1. SIDDAGANGA INSTITUTE OF TECHNOLOGY
REPORT OF INTERNSHIP AT DHVANI RESEARCH AND
DEVELOPMENT SOLUTIONS
IIT MADRAS RESEARCH PARK
CHENNAI-600036
BY:-
VEETURI SANYASI SRICHARAN
USN: 1SI10ME134
B.E, MECHANICAL ENGINEERING
SIT, TUMKUR-572103
2. CONTENTS
1. Acknowledgement
2. Abstract
3. Introduction
4. Parametric functions
5. Design of HAPP tungsten rod inspector
6. Four wheel scanner
7. Segment scanner-650
8. Manual four wheel scanner
9. Compact manual four wheel scanner
10. Summary
3. ACKNOWLEDGEMENT
Firstly, I would like to thank Prof. Krishnan Balasubramaniam, Professor,
Department of mechanical engineering, IIT Madras and Mrs. Sujatha Chakravarthy
for giving me this opportunity to do my summer internship at Dhvani research and
development solutions pvt. Ltd.
I would also like to thank my mentor and guide in Dhvani Mr. Ressel P Painingal,
for his ever- supporting and able guidance.
I would like to thank Mrs. Padma Purushothaman for introducing me to a few new
aspects of the software I was using (Solidworks).
Last, but not the least, I would like to thank all employees of Dhvani research and
co-interns for making my stay fruitful and enjoyable.
4. ABSTRACT
Inspection of product during fabrication and operation is an important and essential
part in the industry to enhance the lifetime of the component. Failure of such
inspections leads to breaking down of the component resulting significant delays as
well as growth and finance of the company. Therefore, on-site routine non-
destructive testing helps in monitoring the ageing effects, such as, corrosion,
cracks, faults etc. Non-destructive testing includes many methods and among them
Liquid penetrate test, ultrasonic test, eddy current test are simple and versatile.
The most widely used apparatus is the ultrasonic scan test machines. Development
of such machines requires expensive and time consuming efforts. In addition to
this, each client may have a different demand to which we should either modify the
existing model or come up with an entirely new model. Ideally, it is desirable to
have a flexible machine which can be used in different environments to do the
required job with minimum manpower requirements. Therefore, it is advisable to
optimize all these parameters before proceeding to the final fabrication of the
product. There are several CAD (Computer aided Design) software packages
which help in designing and optimizing of a required product.
In the present work, Solidworks CAD package has been used to design various
types of assemblies which are used for a wide range of applications from a four
wheel driven scanner for the inspection of axial pipe or rods or objects with similar
geometry. Further the efforts were also devoted to parameterize the several objects
including above geometries.
5. INTRODUCTION
The ultrasonic testing is done with the help of a transducer which is made of a
piezoelectric substance i.e. a substance which changes its shape depending on the
amount of electric charge applied on it. Hence, when an AC source is applied,
these molecules/atoms oscillate at high frequencies thus giving rise to a high
frequency wave which is guided through a specimen to. There are two ways of
receiving the waves namely reflection and attenuation.
Reflection (Pulse echo mode):- Here, the transducer sends the sound and
receives it through an interface such as the back wall of an object or from an
imperfection in the object. The diagnostic machine then displays these
results in the form of a signal with amplitude representing the intensity of
the reflection and the distance representing the arrival time of the reflection.
Attenuation (Through transmission):- Here, the transmitter sends the
ultrasound and a separate receiver receives the sound and the diagnostic
machine interprets the signal and shows where the defect is.
There are three principle ways of ultrasonic test.
1. A scan: Here, the probe is fixed at a point, and readings are taken only at the
point. To get readings at different points on a specimen, the work piece will
have to be moved to the desired orientation.
2. B-Scan: Here, the probe can be moved in a linear path. Hence, for this type of
scan, indexing of the specimen is required. That is, the probe moves along a
line and takes readings, then the specimen is moved by some amount, and the
readings are taken along a different line.
6. 3. C-Scan: The probe in this type of scan is capable of moving in two
perpendicular directions. Hence, readings could be taken anywhere on the
plane containing the two axes of motion.
There are numerous advantages. Some of them are:-
1. High penetrating power, hence can detect deep flaws.
2. High sensitivity.
3. Only the surface needs to be accessible
4. Non-hazardous and portable.
5. Greater accuracy than other NDT methods.
1. PARAMETRIC FUNCTIONS
1.1 Introduction
Parameters are numeric entities (in this case dimensions) which are specified by
the user to build a model e.g. length, breadth, height etc.
1.2 Parameters in Solidworks
Parameters in Solidworks are nothing but the dimensions which we use to define a
body. Each feature like boss extrude, cut extrude etc. and sketch dimensions are
individual parameters which can be altered separately. These parameters can be
altered through the design table. We can create a design table by going to the insert
7. tab in the toolbar and then in the tables tab, we find the design table option, as
shown in the screen shot.
