginning. Speed should

varied for some purposes. Then we arrived of using a regulator.

First we fixed the sponge directly on the vertical plate. Then we thought the

attachment of duster could be better. So we attached a plywood on it the

duster was fixed

The length of the belt first cut was extra length because we dint consider the

elasticity of the material. Then we realized it and a proper length of rubber

belt was cut

Design calculations:

Motor speed N1=100 rpm

Speed of vertical plate N2=60 rpm

Smaller Pulley d=12mm

Center distance = 300 mm

1.Calculation of pulley diameter

velocity ratio=D/d =N1/N2 =100/60 =1.666

Larger Pulley D=1.666 X 12 =20mm

2 Calculation of Design Power in KW:

Rated KW=0.460

Load Correction factor Ks=1.2

Arc of contact =180 – (D-d/c) X 60*=180 – (8/500) X 60*=179.04*

Kd=1

Small Pulley Factor =0.5

Design KW = 0.46 X 1.2 / 1 X 0.5 =1.104 KW

3.Selection of Belt : HI-Speed Duck Belting

Capacity is 0.023 KW/mm/ply

4.Load rating calculation:

V=3.14 X d X N1/60 = 3.14 X 0.012 X 100/60 = 0.0628 m/sec.

Load rating at V m/sec = Load rating at 10 m/sec X V/10

0.023 X 0.0628 /10 = 0.00144 KW/mm/ply

5 Determination of Belt width:

Width of belt = Design Power / Load rating X no. of plies

=1.104/0.00144 X 8

=95.833 mm

Standard Belt width = 100mm

7 Length of belt (L):

L=2C + 3.14/2(D+d) + (D – d)^2 / 4*C

=2 X 300 = 3.14?2 (20+12) + 8^2 /4 X 300

=600 + 50.2654 + 0.053

=650.3184mm

L=0.650 mm

HENCE THE DESIGN IS SAFE.

MERITS AND DE-MERITS:

MERITS:

It can operate for long hours.

It's efficiency is higher

Operating cost is less

The weight of the Project is less

Output of the Project is high.

It is fully automated

Use of relay switch reduces the maintenance cost

DEMERITS:

The life time of the sensors is limited.

Cost of the project is quite expensive.

REFERENCES:

1. Machine Design by Sharma & Agrawal - Katson publications

2. Salivahanan S, Suresh Kumar N, Vallavaraj A, “Electronic Devices and Circuits” First Edition, Tata McGraw-Hill, 1999. 

www.automationdirect.comwww.beltdrives.com

TOP VIEW OF THE SELF BOARD ERASER

3-D VIEW OF SELF BOARD ERASER

FRONT VIEW OF SELF BOARD ERASER