IRJET- Design and Development of Fixture for Skid Sole of Rotavator

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 06 Issue: 04 | Apr 2019 www.irjet.net p-ISSN: 2395-0072
© 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1768
Design and Development of Fixture for Skid Sole of Rotavator
Ankit Gole1, Dhirajkumar Kamble2, Kushal Gawande3, Vipul Gathekar4
1,2,3,4Final Year B.E. Mechanical Engineering, Dr. Rajendra Gode Institute Technology & Research, Amravati.
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Abstract - Fixtures play an important role in manufacturing.
Its function is to arrange the material in a definite position, so
the machine tool is able to weld the required path on the
workpiece. The case study of this research is conducted in
Jadhao Layland. One high demand product is “Rotavators”
which is the focus of this research. The existing problem of
product setup time is too long. Four techniques of setup time
reduction were introduced in thisresearchisjust-in-time(JIT).
Key Words: Fixture, product Quality, Improve Accuracy,
Save time
1. INTRODUCTION
A fixture is a mechanism used in manufacturingtohold
a work piece, position it correctly withrespecttoa machine
tool, and support it during machining.Fixtureisa devicefor
locating, holding and supporting a work piece during a
manufacturing operation.Fixturesareessential elements of
production processes as they are required in most of the
automated manufacturing, inspection, and assembly
operations.
Fixtures must correctly locate a work piece in a given
orientation with respect to a cutting tool or measuring
device .They are normally designed for a definite operation
to process a specific work piece and are designed and
manufactured individually. Widely used in manufacturing,
fixtures have a direct impact upon product quality,
productivity and cost.
Generally, the costs associated with fixture design and
manufacture can account for 10%–20% of the total cost of a
manufacturing system. Approximately40%ofrejectedparts
are due to dimensioning errors that are attributed to poor
fixture design. Fixture design work is also tedious and time-
consuming. Traditionally, the design and manufacture of a
fixture can take several days or even longer to complete
when human experience in fixture design is utilized. And a
good fixture design is often based on the designer’s
experience, his understandingoftheproducts,anda try-and-
error process. Therefore,withtheincreasinglyintenseglobal
competition which pusheseverymanufacturerinindustry to
make the best effort to sharpen its competitiveness by
enhancing the product’s quality, squeezing the production
costs and reducing the lead time. There is a strong desire for
the upgrading of fixture design with the hope of making
sound fixture design more efficiently and at a lower cost.
1.1 Elements of Fixtures
Generally, all fixtures consist of the following elements:
1. Locators
A locator is usually a fixed component of a fixture. It is used
to establish and maintain the position of a part in the fixture
by constraining the movement ofthepart.For work piecesof
greater variability in shapesandsurfaceconditions,a locator
can also be adjustable.
2. Clamps
A clamp is a force-actuating mechanism of a fixture. The
forces exerted by the clamps hold a part securely in the
fixture against all other external forces acting on to the
component.
3. Supports
A support is a fixed or adjustable element of a fixture. When
severe part displacement/ deflection is expected under the
action of imposed clamping and processing forces, supports
are added and placed below the work piece so as to prevent
or constrain deformation. Supports in excess of what is
required for the determination of the location of the part
should be compatible with the locators and clamps.
2. Fixture Design Procedure
In the design of a fixture, a definite sequence of
design stages is involved. They can be grouped into three
broad stages of design development.

Stage one deals with information gathering and
analysis, which includes study of the component
which includes the shape of the component, size
of the component, geometrical shape required,
locating faces andclampingfaces.Determination
of setup work piece orientation and position.

Stage two involves product analysis such as the
study of design specifications, process planning,
examining the processing equipment’s and
considering operators safety and ease of use.
Determination ofclampingandlocatingposition.
In this stage all critical dimensions and feasible
datum areas are examined in detail andlayoutof
fixture is done.

Stage three involves design of fixture elements
such as structure of the fixture body frame,

locators, baseplate, clamping and tool guiding
arrangement.