The design table
8. 1.3 Equations
Solidworks gives us the option to define equations and relate the different
parameters in a given part. You can make as many configurations (with different
names) as possible and can select them in an assembly by clicking on the
component and then selecting the desired configuration from the component
properties as shown. Even in assemblies, we can relate the driving dimension of
one part to another dimension of another part and in this way, we can change the
scale of the entire assembly by changing one dimension.
This was very useful especially in case of the three wheel inspector, where you
have to make an inspector of a different scale for a pipe of different outer diameter.
2. HAPP TUNGSTEN ROD INSPECTOR
2.1 Design requirements
The tungsten inspector is intended for structural integrity inspection of Heavy alloy
blanks manufactured through Powder Metallurgy route.
The other requirements made were as follows:-
The inspector should be able to accept specimen of diameter ranging from 22mm
to 35mm and length ranging from 300mm to 1200mm.
The density of the specimen ranges from 16.5 to 18.5gm/cc
The design should have an immersion tank for A, B and C scan inspection.
9. The design should have fully automated 2 axis 5 probe ultrasonic flaw detecting
mechanism.
The design should have a fully automated feed in and feed out system.
The machine should be able to inspect 120 pieces in 10 hours i.e. one specimen
must not take more than 5 minutes for inspection.
2.2 Conceptual design
An overall outline of the design is as follows:-
The feed mechanism consists of an inclined sheet on which the rods to be
inspected are placed. The sheet is inclined at an angle of 5 degrees to the
horizontal.
The specimen should then be shifted towards the inspection tank, for which we
have an assembly of rollers on a 20X20mm aluminium extrusion supported by
160X40 mm aluminium extrusion at the base.
The specimen is moved on the rollers and is sensed by a proximity sensor.
Then it is taken into the tank with the help of a lifting system placed between
the rollers.
10. The specimen is the moved in the vertical direction with the help of an LM
guide system which places the specimen at the bottom of the tank on two
rollers which are coupled with the help of chain and sprocket drive.
Only one of the shafts is driven (since the other one is connected) by a motor.
Since the motor cannot be placed inside the tank, hence it is placed just outside
the tank beneath the feed tray. The place where the motor shaft enters the tank
is sealed with a mechanical seal to avoid leakage.
A vertical guide is used for performing the scan which can travel in horizontal
direction also (rack and pinion system).
The specimen is again placed on the rollers the way it was taken.
The specimen is then placed in the acceptor tray and is rolled down.
2.3 Conclusion:-
The design given above is just a proposed model and is only the first iteration.
Many practical problems may arise during the fabrication and in the working of the
inspector which have to be taken into account and more iterations should be
performed. But since this project is not sanctioned as yet, hence I was told to leave
it there.
11. 3. FOUR WHEEL SCANNER
3.1 Disadvantages of the present three wheel scanner
The three wheel scanner which we have has quite a few disadvantages some of
which are:-
LOW STABILITY:- The three wheel scanner could only
travel a small distance at a stretch i.e. we could not
assure the stability of this scanner since it has three wheels and was a one
wheel drive. Hence, once the centre of gravity shifts from the path of travel, the
scanner starts to deviate from its original path.
12. ONE WHEEL DRIVE:- The three wheel scanner was powered by a single kn
lk motor. This motor was attached to the rear wheel
and the power was transmitted with the help of a system of spur gears. Hence
the whole load of the scanner used to fall on this motor.
NO STEERING FACILITY:- The three wheel scanner has
no steering facility i.e. it can only move in a
straight line path and the user cannot steer the scanner manually. This creates a
grave problem because if the scanner slips/deviates from its original path, then
it is almost impossible to get the scanner back to its original path without
human intervention.
3.2 Advantages of four wheel scanner
The newly drafted design for the four wheel scanner for pipe inspection has
several advantages over the previous scanner.
13. HIGHER STABILITY:- The new scanner has four ads‟
wheels supporting it i.e. it has good geometric symmetry and
hence can travel in a specified path with ease.
FOUR WHEEL DRIVE:- This scanner has all four a
driving wheels i.e. two wheels, on opposite sides,
are directly connected to the wheels and the other wheels on their
respective sides are connected to these wheels with the help of a timing
pulley as shown in figure.
MANUAL STEERING IS POSSIBLE:- In this type of scanner,
manual steering is possible since we can alter the direction of the
rotating wheels by changing the polarity of the wheels. Hence we can
steer the scanner back onto path even if it deviates from its original path.
3.3 Key features of the four wheel scanner:-
The main highlights of the four wheel scanner are as follows:-
14. 1. The four wheel scanner employs high performance Swiss motors which
are capable of delivering a speed of 20 rpm.
2. This is a four wheel drive hence we can assure higher stability,
repeatability, accuracy, speed and precision to the client.
