DESIGN AND FABRICATION OF AN
EXPERIMENTAL SETUP FOR SINGLE
PLANE BALANCING
A project byNithin Seenivasan
Nandaganesh
M.R.Chitthaarth
INTRODUCTION
• This project involves design and fabrication of
an experimental setup to help the mechanical
engineering students to understand
the
concept of balancing of rotating masses
(single plane balancing) by conducting an
experiment in the Dynamics Laboratory.
• The system works in close tandem between
theory and practical application.
IMPORTANCE OF BALANCING
• Balancing of masses is a very critical and an important
in rotating machineries of modern day industries
• Unbalance refers to the center-of-gravity of the rotor
being out of alignment with its center-of-rotation
(eccentricity)
• In most homes, looking around many rooms you can
find air conditioners, CD or DVD player and the
television
• All of these consumer electronic products include
internal rotating parts (motors), which if unbalanced,
will generate vibration and noise during rotation
THEORY
There are two types of Imbalance• Static Unbalance - The unbalance experienced
when an object is static
• Dynamic Unbalance - The unbalance experienced
when an object is moving
The model is based on the Dynamic balancing of
masses.
DYNAMIC BALANCING
• When a shaft rotates at an angular velocity ω
rad/sec about a fixed axis, say the x-axis, and
carries a body of mass m on a plane P with its
centre of mass not lying on the x-axis, a
centripetal force of mr ω 2 acts on the mass
• This force, if not counter-balanced, leads to an
imbalance called Dynamic Balancing
DYNAMIC IMBALANCE OF SINGLE
MASS
DYNAMIC IMBALANCE OF SEVERAL
MASSES
COMPONETS OF SETUP
The following components are fabricated and
assembled in our setup
• An electric motor of 1/12 hp power
• A rope drive system
• A supporting frame
• A shaft
• A disc
• Ball bearings
• Eccentric masses
CAD DIAGRAM OF SHAFT AND DISC
DIMENSIONS OF COMPONENTS
The materials selection, cross sections, size of the components
are calculated using strength based design approach and are
listed as follows
S.No
COMPONENT
DIMENSIONS (mm)
1
Supporting
Frame
50 x 16 x 345
2
Ball Bearing
20 mm I.D, 42 mm OD
3
Shaft
24 mm diameter MS rod
4
Motor
1/12 HP at rated speed 6000 RPM
5
Drive
Rope Drive (leather)
EXPERIMENTAL SETUP
•The experimental setup consists of a shaft, mounted on two
bearings.
•The shaft is a stepped type shaft, with a M24 thread of 1 mm
pitch machined on 75 millimeters of the length. It is a solid
mild Steel shaft.
•The rest of the length is a plain machined type, with a 20
millimeters diameter.
•The bearings used are nonshield type ball bearings, of 20 mm
internal diameter and 42 mm external diameter and 11
millimeters thickness.
•The disc is a 4 mm thick, also made of Mild Steel and a 23
millimeter hole is drilled in the center and a M24 internal
thread is made on it, with a pitch of 1 millimeter.
• 10 holes of 3 millimeters diameter, spaced at 10 millimeters
each are made at every 45 degrees of the disc, amounting to
60 holes in the disc.
DIFFERENT VIEWS OF THE MODEL
DIFFERENT VIEWS OF THE MODEL
PROCESSES USED FOR FABRICATION
•
•
•
•
Drilling (frame, disc, eccentric masses)
Welding (chain, disc and shaft)
Facing (disc)
Threading (disc, shaft)
COST ANALYSIS
S.No
COMPONENT
SPECIFICATION
QUANTITY
COST (Rs)
1
MS Bars
(340x16x50) mm
2
150
2
MS Bars
(345x11x50) mm
2
150
3
Motor
1/12 HP
1
600
4
Tap tool
6 mm Grade 3
1
50
5
Allen Screw
6 mm, Tempered
10
50
6
Allen Key
6 mm
1
50
7
Nut and Bolt
M10
5
30
8
Drill Bit
3 mm
1
25
9
Shaft
27 mm, 1.8 Kg
1
60
10
Disc
300 mm diameter
1
300
11
Chains
20 mm length
4
40
12
Nut and bolt
M 12
2
30
10
50
13
Washer
12 mm dia (Int)
13
Leather belt
2 meters
1
30
14
Bearings
20 mm dia (int)
4
240
Total
1850
MODEL SUM
“Two masses A, B are placed on a balanced disc
as shown in Fig.7.1, both at radii of 70 mm
respectively. Both the masses are 100 grams at
right angle to each other. Find the counter
balance mass that must be added at a radius of
62 mm in order to balance the system “
UNBALANCED SYSTEM
FORCE POLYGON
Scale- 1 cm= .0023Kgm
TABLE
MASSES
MASS VALUE
(Kg)
ECCENTRICITY
r (m)
‘mr’
Value
(Kg-m)
A
.1
.07
.007
B
.1
.07
.007
C
X
.062
.0625
S mr
BALANCED SYSTEM
EXPERIMENTAL VERFICATION
• The two 100 grams masses are fixed to the disc, at
right angles to each other, at 70 mm from the disc
center.
• One mass is taken as reference and 150 grams mass,
whose value is obtained by solving the sum, is placed
at 225o to the reference mass.
• The radius of the third mass is taken as 62 mm, which
is also obtained from solving the sum.
• The motor is then run using the accelerator and if the
frame does not vibrate vigorously at moderate speeds,
then the sum is solved accurately.
PROBLEMS ENCOUNTERED
• Threading on a 4 mm thickness disc
• Facing a 300 mm dia disc, due to the
unavailability of large size chuck
• Dealing with the static imbalance in the disc,
due to density gradient
IMPORTANT LESSONS LEARNT
• Various processes like drilling, turning, facing,
cutting etc were put to practical use, which led to
deeper understanding of their working and
importance
• To design a product from scratch- the various
processes and nuances involved
• Team work
• Industry standards and a thorough knowledge of
the layout of Broadway’s industrial area,
including fruitful contacts being made
CONCLUSION
This model was constructed for conducting the
Single Plane balancing experiment in the
Dynamics Lab. By solving the sum given and
experimentally proving the results by using the
model, the students are able to prove their
results practically. Hence, after demonstrating
the working of the machine, the apparatus is
now ready to use for the Dynamics of Machinery
Laboratory.
SPECIAL THANKS TO
• Prof. M.Kumar (our guide)and Prof. V.Jayakumar ,
for his wonderful guidance and help throughout
this project.
• Mr. S. Murugan and Mr. P. Gajapathy (Workshop
Assistants), who were so gracious in providing
their valuable input and assistance.
• We also thank Mr. A. Balasubramaniam, of Balkan
Electronics for his continued support and help
throughout the project and for helping us to
become better engineers.
THANK YOU!