Stage four deals with final design and verification,
assembly of the fixture elements, evaluation of
the design, incorporating the design changes if
any required and completion of design.
Work piece SOLID WORKS model
Machining Information
Design requirement
Finished Setup Plan
Fixture Design
Material Listing
3. Fixture Functional Requirements
From a layout point of view, fixtureshavesixbasic functional
requirements:
(1) Stable resting, (2) accurate localization, (3)support
reinforcement, (4) stable clamping,
(5) quality performance.
The functions have strong precedence
conditions. The first five functions are required at the
fixturing stage, and sequentially. When a workpiece is
placed into a fixture, it must first assume a stable resting
against the gravity. Then, the locators should provide
accurate localization. Next, supports are moved in place,
and finally clamps are activated for the part
immobilization (force-closure). The part location must be
maintained in the process of instantiating clamps without
workpiece lift-off. The performance of the fixture is
ultimately defined as workpiece geometric error during
the manufacturing stage. The geometric error is mainly
determined by the fixture localization accuracy and the
workpiece static and elastic deformation during
manufacturing. There are additional constraints to be
satisfied such as interference-free and easy loading and
unloading.
4. Design Considerations in Fixtures
a. The main frame of fixture must be strong enoughsothat
deflection of the fixture is minimum as possible. This
deflection of fixture is caused because of forces of cutting,
clamping of the workpiece or clamping to the machine
table. The main frame of the fixture should have the mass
to prevent vibration and chatter.
b. Frames may be built from simplesectionssothatframes
may be fastened with screws or welded whenever
necessary. Those parts of the frame that remain
permanently with the fixture may be welded. Those parts
that need frequent changing may be held with the screws.
In the situation, where the body of fixture has complex
shape, it may be cast from good grade of cast iron.
c. Clamping should be fast enough and require least
amount of effort.
d. Clamps should be arranged so that they are readily
available and may be easily removed.
e. Clamps should be supported withspringssothatclamps
are held against the bolt head wherever possible.
f. If the clamp is to swing off the work, it should be
permitted to swing as far as it is necessary for removal of
the workpiece.
g. All clamps should be easily visible to the operator and
easily accessible for cleaning, positioning or tightening.
h. Provision should be made for easy disposal of chip so
that storage of chips doesn‟t interfere with the operation
and that their removal during the operation doesn‟t
interfere with the cutting process.
Set up Planning:
Determine numbers of setups.
Determine the work piece orientation and
position.
Determine machining datum features and
locating surfaces.
Fixture Planning:
Determine locating position.
Determine clamping surface.
Determine clamping position.
Unit Design:
Generate base plate design.
Generate locating designs.
Generate clamping unit designs
Verification:
Perform location accuracy verification.
Perform stiffness verification.
Perform cost, weight verification.
Perform fixture accessibility.

i. All clamps and support points that need to be adjusted
with a wrench should be of same size. All clamps and
adjustable support points should be capable of being
operated from the fronts of the fixture.
j. Work piece should be stable when it is placed in fixture.
If the work piece is rough, three fixed support points
should be used. If work piece is smooth, more than three
fixed support points may be used. Support pointshouldbe
placed as farthest as possible from each other.
k. The three support pointsshouldcircumscribethecentre
of gravity of the workpiece.
l. The surface area of contact of support should be as small
as possible without causing damagetothe workpiece.This
damage is due to the clamping or work forces.
The importance of fixture design automation is
emphasized by Djordje Vukelic [3]. General structure of
the automated design system showninfig.witha highlight
on the fixture design.
Now in a Jadhao Leyland Company they manufacture
rotavators which is used in Agriculture. One part of
rotavator is skid sole of Rotavator which is assembled by
Robotic Welding with the help of fixture.
Fig -1: Rotavator
Fig -2: Skid Sole of Rotavator
5. Existing fixture in Jadhao Leyland Company
Fig -3: existing fixture in company
Skid sole of Rotavator assembly there arefourparts
that assemble by robotic welding. So in this fixture thereare
eight clamps to fixed this four parts of skid sole of
rotavator. (as shown in fig.) So there is long duration to fix
the components for welding. and Accuracy is not proper.
Skilled operator requiredfor adjustmentofpartsforwelding
to assembly of skid sole of Rotavator.
After design and development of this fixture we
reduce five clamps in fixture (shown in fig.). Now in this
fixture assemble all parts on three clamps only. It reduces
time, increase accuracy and here semi-skilled operator
required.
Design of existing fixture in Jadhao Leyland