3. The four wheel scanner also uses high quality lifton magnets which have
high magnetic power. These are used in the wheels for scanning on
ferrous surfaces e.g. pipes, tanks, plates etc.
4. The four wheel scanner has a wide range of application since it can be
used on pipes of 6 inch outer diameter to flat surface inspection.
5. This scanner is very robust and can scan almost all type of surfaces for
defects.
3.4 Applications
The four wheel scanner can be used in many areas and for almost any type of
scan some of which are:-
i. This can be used to perform phased array scans on pipes.
ii. This can be used for inspection of storage tanks.
iii. This can be used for inspection of flat surfaces also.
15. 4. SEGMENT SCANNER-650
4.1 Introduction
This scanner has been named so because it is capable of scanning a specific
segment/ a custom defined area of breadth 650 mm for defects. This is
especially useful for scanning large storage tanks where you know scanning the
whole area will take a lot of time but you know the approximate area where the
defect is present.
4.2 Advantages
There are several advantages of this scanner:-
1. This is a completely automatic system which can be used for inspecting
large areas which otherwise take a lot of time and the data can be stored
for later analysis.
2. This can be used to inspect an individual segment of a large structure as
many times as the user wants.
3. This is capable of travelling even on vertical surfaces since it has
magnetic wheels.
4. This can be used to perform axial scans on large diameter pipes.
4.3 Key design features:-
16. This scanner is made of two smaller four wheel “carriages” which
support the scanner.
Each individual carriage is driven by two swiss 20 rpm motors through a
worm wheel-worm arrangement as shown in the figure.
The two carriages are connected with a 20X20 aluminium extrusion.
A GSR-R series linear motion guide with a rack at one end is mounted
on this aluminium extrusion for the linear motion of the transducer.
A stepped motor is provided on top of the LM guide piece for moving
the transducer.
The power is transmitted through a system of spur gears to the pinion at
the other end. This pinion directly mates with the rack as shown in the
figure.
18. 5. MANUAL FOUR WHEEL SCANNER
5.1 Introduction
This four wheel scanner is a manual one i.e. it can be manually driven wherever
the user wants to inspect. There are two swiveling arms on either side of the
scanner which carry two transducers each which consist of torsion springs which
ensure that the transducers always remain in contact with the surface being
inspected.
5.2 Advantages
The advantages of this type of scanner are:-
Manual scanner, hence stability, path followed etc. entirely depend on the
user.
There are two swiveling arms which can be adjusted to a suitable position
based on the outer diameter of the pipe.
There are two transducers on either side of the scanner which can give more
precise results.
This scanner can be used to scan in any user defined way i.e. the user can
specify the area, location and the number of times (If no satisfactory results
are obtained the first time) the scanner has to perform the scan, since it is
completely handled by the user.
This scanner has a soft spring suspension which resists excessive human
force and hence prevents the scanner from damage.
19. 5.3 Key design features
The key design aspects of this scanner are as follows
This scanner mainly has a central „I‟ shape frame to which there are two
swiveling arms attached.
This scanner has two adjustable transducers on each arm which have
torsional springs to ensure that the transducer always remains in contact with
the specimen.
The scanner‟s wheels are just 110mm apart, hence can move with ease on a
pipe of external diameter ranging from 6 inches to a flat surface.
The wheels have soft springs between the wheels and the rigid frame which
are used to absorb excessive human force
THE MANUAL SCANNER
21. 6. COMPACT MANUAL FOUR WHEEL SCANNER
6.1 Introduction
This is but a smaller version of the manual four wheel scanner. This is useful for
scanning irregular surfaces. This scanner has two transducer holders placed on
either side of the scanner i.e. it can accommodate a total of four transducers.
6.2 Advantages
There are several advantages of this type of scanner some of which are:-
This scanner is very compact with dimensions 390mm X 120mm
This scanner is manually driven and can be used for custom scanning.
Major applications include scanning rugged surfaces.
This scanner has two transducers on either side with springs to hold
them down i.e. a total of four transducer holders.
6.2 Key design features
The key design features include:-
This scanner consists of a central „I‟ shape frame which is made of 20 X 20
mm aluminum extrusions.
This scanner has four wheels of 50 outer diameter lifton magnets separated
by 52 outer diameter washers.
22. This scanner consists of spring loaded transducer holders.
THE COMPACT FOUR WHEEL SCANNER
THE FOUR WHEEL SCANNER ON A SHEET
23. 7. SUMMARY
Thus, I would like to conclude my report stating that my stay at DHVANI
RESEARCH AND DEVLOPMENT has been fruitful and satisfactory.
Solidworks drafting and designing have been learnt successfully
and also taught to other employees. Thanks to my co- intern Aravind
Govindarajan, I even learnt basics of Solidworks simulations.
Thus all the different models were made but since designing is
an iterative process and factors such as availability of parts in market,
feasibility, cost of production etc have to be taken into consideration, hence I
conclude that the first iteration for each model has been completed.