Fig -4: Design of existing fixture in company
Fig -5: Design of existing fixture in company
Existing fixture in company to fix all parts procedure is:
Step 1:
First step of this fixture is first they put part A on
rack then fixed it by pressing clamp. Thickness of
this part is 15 mm and material of part is C.I.
Step 2:
Second step of this fixture is put part B on rack then
again fixed by pressing clamp. Thicknessofthispart
is 15 mm and material of part is C.I.
Step 3:
Third step of this fixture is put part C on fixture and
fixed it by five push pull clamps one by one.
Thickness of this part is 5 mm and material of part
is C.I.
Step 4:
Final step of this fixture is put part D on part A and
B and fixed it by pressing clamp. Thickness of this
part is 2 mm and material of part is C.I
6. After Design and Development of fixture
After Design and Development of fixture five clamps are
reduced. Now design of fixture is
Fig -6: After Development of this fixture
Fig -7: After Development of this fixture
Step 1:
First step of this fixture is first put part C in front of back rest
plate and it is fixed by embossing of back rest plate.
Step 2:
Second step of this fixture is put part A part B on rack and
apply the push pull clamp then part A and part B slides and
joined to part C.
Step 3:
Final step of this fixture is put part D on part A and B and
fixed it by pressing clamp.
7. CONCLUSION
It reduces or sometimes eliminates the efforts of marking,
measuring and setting of workpiece on a machine and
maintains the accuracy of performance. The workpiece and
tool are relatively located at their exact positions before the
Part A
Part B
Part C
Part D

operation automatically within negligible time. Soit reduces
product cycle time. Variability of dimension in mass
production is very low so manufacturing processes
supported by use of fixtures maintain a consistent quality.
Due to low variability in dimension assembly operation
becomes easy, low rejection due to less defectiveproduction
is observed. It reduces the production cycle time so
increases production capacity. Operators working become
comfortable as his efforts in setting the work piece can be
eliminated. Semi-skilled operators can be assignedthework
so it saves the cost of manpower also. There is no need to
examine the quality of product provided that quality of
employed fixtures is ensured.
REFERENCES
1) Sheldon Levine, “Vibration test fixture: theory and
fixture” AeroNav Laboratories New York, PP1-2
2) Sheldon Levine, “Vibration test fixture: theory and
fixture” AeroNav Laboratories New York, PP1-2
3) Eiji Nabata & Yuji Terasaka in his paper “jig rigidity
evaluation technology by vibration analysis”,
Komastu Technical Report 2006,Vol52No157,PP1-
4
4) Xiumei Kang and Qingjin Peng in his paper “Recent
research on computer-aided fixture planning”,
Recent Patents on Mechanical engineering 2009,
PP2,12-14
5) Necmettin Kaya in his paper “Machining fixture
locating and clamping position optimization using
genetic algorithms” 2005 Elsevier, Computers in
industry, PP120
6) Yi Zheng in his Ph.D. dissertation of “Finite element
analysis for fixture stiffness” Worcesterpolytechnic
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7) J.E. Akin “Finite Element Analysis Method” “FEA
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Engineers” Slides 2-26
9) Courseware on jigs & Fixtures, CAD-CAM center,
Indo German Tool Room, Nagpur
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Dynamic Stability in Machining Accounting For
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15) Kulankara Krishnakumar, Shrwyes N.Melkote
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errors” International Journal of Machine Tools &
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17) Jaime Camelio and S. Jack Hu “Diagnosis of Multiple
Fixture Faults in Machining Processes Using
Designated Component Analysis” International
Journal of Machine Tools & Manufacture 39(1999)
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